Web Homepage: http://www-frd.fsl.noaa.gov/
Steven C. Albers, Senior Meteorologist, 303-497-6057
(The above roster, current when document is published, includes
The Forecast Research Division comprises three branches:
RUC Applications Development of coupled atmospheric/land surface model capability in support of the Global Energy and Water Cycle Experiment (GEWEX) programs and the NCEP implementation of the RUC, forecasting of aviation impact variables (icing, turbulence, ceiling, and visibility) in support of the Federal Aviation Administration (FAA), wind forecasting applied to wind energy utilization, and real-time support for field projects in which NOAA is engaged.
Collaborative Modeling Projects Lead role in the development and evaluation of the coupled MM5/Air Chemistry model (Figure 16) and the WRF/Air Chemistry model, continued collaboration with NCAR in the advancement of the science of modeling precipitation physics, participation in the development of the Weather Research and Forecasting (WRF) model system and nonhydrostatic generalized vertical coordinate model, and, finally, development of a RUC Short-Range Ensemble Forecast (SREF) system in collaboration with NCEP.
LAPS Observation Simulation System (OSS) Evaluation of new observation technology or siting of existing observational systems. This system has been employed to assess the potential of new satellite systems for instrument placement around eastern and western space centers of the U.S. Air Force and spaceborne wind lidar systems for NOAA.
Satellite Products Utilization and evaluation of raw radiances and products derived from GOES atmospheric soundings, for the purpose of developing a complete national-scale moisture analysis useful for high-resolution model initialization. The branch also participates in the Joint Center for Satellite Data Assimilation.
Weather Research and Forecasting (WRF) Model Support Development of a Standard Initialization procedure for community use in initializing the WRF model with background fields obtained from other models and static data defining the surface properties. High-resolution local applications of WRF are being developed and tested, including evaluation during the International H2O (IHOP-2002) field experiment in the Southern Plains and application for the Coastal Storms Initiative.
WFO-Advanced Support Full support of an operational version of LAPS on the WFO-Advanced workstation, including both analysis and prediction. The WFO-Advanced forecaster workstation is used to demonstrate Advanced Weather Interactive Processing System (AWIPS) functions in support of future Weather Forecast Office (WFO) operations.
Local Model Implementations and Demonstrations Configuring and installing modeling systems that take advantage of local datasets, advancements in affordable parallel computing, and the results of weather modeling research and developments from FSL and elsewhere. Current and upcoming applications of various models on different computing platforms all take advantage of LAPS initialization. Ensembles of local models will be an increasingly useful approach to numerical weather forecasting problems and applications to a broad spectrum of uses ranging from fire weather prediction to ground transportation needs.
Diagnostic Turbulence Forecasting Development, testing, and verification of diagnostic tools using the RUC model for forecasting turbulence in support of the Aviation Weather Research Program.
Mesoscale Diagnostic Studies Research performed to increase the understanding of weather systems, improve conceptual and diagnostic models of the atmosphere using data from conventional instruments and new state-of-the-art sensors, and investigate mesoscale dynamical processes. Current studies include potential vorticity streamers, the structure and dynamics of the low-level jet and its role in moisture transport, and the role of gravity waves in turbulence generation and convection initiation.
Research Quality Datasets Production of quality-controlled hourly precipitation data, meteorological data from commercial aircraft (ACARS and AMDAR), and North American radiosonde data for access on CD-ROMs and the Web. Assessments of and improvements to the set of hourly precipitation measurements are utilized for verification purposes by the Real-Time Verification System (RTVS).
Websites for FSL Data Development of Websites for GAINS, the NOAA Chemical Weather Research and Development program (with information such as the MM5/Chem model domain in Figure 16), national precipitation data, ACARS data, interactive soundings, national mesonetwork data, and FSL publications.
Regional Analysis and Prediction Branch
|RUC20/Eta|| 60 Hours
| MM5/Chem -
|24 Hours|| Twice
| M5/Chem -
| MM5/Chem -
|24 Hours|| Twice
| MM5/Chem -
In addition, data from July and August 2002 have since been rerun to create a complete testbed dataset. A statistical comparison with observations over this time period was performed by AL and is now available as a baseline dataset to compare against. (See Figure 29 for an example of a comparison of ozone forecasts and observations at one particular station.) Development of this type of testbed dataset is a powerful tool in model development to aid the assesment and understanding of currently available atmospheric numerical modeling systems, and point to areas where further development is needed as we work toward production of reliable air quality forecasts.
In addition, FSL is taking the lead in developing the next-generation air quality forecast model, WRF/chem. The first version of this model already exists and includes all chemical modules that are a part of MM5/Chem (grid-scale and subgrid-scale transport, biogenic emissions, deposition, photolysis, and the RADM2 chemical mechanism). Evaluation of this model is currently in progress, and it will probably be run in real time during the summer of 2003.
Participation in Development of the Weather Research and Forecast (WRF) Model System The overall goal of the WRF model project is to develop a next-generation mesoscale forecast model and assimilation system that will advance both the understanding and prediction of important mesoscale weather, and promote closer ties between the research and operational forecasting communities. The model and associated system are being developed as a collaborative effort among NCAR, NCEP, FSL, the Center for the Analysis and Prediction of Storms (CAPS), and other research institutions together with the participation of a number of university scientists.
In collaboration with NCAR, FSL has worked on the development of physics packages and a three-dimensional (3DVAR) analysis system. FSL has contributed two physics components to the WRF forecast model an alternative land-surface model based on the RUC land-surface model and the Grell-Devenyi ensemble convective parameterization. Both of these schemes have been fully implemented and tested in the WRF model. FSL has also developed the standard initialization package for the WRF model, and has worked with the University of Miami on development of a quasi-isentropic variant of the WRF nonhydrostatic model.
The WRF model is being tested with RUC initial conditions for two different domains, the 20-km CONUS RUC domain; and the 10-km TAQ New England domain. The WRF standard initialization (SI) procedure was modified to fully use RUC native-coordinate initial conditions, including hydrometeor and land-surface fields. In addition, a post-processor was developed from the WRF model to produce RUC-like GRIB output files, facilitating comparisons with RUC model forecasts. FSL will adapt WRF assimilation and model systems over the next several years to include an advanced rapid update capability for operational implementation at NCEP. It is planned that the WRF model will supplant the current RUC forecast model in the Rapid Update Cycle by 2006.
Implementation of Three-Dimensional Variational (3DVAR) Analysis in the 20-kilometer RUC With tuning to ensure sufficient accuracy for short-range wind forecasts, the RUC 3DVAR analysis will be added to the 20-km RUC running at NCEP. The 3DVAR implementation will provide smoother analyses, more accurate forecasts, and a framework for assimilation of radial wind observations from radar in the future. Development and real-time testing will continue on the 3DVAR analysis, both for incorporation into the RUC and toward the development of the 3DVAR analysis for the WRF model.
Continued Development of a National-Scale Cloud/Hydrometeor Analysis Development and real-time testing will continue for further improvements to the RUC national-scale cloud analysis, with the addition of radar, lightning, and surface observations to satellite cloud-top data. Experiments will be carried out testing assimilation of a GOES imager-based multilevel cloud product, as described below under the JCSDA plans.
Refinement and Testing of Improved Physical Parameterizations for Soil/Vegetation Processes, Turbulence, Convective Clouds, and Cloud Microphysics Some of this work will be done in collaboration with NCAR, since the RUC model uses some of the MM5 parameterizations, which will be options for the WRF model.
National Observing System FSL will continue its efforts with a team working toward an initiative to develop a national mesoscale observing system consisting of tropospheric and boundary layer profilers, ground GPS receivers, and radiosondes with ground tracking systems. This is an initiative with great potential impact for mesoscale forecasting. Also under development is an observation system simulation experiment (OSSE) with a practical observation network design and numerical model to verify the budgets and applicability.
Data Assimilation Work will commence to test the WRF 3DVAR system within the RUC assimilation cycle.
High-Resolution Experiments Using RUC for the New England Temperature Air Quality Experiments RUC forecasts will continue to be made at 10-km resolution in support of this experiment. In addition, the WRF model will be run over the same domain, also at 10-km resolution, initialized from the RUC. This will allow initial intercomparisons between the current RUC hydrostatic model and the WRF nonhydrostatic model including RUC physical parameterizations, the RUC land-surface model, and the Grell/Devenyi ensemble-closure cumulus parameterization. Objective verification of the model forecasts will be performed as part of these studies.
Participation in GEWEX Collaboration will continue on the GEWEX/GAPP program, with the focus on development of a coupled atmospheric/land-surface assimilation system that uses an optimal combination of radar and satellite observations to modify clouds and precipitation along with model forecasts in regions where observations are unavailable.
Contribution of RUC Forecasts to the NCEP Short-Range Ensemble Forecast System As part of an expansion to NCEP's Short-Range Ensemble Forecast (SREF) project, FSL will complete its effort begun this last year to set up an ensemble version of the RUC model running out to 63 hours on a 48-km grid over the Eta domain. The RUC SREF is spawned from a set of five members bred from the NCEP Eta model, and is a candidate for inclusion in the NCEP SREF set currently composed only of Eta and Regional Spectral Model bred members. Tentative results from the RUC SREF show substantial spread in the ensemble, but it needs to be determined whether the forecast skill for the ensemble mean exceeds that of the operational RUC20 model, and statistical techniques must be developed to assess the results.
Joint Center for Satellite Data Assimilation Activities Future work will first involve running and testing the Optical Test Transmittance (OPTRAN) radiative transfer model to replace the European Centre for Medium-Range Weather Forecasts' RTTOV code that has been used in all RUC forward model calculations thus far. OPTRAN has been chosen as the community radiative transfer model by the Joint Center for Satellite Data Assimilation. Outgoing radiances from the RUC will then be subjected to OPTRAN forward model calculations to compare with the GOES radiances. The imager data will be used to determine clear-air radiances with greater resolution than using the sounder estimates. Eventually, the goal is to incorporate the adjoint of the forward calculations into the RUC three-dimensional variational (3DVAR) analysis and to begin using this to rapidly update the radiance data in the RUC and, later, the WRF models.
Data Analysis Accomplished using an integrated software package containing well-documented objective analysis schemes that apply quality control criteria to the data, spatially represent atmospheric conditions, perform spectral filtering, and ensure vertical consistency. The data analysis system is running within AWIPS in National Weather Service (NWS) forecast offices, at the eastern and western space ranges at Cape Canaveral, Florida, and Vandenberg Air Force Base (AFB), California, for the National Ocean Service for Chesapeake and Naragansett Bays, for the U.S. Forest Service (USFS) in support of fire mitigation and firefighting, and for the U.S. Army in support of precision parachute airdrop activities.
Mesoscale Model Implementation Accomplished using an expanding variety of mature nonhydrostatic modeling systems, such as the Regional Atmospheric Modeling System (RAMS) developed at Colorado State University, MM5 developed jointly by NCAR and Pennsylvania State University, the hydrostatic version of Eta developed at NCEP, and the Weather Research and Forecast (WRF) model under joint development by FSL, NCAR, and NCEP. These models have been configured to be initialized by LAPS analyses and with time-dependent boundary conditions furnished by all operationally available gridded datasets (RUC, Eta, Aviation, and the U.S. Navy Operational Global Atmospheric Prediction System). Implementation of the LAPS system at some NWS forecast offices has demonstrated the portability and effectiveness of running models locally. One such demonstration, sponsored by NWS, tests the feasibility of local modeling in NWS WFOs. The collocation of FSL with the Denver-Boulder NWS Forecast Office has demonstrated the effectiveness of locally run models during the past few years, as LAPS-initialized mesoscale models have been run on their local AWIPS hardware and on FSL's High-Performance Computing System for operational evaluation. Models have the option of being initialized using the LAPS diabatic analysis that allows a full representation of clouds and vertical motion in the initial state. A unique ensemble of mesoscale models (RAMS, MM5, and WRF) is currently supporting the weather forecast input to a road maintenance decision support system demonstration for the Federal Highway Administration.
Dissemination Includes delivery of weather products and basic fields developed from LAPS to users in operational forecast offices and state and local government agencies, including emergency managers and other users specializing in fields such as winter highways operations, fire weather, aviation and space operations, and military operations such as those mentioned later. LAPS fields are compatible with AWIPS file formats and appear in a number of dedicated Webpages for specified customers. For fire weather support, LAPS analysis and model fields can be dynamically located to specific fire locations. This text format for 24-hour point forecasts proved to be popular with USFS personnel.
LAPS can be displayed in three dimensions using the experimental D3D (Display Three-Dimensional) add-on to AWIPS. Figure 30 illustrates an end product of the LAPS effort, namely to completely define the local meteorological environment using this D3D display (in the form of isosurfaces). Such three-dimensional displays can help forecasters achieve a better conceptual view of complex meteorological processes. The LAP Branch, along with some NWS Forecast Offices, continues to explore the potential of three-dimensional displays for operational use, perhaps eventually as a part of AWIPS within the NWS as well as within other operational environments.
An ongoing data denial experiment provides insight into the impacts of the various data sources on the analysis. In addition, this assessment tool can be used to gauge the strength and weakness of the different data sources, in order to optimize their respective weights in the variational equation. The statistics used in this study are a comparison of analysis output to radiosonde data (taken as referenced truth). This is possible since radiosonde data are not typically used in the operational LAPS system due to their latency (poor timeliness). The goal of the moisture variational application is to provide a complete product that describes the atmospheric water distribution from vapor to cloud droplets to precipitation, both liquid and frozen. This analysis has been used to improve model initialization. This analysis utilizes all conventional data, along with satellite, radar, and GPS data. The routine is based on the LAPS cloud analysis, but then seeks to quantify all water substance. Variational methods are used to impose dynamic balance and continuity on the first-stage analyzed fields to accommodate the "Hot Start" analysis described below.
LAPS Advanced Quality Control Quality control of observations is a continuing focus of LAPS analysis development. A Kalman filtering scheme is used to improve the quality and timeliness of surface observations. The method allows users to optimally exploit local model output and past station trends and buddy trends to produce check values for surface stations. In conjunction with LAPS support of a three-dimensional 30-minute analysis cycle, the Kalman scheme allows the merging of mesonetworks with varying cycle times. Working exclusively in data space, the Kalman filter scheme is economical for use in the local computing environment and provides a continuously updated and accurate set of observations where all stations appear at each cycle. This is an appropriate approach for instances when a user requires good product time continuity, but has high variability in observation count from cycle to cycle. Since the Kalman scheme still requires more computer storage than is currently available in the local weather office, it has not been widely used.
LAPS "Hot Start" Procedure The LAP Branch continues to improve the Hot Start procedure for diabatic initialization of mesoscale models. The Hot Start initialization scheme is designed to develop initial conditions for mesoscale models such as the MM5, RAMS, and the mass-coordinate version of the (WRF) model. This scheme is unique in that it runs on small PC clusters with Linux operating systems and is ideal for applications in local weather offices where accurate short-term cloud and precipitation forecasts are needed. This system depends greatly on the accuracy of the background modeling system, currently the NCEP versions of the RUC and Eta models. The Hot Start scheme uses estimates of vertical motion and cloud water and ice mixing ratios from the LAPS cloud analysis. A variational analysis that applies both mass continuity and mass-momentum balance makes small adjustments to the wind and temperature field to accommodate and sustain the clouds in the first few time steps of the model integration. The cloud retrieval algorithm includes a broad range of microphysical species, cloud-type dependent estimates of cloud vertical motion, and saturation of the cloud environment.
Verification with MM5 during the 6-week International H2O Project showed that the Hot Start outperforms other initialization techniques in the 0 6-hour time frame in forecasts of precipitation, most state variables, and 3-D cloud and radar fields. Figure 31 shows equitable threat scores for precipitation for the entire experiment. Note that the bias for the LAPS Hot Start 3-hour forecasts is nearly 1.0 across all precipitation categories (i.e. it is nearly unbiased), whereas the other models characteristically overforecast very light precipitation amounts and display a large dry bias for precipitation amounts >0.25 inch. The Hot Start method is used to initialize MM5 over a variety of domains including the local Denver forecast area, where forecasters use it as an operational tool; the U.S. Air Force Western Range at Vandenberg Air Force Base as part of the Range Standardization and Automation (RSA) implementation discussed below, and IHOP field operational areas at 12- and 4-km grid resolution. The Hot Start system has been coupled to the WRF-mass coordinate model for testing in a local weather service office in conjunction with the Coastal Storms Initiative carried out with the National Weather Service and National Ocean Service. It is also under evaluation as part of the MM5 modeling system at the Central Weather Bureau of Taiwan.
GOES Improved Measurements and Product Assurance Plan The GOES Improved Measurements and Product Assurance Plan (GIMPAP) project has been a key part of the LAPS moisture algorithm development for integrating the high spatial structure of GOES imagery and sounder data into the LAPS system. GIMPAP includes NESDIS cloud-top pressure and layer-precipitable water products.
The total precipitable water analysis over the IHOP domain as generated by the LAPS analysis system incorporated real-time NESDIS product data with greatly reduced latency (a 30-minute cycle instead of the customary 60-minute cycle) and experimental GOES-11 single field-of-view (unsmoothed) radiance data. It also used indirect NESDIS cloud-top product data via the LAPS cloud analysis. The IHOP product stream was accurate and timely throughout the 6-week field project.
Joint Center for Satellite Data Assimilation (JCSDA) The latest OPTRAN code was obtained from NCEP, compiled and tested, and made to run under IBM AIX, Linux Dec Alpha and Linux PC, and Sun OS. Current work involves writing the interface between OPTRAN and LAPS, and exploring the mesoscale nature of the background and observed error covariances for moisture analyses.
The WFO-Advanced workstation in Boulder receives 10-km resolution MM5 model output from twice daily model runs on exactly the same grid and projection as the LAPS analysis. This permits the display of mesoscale model output in a fully integrated fashion, along with radar, satellite, and surface data. Forecasters can check the quality of a model run by directly comparing model output with observations. The model is running experimentally in the Denver-Boulder NWS Forecast Office on a system within the AWIPS application hardware suite. The model runs in automated mode with little intervention required, and is diabatically initialized using the Hot Start procedure discussed above. Another onsite model implementation is now in progress for the Jacksonville, Florida, WFO under the Coastal Storms Initiative. This model is being established to test short-term forecast capabililty and application of high-resolution wind forecasts to improve estuarine water flow for harbor operations.
U.S. Army Precision Air Drop Project In 2002, the LAP Branch became involved with a U.S. Army-sponsored development to improve the accuracy of middle-level and high-level parachute delivery of logistical material to military units (Precision Air Drop Systems, PADS). Because of the complexity of wind profiles and air channeling terrain, computed air drop release points (CARP) were often inaccurate, resulting in cargo being substantially off target. In regions of Bosnia, for example, the errors were often whole valleys off target, resulting in long excursions to recover the needed material. In conjunction with Planning Systems Inc., of Reston, Virginia, the LAPS group was asked to port the LAPS analysis onto a laptop that would be taken on drop missions. The concept of operations is for the aircraft to make a close proximity pass over the drop zone, release a dropsonde, process and assimilate the dropsonde with model background fields, and create a high-resolution profile that accommodates time and space displacements from the dropsonde to cargo release time, while accounting for flow channeling over rugged terrain. The laptop computes an updated CARP, within minutes, reducing the threat period for the aircraft. LAPS was ported into the PADS and is now undergoing testing at an Arizona drop range. LAPS is able to ingest the data quickly and provide the wind data to recompute the CARP in less than 3 minutes. Tests so far have been good for mid-level drops, but less so for high-level drops.
Participation in IHOP FSL participated in the International H2O project (IHOP) in May and June 2002. Different versions of mesoscale models run in real time were used to aid in the nowcasting and forecasting effort to support IHOP operations. Formal real-time evaluation and documentation of the model forecasts were part of the IHOP effort, using online forms to record forecaster assessment of the quality and usefulness of the models. A more formal evaluation is taking place after the end of the IHOP field phase, in coordination with researchers at NCAR and at the Storm Prediction Center (SPC). Figure 32 shows example forecasts from three of the models for a rather subtle dryline situation during a very dynamic convective event and a comparison of the composite radar imagery over the IHOP region to a forecast from the 4-km MM5 model showing a pronounced bow echo forming along a developing squall line.
The Range Standardization and Automation (RSA) Project Several years ago, the Air Force initiated the Range Standardization and Automation (RSA) program to modernize and standardize the command and control infrastructure of the two U.S. Space Launch facilities (ranges), located at Vandenberg Air Force Base, California, and Cape Canaveral Air Station, Florida. During this past year in cooperation with Lockheed Martin Mission Systems, an integrated local data assimilation and forecasting system was installed at both ranges. The RSA system runs on Linux "Beowulf" clusters from IBM at each range and a test cluster at FSL for use in system development. The clusters consist of 8 dual-processor Pentium III nodes and 1 dual-processor front-end node, totaling 18 processors. A Myrinet interconnect is used for high-speed message passing between nodes.
The first version of the RSA Data Assimilation and Forecast System, based on LAPS coupled with the NCAR fifth-generation Mesoscale Model (MM5), is in testing mode. The system produces hourly LAPS analyses and a new MM5 forecast run every 6 hours on a triple-nested domain with 10-km, 3.3-km, and 1.1 km grid spacing, respectively. These analyses make use of the AWIPS Local Data Acquisition and Dissemination (LDAD) interface to incorporate data sources unique to the launch facilities in addition to the radar, satellite, and other datasets available via the AWIPS data feed. Every 6 hours, these analyses are used to perform a diabatic initialization of an MM5 forecast run. The forecast model outputs hourly forecast fields out to 14, 12, and 9 hours for the 10-km, 3.3-km, and 1.1-km grids, respectively, using 2-way nested feedback. The entire system is integrated with the Linux version of AWIPS installed at the Air Force ranges. Figure 33 shows an example of a product on the interior (1-km mesh) of forecast surface wind and temperature, verifying surface plots, and comparative wind forecasts from the MesoEta model over the local area surrounding Vandenberg AFB.
The RSA and projects spurred numerous improvements to the LAPS/MM5 prediction system. First, the cloud analysis was adapted to ingest and use narrowband radar reflectivity from multiple WSR-88D sites, available via the Satellite Broadcast Network (SBN) feed into AWIPS. This provides better coverage over the entire domain of the grid used for the RSA, which is spatially larger than a typical NWS Forecast Office domain. Second, the cloud analysis was modified to use a climatological albedo field to increase the utility of the visible satellite imagery. This, combined with the recent integration of the GOES 3.9 micron channel, has greatly improved the system's ability to detect low stratus clouds over the ocean surrounding the Western Range. Third, for the purposes of initializing a numerical weather prediction model, the final three-dimensional concentrations of the hydrometeor species are scaled as a function of horizontal grid spacing. Finally, to ensure compatibility with current numerical weather prediction model microphysics schemes, any grid box volume containing cloud liquid or ice is raised to its saturation level with respect to the phase of the cloud species. This prevents rapid evaporation of the cloud and the concomitant spurious generation of cool downdrafts within the first few time steps of model integration.
These RSA capabilities together represent the first operational installation of a local modeling system completely integrated with AWIPS in a WFO-like environment, the first operational installation of the LAPS diabatic initialization-Hot Start method, and the first operational use of a Linux-based AWIPS system. Ongoing FSL work includes ingesting and optimizing the use of all local meteorological datasets, incorporating new capabilities such as online verification of the forecast grids, enhancing utilization of the satellite data to improve cloud analyses, and improving the LAPS diababic initialization method.
High Performance Computing The FSL High-Performance Computing System (HPCS) has been a critical resource for all of the numerical modeling activity in the branch, including the unique mesoscale model ensemble used for the Federal Highways Project described below. This experience continues to provide important feedback to the system developers and computer specialists regarding configuration issues and future upgrade plans.
The CWB-LAPS products feed into CWB's Weather Information and Nowcasting System workstation. The onsite and "shadow systems" (running at FSL) were improved to completely mimic the CWB system. The surface analyses were upgraded to handle analysis of variables in the coastal zones by increasing correlation over similar earth surface characteristics. Use of model backgrounds into LAPS was improved and coupled to bogussing techniques for tropical cyclone positioning. Satellite imagery for infrared and visible bands are ingested in the cloud analysis scheme.
The CWB MM5 modeling effort was the focus of a visiting scientist at FSL who worked with the group to configure a multinested modeling domain, a LAPS Hot Start initialization capabililty, inclusion of bogussing, and a precipitation verification system. Results indicated that the Hot Start scheme helped to better define tropical rainbands leading to improved 0 9 hour forecasts. As an example, Figure 34 shows forecasts of Typhoon Rammasun, which skirted the islands to the northeast of Taiwan. Experiments were run with cold start, hot start only, and hot start with bogussing. Three 6-hour forecasts are shown along with comparative track forecasts out to 24 hours for each realization. The Taiwan MM5 system is being implemented at the CWB.
Branch staff visited with Central Weather Bureau forecasters and researchers in Taipei to conduct training on the potential use of LAPS in operational forecasting and discuss ideas for nowcasting. A Webpage...
was created to display the training sessions online and provide a subjective evaluation of the LAPS performance at the Taiwan CWB.
Additional collaboration with the Korean Meteorological Agency (KMA) and Hong Kong Observatory (HKO) has been less formal but ongoing. Both agencies are interested in developing a high-resolution modeling and analysis capability. KMA has already developed a prototype LAPS/MM5 system, which is being tested, and HKO is working on a LAPS development.
Ensemble Modeling of Winter Road Conditions In collaboration with NCAR, LAP Branch scientists began designing an ensemble of mesoscale models to support a Federal Highways Administration (FHWA) road weather project. The ensemble includes multiple models (MM5, RAMS, and WRF) with lateral boundaries provided by multiple large-scale models (AVN, Eta, and RUC) that run at relatively high spatial resolution. Although ensemble techniques have been applied before on grids with approximately 25-km resolution, runs for this experiment were performed on 12-km grids and were used to make site-specific (road) probabilistic forecasts. The need for quantitative precipitation forecasts early (0–3 hours) in the forecast cycle necessitated the use of the LAPS hot start for all model runs. Cold started model runs were attempted, but these were of little value. Grids from the 9-member ensemble were fed into the NCAR Maintenance Decision Support system where the weather probabilities were used to make road maintenance decisions (mobilization of trucks, routes, types of chemicals, duration, etc). The system has been tested during the 2003 winter. Figure 35 shows four ensemble members and forecasts centered over the Iowa test area.
Developments for the Weather Research and Forecast Model The branch is involved in three key areas of the WRF modeling system. The Standard Initialization (SI) software creates model start-up grids from the NCEP national AVN, RUC, or Eta models. The land-surface module (LSM) of WRF uses "static" fields (such as vegetation greenness, albedo, land use, terrain height, land fraction) that have been assembled and reformatted, along with efficient interface software. The third area is a graphical user interface (GUI) for the localization of the WRF to be used by the WRF community. The initial version of the GUI was released to the WRF user community in early 2003. These software components developed by the LAP Branch and sponsored jointly by the Air Force Weather Agency, FHWA, and FAA are released routinely with the WRF model itself.
Lidar OSSE Studies A strong interest has evolved over the last 20 years in the possibility of inferring atmospheric winds from Doppler lidar measurements aboard a polar orbiting satellite. Two satellites in appropriate orbits could provide daily global wind coverage, at least where the pulses of energy from the lidar are not blocked by clouds. Cost is not the only issue with this observing system. The technology for obtaining radial wind velocities with good signal-to-noise ratio is still being perfected, and more than one lidar has been proposed to do the job. For this reason, FSL cooperated with the Environmental Technology Laboratory (ETL), NCEP, and NCAR to study the impact of Doppler wind lidar data on numerical models. FSL was responsible for studying the impact of the data on forecasts over the U.S. using a regional observing systems simulation experiment (OSSE).
For the case study, a long-duration, pure forecast from February 1993 was generated using the global model developed at the European Center for Medium-Range Weather Forecasts (ECMWF). LAP Branch ran the Regional Nature Run (RNR) using the PSU/NCAR mesoscale model (MM5) initialized from the ECMWF Nature Run to simulate onboard lidar data (clouds, winds, vertical velocity). The huge MM5 domain of the RNR covered most of North America with a 10-km horizontal (740 x 520) grid spacing and 43 vertical levels. This domain was tailored to include the present domain of the RUC model. Simulated observations were extracted from the RNR over an 11-day period for inclusion into the RUC data assimilation system. The simulated data included the entire suite of operational and future lidar observations; thus, synthesized rawinsonde, ACARS/MDCRS, surface, METAR, wind profiler, and VAD winds were all extracted from the RNR fields with appropriate error characteristics. The lidar line-of-sight winds from the satellite positions in four-dimensional space were determined by ETL from the Cartesian winds and cloud hydrometeor fields provided from the RNR. The last remaining task was to conduct a variety of sensitivity experiments with the mesoscale data assimilation system (RUC) with and without the lidar data, with various combinations of boundary conditions, and with and without liquid and/or ice clouds present. Results from this experiment can be found in the section on the Regional Analysis and Prediction Branch.
NOAA Coastal Storms Initiative With the cooperation of the NOAA National Ocean Service, the NWS embarked on a project to test and evaluate locally produced, high-resolution grids derived from an onsite, high-resolution mesoscale model, driving an estuary flow model that predicts harbor and river depths for safe navigation. A secondary purpose is to test the model for forecasting marine hazards like thunderstorms, winds, and heavy precipitation events. LAP Branch's role in this is to bring to bear the experience gained from other deployments (such as RSA), link the LAPS analysis to the new WRF model, and set up the system at the Jacksonville, Florida WFO. Jacksonville is uniquely qualified for the test with a busy harbor, two major estuaries (St. Mary and St. John rivers), and frequent occurrence of thunderstorms and tropical weather. The sea and river breezes make for a complex land/water interaction and justifies the high-resolution modeling approach. The system runs on a 9 dual processor linux cluster and ingests all local data. The 24-hour forecasts (4 times a day, both cold and hot start) run in about 3 hours. The grid is a single nest of 5-km resolution and uses the Eta model as background and boundary conditions. The need for short range quantitative precipitation forecasts necessitates the use of the LAPS diabatic initialization scheme. Adjusting the scheme for the sub-tropics will be a major challenge. This demonstration will be an important consideration for the NWS in the decision to support local modeling in weather offices.
U.S. Forest Service Fire Consortia for Advanced Modeling of Meteorology and Smoke (FCAMMS) In 2002 the LAP Branch became involved in a project to develop an FCAMMS for the Rocky Mountain Research Station in Ft. Collins, Colorado. The goal of this project was to develop an analysis and modeling capability that encompassed needed fire-specific (both planning and incident) support products. The MM5 model was used to develop 12-km and 4-km nests for large sections of Arizona and New Mexico (the Southwest Area Coordination Center) and Colorado and Wyoming (the Rocky Mountain Area Coordination Center). These models and analyses were run over the newsworthy 2002 fire season. Products were disseminated using a Webpage. The fire manager/user had the option of initiating specific point forecasts for new fire locations by simply entering the latitude and longitude. During the next model cycle (4 times per day) a test product was generated with weather for the next 24 hours. Development is continuing to add new products, increase resolution, and improve existing products and the appearance and utility of the Webpage. Once the initial capability is completed, new members of the consortium will be sought. State and federal agencies with a need for high resolution weather support are likely candidates.
GAINS PIII Flight The maiden flight of the 60-ft diameter GAINS Prototype III (PIII) balloon occurred on 21 June 2002. This flight met several development objectives, including launching the PIII balloon, floating it at altitude for more than eight hours, transforming the balloon envelope into a deceleration device, achieving a safe descent rate, tracking the balloon from an aircraft; forecasting balloon trajectory before launch, updating balloon landing position during flight, and recovering the balloon and payload.
Manufactured by GSSL, Inc., of Hillsboro, Oregon, and launched from their Small Balloon Facility at Tillamook, Oregon, the 500-pound balloon carried a 325-pound payload containing packages from four organizations. The FSL payload included GPS for locating the system, two independent radio- and software-controlled termination methods, and environmental sensors to monitor balloon performance. The payload also contained a GPS reflection experiment from NASA/Langley, redundant locating capability based on a design adapted from the Edge of Space Science (EOSS) of Denver, Colorado, and backup location and termination units from the Physical Science Laboratory of New Mexico State University and from GSSL.
Nominal float altitude of 54,000 ft was achieved after reaching a maximum altitude of 57,000 ft. A tracking aircraft kept the balloon within radio line of sight at all times during the 225-mile flight, and personnel on board coordinated the flight with FAA Air Traffic Control. Two additional vehicles tracked the balloon from the ground and recovered the payload. The balloon's descent was slowed by the GSSL BERSTM (Balloon Envelope Recovery System), in which the balloon envelope transformed to a parachute and the system descended at about 500 ft per minute. The soft landing caused no damage to the payload capsule, and minimal damage to the wheat field south of The Dalles, Oregon, where it landed. The entire system was removed from the landing site and returned to Tillamook within 24 hours of landing. Figure 36 shows the actual flight path and the path predicted using winds from the global AVN numerical model.
GAINS Pump Test Flight On 17 August 2002 a flight was launched from Meadow Lake Airport, northeast of Colorado Springs in a cooperative effort between the GAINS and EOSS groups. The main objective of the flight was to test the operation of the turbine developed by Advanced Engineering at GAINS operational altitudes. Results from laboratory experiments indicated that the turbine met the requirements for flow rate, power needs, and weight; this experimental flight was intended to affirm these results under true atmospheric conditions. Turbine electronics and control software algorithms were also tested. A 19,000 cubic-ft polyethylene balloon was used for lift, and a 500-gram latex balloon in a GAINS P-I 8-ft nylon shell used as a ballast balloon. The plan was for the turbine to pump ambient air into the ballast balloon until the desired super pressure was achieved. For this experiment, the turbine was to be tested at 50,000, 60,000, and 70,000 ft, with inflation continuing until a super pressure of ambient plus 15% was achieved. The payload, consisting of all control and communication electronics, was located in an insulated ring that encircled the turbine on a lightweight disc with three supporting legs, known as the "lander" (Figure 37).
The gusty nature of the surface winds prior to launch made for complications, the most significant being the introduction of small holes in the polyethylene lift balloon from contact with the ground. Most, but not all, of these were repaired prior to launch, resulting in a flight duration shorter than expected. The balloon reached a maximum altitude of 32,000 ft before descending back to earth. Unfortunately, this altitude was not sufficient to allow testing of the GAINS pump. Although the pump performance could not be tested, the setup and launch procedures as well as tracking and recovery were successful. This will enhance the ability to achieve the goals when the test is repeated later.
Evaluation of Balloon Trajectory Forecast Routines Software has been developed that uses observations and model wind data for prediction of balloon trajectories for GAINS. A fifth version of the software, utilizing output from the U.S. Navy NOGAPS model, was added to the four other versions that currently use rawinsonde data, global AVN model winds and RUC-2 model winds. Each version produces predicted balloon positions in 1-minute increments, and these are available to FSL personnel and collaborators in textual and graphical form at the GAINS Website, http://www-frd.fsl.noaa.gov/mab/sdb/overview.htm.
A verification study was performed on the predictions made for the period 1 March 2001 31 August 2001, building upon a 1-month study performed in 2001. Prior to that initial study, comparisons were limited to examination of experimental flight data on a case-by-case basis. Since resource constraints have not permitted twice daily balloon launches (from which actual balloon trajectories can be obtained), a verification system was developed using predictions from hourly analyses from the MAPS RUC-2 model as a baseline to examine differences between baseline and predicted trajectories from the rawinsonde and AVN model-based predicted trajectories. When segregated by season (spring and summer), the comparisons show a significant decrease in correlation of longitudinal errors from spring to summer. Median values appear to indicate stronger zonal winds in the RUC data in comparison to the values obtained from the AVN-based predictions. Further study is planned, including comparison with GAINS and other actual balloon flights.
Support of NCAR Dropsonde Experimental Flight The InterContinental Radiosonde Sounding System (ICARUSS), also called Driftsonde, is a proposed new atmospheric sounding system for use during the upcoming THORpex (THe Observing-system Research and predictability experiment) field projects in 2003 or 2004. The ICARUSS concept uses a thin polyethylene balloon (0.35 mm) with a volume of 268 cubic meters to lift a payload (up to 40 kg) of 24 dropsondes or modified radiosondes to an altitude of about 100 75 mb (53,000 60,000 ft) and maintain that altitude for 5 or 6 days. The altitude of the balloon can be adjusted over a limited range to take advantage of the most favorable upper-level westerly wind flow.
Simulations using 1999 wind data over the Atlantic and Pacific oceans show that balloons launched from coastal radiosonde sites (in the eastern United States or Asia) will travel across the oceans in approximately 5 or 6 days. The dropsonde would telemeter the measured profile data back to the balloon where it would be received, processed, and stored. A compressed dataset (e.g., WMO message or 10-second data) would be sent through a Low Earth Orbiting Satellite (e.g., ORBCOM) to a ground station and on to the THORpex control center for further processing and/or input into the Global Telecommunications System (GTS).
A 2-hour experimental flight was launched from Tillamook, Oregon, on 28 February 2002. Software written for GAINS balloon trajectory prediction was modified to use flight parameters appropriate for the Dropsonde flight, and these changes were provided to NCAR personnel at Tillamook. Through use of these predictions, NCAR was able to make a prelaunch assessment of the expected flight path, and recovery personnel were positioned in the proper area.
Station-keeping Balloon Concept A cursory examination of the technical feasibility/capabilities of a self-propelled Aerodynamic Canopied Balloon Cluster (ACBC) was prepared, and a rudimentary model was constructed and demonstrated. This concept evaluation was toward a buoyant craft that could float (rather than fly) to high altitudes where the air is thin enough so that aerodynamic streamlining and solar powered turbines could allow the craft to fly against the prevailing wind with enough speed to remain fixed in space at altitudes exceeding 70,000 ft. As envisioned, the systems onboard an ACBC craft might include:
The overall ACBC concept suggested here is radical, but the various components exist and in some cases are "off the shelf." The net payloads may be substantial, as balloon technologies allow for payloads into the thousands of kilograms at relatively low cost.
FSL scientists have analyzed data collected by the NOAA Gulfstream-IV (G-IV) aircraft from one of the SCATCAT missions. In-flight observations were made at several altitudes and dropsondes were launched from the 41,000-ft level along a track perpendicular to the core of an upper-level jet streak. The aircraft encountered moderate-or-greater (MOG) turbulence on three legs of the stack, highlighted in yellow in Figure 38. This figure is a cross-section analysis of wind speed, potential temperature, and DTF3-diagnosed Turbulent Kinetic Energy (TKE) fields computed from the dropsonde data. Regions of strong vertical wind shear are evident above and below the level of the jet core. There is also a strong suggestion of vertically propagating gravity waves above the jet core and to its cyclonic side in the lower stratosphere (in the 260 176-mb layer). Coherent streaks of MOG turbulence are predicted by the DTF3 (Diagnostic Turbulence Flux Algorithm) field primarily in the layers of strong shear just above and below the jet core and within the warm front stable layer. These layers of high DTF3 correspond well to the observed in-flight turbulent regions.
The RUC20 model was run for this SCATCAT case, representing the first time that the RUC had ever been positioned to run entirely over the Pacific Ocean. The AVN model was also used for the first time instead of the Eta model for specification of the RUC boundary conditions. Figure 39 shows a cross section of isentropes and isopleths of isentropic potential vorticity taken perpendicular to the jet core but over a longer length than the dropsonde cross section in Figure 38. These model predictions were compared to fields of winds, potential temperature, and ozone (potential vorticity is taken as a surrogate for ozone) measured by the aircraft. This comparison revealed very similar features, including the warm frontal zone, the upper-tropospheric front/jet system zone, and regions of strong vertical wind shear and associated large DTF within these zones. A deep tropopause fold is present along the warm frontal zone down to almost 700 hPa, but of greater interest are multiple tropopause "undulations" in the upper-level front of the model. Also of interest are mesoscale gravity waves in the lower stratosphere directly above the jet core, with vertically varying horizontal wavelengths of ~100 160 km. Similar waves in the dropsonde analyses in the lower stratosphere directly above the jet core displayed wavelengths of ~80 km. A higher-resolution version of the RUC, of course, might have produced shorter wavelength features.
Wild fluctuations in ozone measurements from the NOAA/ARL experimental instrument were measured at the 41,000-ft level, but fluctuations in the potential temperature and wind in-flight observations did not correlate highly with the ozone data, nor was much turbulence reported on this flight leg. It was concluded that these rapid fluctuations in ozone at this level represented "fossil turbulence" or remnants of earlier stratosphere-troposphere turbulent exchange processes. By contrast, the correlation between the ozone and in-flight variables, as well as with the RUC model potential vorticity variations, was very high at the 33,000-ft altitude. Also, moderate turbulence was reported at this flight altitude, as the G-IV was penetrating a rather pronounced gravity wave within the upper-tropospheric frontal zone. Thus, active turbulence was occurring in association with gravity wave activity at this altitude, but not at the higher level.
Time series and spectral analyses were performed for each of these flight legs in an attempt to relate the appearance of turbulence to mesoscale gravity wave activity. Potential temperature and longitudinal wind exhibited a high degree of cross correlation, as did the potential temperature and ozone data at the 33,000-ft level. Such a strong "in-phase covariance" is expected of either deep propagating gravity waves or, more likely, decaying (evanescent) waves.
The SCATCAT research revealed that MOG turbulence occurred in conjunction with gravity waves shed within an upper-level fractured front on the cyclonic shear side of the jet core. Besides this major finding, it was concluded that RUC-forecast DTF is a useful diagnostic of turbulence, whereas ozone is not, and that both the MOG turbulence and the high DTF regions occurred in the vicinity of the strongest mesoscale gravity wave activity in both the model forecasts and the aircraft observations.
Diagnostic Algorithm Development The forecast skill of Integrated Turbulence Forecasting Algorithm (ITFA) and its component algorithms has been evaluated both objectively and by forecasters. These studies show that the best of the algorithms display similar probability of detection (POD) curves, and that there is considerable room for improvement. Research conducted at FSL indicates that these algorithms also typically predict patterns that are similar to one another, and that MOG pilot reports (PIREPs) of turbulence often fall in the margins of the predicted ITFA regions. The best of these algorithms are fundamentally based on the destabilizing dynamics of vertical wind shear.
FSL developed an experimental turbulence prediction scheme based on a radically different dynamical concept, namely that turbulence is generated as mesoscale gravity waves are shed when an unbalanced jet streak propagates toward an inflection axis in the upper-level height field (the SCATCAT analyses discussed above lend additional support to this contention). Diagnosed gravity waves and model flow imbalance have been shown in detailed case studies by Forecast Research Division scientists to relate strongly, not only to each other, but also to MOG turbulence reports. The flow is considered to be unbalanced when there is a pronounced residual in the computed sum of the terms in the nonlinear balance equation from the RUC model. Imbalance typically occurs in essentially the same region as where mesoscale gravity waves develop and upstream of where the turbulence is reported, as demonstrated in one case shown in Figure 40. Note in this example that the imbalance is occurring precisely at the tip of the dry air stream associated with subsidence within a pronounced jet streak (or "potential vorticity streamer," discussed below). The conventional turbulence diagnostic DTF3, which is a major contributor to the ITFA, fails to predict the swath of turbulence reports in the Ohio River Valley region, whereas the imbalance indicator field successfully captures this event. On the other hand, DTF3 does a credible job at delineating the other swath of turbulence reports in the Great Lakes region, not captured by the imbalance field. This complementary nature of the imbalance indicator fields and DTF/ITFA is typically observed to occur.
A Webpage was created this past year to examine the relationships between diagnosed flow imbalance from the RUC20 model and MOG turbulence reports on a daily basis. This more thorough investigation has shown that mountain waves generated by strong flow over rough terrain like the Rocky Mountains are even more highly correlated with turbulence and flow imbalance than are the imbalances associated with the jet stream and cyclonic storm systems. While mesoscale models like RUC can be useful for diagnosing the flow imbalance regions and where generally gravity waves are likely to form, they do not reliably predict the details of the gravity waves themselves, such as their wavelength, phase speeds, and so forth. The new predictive scheme being developed at FSL not only produces patterns systematically different from the current ITFA algorithms but also predicts turbulence regions missed by those methods. Further refinement of forecast turbulence regions might be obtained by adding the requirement that an efficient wave duct must be present downstream of the region of diagnosed flow imbalance to retard the vertical leakage of wave energy, thus allowing coherent waves to persist. The optimum amount of smoothing of the imbalance fields, the proper thresholds, and other numerical issues must all be resolved, before the new imbalance indicator field can be incorporated into ITFA to increase its utility.
The IHOP project offered a unique opportunity to carry out two aircraft missions (led by the Forecast Research Division Chief) to observe the morning LLJ over Oklahoma and Kansas. Each mission utilized airborne dropsonde data, Differential Absorption Lidar (DIAL) data flown on the German Falcon, High-Resolution Doppler Lidar (HRDL) data from NOAA/ETL also flown on the Falcon, and in one of the cases, hyperspectral radiometric data from the NASA Proteus aircraft, to observe a strong LLJ in good atmospheric conditions (i.e., substantially free of clouds). These observations offer an excellent opportunity to prepare detailed three-dimensional meteorological fields of moisture and winds at a multitude of scales and the possibility to compute a moisture budget. The objective is to examine these data to determine the impact of fine-scale moisture observations on the numerical prediction of precipitation. Another ongoing task is combining datasets obtained from the two aircraft missions to compute moisture budgets and perform diagnostic and numerical modeling studies of these cases to test the hypothesis that warm-season QPF skill can be significantly improved by better characterization of the transport of water vapor by the LLJ.
Structure and Dynamics of Gravity Currents and Undular Bores The IHOP field phase collected a surprisingly large number of events in which either a thunderstorm outflow boundary or cold front, acting as an atmospheric gravity current, intruded into a stably-stratified boundary layer and generated an undular bore (a kind of hydraulic jump) on the top of the inversion. In some cases, deep convection appeared to have been generated by the vertical motions attending this phenomenon, which are quite strong (updrafts of several meters per second magnitude). An unprecedented number of ground-based and airborne remote sensing systems observed the passage and evolution of bores in IHOP, including FM-CW radar, the NCAR Multiple Antenna Profiler (MAPR), Raman lidar, the NASA GLOW and HARLIE aerosol backscatter lidars, refractivity fields obtained from the NCAR S-POL radar, an Atmospheric Emitted Radiance Interferometer (AERI) system, the French Leandre-II DIAL system aboard the NRL P-3 aircraft, and the University of Wyoming King Air aircraft. FSL is collaborating with a team of international scientists to analyze these data. Also, very high-resolution numerical simulations of two bore events are underway to better understand the origin, dynamics, entrainment mechanisms, and influence on convection initiation by undular bores. Much more will be reported on these studies in the next issue of FSL in Review.
Potential Vorticity Streamers Researchers in Europe and the United States have noted the frequent occurrence on water vapor satellite imagery (GOES and METEOSAT) of pronounced dark filaments, which are mesoscale in width and varying in length up to the largest scales of atmospheric motion (see Figure 41). The most pronounced of these dry filaments have a parallel jet stream immediately to the south, and according to recent studies conducted at FSL, a similarly shaped band of collocated, enhanced potential vorticity (a "PV streamer"). Another satellite-observed feature enhanced ozone suggests that a PV streamer is a downward intrusion of stratospheric air along an upper-level front.
Monitoring PV streamers has prognostic value. In Europe, PV streamers have been identified as precursors to flooding along the Mediterranean slopes of the Alpine piedmont. In the United States a number of case studies have documented MCS development near a preexisting PV streamer. Some of these MCSs were accompanied by severe weather and flash flooding, as was the case with one occurring 28 June 1999 over Kansas (described in the 2002 FSL In Review). This storm was one in a series of four MCSs that occurred along a PV streamer that persisted six days over the central and southeastern United States. The total precipitation from these four MCSs produced a significant fraction of the area's annual precipitation.
In addition to being a valuable forecasting ingredient to organized convection and heavy precipitation, the PV streamer is a fascinating phenomenon, rich in dynamical and thermodynamic implications deserving of serious scientific study. It combines upper-level jet stream dynamics with the flow of midtropospheric, dry, potentially cold air having a low static stability. Some researchers have suggested that the exit region of an upper-level jet streak enhances a transverse low-level jet as a result of mass balance. Others have suggested that upper-level PV passing over a low-level front can organize a developing cyclonic circulation. With the addition of moisture to the low-level jet, the mechanisms for producing organized convection are all present. The details of how the ingredients combine to shape an MCS await results of field experiments (such as BAMEX) and those of mesoscale modeling at FSL.
NCEP Gauge Quality Control Project A system for the automated screening of hourly gage precipitation observations has been designed to find failing gauges in the Hydrometeorological Automated Data System (HADS). Funded by the USWRP, this system was solicited by National Centers for Environmental Prediction (NCEP) to provide more timely gauge quality indicators to prevent the use of faulty gauges in analyses used to initialize model runs. Following the identification of several characteristic failure types (e.g., gauges that jam on or off for long periods), tests for these failures on individual gauges have been devised. Several of these tests are based on the most recent 30-day distributions of precipitation characteristics such as daily and hourly rainfall frequency. Gauges that fail these tests can then be entered on a reject list to eliminate them from precipitation analyses and model verification. Because old or inaccurate station metadata have often been a weak link, procedures to automatically update relevant station lists have been introduced. An automated procedure for gauge quality control and rejection will be completed during 2003 and delivered to NCEP for implementation.
Assessing the Quality of Real-Time Precipitation Gauge Observations An ongoing collaboration with the Real-Time Verification System project group seeks to improve verification procedures for model-based precipitation forecasts. Over the past year, this verification effort concentrated on the use of hourly point precipitation observations at sites to which model fields were interpolated. Of major concern was the determination of the quality of hourly observations in order to screen out unsatisfactory observing sites and to reincorporate sites with good observations that in the past have not been included in the set of stations presented in near real time by River Forecast Centers.
ACARS/AMDAR Quality Control System A computer program to flag and in some cases correct weather data from automated sensors on commercial aircraft (called ACARS in the U.S. and AMDAR in the rest of the world) was upgraded. The quality control system uses temporal and spatial consistency checks along each flight track and altitude-adjusted climatological consistency checks to discover errors. It also interpolates locations and times for high-resolution observations taken during ascent and descent enabling these data to be used in numerical weather prediction model research and weather forecasting. The quality control system was upgraded to ingest and display data from the MDCRS (Meteorological Data Collection and Reporting System) data stream, produced by Aeronautical Radio, Inc. MDCRS data are largely the same as data provided by airlines directly to FSL, and decoded here, but have some differences. Because MDCRS feeds numerical weather prediction models run by NCEP, it is important to understand these differences. The QC system attempts to match each MDCRS observation with one decoded directly by FSL, and report the differences. The QC system was also upgraded to process experimental icing data from Delta Airlines, in support of a research effort led by the National Center for Atmospheric Research and funded by the FAA.
ACARS-RUC Intercomparison Database A database has been developed that compares ACARS data with 1-hour RUC forecasts. RUC data are interpolated to the location of each ACARS observation. This database, with 9 months accumulated data, is used to develop error statistics for longitudinal and transverse winds, and for other RUC and aircraft error analyses.
North American Radiosonde Dataset For years FSL has been providing a CD-ROM archive of quality-controlled radiosonde data for use by the research community. During 2002, updates were made to the global and North American station history files to reflect changes in the network sites, including moves, station identification changes, and addition of new stations. The Website was modified to correct problems in the generation of duplicate skew-T plots for different stations, and software was incorporated to handle the change to a new year without interrupting service.
Chemical Weather Research and Development Website
(http://www-frd.fsl.noaa.gov/aq) In support of a major NOAA initiative to improve temperature and air quality forecasting, a Website was developed that that will present real-time and retrospective results from air quality models. The region of interest is primarily New England, the location of the Temperature and Air Quality (TAQ) project conducted in 2002. A related site on high-resolution temperature forecasting may be found at http://www.temp-aq.org.
National Hourly/Daily Precipitation Website
(http://esrl.noaa.gov/precip/hourly_precip.html) Development work continued on a Website that displays hourly and daily precipitation data from NCEP. Data are displayed on a national map that optionally shows rivers and county boundaries. Moving the cursor across the map reveals the available data, and a mouse click provides a daily time series of the data. Users can zoom and roam on the map for detailed local structure of precipitation events. Years of precipitation observations are available at the site. Significant improvements have been made to this Website as part of a USWRP-funded project with NCEP to improve screening of the operational network of real-time hourly precipitation observations. Included in the set of new features are a utility to locate individual stations on the display, extension of the geographical display to a global domain, incorporation of standardized Java code from several FSL Websites to simplify site maintenance, and improved ability to distinguish stations that are in very close geographical proximity.
(http://amdar.noaa.gov/) Many upgrades were made to this site, which displays weather data from automated sensors on commercial aircraft. Air Route Traffic Control Center boundaries were added to aid users working at Center Weather Service Units (CUSUs). Additional North American VOR stations were added, primarily at the request of users at CWSUs. Experimental icing data from Delta airlines can now be displayed. Data can be selectively displayed based on data source: either ACARS (decoded at FSL), MDCRS (decoded at ARINC and ingested into NCEP models), or AMDAR (non-U.S. data). Observations with missing or bad wind and temperature data can be excluded from the display. Additional statistics (such as number of observations in a particular geographic region) are displayed. Data reporting wind speeds in excess of 200 kts are now displayed. Data downloads may now be restricted to specific types of data (such as ACARS or AMDAR) and data in specific geographic regions, thereby potentially speeding up data loading. Java code was upgraded to be consistent with the latest versions of Java, such as those used by Netscape version. Several audiovisual tutorials were created and made available on the Web; these show in detail how to use the various options available on the Web display.
Recently, 86 sites (such as participating airlines, United States and foreign forecast offices, and research institutions) accessed the site, which is restricted to specific users at the request of the airlines providing the data. These sites requested more than 2,500 data loads and looked at more than 4,100 soundings. Figure 42 shows the upgraded display.
Interactive Soundings Website
(http://www-frd.fsl.noaa.gov/mab/soundings/java/) This Website interactively displays past and forecasted soundings from two versions of the RUC model, as well as from wind profilers, radiosondes, and aircraft. This page is becoming increasingly popular, with more than 56,000 accesses from over 450 major domains (such as "noaa.gov" or "delta.com") nearly twice as many as in January 2002. The easily adaptable Java code that runs this site has been requested by more than 80 organizations, and has been released to them under FSL's open-source software license/disclaimer. The site was upgraded to display worldwide radiosonde data. Also, the latest available data from any radiosonde site are listed, to save users the trouble of seeking data from sites that have not reported recently.
National Mesonet Website
(http://madis.noaa.gov/sfc_display/) Using Java, a national mesonet Website was developed to interactively display observations from 22 mesonetworks (up from 17 a year ago), maritime buoys, and the METAR network, with typically more than 7,000 stations from around the world (up from 3,200 a year ago). The site displays weather data and quality control information from FSL's Meteorological Assimilation Data Ingest System (MADIS). The Java code has been modularized into packages, which are shared with other FSL Websites to allow easier code maintenance, and upgraded to be consistent with the latest versions of Java, while remaining compatible with earlier versions. Recently, North American highways were added as an overlay, thereby helping to put site locations in perspective, particularly when the map is zoomed in to a local region. The site, previously restricted, is now publicly available. During January 2003 it was accessed more than 2,900 times from 525 unique domains. Figure 43 shows mesonet data for a region centered on Washington, D.C.
(http://amdar.noaa.gov/ruc_acars/) This page is similar to the ACARS/ AMDAR Website (above), and similarly restricted. It displays ACARS data along with RUC 1-hour forecasts interpolated to the location of the ACARS data. Standard meteorological variables (wind and temperature) from either the aircraft or the RUC model may selectively be displayed, along with ACARS-RUC differences in vector wind, wind speed, and temperature. The site is used primarily within FSL, and is useful for identifying aircraft wind and temperature biases, and RUC errors. The page displays data from the ACARS-RUC intercomparison database, and as of this writing, 9 months of data are available for display.
(http://www-ad.fsl.noaa.gov/fvb/rtvs/turb/2003/interrogation_tool/) This page displays pilot reports (PIREPs) and AIRMETS (warnings issued by the Aviation Weather Center). Currently it displays only AIRMETs and PIREPs related to turbulence. Raw PIREPs along with their decoded values are displayed when the cursor is moved over a data point. AIRMET skill statistics may be generated for each AIRMET, and for each Aviation Weather Center region, including Alaska. This site has been useful for understanding more deeply AIRMET turbulence skill statistics generated by FSL's RTVS project. Also, because this site allows displays of turbulence PIREPs reported since 21 January 2002, it has been useful in verifying turbulent events identified by other means, such as infrasound.
North American Radiosonde Database Website
(http://esrl.noaa.gov/raobs/) This site provides access to the most recent years of global radiosonde data. Upgrades last year included updates to the global station history and provisions to accommodate the change over to the most recent year without service interruption or loss of data. The FSL format was slightly changed to show north or south latitudes and east or west longitudes to avoid confusion. Problems with duplicate skew-T images being generated for different stations were resolved.
Diagnostic Algorithm Development The residual of the nonlinear balance equation and other methods will be further investigated to arrive at the optimum method for diagnosing imbalance and for determining the appropriate threshold values. Real-time evaluation of these approaches will continue to be performed in preparation for planned implementation and full evaluation within ITFA in the next year. Idealized modeling studies will be performed to develop a basic understanding of the nonlinear-scale contraction process by which mesoscale gravity waves may steepen and saturate, leading to turbulence production at smaller scales.
Structure and Dynamics of Gravity Currents and Undular Bores The remote sensing data observing bores in IHOP will be analyzed in collaboration with a team of international scientists. Very high-resolution numerical simulations of two bore events, possibly to include Large-Eddy Simulation (LES) studies with specialized treatment of the boundary layer, will be conducted to increase understanding of the origin, dynamics, entrainment mechanisms, and influence on convection initiation by undular bores.
Potential Vorticity Streamers FSL plans to participate in the BAMEX field experiment and complete its mesoscale modeling of PV streamer interactions with mesoscale convective systems, and to publish the results within the year.
NCEP Gauge Quality Control Project Software to apply a set of retrospective checks on distributions of key precipitation characteristics (e.g., frequency of hourly and daily precipitation intended to determine, respectively, gauges that stick on or off and observing sites that report only non-zero precipitation amounts) will be completed and forwarded to the Environmental Modeling Center of NCEP for installation. A period of monitoring system performance at FSL (via the RTVS, where the system will also be installed) and at EMC will be instigated prior to final application at EMC. Also during this period, a daily automated procedure to update and collate daily and hourly reporting stations and produce a reduced station list will be written and installed. There are no firm plans for additional improvements to the Real-Time Precipitation Website.
ACARS/AMDAR Quality Control This system will be fully documented and passed on to a group of programmers at FSL so that there is no single point of failure for the system. Data from additional airlines, will be integrated into the system, and the error characteristics of these data will be investigated.
ACARS-RUC Intercomparison Database Once an entire year of data have been accumulated, detailed ACARS-RUC statistics will be generated and stratified by season.
North American Radiosonde Dataset Plans to continue with upgrades to this dataset are pending sufficient funding.
National Hourly Precipitation Website The collaborative project with NCEP to improve rain gauge QC and assess the Stage IV precipitation product involves further improvements to this Website, to be completed over the next year.
ACARS/AMDAR Website This system will be fully documented and passed on to a group of programmers for several points of failure for the system. Data from additional airlines and additional sensors will be integrated into the system.
Interactive Soundings This site will continue to be maintained and data flow into it monitored, but it will probably not be upgraded, because the early version Java code used in it is useable on a wider variety of computers that cannot run newer versions of Java. Pending identification of resources, scripts will be written to ease the reloading of past data cases upon request.
National METAR Website New mesonets will be added as they become available, and data loading will be speeded up. Pending identification of additional resources, wind gust and precipitation amounts will be shown for those sites that support them.
RUC-ACARS Website Pending identification of resources, this site will be expanded to include additional RUC forecasts longer than 1 hour, such as 3-, 6-, and 12-hour forecasts. Skill statistics will be generated.
PIREPs-AIRMETs Website This page is designed primarily to provide feedback for forecasters at the Aviation Weather Center. Feedback will be gathered, and future upgrades will be tailored to the forecasters' needs.
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