ESRL Air-Sea Flux and Cloud Observations


October 16, 2007

Scientists Chris Fairall, Sergio Pezoa, and Simon deSzoeke from the NOAA Earth System Research Laboratory (ESRL) will be onboard the NOAA Ship Ronald H. Brown for a climate processes study in the marine stratocumulus region off Northern Chile. The cruise begins on October 16, 2007 in Panama, proceeds to an experimental area centered at a Woods Hole Oceanographic Institutes (WHOI) climate reference buoy at 20 S 85 W, and ends in the Galapagos Islands on November 6. This investigation will address problems in prediction of short-term climate variations in sea surface temperature and related phenomena such as El Niño. The ESRL observations (conducted while the WHOI buoy at the site is serviced) provide a more detailed atmospheric context for the buoy data, which cover the annual cycle.

Background:
This experiment will be the sixth in an annual series of research cruises to this marine stratocumulus region, performed as part of NOAA's Climate Predictions Program for the Americas (CCPA) and Climate Observations (CO) Programs. Included in this experiment are systems that measure coincident cloud microphysics (i.e., size and number of cloud droplets) and near-surface aerosols (i.e., size and number of atmospheric aerosol particles). Marine aerosols may be transported from land sources or generated locally by sea spray and gas emissions from oceanic plankton. These simultaneous observations will permit the first direct measurements of aerosol effects on the reflectivity and precipitation of marine stratus clouds. The observations draw on ESRL's unique strength in remote sensing of cloud properties with Doppler radar, lidar, and microwave radiometers.

Significance:
The southeastern Pacific Ocean is an important climatic region where the interactions between the atmosphere and ocean affect regional and global climate variability. Present climate models have well-known sea surface temperature biases in stratocumulus regions, which are believed to be partly related to overly simplified treatments of cloud and air-sea interaction processes. This research supports NOAA's climate goal by providing better understanding of the effects of persistent stratus cloud coverage on ocean temperatures in order to improve climate models and predictions.

Contact: Chris Fairall