CPD3 Frequently Asked Questions

Organization and General Information

What are the sections of this FAQ

Where can I find additional information

See http://www.esrl.noaa.gov/gmd/aero/about/faq.html for general aerosol system questions.

See CPD2 FAQ for questions about the CPD2 system

See CPD2 records and CPD2 variables for information about record and variable names and definitions in the CPD2 system. CPD3 uses a different internal approach to representing data, although many of the CPD2 names of records and variables can still be used. See CPD3 data structures for variables used in CPD3.

See CPD3 programs and database for a list of programs available in CPD3 database system.

Detailed help on any CPD3 program is available by supplying the –help argument, and detailed help on any argument is available by using the –help=argname argument, for example

da.export --help
da.export --help=count

In this document “$STATION” refers the the lower case station code (e.x. “mlo”) of the station in question.

Commonly-used Programs

General data access

Editing data

  • da.edit - To view and edit data using the CPX3 graphical user interface (alias to cpx3).
  • da.pass - To pass data into the clean archive.

Viewing data

  • cpx3 - General purpose data viewer.
  • da.show.* - Family of programs for viewing data on the screen
  • da.plot.* - Like da.show.* counterparts, but writes the plot to a file instead of the screen

Getting Information about Data and Instruments

How do I get a list of all the variables available from a station

da.summary.general spo everything forever raw_meta
da.summary.general --description spo everything 2016 raw_meta
da.summary.general --description spo '.*_A82' 2016 raw_meta

How do I get a timeline of instrument availability

da.summary.timeline --interval=1mo --timeline=vertical bld everything 2015 now raw_meta
da.summary.timeline --interval=1y mlo everything forever raw_meta

How do I get general information on data availability

da.summary.general --mode=variable --description spo '.*_A81' 2014

How do I calculate summary statistics for a specified time interval (e.g., overnight nephelometer zero check)

da.summary.general --rows=flavorless thd 'B.*_S11' 51.1 51.72

How do I examine the user entries in the on-line message log

cpd3messagelog bnd 1w now

Editing Data

How do I bring up the Mentor Edits window without loading a lot of data

The easiest way is to load the averaged data, which goes quickly.

cpx3 bnd 2016-05-01 1mo avg

Alternatively, you can use one of the alternative data profiles that only includes a few variables, or that may not include any variables for your station.

cpx3 --profile=met bnd 2016-05-01 1mo  

If you use the latter approach, you need to click on the “Display” button in the Edit Directives window and select “Display all profiles”.

How do I interpolate across a gap in the data

This is done with a script edit, triggered by a flag that is associated with the data gap.

The code below implements an interpolation edit. It is entered in the “Script” window for a mentor edit of type “Script Code General Handler”. The variable to be edited is selected in the “Input” window (BeB_E11 for the example here).

var valueBeforeGap = undefined;
var timeBeforeGap = undefined;
var inGap = false;

include('Interpolation');
data.install_value(function(point) {
    if (inGap) {
        if (ndefined(point.value)) {
            var interpolator = new CPD3.Interpolation.Linear(
                    [timeBeforeGap, point.start],
                    [valueBeforeGap, point.value]);
            for (var i=0; i<data.length; i++) {
                var modify = data[i];
                if (ndefined(modify.value))
                    continue;
                modify.value = interpolator.value(modify.start);
            }
            inGap = false;
            data.releaseAll();
            data.autorelease = 0;
        }
    } else {
        if (ndefined(point.value)) {
            valueBeforeGap = point.value;
            timeBeforeGap = point.start;
        } else {
            inGap = true;
            data.autorelease = undefined;
        }
    }
})

Next, the trigger conditions for activating the script need to be specified. For the example here, the blue channel from a CAPS extinction monitor (E11) is to be interpolated across gaps when the flags “Zero” or “Blank” are set. Because there are two triggers, the trigger is of type “Logical OR”. A symmetric extension of 1 minute is specified to include the valid data points at the start and end of the data gap. The “Add” button is clicked twice to add the two logical conditions that comprise the trigger, and the type of each logical condition is “Flags”. The flag variable for both logical tests is F1_E11 for the example here. Clicking on the “Flags” button allows the flag name to be entered (“Zero” for the first logical test, and “Blank” for the second logical test). The resulting screen for the trigger edit is shown below.

The raw data (with gaps) and edited data (interpolated across gaps) are shown below for three CAPS instruments, which required separate edits for each wavelength.

Working with Data

How do I exclude the summary statistics from averaged data

This is done in da.export, not da.avg

... | da.avg ... | da.export —stddev=0 —count=0

How do I calculate the average of all the data, i.e., not broken up into blocks

... | da.avg —interval=undef | ...

However, special handling is needed if there are breaks in the data, e.g., nephelometer zeros or cut-size changes, because CPD3 was designed to “do the right thing” by default, so it ends up being complicated when you want to override the intelligence. Normally, da.avg will break the data into hourly averages because the metadata for the zeros specifies that they shouldn't be averaged (normally correct, you don't want zeros being folded into hourly averages if you put the two together, since the zero specify “segments” rather than values). Use da.select to handle this special case:

... | da.select --path="^Smoothing" --path-apply=:raw_meta: --explicit-meta=true --path-remove=true | da.avg --interval=undef | ...

How do I select data for a particular time period from an input file

da.select --include=.*,2012:1,2012:2 inputfile.cpd3

How do I select a particular variable from a data stream

... | da.select --include=X1c_A81 | ...

How do I remove the size-cut distinction from variables in a data stream

... | da.select --include=':::cover:!' --set-flavor-remove=cover | ...

–alternatively–

... |da.select --set-flavor-remove=pm1 | da.select --set-flavor-remove=pm10 | ...

How do I exclude nephelometer data when in zero or blanking mode

... |da.where --exclude='F1_S11.hasFlag("Zero") || F1_S11.hasFlag("Blank")' | ...

How do I include only nephelometer data where RH>40%

... | da.where --include='U_S11 > 40' | ...

How do I calculate absorption coefficients with the CTS correction

da.generate.edited --profile=cts bnd 2015-01-01 2015-01-02 | da.select --capture-variable='(.*)_A1(.)' --set-apply='.*_A(.+)' --set-variable='${1}_A9${2}'

This will create new virtual instruments A9x representing the CTS-corrected data from all A1x instruments.

It is possible to merge the virtual instruments back into the CPD3 data stream for combined analysis, e.g., compare the Bond and CTS corrections.

da.mux \
"|da.get bnd '.*_A11' 2015 clean" \
"|da.generate.edited --profile=cts bnd 2015 \
  |da.select --exclude=:avg: --capture-variable='(.*)_A1(.)' --set-apply='.*_A(.+)' --set-variable='${1}_A9${2}'" \
> mergeddata.cpd3
da.show.density --x=BaG_A11 --y=BaG_A91 mergedata.cpd3

For efficiency in doing further analysis, it is recommended to save the results of the da.mux program to a working file.

How do I merge data from multiple CPD3-format files

da.mux file1.cpd3 file2.cpd3 file3.cpd3 | ...

Plotting and Analyzing Data

Project-specific Questions

What is the percentage of hours that the nephelometer RH was above 40% at EGB and is there any any seasonal dependence

data.get egb S11a 2010 2014 avgh | da.select --include=U_S11 | da.where --include='U_S11 > 40' | da.avg --interval=1mo | da.select --include=':::cover:!' --set-flavor-remove=cover | da.export

Change the –interval=1mo to –interval=undef to get a single coverage number for the whole time.

Is there any annual cycle in the % of hours for which Bsp(PM1) < 1.0 Mm-1 at EGB

data.get egb S11a 2010 2014 avgh | da.select --include=::BsG_S11:pm1 | da.where --include='BsG_S11 < 1' | da.avg --interval=1mo | da.select --include=':::cover:!' --set-flavor-remove=cover | da.export

How do I calculate run averages from a lab experiment

Use the “–mean” switch to da.export to have it output unweighted means from the statistics calculation when available. When it's not available (no averaging done) it will output the conventional values instead.

da.generate.edited --profile=aerosol_native `query.run 2` |da.select --include="Ba[BGR]_A1[145]" |da.avg --interval=undef |da.export --mean |transpose

This bash script provides an alternative approach.

#!/bin/bash

RUN=7
TIMES=`/aer/sfa/work/GMD_lab_absorption_study_2015/runs/query ${RUN}`

echo '<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE cpd3data>
<cpd3data version="1.0">    
    <value station="sfa" archive="segment" variable="run" flavors="" 
            priority="0" type="" 
            start="'${TIMES/%\ */}'" end="'${TIMES##* }'">
    </value>
</cpd3data>' |
    da.multiplex "| da.generate.edited sfa ${TIMES}" - | 
    da.smooth.segment --segment=':segment:run' |
    da.select --include=':clean:BsG_S11' |
    da.export

Acquisition System

Configuration

How do I view the local configuration?

da.config.text bnd acquisition 1d now configuration