ER-2 Cloud Physics Lidar

During the SAFARI-2000 campaign of August-September 2000, over 120 hours of CPL flight data were collected. Data processing is proceeding, although we were hampered by lack of navigation data. A software programming glitch (since fixed) caused the nav data to be missed. As a fix, we were able to go back and add the nav data to the data records, with an accuracy of about +/- 10 seconds. Final impact on data processing will be small.

Following is a status of CPL data processing algorithms for each of the primary CPL data products:

1. Creation of Normalized Relative Backscatter (NRB) data sets

· All instrument corrections incorporated.

· Polarization ratio algorithms complete.

· 1-second profile standard deviation algorithm is complete.

· Initial calibration analysis algorithm is complete.

· Saturation condition algorithm in progress.

2. Creation of Layer Boundary and Layer Type data sets

· Layer boundary search algorithm becoming mature. Cirrus and mid-altitude cloud search works well.

· Ground detection/separation algorithm mature.

· Layer aerosol/cloud discrimination algorithm in progress. Processing samples of SAFARI data to build up statistics for aerosol/cloud thresholds.

3. Creation of Quick-Look Images

· Flight summary image algorithm is complete.

· 30-minute segment images (4 strips) algorithm in progress.

4. Creation of Optical Properties data sets

· Final calibration algorithm is complete.

· Ingest of ancillary S-ratio and optical depth information algorithm is complete.

· Default S-ratio algorithm is complete.

· Cirrus zone processing algorithm is complete.

· Cloud-cleared PBL processing algorithm is complete.

· Full (all layers) processing algorithm is complete (includes extinction profiles).

· Error analysis algorithm for optical properties is complete.

· All algorithms have been debugged with 2-hour segments of SAFARI data, but have not yet been quality checked against a known simulated data set.

· Algorithms to plot/display optical properties are completed for cirrus zone optical depth, PBL optical depth, total column aerosol optical depth, total column cloud optical depth, total combined optical depth.

5. CPL Web Site Development

· The CPL home page is operational ( http://virl.gsfc.nasa.gov/cpl/ ) but does not yet have links to data. Ultimately, this web site will be the primary means of data distribution.

· Methods to download the large NRB or optical data sets are being tested.

We estimate that final processing of SAFARI data will begin on or about June 1. Once final processing begins, all data can be processed in 3-4 weeks. A sample of processed backscatter data is shown in Figure 1. The corresponding optical depth is shown in Figure 2.