--------------- MODIS PRODUCTS v1.8 ---------------------------------- Date: July 2005 Version: MODIS Level-2 Products v1.8 Changes: Significant improvements have been made to the MODIS processing algorithms of cloud mask (MOD35), cloud top properties and cloud phase (MOD06CT) and atmospheric profiles (MOD07). These updates make the code compatible with the Collection 5 DAAC products. A short list of the improvements include: Cloud Mask: Improvement of cloud retreival in sun-glint, nighttime and high latitude regimes. Code now requires the gdas and sst ancillary files to be used as input. Cloud Top Properties: New 101 level forward model is now used. New coefficient files are required. The numerical data month must now be used as an input argument SST files are now used as input to improve the estimation of the surface temperature. Profiles: Updates to the training data used to create the regression coefficients, including new profiles and better characterization of the surface. Ancillary: extract_ncep_gdas1.csh now extracts 54 fields out of the grib file instead of 30. These extra fields are used by the cloud top properties software. NISE files sizes are now 218 MB instead of the former 222 MB. -------------------------------------------------------------------------- --------------- MODIS PRODUCTS v1.7 ---------------------------------- Date: December 2004 Version: MODIS Level-2 Products v1.7 Changes: First Near-Infrared water vapor retrieval processing software. -------------------------------------------------------------------------- --------------- MODIS PRODUCTS v1.6 ---------------------------------- Date: September 2004 Version: MODIS Level-2 Products v1.6 Changes: 1) First IMAPP aerosol retrieval software release. This direct broadcast aerosol release is concurrent with DAAC MOD04 operational version v4.01. Only 6 Science Data Sets are included in the output file: Latitude Longitude Optical_Depth_Land_And_Ocean - AOT at 0.55 micron for both ocean (best) and land (corrected) Optical_Depth_Ratio_Small_Land_And_Ocean - Ratio of small mode optical depth at 0.55 micron Corrected_Optical_Depth_Land (3 bands) - Corrected optical thickness at 0.47, 0.55, and 0.66 micron Effective_Optical_Depth_Average_Ocean (7 bands) - AOT at seven bands for average solution at .47, .55, .66, .86, 1.2, 1.6 and 2.1 micron 2) Updated ANCILLARY.tar file. Includes a new script extract_tovs_ozone.csh which unpacks the TOVS total ozone ncep grib file needed to run the aerosol software. 3) Updated FLATFILE.tar file. Includes a new 500m extractor that is required to run the aerosol software. 4) Locations of wgrib ancillary data utility, freelook visualization software and HDF binary and source files have been updated in the README sections of the new ANCILLARY, FLATFILE and AEROSOL releases. -------------------------------------------------------------------------- --------------- MODIS PRODUCTS v1.5 ---------------------------------- Date: January 2004 Version: MODIS Level-2 Products v1.5 Changes: 1) First IMAPP sea surface temperature software release. The technique used differs from the official DAAC MOD28 product. -------------------------------------------------------------------------- --------------- MODIS PRODUCTS v1.4 ---------------------------------- Date: September 2003 Version: MODIS Level-2 Products v1.4 Changes: 1) Terra and Aqua compatible versions of the atmospheric profiles software and band 26 destriping. This direct broadcast profiles release is concurrent with DAAC atmospheric profiles MOD07 operational version 4.1.0. -------------------------------------------------------------------------- Changes from previous version. This release of the profiles software contains these changes from imapp level 2 version v1.2: The software now works for both Aqua and Terra datasets. There is a Satellite Platform Keyword required as input to run the algorithm and the modis_profiles.csh script. Coefficients and bias corrections are chosen based upon the satellite platform name. The modis_profiles.csh script had been modified to include a call to destripe the band 26 data. This is not required, but the thin cirrus detection in the cloud mask algorithm will work correctly when this is used. The modis_profiles.csh has also been changed to point to certain directories when locating data sets. Follow the !!! symbols to direct you to what needs to be modified to work operationally on your system. The IDL routine create_fake_mod07.pro has been updated to change the bottom limit of good values for Lifted_Index. It had been set incorrectly to -10 and has been changed to -20. Science Algorithm changes - Suzanne Wetzel Seemann June 2003 1. Changes to the Regresion Coefficients & Training Data --------------------------------- a. Updated the forward model codes and coefficients used in computing radiances from the training profiles with with the latest version using the HITRAN2000 spectral database. New hdf coefficient filenames are: MODIS_Aqua_regcoef_2003_06_02_header.hdf MODIS_Terra_regcoef_2003_06_02_header.hdf b. Modified the TPW integration routine to handle the levels closest to the surface better. c. Removed band 24 from the regression equation. Due to the improved emissivity data used in training the regression, we no longer need to use the difference 25-24, and removing this differencing reduces noise due to striping. Band 24 also introduced uncertainty because of a solar reflective component to the signal that was particularly obvious in calculating radiance observed minus calculated bias for this band. d. Improved emissivity assigned to profiles in training data. Using emissivity data from UCSB's MODIS emissivity library, representative emissivities for ocean, land, desert, and snow/ice were developed. These emissivities were applied to the training data, +/- a random number of standard deviation from 0.01 to 0.03 depending on variability within the ecosystem data base. Emissivities were limited to 0.99. Previously, only two different emissivities were assigned to the profiles: 0.95 for 13-9 microns, 0.84 for 4.75 to 3 microns, and linear in between. e. New frequencies were used to better represent the emissivity spectra. Old wavelengths were 13, 11, 9, 4.75, 4, 3.5, and 3 microns. The range of wavelengths for the MODIS bands used in this algorithm is 14.3-4.4 microns, so some of these frequencies were not relevant to our data. New wavelengths are 14.3, 10.8, 9.3, 8.3, 7.6, 5.0, and 4.3 microns (700, 926, 1075, 1205, 1316, 2000, 2326 wavenumbers). These were chosen at inflection points of significant changes in emissivity spectra. 2. Changes to the MOD07 Science Code --------------------------------- a. db_mod07_compute_products.f Skin temperature retrieved by regression is now being saved into the 'Surface_Temperature' variable. Previously the ancillary input GDAS surface temperature had been saved to this variable. Bias corrections are now read in from an ascii file, instead of hardwired into the code. An 'init_bias' parameter is set so we only read the bias files once. Depending on the flag set in the bias input file, the radiance bias corrections can be a linear function of GDAS TPW (flag = 2) or MODIS brightness temperature (flag = 1). If any other flag is given, no biases are applied to the radiances. This replaces the earlier latitude-dependent bias corrections. Bias slope and y-intercept are read in for each band and applied to the GDAS PWAT or brightness temperature. An optional min and max bias can also be input as 3rd and 4th columns in the bias input file. To reduce noise due to detector striping, arrays of detector flags (10 for each band) are read in from an ascii file. If a detector for a specific band is flagged with a 0, radiances from this detector are skipped in the retrievals. Parameter averaging: Now, only those zenith angle, latitude, surface pressure, elevation, and GDAS TPW values corresponding to pixels with box_flag == 1 (clear sky) are averaged. Previously, the center value in a 5x5 retrieval area was used, regardless of which pixels were actually used in the retrieval. This is important when some pixels in a 5x5 are not retrieved. Added a provision to only skip the first 10 pixels of each radiance scan line if the data was from Terra (included platform_name.inc to access platform_name variable). These pixels are skipped on Terra due to errors introduced by a cross-talk correction. Problem does not exist on Aqua. b. db_modis_ges101.f A change was made in the way surface level is handled when integrating moisture profiles to obtain TPW. Included variable for retrieved surface skin temperature. New coefficient version number in check of file header. Band 24 was removed from the regression, as well as the predictor BT25-24. c. Other files New subroutine, db_get_coeff.f to read bias values and detector flags. Subroutine db_get_sfcpres_pwat.f replaces old db_get_sfcpres.f. New adds GDAS TPW. Subroutine tprecw_new2.f replaces tprecw.f for new surface handling in TPW integration. Note that layer PW is still integrated using precwv.f. Small changes made in the following files to accommodate the new pwat1 variable (GDAS TPW): db_mod07_check_box.f - QC check of pwat (0-110 kg/m^2) db_mod07_get_data.f - added pwat1, and new call to get_sfcpres_pwat instead of get_sfcpres db_mod07uw_data.inc - added pwat1 (GDAS precipitable water for TPW dependent biases) to mod07 common block Bias and detector informationa added to profiles.inc file. 3. New ancillary files for bias and detector flags --------------------------------- Ascii files containing new radiance bias values and detector flags were added. Filenames are: Terra_bias.dat, Aqua_bias.dat Terra_det.dat, Aqua_det.dat The profiles.cfg file has been updated to include these files. a) format of bias file LINE 1: String containing platform name, version number, and date Current version number for both Aqua and Terra is 2.0. LINE 2: String containing platform name: Terra or Aqua (caps important). LINE 3: Number of bands, number of columns, flag to indicate bias is a function of MODIS BT of that band (1) or NCEP-GDAS TPW (2). if any other flag is given, no biases are applied to the radiances. Biases are OBSERVED minus CALCULATED in degrees K. Number of columns does not including band number itself If 2 columns after band number, these columns are: slope, y-intercept If 4 columns after band number, these columns are: slope, y-intercept, min, max Bias determined by: bias(band X) = slope * TPW + y-intercept [or BT of band X instead of TPW] then bias values > max are set equal to max and similar for min b) format of detector file LINES 1-2 same as for bias file above LINE 3: number of bands, number of detectors, flag not currently used LINES 4-end: band number, detector flag for each detector detector flag = 1 for good, or = 0 to skip -------------------------------------------------------------------------- --------------- MODIS PRODUCTS v1.3 ---------------------------------- Date: January 2003 Version: MODIS Products v1.3 Changes: 1) Terra and Aqua compatible. Platform name a required input for flatfile extractions, cloud mask and cloud top properties execution. See the text below for more explicit details on the changes made in this release. This direct broadcast cloud mask release is concurrent with DAAC cloud mask operational MOD35 version 4.2.0. This direct broadcast cloud top properties and cloud phase release is concurrent with DAAC MOD06CT version 4.0.4. 2) Software release to correct striping in Band 26 (1.38 micron) called DESTRIPE_BAND26.tar 3) To reduce the size of the software tar files, test data is no longer included in the product data directory. Test input data is available separately from the ftp site. This means that the modis_cloudmask.csh script has been modified to look for data in new locations. -------------------------------------------------------------------------- This release of the CLOUD MASK contains several changes from version v1.1: The software now works for both Aqua and Terra datasets. There is a Satellite Platform Keyword required as input to run the algorithm and the modis_cloudmask.csh script. This also means there are separate Aqua and Terra thresholds files. There are checks in the software to make sure that the Platform Keyword and the thresholds file used are consistent. The modis_cloudmask.csh script had been modified to include a call to destripe the band 26 data. This is not required, but the thin cirrus detection in the algorithm will work correctly when this is used. The modis_cloudmask.csh has also been changed to point to certain directories when locating data sets. Follow the !!! symbols to direct you to what needs to be modified to work operationally on your system. An IDL routine is included in this delievery which can convert the mod35.img and mod35qa.img files into a MOD35 HDF file. Please see instructions for use in the cloudmask/README file. The ecosystem file (goge1_2_img.Z) is no longer included as part of the CLOUDMASK.TAR file. It can be found as a separate file on the ftp site. Changes have have been made to improve the quality of the cloud mask: - Added switch for Aqua vs. Terra processing. Use band 6/7 for calculation of NDSI (snow) for Terra/Aqua and adjusted thresholds accordingly. Added reflectance threshold test for band 6/7 for Terra/Aqua. This is an additional test for screening out cloudy pixels incorrectly identified as snow. - Defined small portion of Greenland to be "high elevation" even though it is below 2000 meters. This to eliminate false clouds generated by the 1.38 um test. - Adjusted daytime, land clear sky restoral test thresholds for Aqua data. - Fixed logic error in polar, daytime processing - very small impact on results.- The nighttime land 3.9-11 um brightness temperature difference (BTD) low cloud test threshold is now a function of the 11-12 um BTD. Allows better discrim- ination between low clouds and clear sky especially in humid atmospheres. - A new 7.3-11 um BTD test for mid-level clouds has been included for nighttime land scenes. Clouds with temperatures in the 240-260K range are sometimes very difficult to detect without solar illumination. - The polar night 3.9-11 um cloud test for snowice surfaces will also be used for other polar night land surfaces not explicitly listed as snow-covered by ancillary data. More low clouds will be identified as a result. - A nighttime land 11 um clear-sky restoral test was introduced. It is similar to the daytime 11 um clear-sky restoral test but uses lower thresholds. Aids in identifying clear-sky pixels. - Fixed minor code bug in get_pxldat.f. The error had little or no impact on quality. -------------------------------------------------------------------------- This release of the CLOUD TOP PROPERTIES and CLOUD PHASE ALGORITHM contains changes from version v1.1: The software now works for both Aqua and Terra datasets. There is a Satellite Platform Keyword required as input to run the algorithm and the modis_cloudtop.csh script. Coefficients and noise thresholds are chosen based upon the satellite platform name. Different noise thresholds are now used for Aqua and Terra. Aqua CO2 channels are less noisy; more co2 slicing solutions are expected as a result. The modis_cloudtop.csh script had been modified to include a call to destripe the band 26 data. This is not required, but the thin cirrus detection in the cloud mask algorithm will work correctly when this is used. The modis_cloudtop.csh has also been changed to point to certain directories when locating data sets. Follow the !!! symbols to direct you to what needs to be modified to work operationally on your system. An IDL routine is included in this delievery which can convert the mod06.img files into a MOD06 HDF file. Please see instructions for use in the cloudtop/README file. --------------- MODIS PRODUCTS v1.2 ---------------------------------- Date: October 2002 Version: MODIS Products v1.2 Changes: Initial release of atmospheric profiles software (MOD07) Note: This release consists of the atmospheric profiles product. No other Level 2 products are included in this release, nor do they need to be updated prior to using this software. This release includes software for use with MODIS Terra data only. ---------------------------------------------------------------------- --------------- MODIS PRODUCTS v1.1 ---------------------------------- Date: May 2002 Version: MODIS Products v1.1 Changes: Initial release of products: cloud mask (MOD35) cloud top properties (MOD06) flatfile extractors ancillary data extractors ----------------------------------------------------------------------