Supporting Data for MODIS Aqua L2 SST Correction Project

This dataset consists of two parts:

A) Three data objects needed to ‘fix’ several issues associated with the L2 sea surface temperature (SST) dataset obtained from the MODIS Aqua instrument by the Ocean Biology Processing Group (OBPG) at NASA’s Goddard Space Flight Center. These files are required by the Matlab script, build_and_fix_orbits.m, in the GitHub repo git@github.com:pcornillon/MODIS_L2.git. This script ‘unmasks’ pixels improperly flagged as bad in the vicinity of large SST gradients and those flagged as bad because the difference between the retrieved SST and a reference field exceeds a given threshold. The script also regrids the L2 fields to compensate for the bow-tie effect, which tends to jumble the pixel locations in the along-track direction. The files are:

1) weights_and_locations_from_31191.mat - used to correct for the bow-tie effect.

2) SST_Range_for_Declouding.mat - are monthly climatologies of the minimum and maximum temperatures in 5x5 degree cells determined from the MODIS Aqua L2 SST dataset for 2002-2019. These fields are used to unmask pixels flagged as cloudy based on the reference SST test. The original test used was for a fixed SST range independent of time-of-year and location.

3) Separation_and_Angle_Arrays.n4 - a file containing several fields, one for the along-track separation of pixels at each pixel location, a second for the along-scan separation and a third for the angle the perpendicular to the scan line makes counterclockwise of east. These data are used to determine the eastward and northward components of the SST gradient determined from the 'fixed' SST fields.

B) A set of files used to test build_and_fix_orbits.m. These files are contained in four folders zipped into one file, MODIS_R2019.zip, plus the output file, AQUA_MODIS.20100619T052031.L2.SST.nc4, written by build_and_fix_orbits.m. The .zip file contains the data for one complete MODIS Aqua orbit beginning at 05h20 GMT on 19 June 2010.  The folders in this file are: 

1) Data_from_OBPG_for_PO-DAAC - metadata files copied from a portion of the OBPG SST granules.

2) Day - daytime granules obtained from the OBPG’s web site.

3) Night - nighttime granules obtained from the OBPG’s web site.

4) Orbits - a files indicating which OBPG granules make up individual orbits for June 2010