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Atm Profile Data Issues

Tracking of known problems and subsequent fixes is an important issue for MODIS data users. This page will act as a repository of all known MODIS Atmosphere Data Product problems, as well as how to determine the problematic version (and the fixed version) of the HDF data -- therefore data users should check this page for updates regularly. Data Users unfamiliar with how to properly track problems and fixes by determining the version of their downloaded HDF files should refer to the documentation at the bottom of this page.

Incorrect Terra IR Water Vapor Profiles from Band 27 Crosstalk

Description: 

Description: April 2016 update from PGE03 developers: A band 27 cross-talk problem, that increased (and became more pronounced) over time starting around 2010, produced incorrect IR Water Vapor profiles, with artificially low moisture content in the middle atmospheric layer and excessively high values in the upper troposphere. The MCST is still investigating possible fixes for this problem. Users should note that the IR Water Vapor profile data is in an SDS called "Water_Vapor", "Water_Vapor_Low", and "Water_Vapor_High" in the 07_L2 file.

PGE Versions & Production Dates of Problematic & Corrected Data:

Problematic Data Corrected Data
PGE Versions Production Dates PGE Versions Production Dates
All ≥ 2010 001 (1/1/2010) Not Corrected Not Corrected

Data Dates Affected: January 2010 and on (but worse 2014 and on)

Affected Platform: 
Terra Only
Products Affected: 
Collections Affected: 

Unstable Atmospheric Profile Retrievals over Antarctica

Description: 

In collection 006, the cloud mask is failing to detect high thick clouds over the Weddell Sea area when it is ice-covered. This represents a small area over very dry conditions, but it is causing high and noisy retrievals (high standard deviation) in the integrated water vapor values (440-10 hPa) and unrealistic values in the Retrieved Temperature Profiles and Total Ozone. These problem pixels can be filtered out by users with additional sanity checks until it is fixed in the future PGE03 delivery.

PGE Versions & Production Dates of Problematic & Corrected Data:

Problematic Data Corrected Data
PGE Versions Production Dates PGE Versions Production Dates
≤ PGE03 v6.0.40 All Not Corrected Not Corrected

Data Dates Affected: July 2002 to present

Affected Platform: 
Aqua Only
Products Affected: 
Collections Affected: 

Suspect Atmosphere Profile Retrievals at Night

Description: 

There was a problem in the Collection 6 (C6) Atmosphere Profile Product for nighttime data only. In the nighttime granules, an error occurred in selecting the proper GDAS (NCEP 1-Degree Global Data Assimilation Model) re-analyses ancillary data file. Instead of selecting the file closest in time with a less than 3 hour time differences between the GDAS time and the granule time, the algorithm selected the wrong GDAS file time resulting in as much as a 6 hour time difference. The MOD07 algorithm uses the surface pressure variable of the GDAS reanalyses to determine the lowest level of the atmospheric temperature, moisture, and ozone profiles. To set the lowest level as accurate as possible is very important for integrating the water vapor content of the column and the layer mean of water vapor close to the surface. The error affected the 07 L2 SDS's "Surface_Pressure", "Water_Vapor", "Water_Vapor_Low" as well as levels of the Temperature Profile and Moisture Profile close to the surface. The values were just "marginally off" but affected all granules globally.

PGE Versions & Production Dates of Problematic & Corrected Data:

Problematic Data Corrected Data
PGE Versions Production Dates PGE Versions Production Dates
≤ PGE03 v6.0.39 ≤ 2014 182 (7/1/2014) ≥ PGE03 v6.0.40 ≥ 2014 190 (7/9/2014)

Data Dates Affected: July 2002 to July 2014 (Nighttime Granules only)

Affected Platform: 
Aqua Only
Products Affected: 
Collections Affected: