MODAPS PCR 22-001

PCR Number 22-001
Date 2021-02-07
Initiator Sudipta Sarkar, Huilin Gao
Abstract PGE187 6.1.4

When the area is zero or is an outlier (due to contamination), the fetch and lake depth values may be abnormal. Thus, in these cases, just use prescribed fetch length and prescribed depth.

Problem Statement  
Description of Change This current version of PGE187 (V6.1.4) eliminates unrealistic evaporation peaks (>=15 mm/d) found at some reservoirs during some years. There were some area errors and uncertainty of the area-elevation curves, which resulted in the earlier erroneous depth values, resulting in an unrealistic evaporation rate. In the new code, the calculated dynamic depth at a reservoir is replaced with a constant depth (i.e., depth_at_capacity). Such correction allows the evaporation values stay within the realistic ranges
Products Affected Monthly global water reservoir evaporation volume, MOD28C3/MYD28C3
Software Affected PGE187 6.1.4
Processing String to Receive the Change Terra and Aqua Forward Processing. Terra and Aqua Reprocessing.
Downstream Product Effects None.
Data Granules to be Used for Science Testing A science tests was carried out in AS 1883 to confirm all changes made in this PGE, and the results were reviewed by LDOPE, and the science team and science team approved the use of this code for C61 reprocessing.
Justification This will mitigate occurrences of erroneous evaporation rate values over some reservoirs for some periods of the mission. Reprocessing is required to produce temporally consistent data records for this collection.
Effective Date for Implementation of Change Effective immediately, the said PGE will be used for C61 re-processing as well as forward-processing.
Status Major algorithm development completed. Sadashiva Devadiga approved 02/15/2022.