The NOAA-20 Visible Infrared Imaging Radiometer Suite (VIIRS) Water Reservoir Monthly Level 3 (L3) Global (VJ128C3) Version 2 product provides current data for 151 man-made reservoirs and 13 regulated natural lakes for a total of 164 reservoirs.

The VJ128C3 data product is a composite of the 8-day area classifications from VJ128C2 which is converted to provide monthly elevation and water storage. The Lake Temperature and Evaporation Model (LTEM) with input from VIIRS Land Surface Temperature and Emissivity (VJ121A2) and meteorological data from Global Land Data Assimilation System (GLDAS) are used to produce monthly evaporation rates and volume losses.

The VJ128C3 data product provides a monthly time series that consists of a single layer with information about the reservoir identifier, dam location (longitude and latitude), reservoir surface area, elevation, water storage capacity, evaporation rate, and evaporation volume.

Known Issues

• Water occurrence images generally show smaller surface area dynamics in high latitude regions, creating pixels with low occurrence values that have relatively large uncertainties. In addition, the quality of raw water area classification can be affected by lake ice coverage typically creating an overestimation of surface area in the enhancement algorithm. This issue will be addressed in a future release of the enhancement algorithm. For additional information about known issues, refer to Section 4 in the User Guide.