Altimetry data for the operational water level monitoring of lakes and reservoirs.
NASA and USDA/FAS are currently funding a near real time operational program which monitors lake and reservoir water levels. The input is currently satellite-based radar altimetry data sets (NASA/CNES Topex/Poseidon, Jason-1, Jason-2, ERS, ENVISAT, SARAL). In a qualitative sense USDA/FAS utilize the water level products for observation of (a) long term lake level status, for assessment of hydrological drought, (b) near real time lake level status, for assessment of agricultural drought, and (c) near real time lake level status for detection of high water (flood) levels. Both (b) and (c) have potential impact on crop condition and production. ICESAT-2 products would potentially be utilized in two ways, (i) as a primary data source and the operational monitoring of high latitude reservoirs. This assumes a fast delivery of data products with (at least) monthly temporal sampling, (ii) as a secondary (archive) data source for the validation of radar altimetric derived water level products for lakes and reservoirs at all latitudes.
Integration and assessment (both (i) and (ii)) of ICESat-2 products assumes continued funding of the program by NASA and/or USDA and/or additional future stakeholders. USDA/FAS currently utilize water level products in a qualitative, not quantitative sense - there is no direct assimilation of ICESat-2 data into their DSS. However, elevation products are an additional tool within an array of model and remote sensing products that are utilized in a monthly USDA/FAS 'lock-up' process which inputs model/remote sensed data and outputs global crop statistics, advisories and warnings.
The methods of using ICEsat-2 data will follow standard altimetric repeat track techniques, noting additional benefits provided by ICESat-2 data with respect to improved elevation accuracy, improved spatial sampling, and a potential ability to monitor surface levels during freeze-periods (which is currently excluded within the radar altimetry data sets).
Curt Reynolds, USDA/FAS
TBD: USDA/FAS (POC: Dr. Curt Reynolds, Office of Global Analysis)