It is well-known that the Chesapeake Bay is a troubled estuary, beset by worsening problems caused by pollution and the increasing human presence adjacent to its hundreds of miles of coastline. Chesapeake Bay has experienced oyster die-offs, overfishing, increasing eutrophication, and a host of pollutant incursions; the latter can be due to agriculture (excess nutrients from fertilizer and manure) or urbanization and sprawl (producing more unfiltered stormwater runoff caused by expanding areas of impervious surface).
The Better Assessment Science Integrating Nonpoint Sources (BASINS) is a decisions support tool created by the United States Environmental Protection Agency (USEPA). BASINS includes the Hydrological Simulation Program - Fortran (HSPF), which "computes continuous streamflow rates and pollutant concentration at each basin outlet" (Nigro et al. 2010). HSPF utilizes precipitation data from weather stations, which may be located at a considerable distance from the actual watershed.
In a paper recently published in the Journal of Environmental Quality, Joseph Nigro and his colleagues investigated if the BASINS-HSPF results could be improved by substituting data from two NASA data assimilation products: the North American Land Data Assimilation System (NLDAS) and the "Stage IV 4 km precipitation", which consists of hourly 4 km precipitation values derived by the NOAA River Forecast Center Multisensor Precipitation Estimator (MPE). Each of these products utilizes remotely-sensed data as input. NLDAS uses satellite data to drive the analyses of land surface models (LSMs), while MPE currently uses weather radar and stream gauge data to simulate satellite precipitation estimates from the Tropical Rainfall Measuring Mission (TRMM) and other satellites. Both products are used as input data for the Land Information System (LIS) software (Kumar et al. 2006). Seven sub-watersheds in the Chesapeake Bay watershed were examined in this research study.
According to Space Daily, the use of the NASA model data inputs "dramatically" improved the water quality model performance over the results obtained when weather station precipitation data were used. In particular, improvement was noted in the summer, when storm events are the primary source of precipitation.
BASINS-HSPF is collaborating with the GES DISC to utilize NLDAS-2 data. The GES DISC now has a Grid Analysis and Display System (GrADS) data server (GDS) that serves both parameter- and latitudinally subsetted NLDAS-2 primary forcing precipitation data. BASINS users can download 30-year single grid precipitation time series via a GDS request.
The GES DISC collaboration is noted at the end of the Nigro et al. (2010) paper; see reference below.
Reference: Joseph Nigro, David Toll, Ed Partington, Ni-Meister Wenge, Shihyan Lee, Angelica Gutierrez-Magness, Ted Engman, and Kristi Arsenault (2010) NASA-Modified Precipitation Products to Improve USEPA Nonpoint Source Water Quality Modeling for the Chesapeake Bay . Journal of Environmental Quality, 39(4), 1388-1401, doi: 10.2134/jeq2009.0161
URL for GES DISC GrADS Data Server - NLDAS products: http://hydro1.sci.gsfc.nasa.gov/dods_TS/
NLDAS forcing data are currently available from Mirador; more NLDAS data will be available in the future. Data from the Global Land Data Assimilation System (GLDAS) are available in Mirador and Giovanni.
Supplemental reference: Kumar, S.V., C.D. Lidard, Y. Tian, P.R. Houser, J. Geiger, S. Olden, L. Lighty, J.L. Eastman, B. Doty, P. Dirmeyer, J. Adams, K. Mitchell, E.F. Wood, and J. Sheffield (2006) Land Information System: An interoperable framework for high
resolution land surface modeling. Environmental Modelling & Software, 21, 1402–1415.