BERM (Basin Excess Rainfall Map)
Available Tools
The GeoWRSI is a geo-spatial, stand-alone implementation of the Water Requirements Satisfaction Index (GeoWRSI), as it is implemented by the USGS for the FEWSNET Activity. The program runs a crop-specific water balance model for a selected region in the world, using raster data inputs. The program produces a range of outputs which can either be used qualitatively to help assess and monitor crop conditions during the crop growing season, or can be regressed with yields to produce yield estimation models and yield estimates. Other tools are available to post-process the GeoWRSI outputs so that they can be used in yield estimation models.
The GeoCLIM is a spatial analysis tool designed for climatological analysis of historical rainfall
and temperature data. The GeoCLIM provides non-scientists with an array of accessible analysis
tools for climate-smart agricultural development. These user friendly tools can be used to obtain
and analyze climate data, blend station data with satellite data to create more accurate datasets,
analyze seasonal trends and/or historical climate data, create visual representations of climate
data, create scripts (batch files) to quickly and efficiently analyze similar “batches” of climate
data, view and/or edit shapefiles and raster files, and extract statistics from raster datasets to
create time series.
The Early Warning eXplorer (EWX) software is an interactive web-based mapping tool that allows users to visualize continental-scale rainfall estimate (RFE), land surface temperature (LST) and normalized difference vegetation index (NDVI) data and anomalies at varied time steps and review time series analyses.
The Early Warning eXplorer (EWX) Lite software is an interactive web-based mapping tool that allows users to visualize time series of rainfall, NDVI, evapotranspiration, land surface temperature and snow water volume, where applicable. The EWX Lite allows users to access the same time series database that drives the standard EWX without having to load raster imagery which can inhibit performance in areas with poor internet connectivity.
Product Documentation
A simple method for identifying areas subject to problems of flooding or excess moisture has been developed through the joint use of satellite rainfall estimates (RFE) and digital maps of basin boundaries and river networks. Maps are produced which highlight basins experiencing above-average rainfall in the previous ten-day period, and river reaches with potentially higher-than-average stream flow. NOAA has produced RFE images (Herman et al., 1997) on a dekadal (10-day) time step for FEWS NET since 1995. The images are composed of 0.1-degree (about 10 km) pixels whose values are the estimated number of millimeters of accumulated rainfall for the dekad. A straightforward application of these images has been their use in conjunction with USGS digital maps of basins and river networks. These have been derived from 1-km resolution topographic data, and are part of a topologically coded (Verdin and Verdin, 1999) global data set known as HYDRO1K. Rainfall estimates are summed over river basin areas for each dekad, and cumulatively for the season. These sums are divided by the corresponding values for long-term average conditions (Hutchinson et al., 1995), and excess rainfall scores are assigned to basin areas and river reaches accordingly - the higher the ratios, the greater the scores. Maps are then produced with color codes indicating relative levels of excess precipitation. These products have been named Basin Excess Rainfall Maps (BERMs). BERM products reveal situations of sustained heavy regional rains that adversely affect food security through flooding and consequent widespread disruption of agriculture, transportation, and market systems. The basin (or catchment) map highlights subbasins (out of approximately 3,000 across the continent) receiving above-average precipitation for the dekad, and cumulatively for the season, by color coding the relevant polygons. The river segment (or stream) map highlights reaches of river receiving above-average amounts of dekadal and seasonal cumulative precipitation according to a similar scoring system. The difference is that a reach of river may receive rainfall from a much larger upstream area than that of the subbasin polygon in which it lies. Thus, a subbasin may not be highlighted because only light rain is occurring locally, while the reach of river passing through it is highlighted, due to heavy rains in upstream catchments. References Herman, A., V. Kumar, P. Arkin, and J. Kousky. 1997. Objectively determined 10-day African rainfall estimates created for famine early warning systems. International Journal of Remote Sensing, v. 18, n. 10, 2147-2159. Hutchinson, M., H. Nix, J. McMahon, K. Ord. 1995. Africa - A topographic and climatic database. Centre for Resource and Environmental Studies, Australian National University, Canberra, CD Version 1.0. Showstack, R. 2000. Scientists and planners look for ways to stem future flood disasters in Mozambique. EOS, Transactions, American Geophysical Union, v. 81, n. 13, 133-137. Verdin, K., and J. Verdin. 1999. A topological system for delineation and codification of the Earth's river basins. Journal of Hydrology, v. 218, 1-12. |