Water forecast is one of the major tasks performed at the USDA-NRCS National Water and Climate Center. The task generates essential information for water resource managers to make effective water usage plans. Water forecast requires the integration of accurate geo-spatial data and rigorous hydrological models. Given that US West's high mountain ranges hold a vast snowpack that provides 50 to 80 percent of the year's water supply, it is important for water forecasters to gain access to timely snow cover information.
SNOw Data Assimilation System (SNODAS) is a modeling and data assimilation system developed by NOAA National Weather Service's National Operational Hydrologic Remote Sensing Center (NOHRSC) to provide the best possible estimates of snow cover and associated variables to support hydrologic modeling and analysis. Currently, daily SNODAS data can be downloaded from NSIDC ftp server in compressed file format. The downloaded data need to be decompressed and processed to be “GIS ready.” Specifically, the decompressed files need to be georeferenced and reformatted before they can be used in GIS software such as ESRI’s ArcGIS.
The main goal of the project is to develop tools and a data sharing environment that streamline the SNODAS Snow Water Equivalent (SWE) data acquisition, pre-processing, and dissemination procedures so that the data are more accessible. The specific tasks are to:
Develop a set of tools to automate the acquisition and compilation of SNODAS SWE data
Create an online SNODAS SWE GIS repository for GIS users
Create a web page for accessing daily SNODAS SWE maps with a web browser
Generate a web service for accessing daily SNODAS SWE with desktop GIS software
With the support from USDA-NRCS NWCC, the Center for Spatial Analysis & Research (CSAR) at PSU has created a set of python scripts for processing NOHRSC SNODAS data, made the daily SNODAS modeled snow water equivalent (SWE) GIS data available on the CSAR ftp server and via an ArcGIS Server web service. Please refer to the SNODAS Tools User's Guide (pdf) for more information.
References:
NOAA - National Operational Hydrologic Remote Sensing Center (NOHRSC) (https://www.nohrsc.noaa.gov/)
National Snow and Ice Data Center (NSIDC) at CU Boulder (http://nsidc.org/).
National Operational Hydrologic Remote Sensing Center SNOw Data Assimilation System (SNODAS) Products at NSIDC (see attachment - nsidc_special_report_11.pdf)