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Rainfall Runoff Prediction
Designed and presented by George Limpertin association with CARES and Chris Barnett
Mentor: Dr. Neil Fox
Project Goals
● The prediction of rainfall runoff has useful applications to agriculture
● Prediction depends on terrain, soil type, and rainfall amounts
● Terrain and soil type information is already available via existing GIS systems
● Provide rainfall amounts in a form that can be read by existing GIS software
● Create a product that can be used to assist in the prediction of runoff
Precipitation Estimates
● Precipitation estimates are provided by radar estimates
● Over 100 WSR-88D doppler radar sites throughout the country
● Precipitation estimation algorithm takes into account terrain and reflectivity to produce an accurate estimate
● Several precipitation estimates are distributed as level III data
Level III Data
● Four precipitation estimate products– Digital precipitation array
– One hour precipitation estimate
– Three hour precipitation estimate
– Storm total precipitation estimate
● Tradeoff between various products
One Hour Precipitation Estimate
● Radial data
● Resolution of 1 degree x 2 kilometers
● 16 levels
● Good resolution but poor precision
● Provides a range for possible precipitation total
Digital Precipitation Array
● Provides precipitation totals for the past hour
● 256 levels
● Approximately 4 km resolution
● Gridded data
● Good precision but mediocre resolution
● Provides an actual estimate for total precipitation
Level III Data
● Freely available from NWS ftp server
● Available only in a poorly documented format
● Few third party tools for decoding level III data
● NWS ftp server has limited resources and provides slow downloads
Requirements
● Cover the entire state of Missouri if possible
● Nine radar sites needed– Saint Louis
– Pleasant Hill
– Springfield
– Paducah
– Memphis
– Tulsa
– Omaha
– Quad Cities
– Des Moines
Requirements
● Produce an accurate decoding of the data
● Convert the data into a format which is readable by GIS systems
● Provide the data at reasonable intervals
● System should run automatically if possible
● Some faults should be tolerated, particularly radar downtime and network outages
System Structure
● Three modules organized in a linear fashion– First module downloads appropriate data for radar sites
from NWS ftp servers
– Second module decodes the data and converts it to a format which can be read by GIS systems
– Third module uploads data to a computer with GIS software installed
System Structure
● Second module is the most complex and can be further broken down
● Organized into input modules, a core, and output modules
● Input modules responsible for reading in level III data
● Core selects an appropriate input and output module
● Output module produces readable data in a different format
Development Tools
● Cygwin provides a UNIX-like environment on a computer running Windows
● Compiler of choice is gcc
● Output graphics produced by libpng
● Output to shapefiles produced by shapelib
Demonstration
● March 22, 2005
● One hour precipitation total
● Tallahassee, FL
Demonstration
● March 22, 2005
● One hour precipitation total
● Tallahassee, FL
Demonstration
● March 22, 2005
● One hour precipitation total
● Tallahassee, FL
Demonstration
● March 22, 2005
● One hour precipitation total
● Tallahassee, FL
Demonstration
● March 22, 2005
● One hour precipitation total
● Tallahassee, FL
Demonstration
● March 22, 2005
● One hour precipitation total
● Tallahassee, FL
Demonstration
● March 22, 2005
● One hour precipitation total
● Tallahassee, FL
Demonstration
● March 22, 2005
● One hour precipitation total
● Tallahassee, FL
Demonstration
● March 22, 2005
● One hour precipitation total
● Tallahassee, FL
Demonstration
● March 22, 2005
● One hour precipitation total
● Tallahassee, FL
Demonstration
● March 22, 2005
● One hour precipitation total
● Tallahassee, FL
Demonstration
● March 22, 2005
● One hour precipitation total
● Tallahassee, FL
Demonstration
● March 22, 2005
● One hour precipitation total
● Tallahassee, FL
Demonstration
● March 8, 2005
● Near Montgomery, AL
● One hour precipitation total
Verification
● March 8, 2005
● Near Montgomery, AL
● One hour precipitation total
● Image generated by the NWS
Demonstration
● March 9, 2005
● Melbourne, FL
● Base reflectivity
Verification
● March 9, 2005
● Melbourne, FL
● Base reflectivity
● Image generated by the NWS
Licensing
● Support free and open exchange of data and ideas
● Private weather industry wants to restrict the ability of NOAA to disseminate data to the public
● Open source software, by definition, cannot place licensing restrictions to prevent commercial use
● Therefore, this product will not be released as open source software
Development Status
● Core functionality of decoding level III data is completed and has been tested
● Converting data to GIS readable format has not been tested
● Automatic downloading, conversion, and uploading of data has not been tested
● Data from this project has not yet been integrated into the CARES website
Future Development
● Radar coverage may be improved if NWS places a WSR-88D in Mid-Missouri or north central Missouri
● Make use of actual observed rainfall totals to calibrate precipitation estimates
● Generate precipitation estimates from raw level II data
● Make use of less advanced radar to improve estimates in areas with poor radar coverage