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