WMOD00425

• Title: Demonstration of Improved Operational Water Resources Management Through Use of Better Snow Water Equivalent Information
• Date: 9/1/2002
• Weather Modification - Doc Type: Report

1.5 Annual Progress

This final report addresses Reclamation's activities and findings during the past 3 years of effort
under the contract. Work done in the first and second years is described in two previous annual
reports. The following summarizes work in the third and final year.

The principal investigator (PI) for this research was Dr. Arlin Super, who retired in August 1999.
Dr. Super was replaced by Steven Hunter in May 2000. During the intervening time, work was
carried on by Dr. Edmond Holroyd, the co-PI. The observational network in the north-clentral
U.S. was extended westward to Great Falls, Montana, for a total of 10 WSR-88D stations. The
radar at Sioux Falls, South Dakota, was added for the most recent winter season. SAA observa-
tions were monitored to assess accuracy and to identify features for improvement. A new
algorithm, named the Precipitation Accumulation Algorithm, was developed to address lthe
additional tasks of rain accumulation, bright band identification and its precipitation equivalent,
and virga.

2. TASK SUMMARIES

Tasks as given in the Statement of Work (in italics), along with resulting accomplishments, are
as follows:

1. Access near real-time NEXRAD radar Level III reflectivity products from the Chanhassen,
Minnesota, (KMPX) WSR-88D radar through a NEXRAD Information Dissemination Service
(NIDS) vendor: This was accomplished in the first year of effort. Data were obtained from the
NIDS vendor Weather Services International (WSI) Corporation.

2. Modify Reclamation's SAA to use Level III reflectivities from KMPX as input to the SAA:
Programming and testing of archived KMPX Level ill data occurred in the first year, showing
that it was feasible to use such data. Further testing in the second year indicated good msults,
and the methodology was recommended for operational implementation.

3. Use the modified SAA to provide near real-time SWE estimates with a stand-alone computer
that ingests the Level III data, runs the SAA, displays visual outputs, and provides numaical
outputs: This was accomplished on a Sun UNIX workstation in the second year.

4. Develop software to display the SWE estimates for the past 1 and 3 hours and since the
beginning of each snowstorm, on the same computer used to run the SAA: FORTRAN77, C, net
Common Data Format (netCDF), and NCAR graphics routines were developed and used to
perform this task; storm-total amounts were converted to 24-hour increments instead of 1- and 3-
hour increments.

5. Develop the means to convert radar SWE estimates from polar coordinates into a gl'idded
field coordinate system specified by NOHRSC (in Chanhassen, Minnesota): This method was
developed with output to an approximately 4- by 4-kilometer (Ian) Hydrologic Rainfall Analysis
Project (HRAP) grid. This grid is standard for operational hydrologic purposes.

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