Laserfiche WebLink
CRDSS Memorandum <br />To: Ray Bennett, Ray Alvarado, Andy Moore <br />From: LRCWE, Ross Bethel and Erin Wilson <br />Subject: Colorado River Basin Consumptive Uses and Losses Report -Climate Data <br />Date: September 30, 1999 <br />Overview <br />The estimation of potential crop consumptive use requires climate data for temperature, <br />precipitation and frost dates. For Colorado's Consumptive Use and Losses Report and the Water <br />Resource Planning Model Applications, climate data sets were generated through a data centered <br />approach. <br />General Approach <br />For the generation of climate data sets for CRDSS modeling, linear regression was used to fill <br />the temperature data sets, and long-term averages were used to fill missing precipitation and frost <br />date data for calendar years 1974 through 1996. The filling processes are described in more <br />detail below. <br />Filling of Missing Values in the Temperature Data Sets <br />Linear regression requires dependant (to be filled) and independent (to be used as the basis for <br />filling) data sets. Four weather stations on the west slope were selected for use as primary <br />independent data sets based on their completeness of historic record during the 1974 through <br />1996 period and the length of record outside this period. The four stations selected for use as <br />potential primary independent data sets were: <br />• Grand Junction WSO (NWS No. 3488, 1900-1996) with no missing values during the 1974 <br />through 1996 time period. <br />• Hayden (NWS No. 3867, 1948-1996) with missing values for 7 months during the 1974 <br />through 1996 period. <br />• Dillon (NWS No. 2281, 1910-1996) with missing values for 2 months during the 1974-1996 <br />period. <br />• Telluride (NWS No. 8204, 1900-1996) with missing values for 2 months during the 1974- <br />1996 time period. <br />To avoid as much as possible using regressed values in subsequent regressions, independent data <br />sets were established that included the original historic record up through 1973 and a filled <br />record from 1974 through 1996. TSTooI was used (in three steps) to create the above <br />independent data sets. The three steps were 1) perform regression and save 1974-1996 filled <br />culossapp Page A-2 of A-13 10/31/01 <br />