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United States Department of Agriculture

Agricultural Research Service

Title: Daily Weather from Monthly Averages -- Hocus Pocus, or Useful Tool?

Authors
item Meyer, Charles
item Huang, Chi Hua

Submitted to: ASA-CSSA-SSSA Annual Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: August 15, 2006
Publication Date: September 26, 2006
Citation: Meyer, C.R., Huang, C. 2006. Daily Weather from Monthly Averages -- Hocus Pocus, or Useful Tool?[abstract]. ASA-CSSA-SSSA Annual Meeting Abstracts. November 12-16,2006, Indianapolis, IN. 2006 CDROM.

Technical Abstract: Just how much can you legitimately extract from monthly statistics of daily weather parameters? In this paper we present the utility and limitations of a simple weather generator (CLIGEN) which has over 750 registered users, most of whom are international. CLIGEN's 4,000-plus station files of monthly parameters are within an average distance of 25 miles of any location in the U. S., providing the immediate means to generate daily weather values. An automated way has been provided using a surrogate U. S. station, to build additional station files for any location on the planet, from daily measurements of precipitation, and maximum and minimum temperature. Although CLIGEN's simplicity permits it to be used with minimal data, a common criticism of CLIGEN is that it independently generates variables while in reality these variables are interrelated. If the CLIGEN output is used in a simulation model which is highly sensitive two or more parameters on a daily basis, this is probably a valid concern; however, the models using CLIGEN (WEPP, WEPS, WEPP-SPUR) generally are not. As a result, our primary goal is to ensure that the statistical distributions produced, reflect reality (measured data) as closely as possible. If there are universal relationships between weather data, our secondary goal is to capture them within the logic of the model, so they can be utilized without altering the model inputs, which would disrupt the existing CLIGEN userbase. We will discuss the extent to which we have achieved these goals, and the implications to CLIGEN users.

Last Modified: 10/1/2014
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