Statistical Estimation of an Upperbound on Weekly Stream Temperatures

Abstract

There is interest in how global climate change will affect the earth'ssy stems. One of the systems that will certainly be affected is surface water, in particular, streams. This report addresses, in three parts, change in stream temperatures as a result of global climate change. Work has already boen done on the effects of climate change on stream temperatures (Erickson and Stefan, 2000; Mohseni and Stefan, 1999; Mohsoni et al., 2001; Mohseni and Stefan, 1998, 1999; Sinokrot and Stefan, 1993; Stefan et al., 2001). The first Pilrt of this report is an extension of work done by Erickson et 81. (1998). A method of Hersh field (1961) is employed where a maximum series of data is analyzed and a standard enveloping deviate, K, is determined. We analyze stream temperature data from 993 USGS stream gauging stations and compute K -values for each station. We looked at possible trends and pattems in the K -values, suggest a "reasonable" K, and discuss the significance and applicability of K. Tho secolld part of the report continues the 811alysis of993 stream gauging stations. We analyzed the stations to look for any trends in the data during the periods 1980 - 1990 fll1d 1970 - 1990. We found no significant trends. The final part of this report is an extension of work done by Mohseni et a1. (1997) to fit a curve to air temperatUre/ stream temperature data. We use a transfo\lllation to linearize the equation fit by Mohseni et al.. Then we use our linearized equation to estimate a, the maximum stream temperature, again using the data from 993 stream gauging stations.