Temperature affects Upper Colorado River Basin streamflow

Thursday, March 10, 2016

Connie Woodhouse and Kiyomi Morino, both of the LTRR, are authors on a recently published paper: Woodhouse, C. A., G. T. Pederson, K. Morino, S. A. McAfee, and G. J. McCabe (2016), Increasing influence of air temperature on upper Colorado River streamflow, Geophys. Res. Lett., 43, doi:10.1002/2015GL067613. Perhaps unusually for researchers with a background in dendrochronology, their analysis in this case uses only instrumental observations over the past century. A major influence on streamflow in the Upper Colorado River Basin is obviously precipitation (which here includes the accumulation of snow on mountains as well as rainfall). However the authors show that temperature also has an important influence, with relatively low temperatures mitigating the effects of droughts on streamflow, but importantly that high temperatures can produce severely low streamflows from what would otherwise be moderate droughts. This is of great practical concern, since temperatures around the Upper Colorado have risen in recent decades, and it is one of the critical water supplies in the American West.