Projecting Drought Under Climate Change Scenarios for Southern California Water Resources
Tuesday, April 21, 2015
Brianna Rita Pagan1, Jeremy S Pal1, Moetasim Ashfaq2 and Donald R Kendall1, (1)Loyola Marymount University, Department of Civil Engineering and Environmental Science, Los Angeles, CA, United States, (2)Oak Ridge National Laboratory, Oak Ridge, TN, United States
Abstract:
A 10-member ensemble of coupled global climate models are dynamically downscaled forcing one regional and one hydrological model resulting in a high-resolution 4.6-km output for the Southern California region. Greenhouse gas concentrations are prescribed according to the IPCC Representative Concentration Pathway 8.5 using the present-day period of 1966-2005 and future period of 2011-2050. All imported sources of water to Southern California are evaluated including 1) the Sacramento River basin, 2) the San-Joaquin River basin, 2) the Tulare Lake basin, 3) Mono Lake and Owens Valley basin and 4) the Colorado River basin. Various measures are utilized in this study to determine drought occurrence including precipitation, evaporation, runoff and snow water equivalent. Precipitation is projected to increase across all study areas. As a result, the likelihood of experiencing drought conditions decreases when solely considering precipitation. However, quantity of precipitation is not as vital as quantity of snowfall and subsequently snowpack for Southern California water resources. Temperatures increase throughout the regions driving reductions in snow water equivalent and shifts in snowmelt timing. Therefore, despite increasing precipitation the imported sources of water may exhibit ‘snow droughts’ which can drive water supply reductions for the Southern California region.
