Summertime central U.S. warm bias examined in the short-term hindcasts

Monday, 15 December 2014
Hsi-Yen Ma1, Stephen A Klein1, Shaocheng Xie1, Min-Hui Lo2, Yuying Zhang1 and Yunyan Zhang1, (1)Lawrence Livermore National Laboratory, Livermore, CA, United States, (2)NTU National Taiwan University, Taipei, Taiwan
In this study, we evaluate the central U.S. summertime surface warm temperature bias seen in many climate models. The main focus is to identify the role of cloud, radiation, and precipitation processes in contributing to the temperature biases. We use short-term hindcast approach and look at the growth of the error as a function of hindcast lead time. Our results of Community Earth System Model compared to data from U.S. Department of Energy Atmospheric Radiation Measurement (ARM) Southern Great Plain (SGP) site and other available observations indicate that the lack of soil moisture due to insufficient precipitation in the model is likely the primary source contribution to surface energy and temperature biases. Other processes that may lead to the warm biases are also explored. (http://portal.nersc.gov/project/capt/CAUSES/)

(This study is funded by the RGCM and ASR programs of the U.S. Department of Energy as part of the Cloud-Associated Parameterizations Testbed. This work is performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344. LLNL-ABS-658004)