Applications of RCMs for Understanding Climate Change in the Central US

Climate variability and change in the Central US have high economic impact due to the region's agricultural base. Major annual drops in agricultural production in the region are almost always weather related and mostly due to years with low precipitation. Until 2012, recent trends in corn yields, for instance, have been steadily upward, in part due to abundant spring and early summer rainfall that has recharged subsurface water supplies for use in the precipitation-deficient, agriculturally critical pollination and grain-filling periods of July and August. Although GCMs lack agreement on the sign of projected future changes in precipitation in this region, recent RCM studies (Mearns et al, 2012) show that RCMs driven by GCMs show more agreement and significance in simulating a drier future summer climate, particularly in the southern Great Plains and Midwest. The importance of land-atmosphere feedbacks (Koster et al. 2004), together with rises in Gulf of Mexico temperatures and southward shifts of the low-level jet (Pan et al., 2004) may give RCMs an advantage in representing the key processes that are responsible for recent observed variability as well as longer term change. Understanding these key hydrological processes is essential for developing adaptation strategies to sustain vital food, feed, and biofuel supplies produced in this region.