Simulating Land Surface Change Impacts on Climate in the Northern Plains

Over the past several decades, the coverage of crops has changed dramatically over the Northern Plains. In North Dakota for example, barley and wheat acreages have decreased by 39% and 22%, respectively from 1990 to 2016. At the same time, leafier plants such as corn and soybeans have seen dramatic increases in planting. Compared to crops such as barley and wheat, they are more effective at evapotranspiration, and this interaction between the soil and the atmosphere modifies the atmospheric boundary layer. Most notably, recent decades have seen increases in precipitation and minimum temperatures across the region. Prior studies suggest that at least some of this signal is due to land cover (crop) changes. For this study, the Weather Research and Forecasting (WRF) model is used to downscale a member of the CESM climate model. Initial simulations are performed using standard model settings at 12 km grid spacing to simulate a decade (2006-2015) of warm-season months in the Northern Plains. A subset of simulations is performed at 4 km grid spacing coupled with the Noah-MP-Crop land surface model to alter crop type across the Northern Plains. Crop datasets are constructed for the Northern Plains for use within the crop model. Comparisons are made to historical datasets to see if the addition of the crop model yields better agreement of observed precipitation and temperatures trends.