P28     Using Noah-MP-Crop to study cropland impact on regional climate in the Northern Great Plains.

Scott, Aaron, and Aaron Kennedy, University of North Dakota

Over the past several decades, the coverage of crops has changed dramatically over the Northern Great Plains (NGP). The leafier crops 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. A baseline model simulation using WRF with the Noah-MP land surface model is used to run regional climate simulations over North Dakota with 12-km horizontal grid spacing from 2010-2014. Simulations are reinitialized every 12 months (plus spin-up) with NARR input data. Noah-MP-Crop is used to run the same simulations as previously stated to compare differences in surface temperature and moisture. The Noah-MP-Crop model is first tuned by adjusting the relationship between plant growing stages and leaf area index (LAI). Measurements of LAI from the MODIS instrument on the Terra and Aqua satellites are used by locating MODIS pixels of single crop types in North Dakota. HRLDAS is used to simulate and tune the crop model for each year simulated. Comparisons are made between the model simulations and observations to find impacts of using the crop model within WRF. In addition, work has already started to implement this method for further regional climate studies in the NGP region.