Investigating the Effect of Seasonal Crop Growth on the Climate of NCAR Regional Climate Model

We introduced daily plant growth and development functions into the Biosphere-Atmosphere Transfer Scheme (BATS) coupled to the National Center for Atmospheric Research Regional Climate Model (NCAR RegCM) to simulate the effect of seasonal plant development and growth on the atmosphere-land-surface heat, moisture, and momentum exchange. Energy, moisture, and momentum fluxes were studied over a maize agroecosystem at the scale of a 90 km atmospheric grid cell. We then ran the coupled RegCM/BATS over the conterminous United States domain at a resolution of 90 x 90 km to investigate the effect of seasonal agroecosystem processes on mesoscale atmospheric circulations over the central Great Plains of North America. During the extremely dry season of 1988, compared to the BATS noninteractive control case, 20-35% changes in sensible heat and 30-45% changes in latent heat occurred in response to greatly reduced LAI and canopy height. Changes in temperature, mixing ratio and precipitation followed. We found that the inclusion of plant growth and development functions into RegCM/BATS configuration altered not only seasonal patterns of state variables (T, q, Tv), but also the interannual variability in the simulated results. The interactive model fared better against observations compared to the noninteractive control one.