Investigating the Effect of Seasonal Plant Growth and Development in Three-Dimensional Atmospheric Simulations. Part II: Atmospheric Response to Crop Growth and Development

Abstract

The authors examine the effect of seasonal crop development and growth on the atmospheric boundary layer in the warm season over the central Great Plains region of North America. They introduced daily crop development and growth functions into the Biosphere?Atmosphere Transfer Scheme (BATS) coupled to the National Center for Atmospheric Research Regional Climate Model version 2 (NCAR RegCM2). Coupled RegCM/BATS simulations were performed over the conterminous United States for a dry (1988) and favorably moist (1991) growing seasons at a spatial resolution of 90 km ? 90 km. Largest differences between the control and interactive runs occurred in 1988, when up to 45% differences in surface latent and sensible heat fluxes were simulated in response to different Leaf Area Index (LAI) parameterizations employed by the models (in June and July, LAI was about 5 in the control cases and between 1 and 2 in the interactive cases). Two to four °C differences in air temperatures resulted in response to such changes in surface fluxes. Mixing ratio, lower atmospheric winds, and precipitation were also affected. These effects had a distinct diurnal pattern with the largest differences seen in midafternoon hours and smallest differences seen at night. The differences between the control and interactive simulations were largest near the surface and dampened with height. The boundary layer stratification (i.e., vertical profiles of equivalent potential temperature) produced with interactive runs was more stable compared to the control runs. Anemometer height maximum daily temperature and precipitation simulated in the interactive runs agreed better with observations compared to those of the control runs.