Simulating Impacts of Land Use Change in the Northern North American Great Plains with a Convection-Permitting Model
Abstract
The northern North American Great Plains (NNAGP) are a dynamic agricultural region situated in the center of the North American continent. Mean near surface temperatures in the region decreased at a rate of nearly 0.15 °C per decade in the early vegetative growing season since the 1970's. Coincident with this regional cooling are large shifts in agricultural practices that now favor alternate cropping sequences including no-till agriculture over traditional crop-fallow rotations. Millions of hectares of land that were once kept in fallow during the summer in the 1970s are now planted, and evapotranspiration has increased at the expense of sensible heat flux. Recent studies have shown that the Bowen ratio has decreased from ca. 2 to ca. 1 during the vegetative growing season and convective likelihood has increased by more than 40% across May and June. Observational studies have detailed changes to convective processes in the NNGAP but, so far, no studies have linked land use change to the observations using a high-resolution model.
To answer this question the Weather Research and Forecasting (WRF) model was employed. WRF was run at 4 km convection-permitting horizontal grid spacing in a domain centered on the NNAPG using ERA-Interim as initial and boundary conditions. The model was run for four years from 2011- 2015 with 500 m MODIS land use data as well as from 1981-1985 using 1985 land use data. To ensure the changes between the simulations are robust and due to land cover change rather than changes in weather patterns, we also ran simulations of the 2011-2015 period using the 1985 land use data, and the 1981-1985 period using the modern land cover data. Differences in temperature, precipitation, and near surface energy partitioning, across the land use scenarios will be discussed as well as convective parameters, such as CAPE.- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFM.A32F..07B
- Keywords:
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- 3305 Climate change and variability;
- ATMOSPHERIC PROCESSESDE: 3337 Global climate models;
- ATMOSPHERIC PROCESSESDE: 3355 Regional modeling;
- ATMOSPHERIC PROCESSESDE: 0550 Model verification and validation;
- COMPUTATIONAL GEOPHYSICS