Vegetation-atmosphere interactions: Impacts of Oklahoma's winter wheat crop on temperature and moisture fields

Interactions between vegetation and the lower atmosphere have been documented by both numerical modeling and observational studies. Although critically important to understanding the processes involved in these interactions, modeling studies are subject to the constraints of parameterizations, highly idealized environments, model biases, or a lack of adequate regional observations for model initialization and verification. Observational studies typically use datasets that are limited to case study days, short time periods, small regions (for high-resolution data), or poor spatial resolution (for large regions). In many cases, the length of the observational study period eliminates the opportunity to understand the robustness of results, and the courseness of the spatiotemporal resolution reduces the opportunity to examine the interactions during years of excellent and poor crop yields.

To address some concerns about period-of-record using high-resolution observational data, this study uses 18 years of mesoscale measurements to document robust monthly anomalies of near-surface atmospheric variables across Oklahoma's winter wheat belt as well as the variability of the wheat belt's impact on surface air temperatures. Results also will highlight differences in the vegetation belt's impact on regional climate during both “good” and “bad” crop years for winter wheat.

The imprint of the wheat belt on regional climate in the southern Great Plains can affect forecasts of daily high temperatures as well as energy consumption. This research also is important to understanding the role of more localized anthropogenic factors related to regional climate (i.e., large-scale transformation of native landscapes to agricultural cropland) so that they can be properly represented in dynamically or statistically downscaled simulations and projections.