The impact of an extreme case of irrigation on the southeastern United States climate
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- 作者：Christopher Selman ; Vasubandhu Misra
- 关键词：Regional climate modeling ; Irrigation ; Diurnal climatology ; Diurnal ; Southeast United States ; Southeast US ; Regional model ; Agriculture ; Anthropogenic influences ; Anthropogenic ; Climate ; Climate change ; Regional ; Impact ; Southeast ; Model ; Parametrization
- 刊名：Climate Dynamics
- 出版年：2017
- 出版时间：February 2017
- 年：2017
- 卷：48
- 期：3-4
- 页码：1309-1327
- 全文大小：
- 刊物类别：Earth and Environmental Science
- 刊物主题：Geophysics/Geodesy; Climatology; Oceanography;
- 出版者：Springer Berlin Heidelberg
- ISSN：1432-0894
- 卷排序：48
文摘
The impacts of irrigation on southeast United States diurnal climate are investigated using simulations from a regional climate model. An extreme case is assumed, wherein irrigation is set to 100 % of field capacity over the growing season of May through October. Irrigation is applied to the root zone layers of 10–40 and 40–100 cm soil layers only. It is found that in this regime there is a pronounced decrease in monthly averaged temperatures in irrigated regions across all months. In non-irrigated areas a slight warming is simulated. Diurnal maximum temperatures in irrigated areas warm, while diurnal minimum temperatures cool. The daytime warming is attributed to an increase in shortwave flux at the surface owing to diminished low cloud cover. Nighttime and daily mean cooling result as a consequence repartitioning of energy into latent heat flux over sensible heat flux, and of a higher net downward ground heat flux. Excess heat is transported into the deep soil layer, preventing a rapidly intensifying positive feedback loop. Both diurnal and monthly average precipitations are reduced over irrigated areas at a magnitude and spatial pattern similar to one another. Due to the excess moisture availability, evaporation is seen to increase, but this is nearly balanced by a corresponding reduction in sensible heat flux. Concomitant with additional moisture availability is an increase in both transient and stationary moisture flux convergences. However, despite the increase, there is a large-scale stabilization of the atmosphere stemming from a cooled surface.