Impacts of Agricultural Irrigation on Land-Atmosphere Coupling Strength and Extreme Precipitation
Abstract
Precipitation extremes are expected to become more frequent in the changing global climate, which may considerably affect the terrestrial hydrological cycle. Anthropogenic water management can also dramatically change the local surface energy budgets and the water cycle. In this study, we focus on impacts of irrigation on the land-atmosphere interactions and the extreme precipitation over the North China Plain, Central United State, and Northern India, where with intensive irrigation practices. A state-of-the-art Earth system model is used to simulate the land-atmosphere interaction processes affected by the irrigation and the resulting responses in the atmospheric circulation. Results show that the cooling effect of irrigation usually causes subsidence, leading to the low-level divergence of water vapor, except for North China Plain during early summer. A higher frequency of intense precipitation events is also simulated after the irrigation is applied in the coupled atmosphere-land model simulations. Nonlinear responses to extreme precipitation lead to higher amount of direct runoff, but with reduced groundwater recharge. The nonlinear response is most likely related to the existence of a higher surface soil moisture after irrigation. Thus, increased precipitation extremes lead to an intensified hydrological cycle after applying the irrigation. This has the potential to result in a strong temporal heterogeneity in soil water distribution affecting the ecosystem and increasing the risk of flooding and/or landslides.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFMGC12B..04L
- Keywords:
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- 1616 Climate variability;
- GLOBAL CHANGEDE: 1620 Climate dynamics;
- GLOBAL CHANGEDE: 1630 Impacts of global change;
- GLOBAL CHANGEDE: 4313 Extreme events;
- NATURAL HAZARDS