Impact of irrigation over the California Central Valley on regional climate
Abstract
Irrigation, while being an important anthropogenic factor affecting the local to regional water cycle, is not typically represented in regional climate models. We incorporated an irrigation scheme into the Noah land surface scheme of the Weather Research and Forecasting (WRF) model that has a calibrated convective parameterization, and used a tracer package to tag and track water vapor. To assess the impact of irrigation over the California Central Valley (CCV) on the regional climate of the U.S. Southwest, we ran simulations (for 3 dry and 3 wet years) both with, and without, the irrigation scheme. Incorporation of the irrigation scheme resulted in simulated surface air temperature and humidity that were closer to observations, decreased the depth of the planetary boundary layer over the CCV, and increased the convective available potential energy. The result was an overall increase in precipitation over most of the model domain. Water vapor rising from the irrigated region mainly moved northeastward and contributed to precipitation in Nevada and Idaho. Specifically, the results indicate increased precipitation on the windward side of the Sierra Nevada Range and over the Colorado River Basin. The former is possibly linked to a sea-breeze type circulation near the CCV, while the latter is likely associated with a wave pattern related to latent heat release over the moisture transport belt.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2016
- Bibcode:
- 2016AGUFM.H51H1591Y
- Keywords:
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- 3305 Climate change and variability;
- ATMOSPHERIC PROCESSESDE: 1655 Water cycles;
- GLOBAL CHANGEDE: 1855 Remote sensing;
- HYDROLOGYDE: 4313 Extreme events;
- NATURAL HAZARDS