Influence of Irrigation on Diurnal Mesoscale Circulations: Results From GRAINEX

C. E. Phillips, U. S. Nair, R. Mahmood, E. Rappin, R. A. Pielke

Research output: Contribution to journalArticlepeer-review

Abstract

In order to understand the impact of irrigation on weather and climate, the 2018 Great Plains Irrigation Experiment collected comprehensive observations straddling irrigated and non-irrigated regions in southeast Nebraska. Using these observations, we examine how irrigation affects diurnal terrain-generated slope circulations, specifically the slope wind. We find that irrigation applied to upslope regions of gently sloping terrain reduces terrain-induced baroclinicity and the associated pressure gradient force by up to two-thirds. This leads to the reduction in the afternoon and evening upslope wind and is supported through comparisons to the High-Resolution Rapid Refresh operational model, which does not explicitly account for irrigation. Additionally, the presence of irrigation decreases daytime sensible heat flux (Bowen ratio reduced 40% compared to non-irrigated regions), weakening turbulent transport of momentum. Modifications to the terrain-forced circulation by irrigation has the potential to affect moisture transport and thus cloud and precipitation formation over the Great Plains.

Original languageEnglish (US)
Article numbere2021GL096822
JournalGeophysical Research Letters
Volume49
Issue number7
DOIs
StatePublished - Apr 16 2022

Keywords

  • boundary layer
  • GRAINEX
  • Great Plains
  • irrigation
  • mesoscale circulation
  • slope wind

ASJC Scopus subject areas

  • Geophysics
  • Earth and Planetary Sciences(all)

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