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Does increasing horizontal resolution improve the simulation of intense tropical rainfall?
  • +2
  • Akshaya sr,
  • Akshaya C Nikumbh,
  • Pu Lin,
  • David Paynter,
  • Yi Ming
Akshaya sr

Corresponding Author:[email protected]

Author Profile
Akshaya C Nikumbh
Atmospheric and Oceanic Sciences, Princeton University
Pu Lin
Atmospheric and Oceanic Sciences, Princeton University
David Paynter
Geophysical Fluid Dynamics Laboratory (GFDL)
Yi Ming
Boston College

Abstract

We examine tropical rainfall from Geophysical Fluid Dynamics Laboratory's Atmosphere Model version 4 (GFDL AM4) at three horizontal resolutions of 100 km, 50 km, and 25 km. The model produces more intense rainfall at finer resolutions, but a large discrepancy still exists between the simulated and the observed frequency distribution. We use a theoretical precipitation scaling diagnostic to examine the frequency distribution of the simulated rainfall. The scaling accurately produces the frequency distribution at moderate-to-high intensity (≥10 mm day −1). Intense tropical rainfall at finer resolutions is produced primarily from the increased contribution of resolved precipitation and enhanced updrafts. The model becomes more sensitive to the grid-scale updrafts than local thermodynamics at high rain rates as the contribution from the resolved precipitation increases. On the contrary, the observed tropical precipitation extremes do not show a strong sensitivity to the grid-scale updrafts.
09 Oct 2023Submitted to ESS Open Archive
11 Dec 2023Published in ESS Open Archive