TY - JOUR
T1 - Island Rainfall Enhancement in the Maritime Continent
AU - Ruppert, James H.
AU - Chen, Xingchao
N1 - Funding Information:
Data sets used in this study are described in Text S1 and are available through a permanent archive from https://doi.org/10.26208/5sb9-p776. We thank George Young and two anonymous reviewers for valuable comments on the study. We are grateful for support for this research from the National Science Foundation (1712290) and the U.S. Department of Energy (WACCEM) and for computation resources of the Texas Advanced Computing Center (TACC) at The University of Texas at Austin.
Publisher Copyright:
©2020. American Geophysical Union. All Rights Reserved.
PY - 2020/3/16
Y1 - 2020/3/16
N2 - The hypothesis that the islands of the Maritime Continent (MC) enhance total rainfall and time-mean upward motion is tested using a convection-permitting regional model. Sensitivity experiments with the islands removed greatly diminish both rainfall and upward motion, supporting the hypothesis. We examine the individual factors in this enhancement, isolating the impacts of the diurnal cycle from those of basic-state (i.e., constant) forcing of orography and the land surface. We find that the basic-state forcing by land is the only factor that substantially enhances total island rainfall, specifically through the enhancement of mean surface heat fluxes. The diurnal cycle and orographic forcing, however, substantially enhance rainfall in the seas surrounding the islands. Moreover, the diurnal cycle is found to be essential for promoting mesoscale circulations on the spatial scales of the islands, which are critical to both the upscale growth of deep convection and the most extreme rainfall rates.
AB - The hypothesis that the islands of the Maritime Continent (MC) enhance total rainfall and time-mean upward motion is tested using a convection-permitting regional model. Sensitivity experiments with the islands removed greatly diminish both rainfall and upward motion, supporting the hypothesis. We examine the individual factors in this enhancement, isolating the impacts of the diurnal cycle from those of basic-state (i.e., constant) forcing of orography and the land surface. We find that the basic-state forcing by land is the only factor that substantially enhances total island rainfall, specifically through the enhancement of mean surface heat fluxes. The diurnal cycle and orographic forcing, however, substantially enhance rainfall in the seas surrounding the islands. Moreover, the diurnal cycle is found to be essential for promoting mesoscale circulations on the spatial scales of the islands, which are critical to both the upscale growth of deep convection and the most extreme rainfall rates.
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U2 - 10.1029/2019GL086545
DO - 10.1029/2019GL086545
M3 - Article
AN - SCOPUS:85081733515
VL - 47
SP - no
JO - Geophysical Research Letters
JF - Geophysical Research Letters
SN - 0094-8276
IS - 5
ER -