Sun, R., A. C. Subramanian, B. O. Wolding, T.-Y. Hsu, M. R.
Mazloff, B. D. Cornuelle, J. Sprintal, A. J. Miller, G. Gopalakrishnan, P. Ag and
I. Hoteit, 2026:
Sensitivity of the 2023
Asian summer monsoon water vapor
transport to Arabian Sea surface
temperature anomalies.
Journal of Geophysical Research: Atmospheres, 131, e2025JD044185.
Abstract.
Prior to the onset of the South Asian monsoon, the Arabian Sea experiences a warming phase
during which the Arabian Sea mini warm pool (ASMWP) becomes one of the world's warmest oceanic regions,
characterized by sea surface temperatures (SSTs) exceeding 30°C. To understand the role of this warming in
monsoon evolution, we performed an SST sensitivity experiment using the Weather Research and Forecasting
(WRF) atmospheric model. Our case study focuses on the 2023 monsoon, which was characterized by high
initial SST that declined faster than in normal years. We found that if the SST declines more slowly than normal,
the off‐shore precipitation increases by more than 100% around the ASMWP, but decreases in the northern
Arabian Sea and the western coast of India. To understand the precipitation differences, we separated the
components of the integrated vapor transport (IVT) and found that the changes in both water vapor and wind
affect precipitation. The analysis revealed that the changes in water vapor are due to (a) stronger evaporation and
precipitation in the ASMWP, and (b) moisture advection outside the ASMWP. It is also shown that the pressure
adjustment mechanism can explain the changes in wind speed. With warmer SST conditions, the atmosphere
pressure drops and causes wind convergence, thereby creating a weak cyclonic wind anomaly that redistributes
the water vapor. Finally, we examined the vertically integrated buoyancy in the context of an idealized plume
model. In the ASMWP, temperature changes contribute to increases in buoyancy below 850 hPa, but humidity
changes contribute to far more increases in buoyancy between 800 and 600 hPa, which enhance the convection
and lead to more precipitation.
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