Evaluating the bias of South China Sea summer monsoon precipitation associated with fast physical processes using a climate model hindcast approach
Journal
Journal of Climate
Journal Volume
32
Journal Issue
14
Pages
4491-4507
Date Issued
2019
Author(s)
Abstract
The present study aims to identify the precipitation bias associated with the interactions among fast physical processes in the Community Atmospheric Model, version 5 (CAM5), during the abrupt onset of the South China Sea (SCS) summer monsoon, a key precursor of the overall East Asia summer monsoon (EASM). The multiyear hindcast approach is utilized to obtain the well-constrained synoptic-scale horizontal circulation each year during the onset period from the years 1998 to 2012. In the pre-onset period, the ocean precipitation over the SCS is insufficiently suppressed in CAM5 hindcasts and thus weaker land-ocean precipitation contrasts. This is associated with the weaker and shallower convection simulated over the surrounding land, producing weaker local circulation within the SCS basin. In the post-onset period, rainfall of the organized convection over the Philippine coastal ocean is underestimated in the hindcasts, with overestimated upperlevel heating. These biases are further elaborated as the underrepresentation of the convection diurnal cycle and coastal convection systems, as well as the issue of precipitation sensitivity to environmental moisture during the SCS onset period. The biases identified in hindcasts are consistent with the general bias of the EASM in the climate simulation of CAM5. The current results highlight that the appropriate representation of land-ocean-convection interactions over coastal areas can potentially improve the simulation of seasonal transition over the monsoon regions. © 2019 American Meteorological Society.
SDGs
Other Subjects
Atmospheric thermodynamics; Horizontal wells; Oceanography; Precipitation (chemical); Climate simulation; Community atmospheric model; Convection systems; Convective parameterization; Model evaluation/performance; Monsoons; Ocean convection; South China Sea summer monsoon; Climate models; climate modeling; convection; hindcasting; land-sea interaction; monsoon; parameterization; precipitation assessment; Pacific Ocean; Philippines; South China Sea
Type
journal article