Open AccessImproving the Northeast Asian Monsoon Simulation: Remote Impact of Tropical Heating Bias Correction
Author(s) -
Kyong-Hee An,
ChiYung Tam,
Chung-Kyu Park
Publication year - 2009
Publication title -
monthly weather review
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.862
H-Index - 179
eISSN - 1520-0493
pISSN - 0027-0644
DOI - 10.1175/2008mwr2612.1
Subject(s) - diabatic , climatology , gcm transcription factors , environmental science , monsoon , general circulation model , tropics , boreal , atmospheric sciences , walker circulation , east asian monsoon , tropical cyclone , meteorology , sea surface temperature , geology , climate change , geography , oceanography , physics , fishery , biology , paleontology , adiabatic process , thermodynamics
This study investigates the role of model tropical diabatic heating error on the boreal summer northeast Asian monsoon (NEAM) simulation given by a general circulation model (GCM). A numerical experiment is carried out in which the GCM diabatic heating is adjusted toward more realistic values in the tropics. It is found that the seasonal mean NEAM circulation and rainfall are improved in the GCM. This can be attributed to the reduced positive heating bias in the western Pacific Ocean around 10°–15°N in the model, which in turn leads to better-simulated low-level southerly winds over eastern Asia and more moisture supply to the NEAM region. The GCM’s ability in capturing the year-to-year variation of NEAM rainfall is also markedly improved in the experiment. These results show that the diabatic heating error over the western Pacific can be one reason for poor NEAM simulations in GCMs. The authors also suggest a simple method to reduce model heating biases that can be readily applied to dynamical seasonal prediction systems.