CR 46:85-99 (2011)  -  DOI:

Simulation of the Indian summer monsoon using comprehensive atmosphere–land interactions, in the absence of two-way air–sea interactions

Young-Kwon Lim1,4,*, D. W. Shin1, Steven Cocke1, Sung-Dae Kang2, Hae-Dong Kim3

1Center for Ocean-Atmospheric Prediction Studies (COAPS), Florida State University, Tallahassee, Florida 32306-2840, USA
2National Typhoon Center, Korea Meteorological Administration, Jeju 699-942, Republic of Korea
3Department of Environmental Conservation, Keimyung University, Daegu 704-701, Republic of Korea
4Present address: NASA / Goddard Space Flight Center, Greenbelt, Maryland 20771, USA

ABSTRACT: Community Land Model version 2 (CLM2) as a comprehensive land surface model and a simple land surface model (SLM) were coupled to an atmospheric climate model to investigate the role of land surface processes in the development and the persistence of the South Asian summer monsoon. Two-way air–sea interactions were not considered in order to identify the reproducibility of the monsoon evolution by the comprehensive land model, which includes more realistic vertical soil moisture structures, vegetation and 2-way atmosphere–land interactions at hourly intervals. In the monsoon development phase (May and June), comprehensive land-surface treatment improves the representation of atmospheric circulations and the resulting convergence/divergence through the improvements in differential heating patterns and surface energy fluxes. Coupling with CLM2 also improves the timing and spatial distribution of rainfall maxima, reducing the seasonal rainfall overestimation by ~60% (1.8 mm d–1 for SLM, 0.7 mm d–1 for CLM2). As for the interannual variation of the simulated rainfall, correlation coefficients of the Indian seasonal rainfall with observation increased from 0.21 (SLM) to 0.45 (CLM2). However, in the mature monsoon phase (July to September), coupling with the CLM2 does not exhibit a clear improvement. In contrast to the development phase, latent heat flux is underestimated and sensible heat flux and surface temperature over India are markedly overestimated. In addition, the moisture fluxes do not correlate well with lower-level atmospheric convergence, yielding correlation coefficients and root mean square errors worse than those produced by coupling with the SLM. A more realistic representation of the surface temperature and energy fluxes is needed to achieve an improved simulation for the mature monsoon period.

KEY WORDS: Indian summer monsoon · Monsoon precipitation · Climate modeling · Atmosphere–land interaction · CLM2 · SLM

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Cite this article as: Lim YK, Shin DW, Cocke S, Kang SD, Kim HD (2011) Simulation of the Indian summer monsoon using comprehensive atmosphere–land interactions, in the absence of two-way air–sea interactions. Clim Res 46:85-99.

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