Possible relation between land surface feedback and the post‐landfall structure of monsoon depressions

The effect of pre‐storm land surface on the monsoon depressions (MDs) is studied. The Weather Research Forecast (WRF) model was configured with two nested domains to explore the sensitivity of MDs to antecedent soil moisture and land surface representation for selected three landfalling MDs during August 2006. Results indicate that WRF had good ability to simulate the MDs, and the post landfall model response was sensitive to antecedent soil moisture and modestly dependent on land surface representations. This was verified by reviewing the climatology of 125 MDs (1970–2003) which revealed that if the surface received heavier rainfall a week ahead of MD landfall, the inland intensity was maintained for a longer duration. The gradient in surface heat fluxes as the depression made landfall affected the evolution of the MDs over India. In particular, warmer, wetter (cooler, drier) land surface can intensify (weaken) the landfalling MDs over the Indian monsoon region.

[1]  U. C. Mohanty,et al.  The role of land surface processes on the mesoscale simulation of the July 26, 2005 heavy rain event over Mumbai, India. , 2009 .

[2]  Vinodkumar,et al.  Impact of land surface representation and surface data assimilation on the simulation of an off-shore trough over the Arabian Sea , 2009 .

[3]  Fei Chen,et al.  Development and Evaluation of a Coupled Photosynthesis-Based Gas Exchange Evapotranspiration Model (GEM) for Mesoscale Weather Forecasting Applications , 2009 .

[4]  K. Emanuel,et al.  A Hypothesis for the Redevelopment of Warm-Core Cyclones over Northern Australia , 2008 .

[5]  Yang Hong,et al.  Evaluation of TRMM Multisatellite Precipitation Analysis (TMPA) and Its Utility in Hydrologic Prediction in the La Plata Basin , 2008 .

[6]  Y. Hong,et al.  The TRMM Multisatellite Precipitation Analysis (TMPA): Quasi-Global, Multiyear, Combined-Sensor Precipitation Estimates at Fine Scales , 2007 .

[7]  J. Dudhia,et al.  Coupling an Advanced Land Surface–Hydrology Model with the Penn State–NCAR MM5 Modeling System. Part I: Model Implementation and Sensitivity , 2001 .

[8]  T. N. Krishnamurti,et al.  The landfall and structure of a tropical cyclone: The sensitivity of model predictions to soil moisture parameterizations , 1991 .

[9]  B. Goswami.  A mechanism for the west-north-west movement of monsoon depressions , 1987, Nature.

[10]  B. Efron,et al.  The Jackknife: The Bootstrap and Other Resampling Plans. , 1983 .

[11]  M. Rajeevan,et al.  High resolution daily gridded rainfall data for the Indian region: Analysis of break and active monsoon spells , 2006 .

[12]  B. Efron.  The jackknife, the bootstrap, and other resampling plans , 1987 .