Impacts of Soil Moisture on the Numerical Simulation of a Post-Landfall Storm

• Published in: Journal of Meteorological Research Vol. 33; no. 2; pp. 206 - 218
• Main Authors: Zhang, Feimin, Pu, Zhaoxia, Wang, Chenghai
• Format: Journal Article
• Language: English
• Published: Beijing The Chinese Meteorological Society 01.04.2019; College of Atmospheric Sciences, Lanzhou University, Lanzhou 730000, China; Department of Atmospheric Sciences, University of Utah, Salt Lake City, UT 84112, USA%Department of Atmospheric Sciences, University of Utah, Salt Lake City, UT 84112, USA%College of Atmospheric Sciences, Lanzhou University, Lanzhou 730000, China
• Subjects: Atmospheric Protection/Air Quality Control/Air Pollution; Atmospheric Sciences; Earth and Environmental Science; Earth Sciences; Geophysics and Environmental Physics; Meteorology; Special Collection on Weather and Climate under Complex Terrain and Variable Land Surfaces: Observations and Numerical Simulations; tropical storm; land surface; soil moisture; tropical cyclone landfall; numerical simulation
• ISSN: 2095-6037; 2198-0934
• DOI: 10.1007/s13351-019-8002-8

Surface heat and moisture fluxes are important to the evolution of a tropical storm after its landfall. Soil moisture is one of the essential components that influence surface heating and moisture fluxes. In this study, the impact of soil moisture on a pre-landfall numerical simulation of Tropical Storm Bill (2015), which had a much longer lifespan over land, is investigated by using the research version of the NCEP Hurricane Weather Research and Forecasting (HWRF) model. It is found that increased soil moisture with SLAB scheme before storm’s landfall tends to produce a weaker storm after landfall and has negative impacts on storm track simulation. Further diagnoses with different land surface schemes and sensitivity experiments indicate that the increase in soil moisture inside the storm corresponds to a strengthened vertical mixing within the storm boundary layer, which is conducive to the decay of storm and has negative impacts on storm evolution. In addition, surface diabatic heating effects over the storm environment are also found to be an important positive contribution to the storm evolution over land, but their impacts are not so substantial as boundary layer vertical mixing inside the storm. The overall results highlight the importance and uncertainty of soil moisture in numerical model simulations of landfalling hurricanes and their further evolution over land.