Comparing Rainfall of Landfall Tropical Cyclones on Spatial Mixed and Fractional Mixed Landuse Using Natural Run Simulation

Previous research shows spatial patterns of landuse type could have different influences on rainfall. However, how could spatial patterns of landuse affect the rainfall patterns of a Tropical Cyclone (TC) is not fully understood. In this research, the affects of different layout of mixed landuse type to TC rainfall are simulated based on Hurricane Natural Run Case 2 in Florida, US. The Hurricane Nature Run Case 2 is a down-scaled WRF simulation of one landfall hurricane case from observing system simulation experiment (OSSE). The landuse of Florida are completely replaced by an equal-parts mix of two landuse types in the simulation. The mix contains two landuse types distinguish by one of three variables: roughness length, moisture availability or surface heat capability. Two kinds of mixes are designed, spatially mixed or fractionally mixed. In the spatial mixed land, two landuse types of tile-mosaicked in the coarse domain. Each individual filled completely with one landuse type. The size of each tile is set to match the coarse domain. While in the fractional mixed group, landuse are spatially homogeneous, with two landuse types takes half in fraction. Simulated results show neither mixing pattern significantly affects the TC track after landfall across all simulations. After landfall, TCs are weakening faster when averaged roughness length are higher, moisture availability and surface heat capacity are lower. But the weakening rate shows different flavors in spatially mixed and fractionally mixed patterns.