Sensitivity of local convective precipitation to parameterization of the field capacity and wilting point soil moisture contents

Sensitivity of local convective precipitation to parameterization of the field capacity ( theta sub(f)) and wilting point ( theta sub(w)) soil moisture contents was analyzed. The analysis was performed using simulation results of the Penn State - NCAR MM5 Modeling System obtained on nine days in 2006 and 2007.24-hour accumulated precipitation fields over the territory of Hungary were considered. Precipitation fields were statistically analyzed. The observed fields were obtained from rain gage data applying a kriging interpolation technique. The agreement between simulated and observed fields was estimated using categorical and continuous verification indices. Significance tests were done to estimate how large (important) or small the obtained differences were. The main results are as follows. In average, 20 percent relative differences in the theta sub(f) resulted in about 5-10 percent relative differences in the true skill statistic (TSS) categorical verification index. In several cases these TSS differences are significant on the 10% level. Similarly, in average, 50 percent relative differences in the theta sub(W) resulted in about 10-50 percent relative differences in the TSS. These TSS differences were significant on the 10% level on eight from the nine days. The results obtained can be useful in quantifying the strength of the soil moistureprecipitation feedback mechanisms.