On the Differences in Storm Rainfall from Hurricanes Isidore and Lili. Part II: Water Budget

Abstract

Part I of this two-part paper examined the satellite-derived rainfall accumulation and rain potential history of Hurricanes Isidore and Lili (2002). This paper (Part II) uses analyses from the Navy Operational Global Atmospheric Prediction System (NOGAPS) to examine the water budget and environmental parameters and their relationship to the precipitation for these two storms. Factors other than storm size are found to account for large volumetric differences in storm total rainfall between Lili and Isidore. It is found that the horizontal moisture convergence was crucial to the initiation and maintenance of Isidore's intense rainfall before and during its landfall. When the storm was over the ocean, the ocean moisture flux (evaporation) was the second dominant term among the moisture sources that contribute to precipitation. During Isidore's life history, the strong horizontal moisture flux convergence corresponded to the large storm total precipitable water. The large difference in budget-derived stored cloud ice and liquid water between Isidore and Lili is corroborated from Tropical Rainfall Measuring Mission (TRMM) measurements. During Isidore's landfall, the decrease in environmental water vapor contributed to rainfall in a very small amount. These results indicate the importance of the environmental precipitable water and moisture convergence and ocean surface moisture flux in generating Isidore's large rainfall volume and inland flooding as compared with Lili's water budget history. Both the moisture convergence and ocean flux were small for Lili.

Comparing the Spatial Patterns of Rainfall and Atmospheric Moisture among Tropical Cyclones Having a Track Similar to Hurricane Irene (2011)

“…A comparison of precipitable water values when both TCs were located near this area (Figure 6c,d) shows that values for Irene exceeded 50 mm (Figure 6d) while those for Floyd approximated 40 mm. This finding supports previous research showing that higher amounts of moisture in the environment surrounding a TC can lead to a larger storm with more wide-spread rainfall [30][31][32][33][34]66].…”

Influence of environmental moisture on TRMM‐derived tropical cyclone precipitation over land and ocean

“…The moisture parameters are interpolated into 3‐h temporal resolution to match TMPA data. A simple expression of the vertically integrated water vapor budget is as follows [ Braun , 2006; Jiang et al , 2008b]: where TPW is the total precipitable water (mm, equivalent to kg m −2 ), HMC is the horizontal convergence of water vapor vertically integrated for the whole atmospheric column (mm hr −1 ), OSF is the ocean surface moisture flux (mm hr −1 ), P is precipitation rate (mm hr −1 ), and C is liquid and solid water stored as cloud (cloud storage, mm hr −1 ). Local changes of TPW and cloud storage terms are insignificant.…”

“… Rodgers and Pierce [1995] demonstrated that the SSM/I and ECMWF derived total precipitable water (TPW) fields influenced the precipitation distribution of Typhoon Bobbie (1992). Jiang et al [2008a, 2008b] compared the rainfall history and detailed water vapor budget of Hurricanes Isidore and Lili (2002) and found that large horizontal moisture convergence (HMC) and TPW were crucial to initiate and maintain the heavy rainfall before and during Isidore's landfall. However, no statistics‐based observational studies have documented, at least to the authors' current knowledge, on the relationship between TC rainfall and environmental moisture.…”

Three-Dimensional Circulation Structure of Summer Heavy Rainfall in Central North China

“…However, local water vapor is relatively limited (Jiang et al 2008;Simmonds et al 1999), and thus heavy rainfall is commonly associated with large-scale circulation in favor of moisture transport. Back to the middle of the twentieth century, scholars have laid the foundation for research on the relation between heavy rainfall and circulation in NC.…”