Abstract:
To understand the precipitation microphysical characteristics of typhoon rainstorms at the top and bottom of Mount Tai, based on the data from precipitation phenomenon instruments, automatic weather stations and tropical cyclone optimal path dataset, taking four typhoon rainstorms in the Mount Tai area as examples, the three-parameter Gamma function fitting method was used to compare and analyze the raindrop size characteristics at the mountaintop and the mountain bottom. The results show that: (1) "Yagi" and "Rumbia" ("Lekima" and "In-Fa") have (less) obvious evaporative effects at the top of the mountain, from the peak of the same height falling to the bottom of the mountain, "Yagi" and "Rumbia" show more significant breakup effects, "Lekima" exhibits notable evaporation, breakup, and coalescence effects, and "In-Fa" demonstrates more pronounced evaporation and breakup effects. (2) Convective cloudy precipitation from "Yagi", "Rumbia", and "Lekima" at the summit includes both continental and maritime characteristics, primarily forming through warm rain-ice phase mixing and ice phase mechanisms. At the base, it is predominantly maritime, with the formation mechanism mainly involving coalescence growth in warm clouds. In contrast, "In-Fa" are predominantly maritime at the summit and base. (3) For the four typhoon rainfalls,
μ (form factor) and
λ (slope parameters) decrease with increasing
R (rainfall intensity), the
μ-
λ relationship shows little difference, and the correlation of typhoon paths is better at the summit than at the base. The
Dm (mass-weighted average diameter) and lg
Nw (normalized intercept parameter logarithms) of the four typhoon rainfalls increase with increasing
R. The increase in
R at both the summit and base for "Yagi", "Rumbia", and "Lekima" is mainly influenced by the increase in
Dm, with lg
Nw as a secondary factor. However, for "In-Fa" at the base, the increase in
R is solely influenced by the increase in
Dm.