13:45 〜 14:00
[AAS03-13] A statistical study on precipitation systems associated with warm-season quasi-stationary convective bands around Japan using GPM/TRMM data
In warm season around Japan, precipitation systems associated with quasi-stationary convective bands (QSCBs) often bring persistent, heavy rainfall. Large-scale environments related to QSCBs vary according to cases, leading to inadequate understanding of mechanisms for the formation of QSCBs. Because characteristics of heavy rainfall events, which are closely related to their different vertical structures, vary under diverse environments, investigating the internal structure and its relationships with large-scale environments is important for better understanding the mechanisms of heavy rainfall. In this study, we aim to understand three-dimensional/temporal characteristics of precipitation systems associated with warm-season QSCBs around Japan from a statistical perspective.
To achieve our goal, we combine JMA’s radar-gauge analyzed precipitation product (R/A) with TRMM/GPM DPR observed vertical structures. QSCBs are first detected with three hour accumulated rainfall of R/A both over the ocean and land. They are then collocated with TRMM/GPM precipitation events (PEs) during April-November for 2004-2023.
Various types of PEs with QSCBs are found in terms of the area and maximum 40-dBZ height (max40H). For larger PEs, duration and intensity are different according to max40H. Larger PEs with max40H <7 km tend to be strong, but not the strongest. Obviously, the strongest rainfall rates near the surface are found in larger PEs with max40H >=7 km. Some of them become stationary for longer durations. Smaller PEs with max40H <7 km tend to be weaker, while those with max40H >=7 km are relatively rare. These results suggest that stationariness is related to vertical structures of precipitation. In the presentation, large-scale environments related to these types of PEs will also be shown.
To achieve our goal, we combine JMA’s radar-gauge analyzed precipitation product (R/A) with TRMM/GPM DPR observed vertical structures. QSCBs are first detected with three hour accumulated rainfall of R/A both over the ocean and land. They are then collocated with TRMM/GPM precipitation events (PEs) during April-November for 2004-2023.
Various types of PEs with QSCBs are found in terms of the area and maximum 40-dBZ height (max40H). For larger PEs, duration and intensity are different according to max40H. Larger PEs with max40H <7 km tend to be strong, but not the strongest. Obviously, the strongest rainfall rates near the surface are found in larger PEs with max40H >=7 km. Some of them become stationary for longer durations. Smaller PEs with max40H <7 km tend to be weaker, while those with max40H >=7 km are relatively rare. These results suggest that stationariness is related to vertical structures of precipitation. In the presentation, large-scale environments related to these types of PEs will also be shown.