We found a match
Your institution may have access to this item. Find your institution then sign in to continue.
- Title
Macro‐ and Microphysical Characteristics of Extreme Hourly Precipitation Over the Pearl River Delta on the Monsoon Coast (South China).
- Authors
Qiu, Juliao; Luo, Yali; Wu, Chong; Gao, Yanyu; Yu, Shuting
- Abstract
In this study, the Extreme Hourly Precipitation Areas (EHPAs) of three extreme levels (i.e., between the 95th and 99th percentiles, between the 99th and 99.9th percentiles, beyond the 99.9th percentile) in the Pearl River Delta over South China are identified; then the related events and associated Convective Cores (CCs) are tracked, and their macro‐and‐microphysical characteristics are analyzed using multi‐year dual‐polarization radar observations. Results show that >90% of EHPAs are smaller than 10 km2, and 65%–75% of EHPA events last only one hour. They tend to be more localized and persist longer with increasing hourly‐precipitation extremity. The EHPAs overlap with the CCs during 50%–64% of the EHPAs' life span. Their occurrence frequencies are nearly quadrupled after the monsoon onset over South China Sea (SCS), with a major (secondary) peak at about 1400 LST (0600 LST) in the diurnal variations. The CCs are non‐linear shaped with about 65% being meso‐γ‐scale and embedded within mostly meso‐β or α‐scale 20 dBZ regions. The CCs generally contain active warm‐rain processes and about 70% possess moderate‐to‐intense mixed‐phase microphysical processes. The ratios of ice water path to liquid water path are about 0.37, and coalescence dominates (about 68%) the liquid‐phase processes. The average size of raindrop is slightly larger than the "maritime‐like" regime and the average concentration is much higher than the "continental‐like" regime. These CCs' characteristics roughly resemble those of the convection producing extreme instantaneous precipitation, except for a larger horizontal scale and less evident variations with the increasing hourly‐precipitation extremity. Plain Language Summary: Extreme precipitation is of global concern, but macro‐ and microphysical characteristics of its associated convection remain elusive. Recent studies have analyzed the characteristics of convection producing extreme instantaneous precipitation in a monsoon coastal region of South China. We would like to know the characteristics of extreme hourly precipitation, which is potentially more disastrous, and how they vary with increasing extremity. For this purpose, we use 5‐year dual‐polarization radar observations combined with distrometer observations over the region to compare among three different extreme levels, and with those of extreme instantaneous precipitation. Results show that the extreme hourly precipitation mostly covers a small area, lasts only 1 hour, and overlaps with strong echoes during more than half of its life span. After the onset of summer monsoon over the South China Sea, the extreme hourly precipitation occurs much more frequently with a bimodal feature in the diurnal variation of occurrence frequency, consistent with those of extreme instantaneous precipitation. The microphysical characteristics of convection overlapping with the extreme hourly precipitation area resemble those of the extreme instantaneous precipitation‐producing convection. However, the former vary less evidently with the increasing hourly precipitation extremity likely due to smaller variations in probability distribution of convective intensity. Key Points: The Extreme Hourly Precipitation Areas (EHPAs) overlap with non‐linear shaped Convective Cores (CCs) during 50%–64% of their life spanThe CCs have active coalescence with abundant small‐to‐medium size raindrops and ∼70% have moderate‐to‐intense mixed‐phase processesThe CCs' characteristics generally resemble extreme instantaneous rain‐producing convection but change less evidently with the extremity
- Subjects
CHINA; RAINDROP size; MONSOONS; DISTRIBUTION (Probability theory); EXTREME environments; LIFE spans; COASTS; RADAR meteorology
- Publication
Journal of Geophysical Research. Atmospheres, 2024, Vol 129, Issue 11, p1
- ISSN
2169-897X
- Publication type
Article
- DOI
10.1029/2023JD039929