A Statistical Analysis of the Environmental Parameters for Heavy Rains During the Dragon-boat Rain Periods over the Past 50 Years in Shenzhen
WANG Rui
WANG Ming-jue
CHEN Xun-lai
Abstract：Based on the rainfall data from a national basic meteorological observation station in Shenz-hen and radiosonde data from Hong Kong(site No.:45003),this work statistically analyzed the physical quantities that depict the temperature and humidity,energy and dynamics during heavy rains(with 12 h rainfall amount ≥30 mm)in the recent 50 Dragon-boat Rain periods(spanning annually from May 21 to June 20)from 1973 to 2020,and extracted the thresholds of key environmental parameters with these heavy rains based on 25 percentiles.The results are shown as follows.(1)The heavy rains during the Dragon-boat Rain periods can be better indicated by atmospheric precipitable water(PW),500 hPa temperature-dew point difference((t-td)500),850 hPa temperature-dew point difference((t-td)850)and the K index for depicting energy conditions.Prior to these heavy rains,the PW was sufficient in the atmosphere,water va-por was near the point of saturation,and the atmosphere was full of energy.(2)From a comparison of the characteristics of environmental parameters prior to the heavy rain between the day and the night,it is known that when PW≥62 mm,(t-td)500 ≤3.5 ℃,(t-td)850 ≤2.8 ℃ and the K index ≥35 ℃ at 08:00,it is favorable for daytime heavy rains to take place,and if PW≥61 mm,(t-td)500 ≤3.1 ℃,(t-td)850 ≤3.4℃ and the K index ≥34 ℃,it is likely that nocturnal heavy rains will happen.
Keywords：climatologyDragon-boat Rainheavy rainradiosonde dataphysical parameterShenzhen
Publication Date：2023-12-20
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：6( 11-16 )