Analysis on Thresholds of the"Three-Tier Alert System"for Intense Rainfall Weather in Hezhang County
The purpose of this paper is to investigate the scientificity and rationality of the three-tier alert system"threshold settings for heavy precipitation weather in Hezhang County and make the system more in line with the local realities in Hezhang County.By using the precipitation data of 10 disastrous severe precipitation and the disaster information in Hezhang County from 2013 to 2022,and the mathematical statistical analysis method,this paper analyzes the threshold values of the"three-tier alert system"of meteorological service mechanism for heavy precipitation weather in Hezhang County and provides suggestions for improvement.The analysis results are as follows:(1)The overall precipitation in Hezhang County exhibits a trend of less in the northwest and more in the southeast,while the maximum hourly precipitation generally shows a distribution of more in the northwest and less in the southeast.(2)Disaster-causing severe precipitation in Hezhang County is mainly distributed in Dezhuo,Hezhen,Jiegou,Kele,Fuchu,Anle in the northern part,Caishen,Dayi in the central-eastern part,and Weishe,Zhushi,Songlinpo in the southeastern part.The duration of the disaster-causing intense precipitation is approximately 6 hours.(3)The primary period of heavy precipitation in Hezhang County is from 15:00 to 06:00 the next day.(4)Townships in the northern part of Hezhang County have weaker disaster-bearing capacities,while those in the southeast have relatively stronger capacities.(5)When the hourly precipitation in the jurisdiction reaches 30 mm or more,and heavy rainfall is expected to continue,the fourth-level alert is initiated.When the accumulated precipitation at a station within the jurisdiction reaches 50 mm in 3 h or 70 mm in 6 h or more,and precipitation is expected to continue,the third-level alert is initiated.When the accumulated precipitation at a station within the jurisdiction reaches 80 mm in 3 h or 100 mm in 6 h or more,and precipitation is likely to continue,the second-level alert is initiated.When the accumulated precipitation at a station within the jurisdiction reaches 130 mm in 6 h or200 mm in 12 h or more,and precipitation is expected to continue,the first-level alert is initiated.To sum up,this paper clearly defines the reasonable thresholds for the"three-tier alert system"for severe rainfall weather in Hezhang County,and could provide a support for enhancing the local capacity to respond to meteorological disasters.
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