A Preliminary Study on the Characteristics of Compound Drought and Heat Events in the Summer of Eastern Guangdong
Using the daily maximum temperature data from 20 national meteorological observation sta-tions in eastern Guangdong from May to October in 1967-2021 and a drought index,this work identifies high-temperature(or drought)events and defines compound drought and heat events(to be abbreviated as"CPD-dr/ht event"hereafter)using sliding windows to obtain the thresholds of daily 90(or 10)percentiles for high temperature or droughts.Then,the statistical approaches of linear analysis,sliding t-test,wavelet analysis and EOF decomposition are used to study the spatiotemporal distribution characteristics of the CPD-dr/ht event in this part of the province.The results are shown as follows.(1)The CPD-dr/ht event in the summer of eastern Guangdong presents a spatial distribution that is generally more in the north than in the south,with the trends of large CPD-dr/ht event values distributed in Puning and Jieyang(the central part of eastern Guangdong),corresponding to the second and third modes of EOF decomposition,or the north-south dipole and north-south triple patterns.The main spatial distribution mode of the CPD-dr/ht event is consist-ently more or less across the whole eastern Guangdong(i.e.the first mode).(2)The CPD-dr/ht event in-creases significantly in a general trend of going up,down and then up again.It is noteworthy that a signifi-cant abrupt change was recorded in 1991 that marked with a change from descending to ascending.The CPD-dr/ht event consists of an oscillation at the primary period of about 10 years and periodic variation at a-bout three or five years.(3)The CPD-dr/ht event mainly concentrated in July to August before the 1990s but its increasing trend was much higher in May and September than in the rest of the year after it.(4)A-round the 1990s,the CPD-dr/ht event differed much in persisting duration;it mainly lasted 1 d before the 1990s but 2 d or even 3 d or more(persistently)after it,in which persistent CPD-dr/ht events were the main contributor of this type of event.
climatologycompound drought and heat eventrelative thresholdsliding windowsum-mereastern Guangdong
万方数据
维普
