Two compound dry-hot event indexes,i.e.,standardized compound event indicator(SCEI)and blended dry and hot events index(BDHI),were calculated based on the standardized precipitation index(SPI)and the standardized temperature index(STI).Then,the performance of SCEIand BDHIin monitoring the compound dry-hot events over northwest China was evaluated,by which the risk changes of compound dry-hot events were analyzed based on the severity,area coverage percentage and frequen-cy.The results show that the BDHIhas a better performance in monitoring the compound dry-hot events over northwest China than SCEI,due to its coverage of diverse correlations between different dry and hot conditions;whereas the SCEI may misjudge the hot and wet conditions as compound dry-hot events.The severity,area coverage percentage and frequency of compound dry-hot events were higher during the period of 1994-2022 than that of 1982-1993 over northwest China.During the period of 1994-2022,the area proportions of compound dry-hot events with the light,moderate,and severe categories were 35%,25%,and 10%,respectively.Notably,the central part of Xinjiang,northern and eastern Gansu,southern Qinghai,and most of Shaanxi have hardly experienced compound dry-hot events above the severe level during the period of 1982-1993;however,the frequency of these events has significant-ly increased in these areas during the period of 1994-2022.
compound dry-hot eventsrisk assessment,compound event indexnorthwest China
国家科技期刊平台
NSTL
万方数据
