Spatiotemporal changes of drought in the North2South transitional zone of China

In or der t o ident ify the occurr ence of dro ug ht in the North2So uth t ransitio nal zo ne ( Qinling2Dabashan) of China, t his paper used monthly precipitat ion and mean temperature of 32 meteor olog ical stations f rom 1960 to 2015 to calculate the monthly dr ought in the study ar ea. T he met eo ro lo gical dro ug ht index CI and the cumulat ive anomaly method based on the principle of met eo ro lo gical dr ought classif ication w ere used to analyze the dro ug ht chang es in the No rth2South tr ansitional zo ne of China. The r esults show ed that the droug ht intensity , dur atio n and frequency of different levels o f dro ug ht incr eased wit h time, and the lig ht drought accounted fo r the most in all lev els of dro ug ht, w hich w as 551 6% . The occurrence o f dr ought had a seasonal pat2 ter n. The intensity o f spring dro ug ht w as t he lar gest and the dur ation was lo ng . T he summer dro ug ht w as the most likely to oc2 cur. The frequency of autumn dro ug ht generally increased first and then decr eased, reaching max imum in t he 1990s. The dur a2 tion of w inter dro ug ht was relativ ely short compar ed to ot her seasons. In terms of spatia l change, the northern part o f t he study area was r elativ ely dr y, and the so ut h w as relativ ely humid, the Wudu area and the Henan reg ion w as the airdest, w her eas the so uther n part of Gansu w as the wettest reg io n in the entire study area.

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