Search

The main objective of this study is to reveal the variation characteristics of extreme temperature and precipitation events in Lijiang of Yunnan province.The data of daily maximum and minimum temperature and daily precipitation from 1951 to 2017 were obtained from Lijiang Meteorological Station.The variation trends, mutation and period characteristics of 16 extreme temperature indices and 11 extreme precipitation indices have been analyzed with methods of linear regression analysis, Mann-Kendall abrupt change test, moving 푡 test, and Morlet complex wavelet analysis.The results of variation trends are as follows. As for extreme temperature indices,significant increasing trends were observed in TNx, TNn, SU, TN90p, TX90p and WSDI ; obvious decreasing trends were observed in FD,TN10p,CSDI and DTR ; non-significant increasing trends were observed in TXx, TR and GSL; non-obvious decreasing trends were observed in TXn and TX10p ; and the values of ID remained 0 days during the study period.As for extreme precipitation indices, a significant decreasing trend was observed in R1; a significant increasing trend was observed in R99pTOT; non-significant decreasing trends were observed in R10, CWD, PRCPTOT and Rx5day; whereas non-significant increasing trends were observed in R20, R95pTOT, CDD, Rx1day and SDII. The results of mutation test are as follows.Significant mutation years were observed in some extreme temperature and precipitation indices, which usually fall on period from the 1980s to the beginning of the 21st century or period from the 1950s to the 1970s. Furthermore,the extreme cold events indices of FD, TN10p and TX10p showed decreasing trends after the significant mutation years, while the extreme warm events indices of SU, TN90p and TX90p showed increasing trends after the significant mutation years.The values of TR were 1 day in 2015 and 0 days in the remaining years of the study period.The periodic results of wavelet analysis are as follows.The 15 extreme temperature indices ( except ID) presented 2-6 quasi-periods ranging at 3-56 years, with 1-3 main periods ranging at 10-56 years.The 11 extreme precipitation indices presented 4-6 quasi-periods ranging from 4-56 years, with 1-3 main periods ranging from 12-56 years.Therefore,there are same or similar main periods for some extreme temperature and precipitation indices. [ABSTRACT FROM AUTHOR]

Copyright of Southwest China Journal of Agricultural Sciences is the property of Editorial Department of Southwest China Journal of Agricultural Sciences and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)