Abstract: Based on the daily maximum and minimum temperature data from 1971 to 2012 from five stations in Mt. Qomolangma Region of Tibet,the spatial and temporal change of extreme temperature events were analyzed using the methods of inverse distance weighted (IDW),linear regression and Mann-Kendall test. The main results are obtained as follows: ① The maximum value of daily maximum temperature (TXx),minimum value of daily maximum temperature (TXn),minimum value of daily minimum temperature (TNn) and maximum value of daily minimum temperature (TNx) significantly increased with a rate of 0.30-0.64 ℃·(10a)^-1 during recent 42 years,and the maximum rate in TNn. Frost days (FD) and ice days (ID) showed significantly decreasing at a rate of -4.99 d·(10a)^-1 and -1.24 d·(10a)^-1,especially in the south slopes of Mt. Qomolangma. The length of growing season (GSL) showed statistically significant increasing at the rate of 4.81 d·(10a)^-1,and diurnal temperature range (DTR) showed significant rates of decrease of 0.08 ℃·(10a)^-1. Significant reduction at a rate of -6.54 d·(10a)^-1〔-8.87 d·(10a)^-1〕occurred for cool days (TX10p)〔nights (TN10p)〕,and significant increase at a rate of 8.17 d·(10a)^-1〔12.07 d·(10a)^-1〕occurred for warm days (TX90p)〔nights (TN90p)〕. ② In terms of decadal variations,the warm indices (TNx,TX90p,TN90p and GSL) showed increasing trend,while the cold indices(FD,ID,TX10p and TN10p)has decreased. ③ It is also found that the abrupt change of the TXx and GSL had abrupt change respectively in 1980 and 1984,the other extreme temperature indices occurred in 1900s.

Key words: extreme temperature index, spatial-temporal change, mutation, Mt. Qomolangma, Tibet