Extreme Temperature Events in Eastern Edge of the Qinghai-Tibet Plateau from 1963 to 2012

Based on daily maximum,minimum and average temperatures recorded along the eastern edge of the Qinghai-Tibet Plateau from 1963-2012,linear trend estimation,Mann-Kendall test mutations and wavelet analysis were used to analyze extreme temperature changes. Eleven indices of extreme temperature were included. We found that changes in daily maximum and minimum air temperature in one year,summer days,warm days during day and night and the biological growth season have all risen;the tendency rates were 0.31℃/10 a,0.58℃/10 a,1.56d/10 a,3.45d/10 a,4.44d/10 a and 2.9d/10 a. Changes in daily temperature range,freezing days,frost days and cold days during day and night have declined;the tendency rates were- 0.15℃/10 a,- 1.86d/10 a,- 4.02d/10 a,- 2.74d/10 a and- 5.8d/10 a. This phenomenon is consistent with global warming trends. Under the influence of a variety of factors,spatial differences in the extreme temperature index were obvious. The extremely high(low) temperature,heating and cooling indices and diurnal change were asymmetrical. The extremely low temperature warming trend was more obvious than the extremely high temperature warming trend. Night index trends were more obvious than day index trends. The downward trend in the cold index was more obvious than the rise in the warm index. An obvious sharp change in extreme temperature indices has occurred along the eastern edge of the Qinghai-Tibet Plateau in the last 50 years. The shock period was approximately13 years and less than 5 years of the process of alternating high and low values.