Abstract:
Using daily maximum, minimum and average temperature data from 17 meteorological stations in Henan province during 1961-2016, the spatial and temporal variations of sixteen extreme temperature indices (cooling and warm indices) were analyzed by using multiple methods, such as Sen's tendency estimation, Mann-Kendall test, R/S analysis and spatial analysis. The results showed that:in terms of temporal variations, extreme temperature indices over Henan province presented a warming trend during the last 56 years. The indices (e.g. frost days, cool nights, warm nights and growing season length) showed the most significant warming trend. In terms of spatial variations, each station also showed a warming trend. The warming trends of Zhengzhou, Kaifeng, Xinxiang and Sanmenxia area were the most obvious. The initial warming, the significant warming and abrupt warming of cooling indices occurred earlier and to a greater magnitude. It suggested that the cooling indices were more sensible than warming indices in response to global warming. Extremes temperature indices over Henan province showed a strong persistence, indicating that the warming trend of extreme temperature indices would continue.