Long-term trends in daily temperature extremes over Mongolia

Various indices have been used to investigate recent changes in the annual frequencies of extreme temperature events in Mongolia. A high-quality daily temperature dataset including 53 station records was used to determine trends from 1961 to 2010. The Climdex1.0 software was used to calculate 11 extreme temperature indices for this study. The results showed significant changes in important temperature indices over the study period, especially in the Gobi Mongolia. The analysis showed that an apparent increase in summer days was observed, while an appreciable decrease in frost days was observed. The maximum values of daily maximum temperature (TXx) and daily minimum temperature (TNx) and the minimum values of T-max (TXn) and T-min (TNn) tended to increase. However, for TXx and TNx, this increasing trend was mainly observed in the Gobi Mongolia, while for TXn and TNn, this increasing trend was observed over the entire country. A significant reduction at a rate of -0.6 d decade(-1) (-1.0 d decade(-1)) occurred for cool nights (days), and a significant increase at a rate of 2.8 d decade(-1) (3.1 d decade(-1)) occurred for warm nights (days). The reduction of cool nights and cool days occurred over four seasons, while the increase of warm days and warm nights occurred mainly in summer. (C) 2014 The Authors. Published by Elsevier B.V.