1961-2012年中国5类主要冰冻天气的气候及变化特征

利用1960/1961-2011/2012年中国有冰冻天气观测且序列完整的1 600多站逐日冰冻现象数据, 研究了中国地区冰冻天气的时空气候变化特征. 结果表明: 年平均霜日数超过180天的地区主要分布在青藏高原东北部、天山、大-小兴安岭一带. 霜日数在我国中北部和青藏高原地区以增加趋势为主, 长江流域及其以南地区为减少趋势. 全国平均的霜日数为显著增长趋势, 超过0.05的显著性水平, 线性增长率达到2.03 d·(10a)^-1, 霜日发生频率增强; 年平均积雪日数超过90 d的地区分布在青藏高原东北部、天山、大-小兴安岭一带. 积雪日数无明显时间变化趋势; 年平均结冰日数超过210 d的地区分布在青藏高原、大兴安岭及天山部分地区. 结冰日数全国范围以减少趋势为主. 全国平均结冰日数有明显的年代际变化趋势, 1980-1990年为结冰日数最多年份; 年平均雾凇日数超过30 d的地区主要在天山地区、大兴安岭地区以及四川峨眉山. 雾凇日数以减少趋势为主, 长江中下游部分地区有增加趋势. 全国平均雾凇日数有显著减少趋势, 超过0.01的显著性水平, 线性递减率达到0.60 d·(10a)^-1; 年平均雨凇日数主要分布在南方云贵高原地区以及长江中下游地区的一些高山区域. 雨凇日数在华北平原地区以减少趋势为主, 长江中下游地区部分站点有增加趋势. 全国平均雨凇日数随时间有弱的增加趋势.

Climatic characteristics and variations of the gelivation weathers in China during 1961-2011

Gelivation weathers,including frost,snow-cover,ice-cover,rime,glaze,etc.are catastrophic climate events.Scientists pay more attention to their climatic effects,because the agriculture,forestry,transpor-tation,electric supplying,communication and people′s diet become more sensitivity in the gelivation weathers. Based on the daily observations of the gelivation weather phenomena at more than 1 600 stations,the five kinds of primary gelivation weather characteristics in China from 1960/1961 to 2011/2012 are analyzed.The result shows that the yearly averaged frost weather more than 1 80 days occur mainly in the northeast of the Tibetan Plat-eau,Tianshan Mountains and the Greater and Lesser Xingan Mountains.Frost day has a linear increasing trend in the northern Central China and the Tibetan Plateau,and a decreasing trend in Yangtze River basin and its south.It is an evident increasing trend of the nationwide averaged frost days,which has passed through the test at 0.05 significance level,with an increase rate of 2.03 d per 10a,so the frequency of frost days is increasing. The yearly averaged snow-cover duration more than 90 days occurs mainly in the northeastern Tibetan Plateau, Tianshan Mountains and the Greater and Lesser Hinggan Mountains.There is no evidently linear trend of snow-cover days.The yearly averaged ice-cover duration more than 210 days occurs mainly in the Tibetan Plateau, Greater Hinggan Mountains and parts of the Tianshan Mountains.The nationwide ice-cover duration is mainly decreasing.The nationwide averaged ice-cover duration has evident decadal variation;the longest one was from 1980 to 1990.The yearly averaged rime duration more than 30 days mainly takes place in the Tianshan Mountains,the Greater Hinggan Mountains and the Emei Mountain.The rime duration in China is mainly decreasing linearly,with a partial increase in the Yangtze River basin.The nationwide averaged rime duration is evidently decreasing with a rate of 0.60 d per 10 a,and passing through the test at 0.01 significance level.Galze mainly occurs in Yunnan-Guizhou Plateau and a few high mountains in the middle and lower reaches of the Yan-gtze River.The galze duration is mainly decreasing linearly in North China Plain,with a partial increase in parts of the middle and lower reaches in the Yangtze River.The nationwide averaged galze duration has a faintly increasing.