近60a阿勒泰地区不同等级降温日气候特征

利用阿勒泰地区7个气象站自建站至2014年12月31日的逐日气温资料,以日最低气温及其降温幅度为指标,整理出阿勒泰地区近60 a降温日数据库,按降温幅度将降温日分为寒潮、强降温、较强降温、中等强度降温和弱降温5个等级,分析了全地区各站不同等级降温日数的气候特征。结果表明:(1)阿勒泰地区寒潮日数和强降温日数在地区偏东、偏北多,向偏西偏南逐步递减,其它等级降温日数在河谷平原多,向西、向东逐步递减。寒潮、强降温和中等强度降温日数的EOF分解第一模态方差贡献率较大,全地区呈较好的一致性,较强降温和弱降温日数的EOF分解主要模态分别有3个和5个。(2)阿勒泰地区寒潮日数在冬季12月最多,强降温日数在秋季9月最多,较强降温日数主要集中在夏季6—8月,中等强度和弱降温日数在各季分布较平均。(3)近60 a来,阿勒泰地区各站的年寒潮和强降温日数呈明显减少趋势,年较强降温日数呈明显增多趋势,年中等强度降温日数没有明显的线性变化趋势,年弱降温日数呈地区西部减少、中、东部增多的趋势,且东部增多趋势较显著。

The climatological characteristics of the frequency of temperature decreasing days at different levels in Altay Region during the recent 60 years

Abstract: Using the daily temperature data of 7 meteorological Observation Stations in Altay from the establishment of Meteorological Observation Stations that day to December 31, 2014 and Using the daily minimum temperature and cooling rate as an indicator, the Altay region to sort out the past 60 years the number of days to cool the database, according to the strength of the cooling rate divided into weak cold air, moderate cold air, the strong cold air, the strong cold air and cold five grades, analyzed the frequency of each station at all levels of the cold air region, results showed that: (1) cold wave and strong cold throughout the region air annual average frequency of occurrence was easterly, northerly and gradually decreases towards the south west, other levels of performance for cold valley plain to the west, east and gradually decreasing. (2) frequency of occurrence cold wave across the region most winter, strong cold autumn the most basic strong cold air occurs in the summer, cold and moderate cold air more evenly distributed throughout the year. (4) cold wave stations, frequency of occurrence of strong cold air showed a decreasing trend, a strong cold air showed a growth trend, moderate cold air did not change significantly, weak cold air west tended to decrease, in the eastern part of the growth was trends, and the growth trend is more significant east. EOF analysis (5) stood every level of frequency of occurrence of cold air show, the first mode of variance cold, strong cold, moderate cold air is relatively large, and the whole area was a better consistency than strong cold air and cold air of the main modes, respectively three and five.