Definition and characteristics of the south edge of the subtropical winter monsoon in East Asian

Based on observational daily data of 730 meteorological stations in China, the south edge of the subtropical winter monsoon is defined according to relevant criterion and its variation characteristics are analyzed. Results show that this south edge has obvious inter-annual variation characteristics and shows a northward moving tendency as a whole, but since the 21 st century it has moved southwards and date of the south edge entering winter becomes earlier. Wind fields of the anomalously northward south edge of the subtropical winter monsoon in East Asia has an obvious southerly wind component which prevents cold air from moving southward. The index of this south edge and winter temperature has a positive correlation. Climate warming might be the main reason for the northward movement of the south edge of the subtropical winter monsoon.

夏热冬冷地区城市暖通空调季节划分

夏热冬冷地区具有高温高湿的共同性,又有明显的东、西气候差异。为了解夏热冬冷地区东、西区各城市间暖通空调季节的差异,通过分析东区代表城市南京和西区代表城市重庆的室外空气热湿状态及暖通空调季节转换的天气过程,发现东、西区城市暖通空调各季节间转换过渡期时间的早晚、长短及复杂程度并不相同。进一步分析发现,东、西区城市暖通空调运行调节的重点、难点及节能潜力较大的时段不同,东区城市是供暖季节前后的通风时段,西区城市是除湿、空调季节前后的通风时段。

江淮流域夏季降水对前冬持续时间长短的响应

利用NCEP/NCAR再分析资料计算得到江淮流域1961—2011年前冬持续时间,分析其时空变化特征,并进一步探究它与后期江淮流域夏季降水的关系.结果表明,江淮流域前冬持续时间存在着明显的年际和年代际变化,前冬持续时间显著偏长年份比偏短年份的前冬温度低、气压高、北风强,表明温度、气压、经向风可能是反映江淮流域前冬持续时间的关键因子,且不同区域各气象要素对季节长度的影响存在一定差异;1961—2011年江淮流域前冬持续时间与该区域夏季降水呈显著正相关关系;统计分析亦发现,前冬持续时间显著偏长(偏短)的代表年份中,夏季降水以偏多(偏少)为主;对典型代表年份环流场进行合成分析发现,前冬持续时间显著偏长时,乌拉尔山与鄂霍次克海地区夏季易形成阻塞形势,进而会对江淮流域夏季降水产生影响;最后利用奇异值分解从空间场相关的角度探讨了两者的联系,发现江淮流域夏季降水与前冬持续时间存在非常显著的关系.