Conventional meteorological statistics methods were used to figure out the annual temperature,sunshine hours,precipitation and precipitation days at Jinhua Meteorological Observatory from 1968 to 2020,and to analyze the characteristics of climate change in Jinhua region and the sensitive areas for extreme climate.The results showed that:(1)Under different climate states,the average temperature and precipitation in Jinhua showed increasing trends,and were the most obvious in states Ⅲ and Ⅳ,while sunshine hours and precipitation days showed decreasing trends,and the most obvious in states Ⅱ and Ⅳ;however,with the changes of the Ⅱ-Ⅳ state,the increase of average temperature,the decreases of sunshine hours and the number of precipitation days all weakened,and the increase of precipitation first increased and then decreased.(2)The average temperature in Jinhua was high in Lanxi and was low in Pujiang,and the sunshine hours were more in Yiwu but less in Yongkang and Lanxi.The precipitation was more in Wuyi and Pujiang but less in Dongyang and Yiwu,the precipitation days were more in the south but less in the north.With the change of climate state,the above four elements showed a significant trend of increasing,decreasing,increasing,and decreasing,respectively.(3)Due to the change of climate state,the average temperature level in Jinhua area moved from low to high,the level of sunshine hours moved from high to low,the precipitation level moved back and forth from 4 to 3,and there was insignificant change in the level of precipitation days.(4)With the change of climate state,the whole Jinhua area except Lanxi was sensitive areas for extreme temperature.Lanxi and Yiwu were sensitive areas for extreme sunshine hours,and there were basically no sensitive areas for extreme precipitation and precipitation days.

利用1968-2019年金华市7个台站逐年平均降水量和降水日数资料,将不同气候态、年代际下二者的变化特征进行了对比分析.结果表明,不同气候态下,金华市的平均降水量呈先减小后增大的趋势,而平均降水日数则呈先减少后持平的趋势.随着年代际更替,平均降水量和平均降水日数均呈先增多后减小再增多的趋势.多年平均降水量和降水日数等值线,随着气候态更替,分别呈现出先西退南压后东移北抬以及先南压后维持的趋势;此外,前者在20世纪80年代至90年代主要呈增大趋势,而后者则随着年代际转变(21世纪00年代除外)呈先北抬后南压再北抬的趋势.

Based on NCEP/DOE(National Centers for Environmental Prediction/Department of Energy) reanalysis data of surface sensible heat and latent heat fluxes on the Tibetan Plateau(TP) and datasets of the Tibetan Plateau Vortex(TPV) recognized from MICAPS(Meteorological Information Comprehensive Analysis and Process System) weather maps, this paper studies the near 30-year(1981–2010) climatological characteristics of surface heating and generating frequency of TPVs over the TP in summer, and analyzes the temporal correlation between the TP surface heating and the TPV statistics and its physical cause. The following results are obtained: The climatic average of TP surface sensible heat fluxes in summer is 58 W m-2, showing an overall weak decreasing trend in the near 30-year period. An increasing trend is apparent in the early 1980 s and most of the first decade of the 21 st century, but a fluctuating decline between. Surface heating shows a quasi-three-year periodic oscillation, and an abrupt climate change starts around 1996. The climatic average of surface latent heat fluxes in summer is 62 W m-2, showing fluctuating changes accompanied by an increasing trend over the near 30-year period. The surface latent heat shows a quasi-four-year periodic oscillation, with an abrupt increase beginning around 2004. The climatic average of the surface heat source in summer is 120 W m-2; sensible heat and latent heat on the ground contributes the same to the surface heat source over the TP in summer. The surface heat source shows a modest weakening trend overall, with a strong phase between the 1990 s and 1980 s, an obvious weak phase in the first six years of the 21 st century, and then becomes strong again. The surface heat source shows a three-year periodic oscillation and an abrupt change from strong to weak around 1997. Based on identification using the MICAPS weather maps, the linear frequency of summer TPVs over the near 30-year period showed a certain degree of decline, with a higher frequency mainly concentrated in the 1980 s to 1990 s. The generating frequency of TPVs shows a 7-year periodic oscillation, and features an abrupt change around 1998. The generating frequency of TPVs over the same period is highly positively correlated to sensible heat but weakly negatively correlated to latent heat, but compared with the surface heat source over the TP, is still a significant positive correlation. On the climate scale, therefore, stronger periods of TP surface heating, especially surface sensible heating, correspond to the favorable formation of TPVs. From the perspective of the temporal correlation of climate statistics, this study reveals important impacts of the TP surface heating on promoting TPVs and convective activity.

In January 2008, extreme freezing rain struck South China. At the same time, the Tibetan Plateau (TP) was experiencing pronounced surface heating. The characteristics of this extreme weather and its linkage to the TP surface heating anomaly were analyzed in this paper. The results show that (1) anomalous heating of the TP helps to form and sustain the Siberian blocking high, which is important for persistent southward flow of dry and cold Siberian air; (2) TP heating helps the moisture flux move more north and strengthens the southerly wind above 850 hPa; (3) there are two Rossby wave trains at 500 hPa and the layers above it (at about 20 degrees N-40 degrees N). Correlation analysis reveals that TP heating anomalies are closely associated with these Rossby wave trains; (4) the Rossby wave propagates downstream from the TP to South China in the mid and high layers of the atmosphere when the TP changes swiftly from a heat sink to a heat source. This implies that anomalous heating of the TP may stimulate the Rossby wave train to propagate downward in midlatitudes.

采用REOF、合成分析等方法,研究了1960～2005(共46年)我国南方地区冬季(1月)地面最低气温的时空特征,并探讨了经过REOF分区后各区域影响最低气温的主要因子.结果表明:根据最低气温REOF分区可把我国南方地区最低气温划分为A,B,C三个区域:A区主要包括广西、湖南、贵州;B区主要包括海南、广东、福建和浙江;C区主要包括湖北、河南和安徽.影响这三个分区最低气温的因子各有不同,A区主要是受来自青藏高原东部及其周边的热源影响,B区主要是受西太副高和西南气流的影响,影响C区的则主要是来自北方的冷空气.