青藏高原上空温度场低频变化的垂直结构及其与热带海气的相互关系

采用一点相关法研究了青藏高原东部对流层－平流层下部温度场低频变化的垂直结构,指出了最大负相关层的高度和强度随季节的变化特点,并与高原北部格尔木和我国东部（１２０°Ｅ、３０～５０°Ｎ）区域作了比较。从青藏高原对流层顶高度的季节变化、大气温度层结和动能垂直分布探讨了青藏高原温度场低频垂直结构及季节变化的物理背景。并指出：秋季１０～１１月青藏高原东部垂直热力结构、赤道印度洋－太平洋的两个纬向垂直Ｗａｌｋｅｒ环流圈强度与赤道东太平洋（０～１０°Ｓ、１８０～９０°Ｗ）区域ＳＳＴＡ之间具有极为密切的耦合关系。     

Characteristics and Diagnosis of the Landfalling Tropical Cyclones in the Guangdong-Hong Kong-Macao Greater Bay Area of China During 1981-2018

This paper applies statistical and synthetic analysis methods to study the characteristics of the three types of tropical cyclone (TC) that landed in the Guangdong-Hong Kong-Macao Greater Bay Area (GBA) from 1981 to 2018 and the reasons for the differences of TC-induced wind and precipitation. The results show that there are interdecadal changes in the frequency and intensity of the landfalling TCs in the GBA, with decreased frequency but increased intensity in the 2010s. The TCs that landed in the west of the Pearl River Estuary (PRE) have the most frequency and the strongest intensity during landing, which bring the strongest winds; the TCs that landed in the PRE have the least frequency and the shortest duration after landing, which cause the strongest precipitation; the TCs that landed in the east of the PRE have the relatively longest duration on the land. This study shows that near the center of the TCs that landed in the PRE, there is a weak anomalous cyclonic shear compared with the ones that landed in the west of the PRE. Compared with the TCs that landed in the east of the PRE, it is a confluence area of anomalous north wind and anomalous southwest wind, with better water vapor convergence and dynamic rising conditions, which is conducive to the formation of heavy precipitation. Compared with the TCs that landed in the PRE and in its east, there is a closed positive anomalous center of pressure gradient in the northwest center of the TCs that landed in its west, resulting in higher wind speeds in the west of the PRE. The characteristics of the three types of TCs in the GBA are highly related to TC-induced damage. In the future, the GBA needs to focus on preventing TCs landing in its west. Zhuhai, Jiangmen and Huizhou are key cities to guard against TCs. The results of this study provide foundations for effective management and reduction of TC disaster risks in the future construction of the GBA.     

近百年中国气候变暖趋势之再评估

基于均一化的气温观测序列集,1900年以来中国气温升高趋势1.3—1.7℃/(100 a)。这个已用于新近的中国国家气候变化评估报告的结果,远高于早期的评估结果(0.5—0.8℃/(100 a))。回顾了始于20世纪80年代的中国百年气温序列的研究,指出其中关键进展在于近年来研发了均一化的长期站点气温观测序列集。早年构建的中国气温序列中,20世纪40年代前异常偏高,除了战乱期间观测缺失严重及记录代表性问题外,主要是50年代前后很多台站迁址导致早期气温观测值系统性偏高所致,从而低估长期变暖趋势。40年代前后部分区域确实偏暖,但由于不同区域气温波动位相不一致,因而大范围平均序列中并不明显。这一事实可与近年发展的"北极暖-大陆冷"等气候变化动力学理论以及一些区域气温代用资料相印证。近几十年城市化对中国气温变化趋势之贡献大小尚存争议,但远非主导因素。     

综合气象观测系统的发展

回顾了气象探测发展史,分析了气象探测与气象预报、气象科学发展之间的紧密关系,指出了气象探测的发展推动了气象科学、气象预报和气象服务的发展;进一步描述了气象探测发展的现状,对于新技术的应用前景与气象仪器的未来发展趋势进行了分析与阐述,同时介绍了国际GCOS、GEOSS、WIGOS综合观测计划.     

沿120°E中纬度对流层—平流层下部气候变化及与臭氧变化的联系

利用1958~1995年海拉尔、沈阳、南京三地区地面至30 hPa标准层月平均气温资料,研究了近40年沿120°E、30°~50°N区域气候变率随高度、纬度和季节的分布特征,前、后两个20年气候变率的变动及其与亚欧不同地区臭氧变化的联系。结果指出：近20年来,该区域对流层中下部变暖速率随纬度显著增大,尤其在冬季;200 hPa以上变冷速率亦随高度及纬度显著增大,尤其在冬、春季。而前、后两个20年,高、低层气候变化趋势截然相反,这是一种年代际尺度气候变化。三地区各季节平流层下部变冷率（对流层中下部变暖率）随纬度增高而加大与邻近同纬带地区臭氧减少率随纬度增高而加大的现象基本对应,表明平流层下部因臭氧减少引起的辐射加热减少,可能是支配我国东部平流层下部变冷率（对流层中下部变暖率）随纬度增高而显著加大的一个重要因子。