1 INTRODUCTION Tropical cyclones （TCs） moving north and getting to the Liaodong Peninsula and waters of the Yellow and Bohai Seas are in their late phase of life cycle. While weakening rapidly, TCs carry a large amo...1 INTRODUCTION Tropical cyclones （TCs） moving north and getting to the Liaodong Peninsula and waters of the Yellow and Bohai Seas are in their late phase of life cycle. While weakening rapidly, TCs carry a large amount of warm and humid air that forms heavy rainfall by itself on the one hand and interact with westerlies in the middle latitudes on the other. With their warm-core structure destroyed by intruded cooler air, TCs absorb baroclinic energy while it weakens and experiences extratropical transition （ET）. With right conditions and complicated topographic features of the peninsula, the transformed extratropical cyclone evolves to intensify heavy rainfall in most cases and even results in secondary disasters like storm surges. Therefore, the extratropical transition of TCs is usually responsible for more serious damage in mid-latitude areas. For the forecast of heavy rain associated with north-going TCs experiencing extratropical transition, it not only involves their own intensity and structure but also the distribution of the surrounding field and its interactions with TCs. Most of the present studies discuss TCs-inflicted heavy rains or those taking place south of the Shandong Peninsula. Focusing on intense precipitation resulted from TCs over the Liaodong Peninsula, this work analyzes the distribution of the ambient field and physical quantities hoping to help forecast TCs-related heavy rains accurately.展开更多
Based upon the summer (June-August) precipitation data from 30 stations in the middle and lower reaches of Yangtze River in China, the spatial and temporal distribution of summer precipitation in the Yangtze River Bas...Based upon the summer (June-August) precipitation data from 30 stations in the middle and lower reaches of Yangtze River in China, the spatial and temporal distribution of summer precipitation in the Yangtze River Basin was analyzed. As was shown in the results, the distribution of summer precipitation in the middle and lower reaches of Yangtze River was mainly composed of four types: northern type (2005 and 2007), southern type (2001 and 2003), intermediate type (2000, 2004 and 2006) and integral type (2002). According to the correlation analysis of summer precipitation and atmospheric circulation in East Asia, the precipitation in the Yangtze River Basin and high-low level circulation anomalies were significantly related. In other words,with the increase of the meridional degree of circulation at mid-high latitudes in the middle and upper troposphere as well as anomaly by south of subtropical high at low latitudes,the center or ridge line remained steady in the south of 30° N,thus the precipitation in the Yangtze River Basin was obviously on the high side. The study could provide better guidance for the diagnosis and forecasting of precipitation in the Yangtze River Basin in the future.展开更多
基金Project 973 from the Ministry of Science and Technology of China (2004CB418301)a projectof Natural Science Foundation of China (40175019)
文摘1 INTRODUCTION Tropical cyclones （TCs） moving north and getting to the Liaodong Peninsula and waters of the Yellow and Bohai Seas are in their late phase of life cycle. While weakening rapidly, TCs carry a large amount of warm and humid air that forms heavy rainfall by itself on the one hand and interact with westerlies in the middle latitudes on the other. With their warm-core structure destroyed by intruded cooler air, TCs absorb baroclinic energy while it weakens and experiences extratropical transition （ET）. With right conditions and complicated topographic features of the peninsula, the transformed extratropical cyclone evolves to intensify heavy rainfall in most cases and even results in secondary disasters like storm surges. Therefore, the extratropical transition of TCs is usually responsible for more serious damage in mid-latitude areas. For the forecast of heavy rain associated with north-going TCs experiencing extratropical transition, it not only involves their own intensity and structure but also the distribution of the surrounding field and its interactions with TCs. Most of the present studies discuss TCs-inflicted heavy rains or those taking place south of the Shandong Peninsula. Focusing on intense precipitation resulted from TCs over the Liaodong Peninsula, this work analyzes the distribution of the ambient field and physical quantities hoping to help forecast TCs-related heavy rains accurately.
文摘Based upon the summer (June-August) precipitation data from 30 stations in the middle and lower reaches of Yangtze River in China, the spatial and temporal distribution of summer precipitation in the Yangtze River Basin was analyzed. As was shown in the results, the distribution of summer precipitation in the middle and lower reaches of Yangtze River was mainly composed of four types: northern type (2005 and 2007), southern type (2001 and 2003), intermediate type (2000, 2004 and 2006) and integral type (2002). According to the correlation analysis of summer precipitation and atmospheric circulation in East Asia, the precipitation in the Yangtze River Basin and high-low level circulation anomalies were significantly related. In other words,with the increase of the meridional degree of circulation at mid-high latitudes in the middle and upper troposphere as well as anomaly by south of subtropical high at low latitudes,the center or ridge line remained steady in the south of 30° N,thus the precipitation in the Yangtze River Basin was obviously on the high side. The study could provide better guidance for the diagnosis and forecasting of precipitation in the Yangtze River Basin in the future.
