To ensure the effectiveness of the operation of artificial precipitation enhancement, a potential region for the operation should be determined in advance.As cloud microphysical measurements needed for the determinati...To ensure the effectiveness of the operation of artificial precipitation enhancement, a potential region for the operation should be determined in advance.As cloud microphysical measurements needed for the determination of the potential region of cloud seeding are not available before the operation of routine precipitation enhancement, a new method based on the growth process of ice crystal is put forward for determining the potential region using the numerical weather prediction model output.The ice supersaturation, accumulated water vapor within minus temperature layer (≥9 mm), and upward water vapor transportation are adopted as criteria to determine the potential time, height and region of cloud seeding, and the real-time radar images are applied to make decisions on the seeding commanding.The criteria and Doppler radar images are studied in a case of precipitation enhancement characterized by significant water vapor supply from the north part of a tropical cyclone in the northwest Pacific, which shows that the ocean plays a crucial role in the advection transportation of water vapor to the potential region of the coastal area.The study presents a new method to determine the potential region of precipitation enhancement using macro-physical quantities under ice crystal growth environment.The method possesses a clear physical significance and can be readily applied with the required and easily predicted parameters.展开更多
Aims Alien plant invasion has become a major global environmental issue,causing severe economic and ecological damages.Severe invasions have been reported in some regions of China.However,most studies have been conduc...Aims Alien plant invasion has become a major global environmental issue,causing severe economic and ecological damages.Severe invasions have been reported in some regions of China.However,most studies have been conducted at local and provincial levels,and the overall degree of invasion in natural forests across China remains unclear.Here,we explored the biogeographic patterns and their environmental and socioeconomic controls of the invaded alien woody plants in natural forests across the country.Methods We compiled the data of 3573 natural forest plots across the China's Mainland and mapped spatial distribution of alien woody plant invasion.We also used logistic regression models to identify the key socioeconomic and environmental factors that were associated with the observed invasion patterns.Important Findings We found that only 271 plots among 3573 natural forest plots were invaded by alien woody plants,accounting for 7.58%of all plots.Among all 2825 woody plant species across all plots surveyed,only 5 alien species(0.177%)were found.Both human activities and climate factors were related to the observed invasion patterns.Since China’s natural forests are mostly located in remote mountainous areas with limited human disturbance,alien woody plant invasions are less than those reported in North America and Europe.However,with the development of transportation and increased economic activities in mountainous areas,more invasions by alien plants may be expected in the future.Therefore,proactive management and policy making are desired to prevent or slow down the invasion processes.展开更多
基金the support from the Meteoro-logical Science and Technology Research Project (2009-sdqz05),Shandong Meteorological Bureau
文摘To ensure the effectiveness of the operation of artificial precipitation enhancement, a potential region for the operation should be determined in advance.As cloud microphysical measurements needed for the determination of the potential region of cloud seeding are not available before the operation of routine precipitation enhancement, a new method based on the growth process of ice crystal is put forward for determining the potential region using the numerical weather prediction model output.The ice supersaturation, accumulated water vapor within minus temperature layer (≥9 mm), and upward water vapor transportation are adopted as criteria to determine the potential time, height and region of cloud seeding, and the real-time radar images are applied to make decisions on the seeding commanding.The criteria and Doppler radar images are studied in a case of precipitation enhancement characterized by significant water vapor supply from the north part of a tropical cyclone in the northwest Pacific, which shows that the ocean plays a crucial role in the advection transportation of water vapor to the potential region of the coastal area.The study presents a new method to determine the potential region of precipitation enhancement using macro-physical quantities under ice crystal growth environment.The method possesses a clear physical significance and can be readily applied with the required and easily predicted parameters.
基金This research was supported by the National Natural Science Foundation of China(31988102).
文摘Aims Alien plant invasion has become a major global environmental issue,causing severe economic and ecological damages.Severe invasions have been reported in some regions of China.However,most studies have been conducted at local and provincial levels,and the overall degree of invasion in natural forests across China remains unclear.Here,we explored the biogeographic patterns and their environmental and socioeconomic controls of the invaded alien woody plants in natural forests across the country.Methods We compiled the data of 3573 natural forest plots across the China's Mainland and mapped spatial distribution of alien woody plant invasion.We also used logistic regression models to identify the key socioeconomic and environmental factors that were associated with the observed invasion patterns.Important Findings We found that only 271 plots among 3573 natural forest plots were invaded by alien woody plants,accounting for 7.58%of all plots.Among all 2825 woody plant species across all plots surveyed,only 5 alien species(0.177%)were found.Both human activities and climate factors were related to the observed invasion patterns.Since China’s natural forests are mostly located in remote mountainous areas with limited human disturbance,alien woody plant invasions are less than those reported in North America and Europe.However,with the development of transportation and increased economic activities in mountainous areas,more invasions by alien plants may be expected in the future.Therefore,proactive management and policy making are desired to prevent or slow down the invasion processes.
