Considering the problem that the scattering echo images of airborne Doppler weather radar are often reduced by ground clutters,the accuracy and confidence of meteorology target detection are reduced.In this paper,a de...Considering the problem that the scattering echo images of airborne Doppler weather radar are often reduced by ground clutters,the accuracy and confidence of meteorology target detection are reduced.In this paper,a deep convolutional neural network(DCNN)is proposed for meteorology target detection and ground clutter suppression with a large collection of airborne weather radar images as network input.For each weather radar image,the corresponding digital elevation model(DEM)image is extracted on basis of the radar antenna scan-ning parameters and plane position,and is further fed to the net-work as a supplement for ground clutter suppression.The fea-tures of actual meteorology targets are learned in each bottle-neck module of the proposed network and convolved into deeper iterations in the forward propagation process.Then the network parameters are updated by the back propagation itera-tion of the training error.Experimental results on the real mea-sured images show that our proposed DCNN outperforms the counterparts in terms of six evaluation factors.Meanwhile,the network outputs are in good agreement with the expected mete-orology detection results(labels).It is demonstrated that the pro-posed network would have a promising meteorology observa-tion application with minimal effort on network variables or parameter changes.展开更多
[Objectives]This study was conducted to investigate insect activity rhythms in airport ground cover areas,and provide guidance for insect control and bird strike prevention.[Methods]The daily rhythm of insects in the ...[Objectives]This study was conducted to investigate insect activity rhythms in airport ground cover areas,and provide guidance for insect control and bird strike prevention.[Methods]The daily rhythm of insects in the northern area of the airport was studied,and their activity rhythms and characteristics under different weather conditions were analyzed.[Results]In rainy days,the insect number in the three sample areas was low.In cloudy days,insect activity was relatively stable,and insect number was consistent in the morning and evening,and maintained in a stable range,while in sunny weather,insect activity was increased,and the number changed greatly with time.For a single tussock plant growth area,the number of insects was at a relatively low level under rainy weather.In fine weather,the peak period of insect activity was between 10:00-11:00 and 14:00-15:00.[Conclusions]This study can provide a reference for the formulation of safe flight departure time.展开更多
We introduced query system of the historical high-altitude surface weather chart. Historical high-altitude surface data were converted to Grads data format. Grads as generation tool of the image, ASP was used to compi...We introduced query system of the historical high-altitude surface weather chart. Historical high-altitude surface data were converted to Grads data format. Grads as generation tool of the image, ASP was used to compile WEB page. By B/S mode, only user submitted necessary conditions for the image to server by client browser, historical high-altitude surface weather chart at corresponding time and height could be ob- tained. Without any procedures and related data, only needed client browser, user could use image conveniently to a large extent.展开更多
Heilongjiang Province is the granary of China,which plays a key role in ensuring the national food security.The total grain output of Heilongjiang Province has ranked first in China for 12 consecutive years.In the pas...Heilongjiang Province is the granary of China,which plays a key role in ensuring the national food security.The total grain output of Heilongjiang Province has ranked first in China for 12 consecutive years.In the past four years,it has been stable at more than 75 billion kg,a record high.One bowl of rice in every nine bowls in China comes from Heilongjiang.The work of weather modification and disaster prevention and reduction is an important measure to ensure the development of agricultural production,and is the key of meteorological services for agriculture.Based on the actual work of artificial weather modification in Heilongjiang Province,this paper analyzes the current situation of ground operation in Heilongjiang Province,studies and judges the safety production,and puts forward reasonable countermeasures.The purpose is to improve the ground operation ability of artificial weather modification and provide safe and scientific services for agricultural production.展开更多
[Objective] This paper studied the characteristics of lightning in Tong＇an district in Xiamen City based on the thunder observation and lightning location data. EMethod] Based on thunder observation and lightning loc...[Objective] This paper studied the characteristics of lightning in Tong＇an district in Xiamen City based on the thunder observation and lightning location data. EMethod] Based on thunder observation and lightning location data in Tong＇an district from 2005 to 2010, the distribution characteristics of lightning in Tong＇an district were analyzed. [ Resldt~ Thunder and lightning occurred frequently from March to November and was very active during May and September. Spatial distribution was uneven, more frequently in northern mountainous area and less in south plain area. The related circulation patterns and weather were also studied. The weather type causing severe lightning can be divided into three categories and six types, which were the upper air trough, under the control of the subtropical high and tropical systems, respectively. [ Conclusion] The study pro- vided reference for carrying out damage evaluation, pre-waming and report of thunder and lightning.展开更多
Based on the monitoring data of cloud-to-ground( CG) lightning positioning network and Doppler weather radar as well as MICAPS1°× 1° objective analysis field,a squall line process outside of the subtrop...Based on the monitoring data of cloud-to-ground( CG) lightning positioning network and Doppler weather radar as well as MICAPS1°× 1° objective analysis field,a squall line process outside of the subtropical high in low-latitude plateau on May 7,2010 was analyzed. The results showed that wind direction shear between low and high levels and low-level convergence zones provided favorable circulation background for the strong thunderstorm process,while high energy and high humidity,strong thermal instability and ascending motion at low and middle levels offered beneficial environmental conditions for the formation of the thunderstorm. 9 620 return strokes of cloud-to-ground lightning were monitored by the lightning positioning network,and cloud-to-ground lightning was distributed like bands between 584 and 586 hP a. The occurrence of cloud-to-ground lightning was mainly related to echo top and echo intensity at-10 ℃ stratification height,and it mainly appeared in zones where echo top height was larger than 13 km and echo intensity at-10 ℃ stratification height was 35-40 dB Z. Wind convergence and maintaining of high radial velocity were favorable for the development of convective echoes and occurrence of cloud-to-ground lightning.展开更多
Based on the conventional high-and low-altitude and surface observation data,the weather analysis and diagnosis methods were applied to analyze the cold wave process of Ulanqab in January 2016 from the aspects of weat...Based on the conventional high-and low-altitude and surface observation data,the weather analysis and diagnosis methods were applied to analyze the cold wave process of Ulanqab in January 2016 from the aspects of weather reality,circulation background,weather causes,and forecast test.The results show that strong cold air accumulated gradually near Lake Baikal and Central Siberia,affecting the city in a northwest path.During the cold wave process,the transverse trough moved southwards slowly at 500 hPa,and the ground cold high pressure was strong and stable.The cold air continued to move southwards,resulting in the strong cold wave and gale weather with a large impact range and long duration.The high-altitude jet at 300 hPa strengthened the cold wave pile,which was conducive to the outbreak of the cold wave.The intensity and location changes of the 500 hPa positive vorticity center,850 hPa cold advection region and 24-h ground pressure variation well showed the intensity of the cold wave process and the variation of the affected region.The influence of strong cold advection,ground positive pressure variation,and strong vertical wind shear were the main reasons for a strong drop in temperature and gale weather in this process.The test results of prediction reveal that the forecast value of the maximum temperature were relatively lower than the actual value,while the forecast of the minimum temperature was more accurate.The three warning signals were issued timely and accurately.The circulation pattern predicted by numerical models was more accurate in the early stage of the process,but there was an error in the late stage,and the forecast system moved slower than the actual situation.展开更多
基金supported by the China Ministry of Industry and Information Technology Foundation and Aeronautical Science Foundation of China(ASFC-201920007002)the National Key Research and Development Plan(2021YFB1600603)the Open Fund of Key Laboratory of Civil Aircraft Airworthiness Technology,Civil Aviation University of China.
文摘Considering the problem that the scattering echo images of airborne Doppler weather radar are often reduced by ground clutters,the accuracy and confidence of meteorology target detection are reduced.In this paper,a deep convolutional neural network(DCNN)is proposed for meteorology target detection and ground clutter suppression with a large collection of airborne weather radar images as network input.For each weather radar image,the corresponding digital elevation model(DEM)image is extracted on basis of the radar antenna scan-ning parameters and plane position,and is further fed to the net-work as a supplement for ground clutter suppression.The fea-tures of actual meteorology targets are learned in each bottle-neck module of the proposed network and convolved into deeper iterations in the forward propagation process.Then the network parameters are updated by the back propagation itera-tion of the training error.Experimental results on the real mea-sured images show that our proposed DCNN outperforms the counterparts in terms of six evaluation factors.Meanwhile,the network outputs are in good agreement with the expected mete-orology detection results(labels).It is demonstrated that the pro-posed network would have a promising meteorology observa-tion application with minimal effort on network variables or parameter changes.
文摘[Objectives]This study was conducted to investigate insect activity rhythms in airport ground cover areas,and provide guidance for insect control and bird strike prevention.[Methods]The daily rhythm of insects in the northern area of the airport was studied,and their activity rhythms and characteristics under different weather conditions were analyzed.[Results]In rainy days,the insect number in the three sample areas was low.In cloudy days,insect activity was relatively stable,and insect number was consistent in the morning and evening,and maintained in a stable range,while in sunny weather,insect activity was increased,and the number changed greatly with time.For a single tussock plant growth area,the number of insects was at a relatively low level under rainy weather.In fine weather,the peak period of insect activity was between 10:00-11:00 and 14:00-15:00.[Conclusions]This study can provide a reference for the formulation of safe flight departure time.
文摘We introduced query system of the historical high-altitude surface weather chart. Historical high-altitude surface data were converted to Grads data format. Grads as generation tool of the image, ASP was used to compile WEB page. By B/S mode, only user submitted necessary conditions for the image to server by client browser, historical high-altitude surface weather chart at corresponding time and height could be ob- tained. Without any procedures and related data, only needed client browser, user could use image conveniently to a large extent.
基金Supported by the Project of Heilongjiang Meteorological Bureau(HQZC2018043)。
文摘Heilongjiang Province is the granary of China,which plays a key role in ensuring the national food security.The total grain output of Heilongjiang Province has ranked first in China for 12 consecutive years.In the past four years,it has been stable at more than 75 billion kg,a record high.One bowl of rice in every nine bowls in China comes from Heilongjiang.The work of weather modification and disaster prevention and reduction is an important measure to ensure the development of agricultural production,and is the key of meteorological services for agriculture.Based on the actual work of artificial weather modification in Heilongjiang Province,this paper analyzes the current situation of ground operation in Heilongjiang Province,studies and judges the safety production,and puts forward reasonable countermeasures.The purpose is to improve the ground operation ability of artificial weather modification and provide safe and scientific services for agricultural production.
文摘[Objective] This paper studied the characteristics of lightning in Tong＇an district in Xiamen City based on the thunder observation and lightning location data. EMethod] Based on thunder observation and lightning location data in Tong＇an district from 2005 to 2010, the distribution characteristics of lightning in Tong＇an district were analyzed. [ Resldt~ Thunder and lightning occurred frequently from March to November and was very active during May and September. Spatial distribution was uneven, more frequently in northern mountainous area and less in south plain area. The related circulation patterns and weather were also studied. The weather type causing severe lightning can be divided into three categories and six types, which were the upper air trough, under the control of the subtropical high and tropical systems, respectively. [ Conclusion] The study pro- vided reference for carrying out damage evaluation, pre-waming and report of thunder and lightning.
基金Supported by National Natural Science Foundation of China(No.41305002)Science and Technology Project of Yunnan Province(No.2014RA002,2016RA096)
文摘Based on the monitoring data of cloud-to-ground( CG) lightning positioning network and Doppler weather radar as well as MICAPS1°× 1° objective analysis field,a squall line process outside of the subtropical high in low-latitude plateau on May 7,2010 was analyzed. The results showed that wind direction shear between low and high levels and low-level convergence zones provided favorable circulation background for the strong thunderstorm process,while high energy and high humidity,strong thermal instability and ascending motion at low and middle levels offered beneficial environmental conditions for the formation of the thunderstorm. 9 620 return strokes of cloud-to-ground lightning were monitored by the lightning positioning network,and cloud-to-ground lightning was distributed like bands between 584 and 586 hP a. The occurrence of cloud-to-ground lightning was mainly related to echo top and echo intensity at-10 ℃ stratification height,and it mainly appeared in zones where echo top height was larger than 13 km and echo intensity at-10 ℃ stratification height was 35-40 dB Z. Wind convergence and maintaining of high radial velocity were favorable for the development of convective echoes and occurrence of cloud-to-ground lightning.
文摘Based on the conventional high-and low-altitude and surface observation data,the weather analysis and diagnosis methods were applied to analyze the cold wave process of Ulanqab in January 2016 from the aspects of weather reality,circulation background,weather causes,and forecast test.The results show that strong cold air accumulated gradually near Lake Baikal and Central Siberia,affecting the city in a northwest path.During the cold wave process,the transverse trough moved southwards slowly at 500 hPa,and the ground cold high pressure was strong and stable.The cold air continued to move southwards,resulting in the strong cold wave and gale weather with a large impact range and long duration.The high-altitude jet at 300 hPa strengthened the cold wave pile,which was conducive to the outbreak of the cold wave.The intensity and location changes of the 500 hPa positive vorticity center,850 hPa cold advection region and 24-h ground pressure variation well showed the intensity of the cold wave process and the variation of the affected region.The influence of strong cold advection,ground positive pressure variation,and strong vertical wind shear were the main reasons for a strong drop in temperature and gale weather in this process.The test results of prediction reveal that the forecast value of the maximum temperature were relatively lower than the actual value,while the forecast of the minimum temperature was more accurate.The three warning signals were issued timely and accurately.The circulation pattern predicted by numerical models was more accurate in the early stage of the process,but there was an error in the late stage,and the forecast system moved slower than the actual situation.
