A precipitation enhancement operation using an aircraft was conducted from 1415 to 1549 LST 14 March 2000 in Shaanxi Province. The NOAA-14 satellite data received at 1535 LST soon after the cloud seeding shows that a ...A precipitation enhancement operation using an aircraft was conducted from 1415 to 1549 LST 14 March 2000 in Shaanxi Province. The NOAA-14 satellite data received at 1535 LST soon after the cloud seeding shows that a vivid cloud track appears on the satellite image. The length, average width and maximum width of the cloud track are 301 km, 8.3 and 11 km, respectively. Using a three-dimensional numerical model of transport and diffusion of seeding material within stratiform clouds, the spatial concentration distribution characteristics of seeding material at different times, especially at the satellite receiving time, are simulated. The model results at the satellite receiving time are compared with the features of the cloud track. The transported position of the cloud seeding material coincides with the position of the track. The width, shape and extent of diffusion of the cloud seeding material are similar to that of the cloud track. The spatial variation of width is consistent with that of the track. The simulated length of each segment of the seeding line accords with the length of every segment of the track. Each segment of the cloud track corresponds to the transport and diffusion of each segment of the seeding line. These results suggest that the cloud track is the direct physical reflection of cloud seeding at the cloud top. The comparison demonstrates that the numerical model of transport and diffusion can simulate the main characteristics of transport and diffusion of seeding material, and the simulated results are sound and trustworthy. The area, volume, vidth, depth, and lateral diffusive rate corresponding to concentrations 1, 4, and 10 L-1are simulated in order to understand the variations of influencing range.展开更多
From 0615 to 0749 UTC, 14 March 2000, a precipitation enhancement operation with AgI using an air- craft was conducted at the middle part of Shaanxi Province, China. 80 min after cloud seeding (0735 UTC), NOAA-14 sate...From 0615 to 0749 UTC, 14 March 2000, a precipitation enhancement operation with AgI using an air- craft was conducted at the middle part of Shaanxi Province, China. 80 min after cloud seeding (0735 UTC), NOAA-14 satellite data showed a vivid zigzag cloud track on the satel- lite image. Its length is 301 km, and its average and maxi- mum width are 8.3 and 11 km. The cloud track is very simi- lar in shape with, but different in position and width from that of cloud seeding line. In order to determine that the cloud track is indeed caused by cloud seeding, a three-dimensional numerical model of transport and diffu- sion of seeding material is used to simulate the shape of seeding material concentration distribution, the turning points, width and length of seeding line. The simulated re- sults are compared with the features of cloud track at 0735 UTC. Every segment of the cloud track is consistent with the transport and diffusion of every segment of seeding line. The transport position, length, width and the variation trend of seeding line agree with those of cloud track. All suggest that the cloud track is the direct physical reflection of cloud seed- ing effect on the cloud top, which can respond to the trans- port and diffusion of seeding material. For this study case, the main effecting duration for every segment of seeding line is from 20 to 80 min, the time for each segment of seeding line diffusing to the maximum width is from about 50 to 70 min. This time is obtained from the appearing and disap- pearing time, width variation of the cloud track segments and simulated results. Also, the comparisons demonstrate that the numerical model of transport and diffusion can simulate the main characteristics of transport and diffusion of seeding material, and the simulating results are sound and trustworthy.展开更多
采用耦合中国气象科学研究院CAMS(Chinese Academy of Meteorological Sciences)研发的云参数方案的MM5中尺度模式对2013年8月13日湘南地区受"尤特"台风外围云系影响的一次典型积层混合云降水过程进行数值模拟,分析此次天气...采用耦合中国气象科学研究院CAMS(Chinese Academy of Meteorological Sciences)研发的云参数方案的MM5中尺度模式对2013年8月13日湘南地区受"尤特"台风外围云系影响的一次典型积层混合云降水过程进行数值模拟,分析此次天气过程云微物理量的时空分布特征以及人工增雨作业最佳时机和位置。结果显示,各种水成物混和比随时间变化趋势基本一致,均呈单峰型,最大值都出现在13日14:00左右;在云系整个发展过程中,各类水成物水平分布不均匀,积云部分呈明显块状分布,随着云系发展,水成物混合比大值区有明显的西移趋势;在云系发展成熟阶段,云水经向分布范围不大,约60 km,各类水成物在垂直方向吻合很好,云水垂直发展很旺盛,有过冷水存在;雨水和霰的分布对应很好,说明此次过程霰的融化是雨水的主要来源。积层混合云的发展前期450 h Pa附近最有利于人工增雨催化。展开更多
文摘A precipitation enhancement operation using an aircraft was conducted from 1415 to 1549 LST 14 March 2000 in Shaanxi Province. The NOAA-14 satellite data received at 1535 LST soon after the cloud seeding shows that a vivid cloud track appears on the satellite image. The length, average width and maximum width of the cloud track are 301 km, 8.3 and 11 km, respectively. Using a three-dimensional numerical model of transport and diffusion of seeding material within stratiform clouds, the spatial concentration distribution characteristics of seeding material at different times, especially at the satellite receiving time, are simulated. The model results at the satellite receiving time are compared with the features of the cloud track. The transported position of the cloud seeding material coincides with the position of the track. The width, shape and extent of diffusion of the cloud seeding material are similar to that of the cloud track. The spatial variation of width is consistent with that of the track. The simulated length of each segment of the seeding line accords with the length of every segment of the track. Each segment of the cloud track corresponds to the transport and diffusion of each segment of the seeding line. These results suggest that the cloud track is the direct physical reflection of cloud seeding at the cloud top. The comparison demonstrates that the numerical model of transport and diffusion can simulate the main characteristics of transport and diffusion of seeding material, and the simulated results are sound and trustworthy. The area, volume, vidth, depth, and lateral diffusive rate corresponding to concentrations 1, 4, and 10 L-1are simulated in order to understand the variations of influencing range.
基金the Project of the Ministry of Science and Technology of China(Grant No.2001BA-901A41) the National Natural Science Foundation of China(Grant No.40175003).
文摘From 0615 to 0749 UTC, 14 March 2000, a precipitation enhancement operation with AgI using an air- craft was conducted at the middle part of Shaanxi Province, China. 80 min after cloud seeding (0735 UTC), NOAA-14 satellite data showed a vivid zigzag cloud track on the satel- lite image. Its length is 301 km, and its average and maxi- mum width are 8.3 and 11 km. The cloud track is very simi- lar in shape with, but different in position and width from that of cloud seeding line. In order to determine that the cloud track is indeed caused by cloud seeding, a three-dimensional numerical model of transport and diffu- sion of seeding material is used to simulate the shape of seeding material concentration distribution, the turning points, width and length of seeding line. The simulated re- sults are compared with the features of cloud track at 0735 UTC. Every segment of the cloud track is consistent with the transport and diffusion of every segment of seeding line. The transport position, length, width and the variation trend of seeding line agree with those of cloud track. All suggest that the cloud track is the direct physical reflection of cloud seed- ing effect on the cloud top, which can respond to the trans- port and diffusion of seeding material. For this study case, the main effecting duration for every segment of seeding line is from 20 to 80 min, the time for each segment of seeding line diffusing to the maximum width is from about 50 to 70 min. This time is obtained from the appearing and disap- pearing time, width variation of the cloud track segments and simulated results. Also, the comparisons demonstrate that the numerical model of transport and diffusion can simulate the main characteristics of transport and diffusion of seeding material, and the simulating results are sound and trustworthy.
文摘采用耦合中国气象科学研究院CAMS(Chinese Academy of Meteorological Sciences)研发的云参数方案的MM5中尺度模式对2013年8月13日湘南地区受"尤特"台风外围云系影响的一次典型积层混合云降水过程进行数值模拟,分析此次天气过程云微物理量的时空分布特征以及人工增雨作业最佳时机和位置。结果显示,各种水成物混和比随时间变化趋势基本一致,均呈单峰型,最大值都出现在13日14:00左右;在云系整个发展过程中,各类水成物水平分布不均匀,积云部分呈明显块状分布,随着云系发展,水成物混合比大值区有明显的西移趋势;在云系发展成熟阶段,云水经向分布范围不大,约60 km,各类水成物在垂直方向吻合很好,云水垂直发展很旺盛,有过冷水存在;雨水和霰的分布对应很好,说明此次过程霰的融化是雨水的主要来源。积层混合云的发展前期450 h Pa附近最有利于人工增雨催化。
