ISSN 1000-0526
CN 11-2282/P
CN 11-2282/P
Volume 40,Issue 3,2014 Table of Contents
2014, 40(3):261-268.
DOI: 10.7519/j.issn.1000-0526.2014.03.001
Abstract:
Based on the comprehensive analyses on the implementation of WMO weather service development strategies, the organization of related planned activities and the successful cases of some related countries as well as author’s late experience of joining in the drafting of future weather service strategy and the practice of promotion, this paper states its developing trend, main content and key points from 5 aspects, which includes: (1) the strategy and implementing thinking of WMO weather services; (2) strengthening and enhancing the role that government plays in Emergency Response Action (ERA) and Disaster Risk Resilience (DRR), and the construction of society’s resilience to disasters; (3) encouraging and pushing forward the operation of building the User Interface Platform (UIP) of climate service and the service systems related to integrated weather, climate, water and environment; (4) encouraging and directing the development of new service operations which are supported by seamless operational technologies (e.g. various specific fields like marine meteorology, all kinds of predicting and forecasting technologies such as subseasonal seasonal prediction technique etc.); and (5) encouraging and promoting the construction of Smart public weather service system. In addition, this paper emphatically discusses how to use the modern information network and communication technology to establish intelligent information platform and to strengthen the technical content, individuation and interaction ability of the supplied weather information through the change of supplying ways for meteorological information to cause social resources and mass media to play important and active roles in meteorological services. Weather service should reflect the People oriented idea, caring for people’s health, trips, safety and environment, realizing the social values of weather services and showing the social responsibility of the served groups. Meanwhile, this paper also discusses young people's duties, describing their social responsibilities, encouraging them to make innovation actively and get ready for meteorological services technically for they are the main force in the new types of services. Also, this paper demonstrates the opinion for young people to play a part in the social structure of the new type meteorological services.
Based on the comprehensive analyses on the implementation of WMO weather service development strategies, the organization of related planned activities and the successful cases of some related countries as well as author’s late experience of joining in the drafting of future weather service strategy and the practice of promotion, this paper states its developing trend, main content and key points from 5 aspects, which includes: (1) the strategy and implementing thinking of WMO weather services; (2) strengthening and enhancing the role that government plays in Emergency Response Action (ERA) and Disaster Risk Resilience (DRR), and the construction of society’s resilience to disasters; (3) encouraging and pushing forward the operation of building the User Interface Platform (UIP) of climate service and the service systems related to integrated weather, climate, water and environment; (4) encouraging and directing the development of new service operations which are supported by seamless operational technologies (e.g. various specific fields like marine meteorology, all kinds of predicting and forecasting technologies such as subseasonal seasonal prediction technique etc.); and (5) encouraging and promoting the construction of Smart public weather service system. In addition, this paper emphatically discusses how to use the modern information network and communication technology to establish intelligent information platform and to strengthen the technical content, individuation and interaction ability of the supplied weather information through the change of supplying ways for meteorological information to cause social resources and mass media to play important and active roles in meteorological services. Weather service should reflect the People oriented idea, caring for people’s health, trips, safety and environment, realizing the social values of weather services and showing the social responsibility of the served groups. Meanwhile, this paper also discusses young people's duties, describing their social responsibilities, encouraging them to make innovation actively and get ready for meteorological services technically for they are the main force in the new types of services. Also, this paper demonstrates the opinion for young people to play a part in the social structure of the new type meteorological services.
2014, 40(3):269-279.
DOI: 10.7519/j.issn.1000-0526.2014.03.002
Abstract:
By using CALIPSO (Cloud Aerosol Lidar and Infrared Pathfinder Satellite Observations) data and MM5 numerical simulation output data, the characteristics of vertical structure of dusty layers and its accompanying dynamic and thermal structure in a severe dust storm which occurred in North China from 19 to 22 March 2010 were studied. The results show that in the mature period of dust storm, the dusty layer distributes almost in the whole troposphere from 2 to 9 km. The vertical mixture caused by the cold frontal uplifting and the sinking after the front induces an uniform distribution of dust particles. After that, during the long distance transportation period of dust, the dusty layer is separated to two layers clearly, located at the lower troposphere (below 700 hPa) and the middle upper troposphere (from 600 to 300 hPa) respectively. In each stage of the dust storm process, the weak vertical change of wind speed, potential and equivalent potential temperature are closely coordinated with the dusty layers, which indicates that the neutral mixed layer maintains in the dusty layer. Between the two dusty layers, the frontal region of potential and equivalent potential temperature appear. Meanwhile, the evident tropopause fold and obvious declining of large potential vorticity appear. According to it, when the tropopause sustains at a higher altitude, the dusty layers are expanded to a higher altitude as well. Otherwise, the dusty layers are lower. It should be noted that in the dust long distance transportation stage, a banding area located at 40°N from 7 km to 9 km appears in the stratosphere, indicating that in this dust storm process, parts of the dust particles are transported from troposphere to stratosphere. And it also forms a perisistent dust transportation belt in the stratosphere, so it can be regarded as an observational evidence to prove the troposphere stratosphere transportation of dust aerosol and the transmission of dust aerosol in stratosphere.
By using CALIPSO (Cloud Aerosol Lidar and Infrared Pathfinder Satellite Observations) data and MM5 numerical simulation output data, the characteristics of vertical structure of dusty layers and its accompanying dynamic and thermal structure in a severe dust storm which occurred in North China from 19 to 22 March 2010 were studied. The results show that in the mature period of dust storm, the dusty layer distributes almost in the whole troposphere from 2 to 9 km. The vertical mixture caused by the cold frontal uplifting and the sinking after the front induces an uniform distribution of dust particles. After that, during the long distance transportation period of dust, the dusty layer is separated to two layers clearly, located at the lower troposphere (below 700 hPa) and the middle upper troposphere (from 600 to 300 hPa) respectively. In each stage of the dust storm process, the weak vertical change of wind speed, potential and equivalent potential temperature are closely coordinated with the dusty layers, which indicates that the neutral mixed layer maintains in the dusty layer. Between the two dusty layers, the frontal region of potential and equivalent potential temperature appear. Meanwhile, the evident tropopause fold and obvious declining of large potential vorticity appear. According to it, when the tropopause sustains at a higher altitude, the dusty layers are expanded to a higher altitude as well. Otherwise, the dusty layers are lower. It should be noted that in the dust long distance transportation stage, a banding area located at 40°N from 7 km to 9 km appears in the stratosphere, indicating that in this dust storm process, parts of the dust particles are transported from troposphere to stratosphere. And it also forms a perisistent dust transportation belt in the stratosphere, so it can be regarded as an observational evidence to prove the troposphere stratosphere transportation of dust aerosol and the transmission of dust aerosol in stratosphere.
2014, 40(3):280-289.
DOI: 10.7519/j.issn.1000-0526.2014.03.003
Abstract:
The convective precipitation events that respectively occurred in Tibetan Plateau (TP) and Sichuan Basin are compared and analyzed by using TRMM (Tropical Rainfall Measure Mission) data. The results show that the precipitation system in the TP is mainly convective cloud precipitation and weak rainfall samples are a great many consisting of isolated cloud precipitation cloud clusters. Convective center is scattered, with small precipitation range, uneven rain belt, shallow vertical thickness, fewer precipitation particles and small raindrops. The latent heat which is released at the height of 2-5 km is dominant. The content of ice crystal particles near the ground layer in summer is great. There is a poor correlation between brightness temperature of cloud top and rainfall intensity near surface. The higher the brightness temperature, the larger the number of lightning frequency. In contrast, the precipitation system in Sichuan Basin has more severe precipitation samples, consisting of a main precipitation system and scattered cloud clusters. Convective centers are concentrated, the precipitation scopes are large, rain belt is even, vertical thickness is deep, and raindrops are large. The latent heat is released in the pattern of two peakes and the peak values appear at the heights of 7 km and 16 km. The content of hail particles are much more in the upper level. There is a negative correlation between brightness temperature of cloud top and rainfall intensity near surface. The number of lightning frequency in Sichuan Basin is heigher than the TP areas, and lightnings mainly appear in the clouds with lower bightness temperature.
The convective precipitation events that respectively occurred in Tibetan Plateau (TP) and Sichuan Basin are compared and analyzed by using TRMM (Tropical Rainfall Measure Mission) data. The results show that the precipitation system in the TP is mainly convective cloud precipitation and weak rainfall samples are a great many consisting of isolated cloud precipitation cloud clusters. Convective center is scattered, with small precipitation range, uneven rain belt, shallow vertical thickness, fewer precipitation particles and small raindrops. The latent heat which is released at the height of 2-5 km is dominant. The content of ice crystal particles near the ground layer in summer is great. There is a poor correlation between brightness temperature of cloud top and rainfall intensity near surface. The higher the brightness temperature, the larger the number of lightning frequency. In contrast, the precipitation system in Sichuan Basin has more severe precipitation samples, consisting of a main precipitation system and scattered cloud clusters. Convective centers are concentrated, the precipitation scopes are large, rain belt is even, vertical thickness is deep, and raindrops are large. The latent heat is released in the pattern of two peakes and the peak values appear at the heights of 7 km and 16 km. The content of hail particles are much more in the upper level. There is a negative correlation between brightness temperature of cloud top and rainfall intensity near surface. The number of lightning frequency in Sichuan Basin is heigher than the TP areas, and lightnings mainly appear in the clouds with lower bightness temperature.
2014, 40(3):290-296.
DOI: 10.7519/j.issn.1000-0526.2014.03.004
Abstract:
Applications of vertical velocity in forecast are studied by analyzing the vertical beam data of Beijing wind profiler radar (WPR) data. The different weather cases are analyzed via vertical velocity classification display and surface meteorological records. The results show that the vertical velocity measured by WPR is small in clear sky between ±1 m·s-1. But in precipitation days, boundary vertical velocity is mainly toward to the ground with different speeds between precipitations in different phases. The results indicate that vertical velocity probed by WPR has application values in researching vertical velocity in clear sky, judging the precipitation phases and forecasting precipitation.
Applications of vertical velocity in forecast are studied by analyzing the vertical beam data of Beijing wind profiler radar (WPR) data. The different weather cases are analyzed via vertical velocity classification display and surface meteorological records. The results show that the vertical velocity measured by WPR is small in clear sky between ±1 m·s-1. But in precipitation days, boundary vertical velocity is mainly toward to the ground with different speeds between precipitations in different phases. The results indicate that vertical velocity probed by WPR has application values in researching vertical velocity in clear sky, judging the precipitation phases and forecasting precipitation.
2014, 40(3):297-304.
DOI: 10.7519/j.issn.1000-0526.2014.03.005
Abstract:
Utilizing conventional meteorological data, T Inp and the Longyan and Jianyang CINRAD/SA data, the radar echo characteristics and meso microscale systems of short time rainstorms in western mountainous area of Fujian are analyzed. The results show that the short time torrential rainfall echoes can be classified for continental convective precipitation and tropical marine precipitation. Besides, the relationship between the convective precipitation, the tropical marine precipitation’s low level reflectivity factor and rainfall intensity are statistically analyzed. The rainfall echoes are classified for local developed stagnation echo and “train effect” echo which constantly affects certain regions according to the impact time of rainfalls. Based on the evolution of radar echoes, base velocities and weather systems, three types of meso microscale systems which lead to short time rainstorms are extracted. The first is meso scale shear line or convergence line related to low level shear line (trough) and southwest jet. The second is low level shear line or convergence line which moves to south. The third is adverse wind area or mesocylone related to local convections.
Utilizing conventional meteorological data, T Inp and the Longyan and Jianyang CINRAD/SA data, the radar echo characteristics and meso microscale systems of short time rainstorms in western mountainous area of Fujian are analyzed. The results show that the short time torrential rainfall echoes can be classified for continental convective precipitation and tropical marine precipitation. Besides, the relationship between the convective precipitation, the tropical marine precipitation’s low level reflectivity factor and rainfall intensity are statistically analyzed. The rainfall echoes are classified for local developed stagnation echo and “train effect” echo which constantly affects certain regions according to the impact time of rainfalls. Based on the evolution of radar echoes, base velocities and weather systems, three types of meso microscale systems which lead to short time rainstorms are extracted. The first is meso scale shear line or convergence line related to low level shear line (trough) and southwest jet. The second is low level shear line or convergence line which moves to south. The third is adverse wind area or mesocylone related to local convections.
2014, 40(3):305-312.
DOI: 10.7519/j.issn.1000-0526.2014.03.006
Abstract:
The key to application of weather radar pulse compression technology is to suppress the distance side lobe after pulse pressure. The generalized cosine window which has a bell shaped feature can effectively smooth spectrum edge, reduce the ratio of main lobe and side lobe, so it is widely applied to linear FM signal pulse pressure side lobe suppression technology. This paper studies about the side lobe suppression using the generalized cosine window as the weighted network, and makes a comparative analysis of their ability to detect weak target. At first, the article briefly describes the pulse compression technology and the main performance indicators of judging side lobe suppression effect and then presents a simulation of the spectral characteristics of the generalized cosine window. Finally, the paper brings the generalized cosine window into the signal processing of the real solid state weather radar, getting the echo images, making a comparison of Doppler weather radar and giving comparative analysis results.
The key to application of weather radar pulse compression technology is to suppress the distance side lobe after pulse pressure. The generalized cosine window which has a bell shaped feature can effectively smooth spectrum edge, reduce the ratio of main lobe and side lobe, so it is widely applied to linear FM signal pulse pressure side lobe suppression technology. This paper studies about the side lobe suppression using the generalized cosine window as the weighted network, and makes a comparative analysis of their ability to detect weak target. At first, the article briefly describes the pulse compression technology and the main performance indicators of judging side lobe suppression effect and then presents a simulation of the spectral characteristics of the generalized cosine window. Finally, the paper brings the generalized cosine window into the signal processing of the real solid state weather radar, getting the echo images, making a comparison of Doppler weather radar and giving comparative analysis results.
2014, 40(3):313-326.
DOI: 10.7519/j.issn.1000-0526.2014.03.007
Abstract:
Using the GRAPES model which incorporates a new two moment microphysical scheme, two aircraft artificial precipitation processes that happened in Chongqing on 15 December 2010 are simulated and analyzed. The results show that GRAPES model is able to simulate the real synoptic situation of medium, the precipitation area is credibility, but the intensity is small. Seeding simulation has good correspondence with the observed rainfall in heavier precipitation areas. Seeding twice leads to the increasing of precipitation, the 24 h average enhancement rainfall is 3-5 mm and the maximum amount is 7 mm. The 24 h accumulative total precipitation of seeding is double times than no seeding in seeding area. Obvious enhancement result is seen in 1-2 hours after seeding, and the rain enhancement continues about 4 hours. At the beginning the area of enhancement is the same as the seeding area, spreading near the seeding area with the time. After the first seeding, the liquid water is quickly transformed into solid water by seeding ice crystal, and the vapor inflow accelerates changing into liquid water, so the liquid water quickly restore. There is no rain reduced. After the second seeding, the solid water increases by vapor transforming, the supplement of liquid water is poor, the ascending motion of clouds decreases, and the rainfall is reduced at the stage of natural precipitation.
Using the GRAPES model which incorporates a new two moment microphysical scheme, two aircraft artificial precipitation processes that happened in Chongqing on 15 December 2010 are simulated and analyzed. The results show that GRAPES model is able to simulate the real synoptic situation of medium, the precipitation area is credibility, but the intensity is small. Seeding simulation has good correspondence with the observed rainfall in heavier precipitation areas. Seeding twice leads to the increasing of precipitation, the 24 h average enhancement rainfall is 3-5 mm and the maximum amount is 7 mm. The 24 h accumulative total precipitation of seeding is double times than no seeding in seeding area. Obvious enhancement result is seen in 1-2 hours after seeding, and the rain enhancement continues about 4 hours. At the beginning the area of enhancement is the same as the seeding area, spreading near the seeding area with the time. After the first seeding, the liquid water is quickly transformed into solid water by seeding ice crystal, and the vapor inflow accelerates changing into liquid water, so the liquid water quickly restore. There is no rain reduced. After the second seeding, the solid water increases by vapor transforming, the supplement of liquid water is poor, the ascending motion of clouds decreases, and the rainfall is reduced at the stage of natural precipitation.
2014, 40(3):327-335.
DOI: 10.7519/j.issn.1000-0526.2014.03.008
Abstract:
Two cases of stratiform cloud precipitation in Jilin Province under the upper level trough process on 15 May and the cold vortex on 28 May 2007 are analysed. The microphysical data are sampled with the airborne PMS probes and a hygrothermoscope. It is found that the vertical distribution of particle number concentration, liquid water content, mean diameter of FSSP 100, 2D C and 2D P probes under upper level trough on 15 May are not uniform and the maximum liquid water content is in 0℃ layer. In As Sc under cold vortex on 28 May, the maximum particle number concentration of FSSP 100 in Sc and As are both 350 cm-3; the maximum LWC in As is one ordering more than in Sc and mean diameter in As is far more than in Sc. The particle number concentration and liquid water content of 2D C and 2D P in As are symmetrical, but teeny in Sc because of a dry layer between layers. The layer averaged size distributions of small cloud particles in cloud of 2 cases are quite different. The seedability of cloud is studied. The result shows that the seedability of As clouds under upper level trough is highly seedable clouds, the seedable clouds of As Sc cloud system under cold vortex are 1/2 highly seedable clouds.
Two cases of stratiform cloud precipitation in Jilin Province under the upper level trough process on 15 May and the cold vortex on 28 May 2007 are analysed. The microphysical data are sampled with the airborne PMS probes and a hygrothermoscope. It is found that the vertical distribution of particle number concentration, liquid water content, mean diameter of FSSP 100, 2D C and 2D P probes under upper level trough on 15 May are not uniform and the maximum liquid water content is in 0℃ layer. In As Sc under cold vortex on 28 May, the maximum particle number concentration of FSSP 100 in Sc and As are both 350 cm-3; the maximum LWC in As is one ordering more than in Sc and mean diameter in As is far more than in Sc. The particle number concentration and liquid water content of 2D C and 2D P in As are symmetrical, but teeny in Sc because of a dry layer between layers. The layer averaged size distributions of small cloud particles in cloud of 2 cases are quite different. The seedability of cloud is studied. The result shows that the seedability of As clouds under upper level trough is highly seedable clouds, the seedable clouds of As Sc cloud system under cold vortex are 1/2 highly seedable clouds.
2014, 40(3):336-348.
DOI: 10.7519/j.issn.1000-0526.2014.03.009
Abstract:
Using the monthly autumn precipitation data of 122 observation stations over Yunnan Province from 1961 to 2008 and the NOAA monthly mean reanalysis data, distributions of monthly precipitation and water vapor fluxes and water vapor flux divergence in autumn, as well as the effect of atmospheric circulation anomaly on precipitation are analyzed. The results show that, there exists the best coupling relationship of rainfall and water vapor flux, water vapor flux divergence in November, while in October it is the second, and in September it is the worst. There is a positive correlation between autumn precipitation distribution, and water vapor flux and the divergence of water vapor flux in Yunnan. The autumn precipitation field is consistent with the time variation trend of water vapor flow field. The changes of water vapor flux and water vapor flux divergence directly affect the change of precipitation. The autumn precipitation amount is largely influenced by the atmospheric circulation anomaly. When September precipitation in Yunnan is abnormal, the monsoon in Bay of Bengal blows strongly, the subtropical high is by east and weak, and the cold air is active. Otherwise appears the negative anomaly. When rainfall in October is abnormal, southern trough and southwest monsoon are active, strengthening Yunnan’s southerly warm and humid air flows, otherwise, precipitation is less. When in November the southern trough and the cold airs that influence Yunnan are active, more precipitation produces, otherwise, negative anomaly appears. Regarding the vapor net budget, the zonal net income in September is the largest, while zonal net income in October weakens. In November, under the control of the westerlies, the net income becomes very small. However, meridional water vapor income during September to November transfers from expenditure to inflows. Thinking from the whole layer and low level vapor net budget in positive and negative anomaly years in Yunnan, except for the November in negative anomaly years it is water vapor source, in all the other times it is moisture convergence. When calculating with ERA Interim reanalysis data and 20CR reanalysis data, the water vapor error is found small, and the vapor net budget variations in positive and negative anomaly years are consistent.
Using the monthly autumn precipitation data of 122 observation stations over Yunnan Province from 1961 to 2008 and the NOAA monthly mean reanalysis data, distributions of monthly precipitation and water vapor fluxes and water vapor flux divergence in autumn, as well as the effect of atmospheric circulation anomaly on precipitation are analyzed. The results show that, there exists the best coupling relationship of rainfall and water vapor flux, water vapor flux divergence in November, while in October it is the second, and in September it is the worst. There is a positive correlation between autumn precipitation distribution, and water vapor flux and the divergence of water vapor flux in Yunnan. The autumn precipitation field is consistent with the time variation trend of water vapor flow field. The changes of water vapor flux and water vapor flux divergence directly affect the change of precipitation. The autumn precipitation amount is largely influenced by the atmospheric circulation anomaly. When September precipitation in Yunnan is abnormal, the monsoon in Bay of Bengal blows strongly, the subtropical high is by east and weak, and the cold air is active. Otherwise appears the negative anomaly. When rainfall in October is abnormal, southern trough and southwest monsoon are active, strengthening Yunnan’s southerly warm and humid air flows, otherwise, precipitation is less. When in November the southern trough and the cold airs that influence Yunnan are active, more precipitation produces, otherwise, negative anomaly appears. Regarding the vapor net budget, the zonal net income in September is the largest, while zonal net income in October weakens. In November, under the control of the westerlies, the net income becomes very small. However, meridional water vapor income during September to November transfers from expenditure to inflows. Thinking from the whole layer and low level vapor net budget in positive and negative anomaly years in Yunnan, except for the November in negative anomaly years it is water vapor source, in all the other times it is moisture convergence. When calculating with ERA Interim reanalysis data and 20CR reanalysis data, the water vapor error is found small, and the vapor net budget variations in positive and negative anomaly years are consistent.
2014, 40(3):349-354.
DOI: 10.7519/j.issn.1000-0526.2014.03.010
Abstract:
The regional climate model (RegCM3) is used to simulate the summer (June to August) climate from 2000 to 2006 over the Kaidu River Valley. The results reveal that the model has a good ability to reproduce the distribution of precipitation and temperature. The altitude, observed data and simulated data are used to revise the simulated temperature and precipitation, and then the areal rainfall and average temperature are calculated. It is proved that there is a good consistency between runoff and precipitation over the Kaidu River Basin, and R2 is 0.97. The analyses of the summer average temperature, areal rainfall and runoff show that the main impact factor of Kaidu River’s runoff is precipitation. The reason why temperature makes a negative contribution to runoff is probably because of the reducing of the small and middle sized glaciers, which causes the runoff to decrease and temperature to rise. The other reason maybe is the rise of temperature, which can lead to the increase of evapotranspiration.
The regional climate model (RegCM3) is used to simulate the summer (June to August) climate from 2000 to 2006 over the Kaidu River Valley. The results reveal that the model has a good ability to reproduce the distribution of precipitation and temperature. The altitude, observed data and simulated data are used to revise the simulated temperature and precipitation, and then the areal rainfall and average temperature are calculated. It is proved that there is a good consistency between runoff and precipitation over the Kaidu River Basin, and R2 is 0.97. The analyses of the summer average temperature, areal rainfall and runoff show that the main impact factor of Kaidu River’s runoff is precipitation. The reason why temperature makes a negative contribution to runoff is probably because of the reducing of the small and middle sized glaciers, which causes the runoff to decrease and temperature to rise. The other reason maybe is the rise of temperature, which can lead to the increase of evapotranspiration.
2014, 40(3):355-363.
DOI: 10.7519/j.issn.1000-0526.2014.03.011
Abstract:
Using observation data of wires icing from meteorological stations and field investigation to power line ice coating from local electricity sections, this study comprehensively analyzes the properties, classifications and distributions of wires icing in Guizhou Province as well as its weather conditions. Emphasis is placed on discussing the mechanisms of wires icing and its weather causes of formation. The results show that (1) there are multiple types of wires icing in Guizhou Region. In addition to glaze, rime, and wet snow, mixed freezing types of freezing rain and fog, freezing rain and wet snow are common. Glaze dominates and mixed freezing prevails in mountainous areas, leading to severe wires icing disasters. (2) The freezing weather of continual low temperature and rainy days are the weather conditions of the formation of wires icing, which includes freezing rain, freezing drizzle, sleet, wet snow and freezing fog. (3) Wires icing in Guizhou is generally controlled by moist physical processes with temperature below or near 0℃ and slow wind speed (<6 m·s-1). In most cases wires icing starts and grows under weathers of freezing rains when the temperature falls below 0℃. Therefore, air temperature below 0℃ and occurrence of freezing rain, freezing drizzle, freezing fog or sleet are important indicators to judge wires icing.
Using observation data of wires icing from meteorological stations and field investigation to power line ice coating from local electricity sections, this study comprehensively analyzes the properties, classifications and distributions of wires icing in Guizhou Province as well as its weather conditions. Emphasis is placed on discussing the mechanisms of wires icing and its weather causes of formation. The results show that (1) there are multiple types of wires icing in Guizhou Region. In addition to glaze, rime, and wet snow, mixed freezing types of freezing rain and fog, freezing rain and wet snow are common. Glaze dominates and mixed freezing prevails in mountainous areas, leading to severe wires icing disasters. (2) The freezing weather of continual low temperature and rainy days are the weather conditions of the formation of wires icing, which includes freezing rain, freezing drizzle, sleet, wet snow and freezing fog. (3) Wires icing in Guizhou is generally controlled by moist physical processes with temperature below or near 0℃ and slow wind speed (<6 m·s-1). In most cases wires icing starts and grows under weathers of freezing rains when the temperature falls below 0℃. Therefore, air temperature below 0℃ and occurrence of freezing rain, freezing drizzle, freezing fog or sleet are important indicators to judge wires icing.
12 One Method Based on Template Matching to Remove Strong Anomalous Propagation Echo at Changle Site
2014, 40(3):364-372.
DOI: 10.7519/j.issn.1000-0526.2014.03.012
Abstract:
In China, there are several weather radars built in high mountains. Due to the high altitude and the curvature of earth, low level observation is limited if the conventional volume scan strategies (VCP12/VCP22) are adopted. At Changle Site, new volume scan strategies which adopt 0° or negative elevation angles bring lots of benefits for monitoring and warning severe weather, but also increase the chance of disadvantages, such as ground clutter, wave clutter, anomalous propagation (AP) and so on. This paper discusses the characteristics of strong AP clutter at Changle Site, introducing a method based on template matching to remove it. The method does not have any impact on new volume scan strategies, but can remove the strong AP effectively. Now the method is running in test, and to be used in the Radar Operational Software Engineering (ROSE).
In China, there are several weather radars built in high mountains. Due to the high altitude and the curvature of earth, low level observation is limited if the conventional volume scan strategies (VCP12/VCP22) are adopted. At Changle Site, new volume scan strategies which adopt 0° or negative elevation angles bring lots of benefits for monitoring and warning severe weather, but also increase the chance of disadvantages, such as ground clutter, wave clutter, anomalous propagation (AP) and so on. This paper discusses the characteristics of strong AP clutter at Changle Site, introducing a method based on template matching to remove it. The method does not have any impact on new volume scan strategies, but can remove the strong AP effectively. Now the method is running in test, and to be used in the Radar Operational Software Engineering (ROSE).
2014, 40(3):373-380.
DOI: 10.7519/j.issn.1000-0526.2014.03.013
Abstract:
Long time series Land Surface Temperature (LST) products can be used to quantify representativeness of meteorological stations. However, spatial heterogeneity of LST is dramatically higher than that of air temperature, which is prone to an under estimation of the representativeness. To obtain more accurate results, this paper proposes a new procedure in which spatially continuous air temperature is first estimated from LST and other parameters, and then used for estimating representativeness of meteorological stations. A case study focusing on Linzhi Meteorological Station located in southeastern Tibetan Plateau of China is presented. First, 8 d averaged maximum temperature (T air) and the corresponding MODIS LST product (MOD11A2,8 d composited with 1 km spatial resolution) of meteorological stations during 2000-2011 are extracted. The correlation coefficients between T air and LST are analyzed under different conditions. Then, a Cubist regression tree model for T air estimation is developed using LST, Julian day, and the number of clear skies as predictors (RMSE=1.4718℃, r2=0.95). Finally, the model is applied to the region around Linzhi Station to estimate T air and representativeness. As a result, it is found that the new procedure can produce more reasonable results: 15 km×15 km can be well represented by Linzhi Station, rather than 3 km×3 km when LTS data was used.
Long time series Land Surface Temperature (LST) products can be used to quantify representativeness of meteorological stations. However, spatial heterogeneity of LST is dramatically higher than that of air temperature, which is prone to an under estimation of the representativeness. To obtain more accurate results, this paper proposes a new procedure in which spatially continuous air temperature is first estimated from LST and other parameters, and then used for estimating representativeness of meteorological stations. A case study focusing on Linzhi Meteorological Station located in southeastern Tibetan Plateau of China is presented. First, 8 d averaged maximum temperature (T air) and the corresponding MODIS LST product (MOD11A2,8 d composited with 1 km spatial resolution) of meteorological stations during 2000-2011 are extracted. The correlation coefficients between T air and LST are analyzed under different conditions. Then, a Cubist regression tree model for T air estimation is developed using LST, Julian day, and the number of clear skies as predictors (RMSE=1.4718℃, r2=0.95). Finally, the model is applied to the region around Linzhi Station to estimate T air and representativeness. As a result, it is found that the new procedure can produce more reasonable results: 15 km×15 km can be well represented by Linzhi Station, rather than 3 km×3 km when LTS data was used.
2014, 40(3):381-388.
DOI: 10.7519/j.issn.1000-0526.2014.03.014
Abstract:
The following are the main characteristics of the general circulation of atmosphere in December 2013: There are two polar vortex centers in the Northern Hemisphere with the weaker strength than normal years. The circulation presents the troughridgetrough pattern in middlehigh latitudes. The south branch trough behaves actively, and is located near 90°E averagely. The subtropical high is stronger than normal years. Besides, it is located more westward and northward than normal years. The monthly mean precipitation is 15.4 mm, 46.7% more than normal (10.5 mm). In addition, significant difference is found in different areas: The precipitation in the major part of southern China is 20%-40% more than normal. The precipitation in the northern part to Huaihe River is less than normal, and especially, there is almost no any effective rainfall in the North of China and Huanghuai Region. The monthly mean temperature is -2.8℃, 0.4℃ higher than normal (-3.2℃) which presents a regional characteristic, i.e., the weather is warm in North China and cold in South China. There are three cold air processes nationwide and one major rainfall process in this month. There is a largescale obvious rainfall event and persisting low temperature weather in the southern China. Meanwhile, the fog and the haze appear in the central and eastern part of China.
The following are the main characteristics of the general circulation of atmosphere in December 2013: There are two polar vortex centers in the Northern Hemisphere with the weaker strength than normal years. The circulation presents the troughridgetrough pattern in middlehigh latitudes. The south branch trough behaves actively, and is located near 90°E averagely. The subtropical high is stronger than normal years. Besides, it is located more westward and northward than normal years. The monthly mean precipitation is 15.4 mm, 46.7% more than normal (10.5 mm). In addition, significant difference is found in different areas: The precipitation in the major part of southern China is 20%-40% more than normal. The precipitation in the northern part to Huaihe River is less than normal, and especially, there is almost no any effective rainfall in the North of China and Huanghuai Region. The monthly mean temperature is -2.8℃, 0.4℃ higher than normal (-3.2℃) which presents a regional characteristic, i.e., the weather is warm in North China and cold in South China. There are three cold air processes nationwide and one major rainfall process in this month. There is a largescale obvious rainfall event and persisting low temperature weather in the southern China. Meanwhile, the fog and the haze appear in the central and eastern part of China.
Mobile website
® 2024 All Rights Reserved
Supported by:Beijing E-Tiller Technology Development Co., Ltd.
ISSN:1000-0526 CN:11-2282/P