Pub Date : 2019-12-01DOI: 10.1109/ICMO49322.2019.9026067
Kuifeng Zhao, Zipeng Dong, Xingmin Li, Chuang Chen, Yan Peng
The reliability and accuracy of temperature profiles retrieved by ground-based microwave radiometer (MWR) using neural networks at Jinghe meteorological station (Xi’an, China) was evaluated by comparing the temperature retrievals against simultaneous radiosonde observations. For the comparison purposes, temperature measurements from MWR and radiosonde with altitude difference of less than 10 m and time difference of less than 5 minutes were matched with each other. Finally, a total of 1240 pairs of profiles have been compared for the period from June 2017 to July 2019. The MWR-derived temperature showed consistent negative bias of 0.14–2.44 °C throughout the retrieved profile except at 10 km where with a value of +0.22 °C. The root mean square error is less than 2°C for heights below 100 m, and rapidly increases to 4°C at 2 km and remained stable thereafter. Linear regression between temperature derived from MWR and radiosonde at different altitudes indicated that both the slope and intercept showed altitude-dependent behavior. Fairly good agreement between radiosonde and MWR-derived temperature is observed in the lowest 1 km, with linear regress slopes between 0.91–1.00 and correlation coefficients exceeding 0.96. However, both the slope and intercept decreased dramatically with height. The altitude variations of the slope and intercept suggest that the MWR tends to overestimate the temperature in cold season but underestimate the temperature in warm season in the middle and upper troposphere. Temperature gradient derived from radiosonde showed that the occurrence frequency of temperature inversions peaked at 28% at near surface at Xi’an, and declined to 8% at 2 km. MWR failed to distinguish the temperature inversion in most cases. The missed detection ratio is approximately 40% at surface and beyond 80% at altitude higher than 500 m. There is still big room for improving the accuracy of the temperature retrievals of MWR, especially in the aspect of temperature inversion detection. Our findings suggest that the MWR data needs to be used with caution in the air pollution study.
{"title":"Comparison of Tropospheric Temperature Profiles from Ground-based Microwave Radiometer and Radiosonde at Xi’an, Central China","authors":"Kuifeng Zhao, Zipeng Dong, Xingmin Li, Chuang Chen, Yan Peng","doi":"10.1109/ICMO49322.2019.9026067","DOIUrl":"https://doi.org/10.1109/ICMO49322.2019.9026067","url":null,"abstract":"The reliability and accuracy of temperature profiles retrieved by ground-based microwave radiometer (MWR) using neural networks at Jinghe meteorological station (Xi’an, China) was evaluated by comparing the temperature retrievals against simultaneous radiosonde observations. For the comparison purposes, temperature measurements from MWR and radiosonde with altitude difference of less than 10 m and time difference of less than 5 minutes were matched with each other. Finally, a total of 1240 pairs of profiles have been compared for the period from June 2017 to July 2019. The MWR-derived temperature showed consistent negative bias of 0.14–2.44 °C throughout the retrieved profile except at 10 km where with a value of +0.22 °C. The root mean square error is less than 2°C for heights below 100 m, and rapidly increases to 4°C at 2 km and remained stable thereafter. Linear regression between temperature derived from MWR and radiosonde at different altitudes indicated that both the slope and intercept showed altitude-dependent behavior. Fairly good agreement between radiosonde and MWR-derived temperature is observed in the lowest 1 km, with linear regress slopes between 0.91–1.00 and correlation coefficients exceeding 0.96. However, both the slope and intercept decreased dramatically with height. The altitude variations of the slope and intercept suggest that the MWR tends to overestimate the temperature in cold season but underestimate the temperature in warm season in the middle and upper troposphere. Temperature gradient derived from radiosonde showed that the occurrence frequency of temperature inversions peaked at 28% at near surface at Xi’an, and declined to 8% at 2 km. MWR failed to distinguish the temperature inversion in most cases. The missed detection ratio is approximately 40% at surface and beyond 80% at altitude higher than 500 m. There is still big room for improving the accuracy of the temperature retrievals of MWR, especially in the aspect of temperature inversion detection. Our findings suggest that the MWR data needs to be used with caution in the air pollution study.","PeriodicalId":257532,"journal":{"name":"2019 International Conference on Meteorology Observations (ICMO)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130788393","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-12-01DOI: 10.1109/ICMO49322.2019.9026071
Bing Qi, Rongguang Du, Yong Zhang, Deyun Hu, Huanqiang Yang, H. Sheng
Wind lidar can quickly detect wind profiles, which compensate for the shortcoming of the conventional sounding observation in high temporal and spatial resolution. Thus, it is very useful in the field of meteorology, wind power and aerospace. At present, various types of wind lidars measurement equipment are developed rapidly in China. To verify their detection performance, the synchronous observation data of three-type wind lidars were analyzed at Hangzhou National Reference Climate Station from January 16 to February 20, 2019, using the data of sounding observation and L-band stationary wind profiler as the reference. The results reveal that the median of the detected range is 1000-1500 m, but the data acquisition rates of threetype wind lidars show strongly difference at the height of 1000 m, with the value of 93%, 52%, 74%, respectively. The precipitation has an obvious influence on the detected range, which decreases by more than 50 %. The wind speed has a good relationship between wind lidar and L-band stationary wind profiler, with the correlation coefficient higher than 0.75 under the height of 2000 m, and the wind speed deviation is less than 1.5 m/s. Moreover, the wind direction angle deviation decreases with the increase of altitude, from 28 ° to 10 ° below the height of 1500 m. Compared with the sounding observation, the wind speed correlation of the three-type wind lidars is greater than 0.9, while the wind speed deviation is less than 1.0 m/s, and the wind direction angle deviation mainly decreases with the increase of altitude, with the value basically lower than 25 °. Furthermore, above the height of 600 m, the wind direction angle deviation between three-type wind lidars and the sounding observation has a better performance, with the value less than 15 °. These results can provide some technical and scientific reference for the reliable observation data of wind lidar.
{"title":"The Detection Performance of Different Wind Lidar","authors":"Bing Qi, Rongguang Du, Yong Zhang, Deyun Hu, Huanqiang Yang, H. Sheng","doi":"10.1109/ICMO49322.2019.9026071","DOIUrl":"https://doi.org/10.1109/ICMO49322.2019.9026071","url":null,"abstract":"Wind lidar can quickly detect wind profiles, which compensate for the shortcoming of the conventional sounding observation in high temporal and spatial resolution. Thus, it is very useful in the field of meteorology, wind power and aerospace. At present, various types of wind lidars measurement equipment are developed rapidly in China. To verify their detection performance, the synchronous observation data of three-type wind lidars were analyzed at Hangzhou National Reference Climate Station from January 16 to February 20, 2019, using the data of sounding observation and L-band stationary wind profiler as the reference. The results reveal that the median of the detected range is 1000-1500 m, but the data acquisition rates of threetype wind lidars show strongly difference at the height of 1000 m, with the value of 93%, 52%, 74%, respectively. The precipitation has an obvious influence on the detected range, which decreases by more than 50 %. The wind speed has a good relationship between wind lidar and L-band stationary wind profiler, with the correlation coefficient higher than 0.75 under the height of 2000 m, and the wind speed deviation is less than 1.5 m/s. Moreover, the wind direction angle deviation decreases with the increase of altitude, from 28 ° to 10 ° below the height of 1500 m. Compared with the sounding observation, the wind speed correlation of the three-type wind lidars is greater than 0.9, while the wind speed deviation is less than 1.0 m/s, and the wind direction angle deviation mainly decreases with the increase of altitude, with the value basically lower than 25 °. Furthermore, above the height of 600 m, the wind direction angle deviation between three-type wind lidars and the sounding observation has a better performance, with the value less than 15 °. These results can provide some technical and scientific reference for the reliable observation data of wind lidar.","PeriodicalId":257532,"journal":{"name":"2019 International Conference on Meteorology Observations (ICMO)","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114491307","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Based on the detection of dual-polarized radar, combined with the observation data of lightning, parts of the radar observation products are analyzed for some lightning weather processes occurred in Guangzhou. By studying the variation characteristics of these products before and after the first flash, the lightning nowcasting method based on radar data is offered. In the process of studying radar parameters variation of lightning weather, this paper analyzes the characteristics of radar echoes in different time periods, counts the distribution of polarization parameters, and judges the development process of thunderstorms according to the echo intensity and echo area of different stages. The results show that during lightning, the echo intensity Z, the echo top height ET, the differential reflectivity factor Zdr, the differential propagation phase shift rate Kdp and the vertical accumulated liquid water content VIL of the convective cloud have obvious changes. The radar detection of polarized weather can realize the discrimination of thunderstorm formation state and lightning warning.
{"title":"Analysis of Echo Characteristics of Dual-Polarization Doppler Weather Radar in Lightning Weather","authors":"Shaofeng Wu, Jinglu Si, Dongming Hu, Zaihua Guo, Yu Zhang, Qin Zhao","doi":"10.1109/ICMO49322.2019.9026028","DOIUrl":"https://doi.org/10.1109/ICMO49322.2019.9026028","url":null,"abstract":"Based on the detection of dual-polarized radar, combined with the observation data of lightning, parts of the radar observation products are analyzed for some lightning weather processes occurred in Guangzhou. By studying the variation characteristics of these products before and after the first flash, the lightning nowcasting method based on radar data is offered. In the process of studying radar parameters variation of lightning weather, this paper analyzes the characteristics of radar echoes in different time periods, counts the distribution of polarization parameters, and judges the development process of thunderstorms according to the echo intensity and echo area of different stages. The results show that during lightning, the echo intensity Z, the echo top height ET, the differential reflectivity factor Zdr, the differential propagation phase shift rate Kdp and the vertical accumulated liquid water content VIL of the convective cloud have obvious changes. The radar detection of polarized weather can realize the discrimination of thunderstorm formation state and lightning warning.","PeriodicalId":257532,"journal":{"name":"2019 International Conference on Meteorology Observations (ICMO)","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121303196","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-12-01DOI: 10.1109/ICMO49322.2019.9025886
S. Yao, Jianxin He, Hao Wang, Shunxian Tang, Xiaofeng Liang
To correct the attenuation of radar echo at millimeter-wave Ka-band cloud radar, stratus cloud, precipitating stratus cloud and convective cloud echo data were chosen as the samples for the test. In this paper, the precipitation clouds attenuation correction in vertical direction which detected by Ka-band ground-based in July 2016 in the south suburb meteorological observatory of Beijing Province in China to observe by bin-by-bin attenuation correction algorithm and the hierarchical bin-by-bin attenuation correction algorithm were researched and their difference was compared. The results showed that, (1) in case of stratus clouds with weak echo, the corrections were minor and these echoes were almost right. (2) In case of rainfall, both water droplets and rich water vapor along the ray path caused strong attenuation, and it was difficult to carry out the correction. After attenuation correction, the quality of millimeter wavelength radar data definitely improved though difference still existed. (3) The effect of hierarchical bin-by-bin attenuation correction was stronger than that of bin-by-bin attenuation correction.
{"title":"The Attenuation Correction for Ka Band Cloud Radar","authors":"S. Yao, Jianxin He, Hao Wang, Shunxian Tang, Xiaofeng Liang","doi":"10.1109/ICMO49322.2019.9025886","DOIUrl":"https://doi.org/10.1109/ICMO49322.2019.9025886","url":null,"abstract":"To correct the attenuation of radar echo at millimeter-wave Ka-band cloud radar, stratus cloud, precipitating stratus cloud and convective cloud echo data were chosen as the samples for the test. In this paper, the precipitation clouds attenuation correction in vertical direction which detected by Ka-band ground-based in July 2016 in the south suburb meteorological observatory of Beijing Province in China to observe by bin-by-bin attenuation correction algorithm and the hierarchical bin-by-bin attenuation correction algorithm were researched and their difference was compared. The results showed that, (1) in case of stratus clouds with weak echo, the corrections were minor and these echoes were almost right. (2) In case of rainfall, both water droplets and rich water vapor along the ray path caused strong attenuation, and it was difficult to carry out the correction. After attenuation correction, the quality of millimeter wavelength radar data definitely improved though difference still existed. (3) The effect of hierarchical bin-by-bin attenuation correction was stronger than that of bin-by-bin attenuation correction.","PeriodicalId":257532,"journal":{"name":"2019 International Conference on Meteorology Observations (ICMO)","volume":"76 11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121264745","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-12-01DOI: 10.1109/ICMO49322.2019.9026111
Yuyu Tao, Xiaobo Deng, Hailei Liu, Qihong Huang, Ke Zhou, Yuping Ji
Southern Shaanxi refers to the southwestern part of Shaanxi, and from the west to the east of Shaanxi Province, there are three cities: Hanzhong, Ankang and Shangluo. The annual precipitation data of 8 meteorological stations in the southern part of Shaanxi Province from 1977 to 2017 were selected, and the area was analyzed by EOF (empirical orthogonal function method). The results show that the EOF method can well reveal the temporal and spatial distributions of precipitation field. For the southern part of Shaanxi Province, the first two eigenvectors reveal two typical distribution fields, which are global and eastwest patterns. Its cumulative contribution rate is 79.90%. In general, the eigenvectors of the two fields are expressed as the western region is larger than the eastern region. And high-value centers appear in Hanzhong City. The analysis of the time coefficient corresponding to the eigenvectors shows that the precipitation fields in the southern part of Shaanxi Province mainly show four types. Which includes the wetter in the whole region, the drier in the whole filed, the wetter in west and drier in east, and the wetter in east and drier in west. Compared to the statistical results of 41 year, these results were consistent with the typical precipitation fields
{"title":"Analyzing Spatial and Temporal Distributions of Precipitation in the Southern Part of Shaanxi Province","authors":"Yuyu Tao, Xiaobo Deng, Hailei Liu, Qihong Huang, Ke Zhou, Yuping Ji","doi":"10.1109/ICMO49322.2019.9026111","DOIUrl":"https://doi.org/10.1109/ICMO49322.2019.9026111","url":null,"abstract":"Southern Shaanxi refers to the southwestern part of Shaanxi, and from the west to the east of Shaanxi Province, there are three cities: Hanzhong, Ankang and Shangluo. The annual precipitation data of 8 meteorological stations in the southern part of Shaanxi Province from 1977 to 2017 were selected, and the area was analyzed by EOF (empirical orthogonal function method). The results show that the EOF method can well reveal the temporal and spatial distributions of precipitation field. For the southern part of Shaanxi Province, the first two eigenvectors reveal two typical distribution fields, which are global and eastwest patterns. Its cumulative contribution rate is 79.90%. In general, the eigenvectors of the two fields are expressed as the western region is larger than the eastern region. And high-value centers appear in Hanzhong City. The analysis of the time coefficient corresponding to the eigenvectors shows that the precipitation fields in the southern part of Shaanxi Province mainly show four types. Which includes the wetter in the whole region, the drier in the whole filed, the wetter in west and drier in east, and the wetter in east and drier in west. Compared to the statistical results of 41 year, these results were consistent with the typical precipitation fields","PeriodicalId":257532,"journal":{"name":"2019 International Conference on Meteorology Observations (ICMO)","volume":"78 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115965838","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-12-01DOI: 10.1109/ICMO49322.2019.9025837
Yin Liu, Honggen Zhou, Hong Zhao
A large-scale strong convection which is occurred in Jiangsu Province on August 6 2015 is diagnosed and analyzed from various angles using reanalysis data, surface observation data and the new generation radar data. The main conclusions are the followings: the ground squall line is the direct impact system of this strong convection. The upper air is dry and cold and the low level is warm and humid. During this convection, the wind direction is suddenly changed, wind speed is shot up, the pressure is upwelling, the temperature is dropped sharply, and the relative humidity rises sharply. The atmosphere energy is accumulated in the ground, there is an energy front area between the middle level and lower level, the strong vertical rising speed, the low-level convergence and high-level divergence of water vapor flux are the favorable factors for heavy precipitation. The radar echo shows that there is a clear gust front on the right side of the thunderstorm in Liuhe area, simultaneously, and there is a distinct weak narrow-band in the left front of the echo, corresponding to the outflow boundary of the rear side of the thunderstorm. In addition, the center of the radar echo is observed decline rapidly in the vertical direction. The above characteristics have a good indication of the prediction of severe winds.
{"title":"Mesoscale Diagnostic Analysis of a Strong Convective System in Jiangsu Province","authors":"Yin Liu, Honggen Zhou, Hong Zhao","doi":"10.1109/ICMO49322.2019.9025837","DOIUrl":"https://doi.org/10.1109/ICMO49322.2019.9025837","url":null,"abstract":"A large-scale strong convection which is occurred in Jiangsu Province on August 6 2015 is diagnosed and analyzed from various angles using reanalysis data, surface observation data and the new generation radar data. The main conclusions are the followings: the ground squall line is the direct impact system of this strong convection. The upper air is dry and cold and the low level is warm and humid. During this convection, the wind direction is suddenly changed, wind speed is shot up, the pressure is upwelling, the temperature is dropped sharply, and the relative humidity rises sharply. The atmosphere energy is accumulated in the ground, there is an energy front area between the middle level and lower level, the strong vertical rising speed, the low-level convergence and high-level divergence of water vapor flux are the favorable factors for heavy precipitation. The radar echo shows that there is a clear gust front on the right side of the thunderstorm in Liuhe area, simultaneously, and there is a distinct weak narrow-band in the left front of the echo, corresponding to the outflow boundary of the rear side of the thunderstorm. In addition, the center of the radar echo is observed decline rapidly in the vertical direction. The above characteristics have a good indication of the prediction of severe winds.","PeriodicalId":257532,"journal":{"name":"2019 International Conference on Meteorology Observations (ICMO)","volume":"37 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114494192","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-12-01DOI: 10.1109/ICMO49322.2019.9025971
C. Haibo, Li Peng, Shi Likui
Among China's meteorological observation items, frozen soil, soil temperature, soil moisture and dry soil layer are elements which related to soil. These items are observed by a variety of single element observation equipments, while the frozen soil and dry soil layer have not yet achieved automatic observation. This paper proposes a multi-element integrated observation method for soil environment. The sensor measures the soil dielectric constant and temperature change through a planar capacitor and a semiconductor temperature measuring element to achieve the measurement of soil moisture and soil temperature. The water-induced freezing phase change causes dielectric The characteristics of the constant change of the constant, establish a mathematical model based on soil dielectric constant and ground temperature to invert frozen soil to achieve accurate measurement of frozen soil; soil moisture combined with soil hydrophysical constants can realize automatic observation of dry soil layers. The experiment shows that the multi-element sensor of soil environment can accurately measure the elements such as soil moisture and frozen soil. The measurement data is consistent with the trend of manual observation, and the automatic observation of frozen soil and dry soil layer is realized.
{"title":"Study on the Integrated Observation Method of Multi Elements of Soil Environment","authors":"C. Haibo, Li Peng, Shi Likui","doi":"10.1109/ICMO49322.2019.9025971","DOIUrl":"https://doi.org/10.1109/ICMO49322.2019.9025971","url":null,"abstract":"Among China's meteorological observation items, frozen soil, soil temperature, soil moisture and dry soil layer are elements which related to soil. These items are observed by a variety of single element observation equipments, while the frozen soil and dry soil layer have not yet achieved automatic observation. This paper proposes a multi-element integrated observation method for soil environment. The sensor measures the soil dielectric constant and temperature change through a planar capacitor and a semiconductor temperature measuring element to achieve the measurement of soil moisture and soil temperature. The water-induced freezing phase change causes dielectric The characteristics of the constant change of the constant, establish a mathematical model based on soil dielectric constant and ground temperature to invert frozen soil to achieve accurate measurement of frozen soil; soil moisture combined with soil hydrophysical constants can realize automatic observation of dry soil layers. The experiment shows that the multi-element sensor of soil environment can accurately measure the elements such as soil moisture and frozen soil. The measurement data is consistent with the trend of manual observation, and the automatic observation of frozen soil and dry soil layer is realized.","PeriodicalId":257532,"journal":{"name":"2019 International Conference on Meteorology Observations (ICMO)","volume":"50 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127423030","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-12-01DOI: 10.1109/ICMO49322.2019.9026061
Xiaoqiong Zhen, Jian Li, Lei Ye, Zhendong Yao, Weifang Liu, Lin Chen
The performances of the weather system echoes are determined by the wave beam characteristics of the weather radar antenna. The main lobe gain and beam width of the antenna are related to the sensitivity and resolution of the radar, meanwhile, the level of the side lobe may lead the generation of false ground clutter and side lobe echoes that should not exist. Therefore, professional antenna test experiments are necessary but inconvenient for the general radar users because of the harsh experiment conditions of the test. In this paper, a simply method for measuring radar antenna wave beam pattern by using a horn and a signal generator is proposed. In the method, a horn antenna with a standard gain is fixed by a stand. The fixed horn antenna is moved to a location with a relatively clean electromagnetic environment 1 to 2 km away from the radar. A microwave signal generator is connected with the horn antenna with a low loss coaxial cable for generating the input wave during the radar antenna test. The test is completed by rotating the antenna. The gain of the radar antenna can be calculated by using transmitting power, the horn gain, the distance between the radar and the horn antenna. The validity of the method is verified by testing the antennas of a WXR_MD_1 and an MaXPol radar.
{"title":"A Simply Method for Measuring Radar Antenna Wave Beam Pattern by Horn and Signal Generator","authors":"Xiaoqiong Zhen, Jian Li, Lei Ye, Zhendong Yao, Weifang Liu, Lin Chen","doi":"10.1109/ICMO49322.2019.9026061","DOIUrl":"https://doi.org/10.1109/ICMO49322.2019.9026061","url":null,"abstract":"The performances of the weather system echoes are determined by the wave beam characteristics of the weather radar antenna. The main lobe gain and beam width of the antenna are related to the sensitivity and resolution of the radar, meanwhile, the level of the side lobe may lead the generation of false ground clutter and side lobe echoes that should not exist. Therefore, professional antenna test experiments are necessary but inconvenient for the general radar users because of the harsh experiment conditions of the test. In this paper, a simply method for measuring radar antenna wave beam pattern by using a horn and a signal generator is proposed. In the method, a horn antenna with a standard gain is fixed by a stand. The fixed horn antenna is moved to a location with a relatively clean electromagnetic environment 1 to 2 km away from the radar. A microwave signal generator is connected with the horn antenna with a low loss coaxial cable for generating the input wave during the radar antenna test. The test is completed by rotating the antenna. The gain of the radar antenna can be calculated by using transmitting power, the horn gain, the distance between the radar and the horn antenna. The validity of the method is verified by testing the antennas of a WXR_MD_1 and an MaXPol radar.","PeriodicalId":257532,"journal":{"name":"2019 International Conference on Meteorology Observations (ICMO)","volume":"25 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126024656","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-12-01DOI: 10.1109/ICMO49322.2019.9025835
Lei Ye, Jian Li, Zhendong Yao, Longfei Yi, Yong She, Shuo Wang
This paper presents a weather radar servo system based on DSP chip. In this system, a set of high-precision shaft angle digital coding modular circuit is designed with a resolver, a monolithic resolver-to-digital converter and an excitation signal driver, and meets the requirements of precise angular-position information measurement of the DC motor shaft. The shaft encoder information mapped on DSP’s external data memory space can be directly accessed by its parallel interface. With comparing technical characteristics of unipolar and bipolar PWM, the unipolar PWM technique is chosen and applied in this design, and its pulse width and direction signal are generated by the DSP chip. In order to overcome the limitations of the existing half-bridge driver in applications, a special unipolar PWM logic distribution and inverter circuit is designed, which has ultimately solved the problem of shoot-through in an H-bridge configuration. For scan types of a weather radar servo system, especially antenna angular positioning, the digital PI regulator with saturation algorithm is employed in the design, which meets the accuracy requirements of angular positioning and uniform rotation. At present, the servo system has been successfully applied to X-band Doppler weather radar named WXR-MD-10, which is designed by Radar System Lab of Chengdu University of Information Technology. And it had been installed at the Meteorological Bureau of Weining County, Guizhou Province in July 2011, and put into operation.
{"title":"Design of X-band Doppler Weather Radar Servo System","authors":"Lei Ye, Jian Li, Zhendong Yao, Longfei Yi, Yong She, Shuo Wang","doi":"10.1109/ICMO49322.2019.9025835","DOIUrl":"https://doi.org/10.1109/ICMO49322.2019.9025835","url":null,"abstract":"This paper presents a weather radar servo system based on DSP chip. In this system, a set of high-precision shaft angle digital coding modular circuit is designed with a resolver, a monolithic resolver-to-digital converter and an excitation signal driver, and meets the requirements of precise angular-position information measurement of the DC motor shaft. The shaft encoder information mapped on DSP’s external data memory space can be directly accessed by its parallel interface. With comparing technical characteristics of unipolar and bipolar PWM, the unipolar PWM technique is chosen and applied in this design, and its pulse width and direction signal are generated by the DSP chip. In order to overcome the limitations of the existing half-bridge driver in applications, a special unipolar PWM logic distribution and inverter circuit is designed, which has ultimately solved the problem of shoot-through in an H-bridge configuration. For scan types of a weather radar servo system, especially antenna angular positioning, the digital PI regulator with saturation algorithm is employed in the design, which meets the accuracy requirements of angular positioning and uniform rotation. At present, the servo system has been successfully applied to X-band Doppler weather radar named WXR-MD-10, which is designed by Radar System Lab of Chengdu University of Information Technology. And it had been installed at the Meteorological Bureau of Weining County, Guizhou Province in July 2011, and put into operation.","PeriodicalId":257532,"journal":{"name":"2019 International Conference on Meteorology Observations (ICMO)","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126143108","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-12-01DOI: 10.1109/ICMO49322.2019.9025871
Zhu Yazong, Dong Debao, W. J. Xing
The meteorological Bureau of Anhui Province has deployed DZN2 soil moisture stations since 2009. The layout of the site has greatly reduced the labor capacity of traditional manual observation and increased the spatial and temporal density of observation data for drought monitoring, agricultural meteorological forecasting services and great contribution. In the long-term operation process, due to changes in the observation environment, site migration, and daily maintenance of the site, in recent years, the quality of the automatic soil moisture observation data has decreased, and the observation data has a large deviation from the actual state of the soil characteristics, such as the province. The surface cracks caused by the continuous drought in the central and northern areas, especially in the clay and loam clay areas, make the observation data significantly smaller. The long-term accumulation of water in the field is not discharged in time, causing the soil to continue to be too wet, etc., and it becomes the daily soil moisture data of our province. A big problem in business applications. In this paper, a series of calibration tests were carried out on Shouxian Station in Huainan, and the data before and after the test were compared and analyzed. Before the test, the measured value of the relative humidity of the shallow layer (10-20 cm) of the station showed that the section was moderately moderately dry. However, after on-site investigation, the low machine measurement is due to soil cracking around the sensor of the soil moisture observer. Soil cracking is caused by the hydration expansion of clay. When the moisture of the moist soil evaporates quickly, the soil around the protective tube shrinks due to the exclusion of the protective tube and the soil, thereby forming a crack. As the evapotranspiration increases, the cracks will continue to develop deeper, and the key is to prevent surface cracking. Test rectification plan: When the undisturbed soil test was carried out in the laboratory, it was found that the crack formation was around the soil box, and no cracks were formed around the PVC protection tube. Thus, the idea of separating the soil within a certain range of the PVC sheath to maintain the original shape of the sensor is generated. This paper designs and processes a set of acrylic material drums and installs PVC protection pipes into the center of the drum. After the installation of the acrylic material drum, the field artificial soil test was carried out. It can be seen from the data reading software that in the calibration test, the measured value of soil moisture relative humidity of the station, especially the shallow layer and the artificial value, is very good, and a certain effect is obtained. Since it does not experience continuous drought and less rain, whether the method can solve the problem of soil cracking around the sensor well needs time verification. After the completion of the network of soil moisture automatic
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