摘要 :
Refractivity happens due to stratification in the lower boundary layer over oceans due to variability of moisture, temperature, wind and sea surface temperature which collectively may lead to generate evaporation duct. The evapora...
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Refractivity happens due to stratification in the lower boundary layer over oceans due to variability of moisture, temperature, wind and sea surface temperature which collectively may lead to generate evaporation duct. The evaporation duct has a significant impact on the spread of electromagnetic waves in the atmosphere over oceans both from the meteorological and military point of view. This ducting sometimes supports normal propagation of radar signals and sometimes may cause distortion and attenuation of signals depending on the height of evaporation duct. This leads to over-estimation and under-estimation of rainfall by weather radar meteorologically and for other targets militarily. The aim of this study was not only to locate evaporation duct height but also to check the efficiency of Weather Research and Forecasting Model (WRF) and Babin's model so that results may be used in applying correction measures for precise identification of targets by radar. In this study by utilizing the high vertical resolution of WRF for the simulation of different meteorological parameters, the Babin's method was used for calculating the evaporation duct height over South China Sea for the two months, April and July. Very clear duct heights were calculated at different areas over sea in different time domains. Study reveals that maximum height existed in the month of April although July was rich with different EDHs in different regions in contrast to April. It was found that in most of the cases EDH was higher or maximum when relative humidity was comparatively lower and air temperature and wind speed were comparatively higher. This study paves a way for futuristic study of evaporation duct monitoring and forecasting by assimilation of remote sensing data especially through that of Geostationary satellites by incorporating verification measures from radar.
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摘要 :
Refractivity happens due to stratification in the lower boundary layer over oceans due to variability of moisture, temperature, wind and sea surface temperature which collectively may lead to generate evaporation duct. The evapora...
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Refractivity happens due to stratification in the lower boundary layer over oceans due to variability of moisture, temperature, wind and sea surface temperature which collectively may lead to generate evaporation duct. The evaporation duct has a significant impact on the spread of electromagnetic waves in the atmosphere over oceans both from the meteorological and military point of view. This ducting sometimes supports normal propagation of radar signals and sometimes may cause distortion and attenuation of signals depending on the height of evaporation duct. This leads to over-estimation and under-estimation of rainfall by weather radar meteorologically and for other targets militarily. The aim of this study was not only to locate evaporation duct height but also to check the efficiency of Weather Research and Forecasting Model (WRF) and Babin's model so that results may be used in applying correction measures for precise identification of targets by radar. In this study by utilizing the high vertical resolution of WRF for the simulation of different meteorological parameters, the Babin's method was used for calculating the evaporation duct height over South China Sea for the two months, April and July. Very clear duct heights were calculated at different areas over sea in different time domains. Study reveals that maximum height existed in the month of April although July was rich with different EDHs in different regions in contrast to April. It was found that in most of the cases EDH was higher or maximum when relative humidity was comparatively lower and air temperature and wind speed were comparatively higher. This study paves a way for futuristic study of evaporation duct monitoring and forecasting by assimilation of remote sensing data especially through that of Geostationary satellites by incorporating verification measures from radar.
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摘要 :
Three-fold restriction technique is used to determine the standard deviation of the error in the total-ozone content obtained from the three independent data resources such as ground-based station data, TOMS (Total Ozone Mapping S...
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Three-fold restriction technique is used to determine the standard deviation of the error in the total-ozone content obtained from the three independent data resources such as ground-based station data, TOMS (Total Ozone Mapping Spectrophotometer) and GOME (The Global Ozone Monitoring Experiment) in 1995-2004. The results show that, in general, the accuracy of TOMS V8 data is the best and that of ground-based observations is the worst. Since the ground-based observations can be classified into 3 types according to the equipment principles such as Filter, Brewer and Dobson, the standard deviation of the errors for the 3 types of ground data are also calculated with the 3-fold restriction technique and it has been found that the Filter has the largest error, the Brewer is the second, and the Dobson is the least. The data quality at Shiangher Dobson Station of China is better than either TOMS or GOME. The data quality at Waliguan Brewer Station of China is better than TOMS, but worse than GOME. The error in TOMS V8 is evidently less than in TOMS V7 because of the algorithm amelioration of TOMS V8 over TOMS V7.
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摘要 :
Three-fold restriction technique is used to determine the standard deviation of the error in the total-ozone content obtained from the three independent data resources such as ground-based station data, TOMS (Total Ozone Mapping S...
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Three-fold restriction technique is used to determine the standard deviation of the error in the total-ozone content obtained from the three independent data resources such as ground-based station data, TOMS (Total Ozone Mapping Spectrophotometer) and GOME (The Global Ozone Monitoring Experiment) in 1995-2004. The results show that, in general, the accuracy of TOMS V8 data is the best and that of ground-based observations is the worst. Since the ground-based observations can be classified into 3 types according to the equipment principles such as Filter, Brewer and Dobson, the standard deviation of the errors for the 3 types of ground data are also calculated with the 3-fold restriction technique and it has been found that the Filter has the largest error, the Brewer is the second, and the Dobson is the least. The data quality at Shiangher Dobson Station of China is better than either TOMS or GOME. The data quality at Waliguan Brewer Station of China is better than TOMS, but worse than GOME. The error in TOMS V8 is evidently less than in TOMS V7 because of the algorithm amelioration of TOMS V8 over TOMS V7.
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摘要 :
By field survey, literature research and other methods, the research group takes the University City Town of Huaxi as an example to explore the relationship between the University City Town construction and regional development. T...
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By field survey, literature research and other methods, the research group takes the University City Town of Huaxi as an example to explore the relationship between the University City Town construction and regional development. The research group has studied and found that with a collection of urban modern origin and the development of higher education idea the University City Town of Huaxi Guiyang has its unique advantages in the regional development. It will have far-reaching influence on the development of the regional politics, economics, cultures and ecology.
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Atmospheric motion vectors (AMV) in cloud-free region can not be obtained with current operational cloud-motion tracking and water-vapor channel algorithms. The motivation of this study is to introduce a supplementary algorithm in...
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Atmospheric motion vectors (AMV) in cloud-free region can not be obtained with current operational cloud-motion tracking and water-vapor channel algorithms. The motivation of this study is to introduce a supplementary algorithm in order to work out the low-level AMVs in the clear area with FY-2E long wave, window (10.3～11.5, 11.6～12.8 μm) channel imagery. It has been shown that the weak signals indicating water vapor in "cloud-free region" can be extracted from FY-2E long wave infrared imagery and may be used as tracers for atmospheric motion vectors. The algorithm, named as Second Order difference method, has been raised in order to weaken the surface temperature interference to the weak signals of water vapor in "cloud-free region" by means of split window and temporal difference calculations. The results from theory analysis and cases study show that this method can make up for the wind data in regions lack of cloud but rich of water vapor and comparison between the wind vectors from this method and the NCEP reanalysis data shows a good consistency.
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摘要 :
Atmospheric motion vectors (AMV) in cloud-free region can not be obtained with current operational cloud-motion tracking and water-vapor channel algorithms. The motivation of this study is to introduce a supplementary algorithm in...
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Atmospheric motion vectors (AMV) in cloud-free region can not be obtained with current operational cloud-motion tracking and water-vapor channel algorithms. The motivation of this study is to introduce a supplementary algorithm in order to work out the low-level AMVs in the clear area with FY-2E long wave, window (10.3～11.5, 11.6～12.8 μm) channel imagery. It has been shown that the weak signals indicating water vapor in "cloud-free region" can be extracted from FY-2E long wave infrared imagery and may be used as tracers for atmospheric motion vectors. The algorithm, named as Second Order difference method, has been raised in order to weaken the surface temperature interference to the weak signals of water vapor in "cloud-free region" by means of split window and temporal difference calculations. The results from theory analysis and cases study show that this method can make up for the wind data in regions lack of cloud but rich of water vapor and comparison between the wind vectors from this method and the NCEP reanalysis data shows a good consistency.
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Quick Formulas based on DDA outputs is a set of partitioned polynomials aiming at easy-coding and time-saving during calculating extinction and backscattering properties for oblate spheroid raindrops. The Quick Formulas for the co...
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Quick Formulas based on DDA outputs is a set of partitioned polynomials aiming at easy-coding and time-saving during calculating extinction and backscattering properties for oblate spheroid raindrops. The Quick Formulas for the common radar wave bands of S, C, X and Ka have been obtained. It has been shown that the accuracy of Quick Formulas is more than 95%, that is, the error is less than 5%, and the time consumed is negligible as compared with DDA computation. The resulting codes can be inserted into the software for radar reflectivity simulation and real-time attenuation correction of rainfall estimation with radar.
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摘要 :
Quick Formulas based on DDA outputs is a set of partitioned polynomials aiming at easy-coding and time-saving during calculating extinction and backscattering properties for oblate spheroid raindrops. The Quick Formulas for the co...
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Quick Formulas based on DDA outputs is a set of partitioned polynomials aiming at easy-coding and time-saving during calculating extinction and backscattering properties for oblate spheroid raindrops. The Quick Formulas for the common radar wave bands of S, C, X and Ka have been obtained. It has been shown that the accuracy of Quick Formulas is more than 95%, that is, the error is less than 5%, and the time consumed is negligible as compared with DDA computation. The resulting codes can be inserted into the software for radar reflectivity simulation and real-time attenuation correction of rainfall estimation with radar.
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On the basis of the China's designing method of cement concrete pavement of military airport(GJB 1278-91), the calculating model and steps of remaining life of cement concrete pavement of military airport with the reversed method ...
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On the basis of the China's designing method of cement concrete pavement of military airport(GJB 1278-91), the calculating model and steps of remaining life of cement concrete pavement of military airport with the reversed method brought up by ICAO are shown in this paper. Moreover, some programs were presented to determine the parameters in the model. The remaining life is calculated on the basis of measured data. Through comparing with the historical information on pavement maintaining, it is obtained that the estimation methods can anticipate the remaining life of cement concrete pavement of military airport accurately. The prediction model also could be treated as one part of pavement performance prediction of the military airports pavement management system.
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