ISSN 1000-0526
CN 11-2282/P
CN 11-2282/P
Volume 36,Issue 5,2010 Table of Contents
2010, 36(5):1-11.
DOI: 10.7519/j.issn.1000-0526.2010.5.001
Abstract:
When wind field is detected with Dopper weather radar, there are some different size nonecho areas in largescale radar echoes, which lead to great errors when average divergence and average deformation information are extracted. With the technique suggested by Sirmans to simulate the precipitationecho signal, we obtain a plane linear velocity field which includes 0, 1, 2 step overtones and carry on addschirp processing, and then a nearreal Doppler velocity field is generated. Supposing that the special nonecho area exists in the plane linear velocity field and by the use of VAD technology and the repetitive processing, the continuous gap and the noncontinuous gap in the plane linear velocity field would be filled with repetitive processing. The simulation results indicate that for the simulation of nonnoise plane linear velocity field, the nonecho area of continuity accumulation gap from 10° to 180° can be filled inerrably with the repetitive processing in the velocity field. For continuous accumulation gap, under the conditions of σv=2 m?s-1，SNR≥5 dB and SNR=20 dB,σv≤4 m?s-1, and the continuous accumulation gap less than 120°, the nonecho area with the repetitive processing in the velocity field can be filled inerrably. After filling, the absolute errors of 0, 1, 2 step overtones may be controlled to be less than 15%, and the absolute errors of speed controlled less than 30% which is 80 km away from the circle around the gap place iteration. For the plane linear velocity field of noncontinuous accumulation gap from 0° to 180°, under the condition of additional different noise, not only the accumulation gap less than 180° in the plane velocity field can be filled, but also the speed errors can be controlled to be less than 15% which is 80 km away from the circle around the gap place iteration. This shows that the effect and precision are very good when nonecho areas in Doppler wind field are filled with the repetitive processing, and will have a great help for improving the precision of average divergence and average deformation information extracted from the Doppler wind field.
When wind field is detected with Dopper weather radar, there are some different size nonecho areas in largescale radar echoes, which lead to great errors when average divergence and average deformation information are extracted. With the technique suggested by Sirmans to simulate the precipitationecho signal, we obtain a plane linear velocity field which includes 0, 1, 2 step overtones and carry on addschirp processing, and then a nearreal Doppler velocity field is generated. Supposing that the special nonecho area exists in the plane linear velocity field and by the use of VAD technology and the repetitive processing, the continuous gap and the noncontinuous gap in the plane linear velocity field would be filled with repetitive processing. The simulation results indicate that for the simulation of nonnoise plane linear velocity field, the nonecho area of continuity accumulation gap from 10° to 180° can be filled inerrably with the repetitive processing in the velocity field. For continuous accumulation gap, under the conditions of σv=2 m?s-1，SNR≥5 dB and SNR=20 dB,σv≤4 m?s-1, and the continuous accumulation gap less than 120°, the nonecho area with the repetitive processing in the velocity field can be filled inerrably. After filling, the absolute errors of 0, 1, 2 step overtones may be controlled to be less than 15%, and the absolute errors of speed controlled less than 30% which is 80 km away from the circle around the gap place iteration. For the plane linear velocity field of noncontinuous accumulation gap from 0° to 180°, under the condition of additional different noise, not only the accumulation gap less than 180° in the plane velocity field can be filled, but also the speed errors can be controlled to be less than 15% which is 80 km away from the circle around the gap place iteration. This shows that the effect and precision are very good when nonecho areas in Doppler wind field are filled with the repetitive processing, and will have a great help for improving the precision of average divergence and average deformation information extracted from the Doppler wind field.
2010, 36(5):12-20.
DOI: 10.7519/j.issn.1000-0526.2010.5.002
Abstract:
An axisymmetric Bogus vortex at sea level was used in the traditional bogus data assimilation (BDA) scheme. This vortex could not accurately describe the specific characteristics of the typhoon. The reasonable elements of the background field were discarded. And, the assimilation of thermal and humidity elements, and the impact of the largescale environment, were not taken into account. Thus, an asymmetrical typhoon bogus method with blend information from the analysis and the observation is brought forward while the impact of the subtropical anticyclone is considered as well. Then the fast radiative transfer model RTTOV8 is planted into the adjoint model of the fifth generation NCAR/Penn State Mesoscale Model (MM5) to assimilate the brightness temperature and Bogus data based on the fourdimensional variational data assimilation (4DVAR) technique. A group of BDA experiments on landing typhoon “Weipha” for 48hour simulation are studied. The Bogus sea level wind and pressure, and the multisatellite and multiorbital ATOVS data are assimilated. The Noah land surface model is employed in simulation. The results show that, the BDA scheme which assimilates Bogus data alone transmits the Bogus information from the sea surface to high layers, and an asymmetrical threedimensional circulation assorted with the model is brought out, the temperature is indirectly adjusted in whole layers, and a warmcore structure is strengthened. Whereas, the adjusting of humidity is deficient, the environmental fields outside the typhoon area cannot be adjusted well, and the improvement of track forecast is not obvious while the intensity forecast is greatly improved; The employment of Noah land surface model can improve the track forecast after landing; When ATOVS data are assimilated, significant adjustments are made on the humidity condition and environmental fields, lots of mesoscale information is reconfigured, more precise typhoon circulation and more precise thermal and humidity structure in the initial field is obtained. And the advantage of BDA scheme in track and intensity forecast is maintained, the precipitation intensity in forecast is increasing, and the precipitation location is changed.
An axisymmetric Bogus vortex at sea level was used in the traditional bogus data assimilation (BDA) scheme. This vortex could not accurately describe the specific characteristics of the typhoon. The reasonable elements of the background field were discarded. And, the assimilation of thermal and humidity elements, and the impact of the largescale environment, were not taken into account. Thus, an asymmetrical typhoon bogus method with blend information from the analysis and the observation is brought forward while the impact of the subtropical anticyclone is considered as well. Then the fast radiative transfer model RTTOV8 is planted into the adjoint model of the fifth generation NCAR/Penn State Mesoscale Model (MM5) to assimilate the brightness temperature and Bogus data based on the fourdimensional variational data assimilation (4DVAR) technique. A group of BDA experiments on landing typhoon “Weipha” for 48hour simulation are studied. The Bogus sea level wind and pressure, and the multisatellite and multiorbital ATOVS data are assimilated. The Noah land surface model is employed in simulation. The results show that, the BDA scheme which assimilates Bogus data alone transmits the Bogus information from the sea surface to high layers, and an asymmetrical threedimensional circulation assorted with the model is brought out, the temperature is indirectly adjusted in whole layers, and a warmcore structure is strengthened. Whereas, the adjusting of humidity is deficient, the environmental fields outside the typhoon area cannot be adjusted well, and the improvement of track forecast is not obvious while the intensity forecast is greatly improved; The employment of Noah land surface model can improve the track forecast after landing; When ATOVS data are assimilated, significant adjustments are made on the humidity condition and environmental fields, lots of mesoscale information is reconfigured, more precise typhoon circulation and more precise thermal and humidity structure in the initial field is obtained. And the advantage of BDA scheme in track and intensity forecast is maintained, the precipitation intensity in forecast is increasing, and the precipitation location is changed.
2010, 36(5):21-31.
DOI: 10.7519/j.issn.1000-0526.2010.5.003
Abstract:
To improve the effect of ensemble prediction, a 13member ensemble forecast of Masta was generated by using T106L19 model and breeding growth method(BGM),and the research of the application of ensemble prediction products from the results was carried out. Firstly, the pattern fields of ensemble forecast were clustered through variance analysis according to discrete distance between members. Through this method, the pattern fields are grouped into three different clusters, especially the several possible tracks and the proportions of every cluster member are provided. The 96 h forecast results were used as the basis of clustering in the previous method of discrete distance clustering. In comparison with the previous method, the results of variance analysis are better. Secondly, the evolvement of variables is categorized by using the method of systemic classifying and several possible typhoon landing positions can be concluded from clustering averaged plots. Based on these special points, the plumes plot with systemic classifying of variables can be used to analyze the sea level pressure of the special points. Through discussing the evolvement characteristics of these points, the prediction results of the landing time and position of typhoon are more similar to observations than the cluster average. In addition, boxwhisker plot has been presented. Several special ensemble members have been identified through the analysis of data beyond the main distribution of data. The information provided by the special points from boxwhisker plot can reduce the missing rate of severe weather event. The research results indicate that the effects of prediction and the application of ensemble prediction products were improved by using the method of the clustering basis determined by using variance analysis, systemic classifying and boxwhisker plot.
To improve the effect of ensemble prediction, a 13member ensemble forecast of Masta was generated by using T106L19 model and breeding growth method(BGM),and the research of the application of ensemble prediction products from the results was carried out. Firstly, the pattern fields of ensemble forecast were clustered through variance analysis according to discrete distance between members. Through this method, the pattern fields are grouped into three different clusters, especially the several possible tracks and the proportions of every cluster member are provided. The 96 h forecast results were used as the basis of clustering in the previous method of discrete distance clustering. In comparison with the previous method, the results of variance analysis are better. Secondly, the evolvement of variables is categorized by using the method of systemic classifying and several possible typhoon landing positions can be concluded from clustering averaged plots. Based on these special points, the plumes plot with systemic classifying of variables can be used to analyze the sea level pressure of the special points. Through discussing the evolvement characteristics of these points, the prediction results of the landing time and position of typhoon are more similar to observations than the cluster average. In addition, boxwhisker plot has been presented. Several special ensemble members have been identified through the analysis of data beyond the main distribution of data. The information provided by the special points from boxwhisker plot can reduce the missing rate of severe weather event. The research results indicate that the effects of prediction and the application of ensemble prediction products were improved by using the method of the clustering basis determined by using variance analysis, systemic classifying and boxwhisker plot.
2010, 36(5):32-39.
DOI: 10.7519/j.issn.1000-0526.2010.5.004
Abstract:
A method of improving the Sichuan heavy rainfall forecasting accuracy based on the Bayesian decision theory is explored. This method uses the heavy rainfall climate probability of Sichuan 147 stations from June to September in 1951 to 2004 to modify the ensemble prediction probability products of precipitation more than 50 mm produced by southwest regional ensemble forecasting system. The continuous forecasting test results from June to September in 2008 show that the posterior probability, i.e. the probability modified by the Bayesian mathod, can eliminate the false prediction to some extent. Although the effect of improving the heavy rainfall forecasting accuracy is not obvious compared with the prior probability, it still provides an exploring method-how to use the numerical ensemble prediction products to improve the Sichuan heavy rainfall forecasting accuracy and how to provide more valuable heavy rainfall information for the early warning decision method.
A method of improving the Sichuan heavy rainfall forecasting accuracy based on the Bayesian decision theory is explored. This method uses the heavy rainfall climate probability of Sichuan 147 stations from June to September in 1951 to 2004 to modify the ensemble prediction probability products of precipitation more than 50 mm produced by southwest regional ensemble forecasting system. The continuous forecasting test results from June to September in 2008 show that the posterior probability, i.e. the probability modified by the Bayesian mathod, can eliminate the false prediction to some extent. Although the effect of improving the heavy rainfall forecasting accuracy is not obvious compared with the prior probability, it still provides an exploring method-how to use the numerical ensemble prediction products to improve the Sichuan heavy rainfall forecasting accuracy and how to provide more valuable heavy rainfall information for the early warning decision method.
2010, 36(5):40-45.
DOI: 10.7519/j.issn.1000-0526.2010.5.005
Abstract:
A statistical analysis of the temporal and spatial changes of mainly climatic elements over the North China Plain was conducted, based on the daily climatic data of 53 stations from 1961 to 2005 by using the trend analysis, and the jumping point of temperature was fixed by using the MannKendall test method. It was found that the climate was warming up in the last 45 years, in particular in the 1990s. For annual precipitation, no significant trend was found on the basis of longterm change. Precipitation gradually decreased in the middle and later period of the 1980s. Thus, it was believed that climatic variation in the North China Plain over the 45 years experienced a course of humidcold to drywarm. And the sunshine duration was decreasing significantly. The climate change feature of each month was characterized by monthly linear inclination rates which showed that from January to April, the temperature increased most remarkably, the precipitation decreased most obviously in summer and April, and the sunshine duration decreased rapidly in summer, winter and spring. The results also showed that the temperature difference between the south part and the north part was getting smaller, but the precipitation and sunshineduration were opposite. The heat resources were more abundant for the whole area as the result of the climate warming up.
A statistical analysis of the temporal and spatial changes of mainly climatic elements over the North China Plain was conducted, based on the daily climatic data of 53 stations from 1961 to 2005 by using the trend analysis, and the jumping point of temperature was fixed by using the MannKendall test method. It was found that the climate was warming up in the last 45 years, in particular in the 1990s. For annual precipitation, no significant trend was found on the basis of longterm change. Precipitation gradually decreased in the middle and later period of the 1980s. Thus, it was believed that climatic variation in the North China Plain over the 45 years experienced a course of humidcold to drywarm. And the sunshine duration was decreasing significantly. The climate change feature of each month was characterized by monthly linear inclination rates which showed that from January to April, the temperature increased most remarkably, the precipitation decreased most obviously in summer and April, and the sunshine duration decreased rapidly in summer, winter and spring. The results also showed that the temperature difference between the south part and the north part was getting smaller, but the precipitation and sunshineduration were opposite. The heat resources were more abundant for the whole area as the result of the climate warming up.
2010, 36(5):46-50.
DOI: 10.7519/j.issn.1000-0526.2010.5.006
Abstract:
The summer rain patterns in China were further divided into eight types on the basis of the three patterns divided by Liao Quansun et al. The situations of blocking high and subtropical high were combined together with the summer rain of China. Correspondingly, the circulation of 500 hPa was also divided into eight patterns. The correlation coefficients of the January circulation of forecast year with these eight patterns were calculated. The maximum correlation would be selected to be the forecast of that year. In this way, the precipitation predictions of years 2007 and 2008 were successful.
The summer rain patterns in China were further divided into eight types on the basis of the three patterns divided by Liao Quansun et al. The situations of blocking high and subtropical high were combined together with the summer rain of China. Correspondingly, the circulation of 500 hPa was also divided into eight patterns. The correlation coefficients of the January circulation of forecast year with these eight patterns were calculated. The maximum correlation would be selected to be the forecast of that year. In this way, the precipitation predictions of years 2007 and 2008 were successful.
2010, 36(5):51-55.
DOI: 10.7519/j.issn.1000-0526.2010.5.007
Abstract:
Atmospheric mixing depth is one of most important parameters in air quality potential forecasting. Based on Holzworth’s fundamental and Wang’s stepwise approach, by using daily meteorological data from Beijing Observatory during 1970-2007, the maximum mixing depths (MMD) in Beijing Area were calculated and their variation characteristics with time were analyzed. The results showed that, from 1970 to 1998 the annual mean MMD had a decrease trend and got a minimum value in 1998, then from 1998 to 2007, the annual MMD turned into an increase trend. The seasonal variation showed the mean MMD being low in winter and high in summer. And the air quality and MMD frequency distribution revealed there is a remarkable negative correlation between them.
Atmospheric mixing depth is one of most important parameters in air quality potential forecasting. Based on Holzworth’s fundamental and Wang’s stepwise approach, by using daily meteorological data from Beijing Observatory during 1970-2007, the maximum mixing depths (MMD) in Beijing Area were calculated and their variation characteristics with time were analyzed. The results showed that, from 1970 to 1998 the annual mean MMD had a decrease trend and got a minimum value in 1998, then from 1998 to 2007, the annual MMD turned into an increase trend. The seasonal variation showed the mean MMD being low in winter and high in summer. And the air quality and MMD frequency distribution revealed there is a remarkable negative correlation between them.
2010, 36(5):56-63.
DOI: 10.7519/j.issn.1000-0526.2010.5.008
Abstract:
In August, it is an unfrequent event that there is a storm surge with a height of 518 cm caused by the effects of extratropical cyclone at the Bohai Sea. Using the weather charts, satellite cloud pictures, observations from automatic weather stations and the surge data from the Tianjin Oceanic Administration, the characteristics of two abnormal increasing water events by the storm surges occurring on Tianjin Harbour in August 2008 were analyzed. The influences of meteorological factors on storm surges were summarized. They can offer valuable information for predicting storm surges. The paper discussed the occurring conditions of storm surge and increasing water on account of the offshore wind (northwest wind). The results show that the extratropical storm surge has the characteristics of highintensity for increasing water (the largest height is 121 cm) and long duration time (for 15 hours). The paper also proposed the differences between the water increased by cyclone and by typhoon. And the reasons for occurring storm surges in a semiclosed and shallow gulf were analyzed based on the propagating theory of Kelvin wave.
In August, it is an unfrequent event that there is a storm surge with a height of 518 cm caused by the effects of extratropical cyclone at the Bohai Sea. Using the weather charts, satellite cloud pictures, observations from automatic weather stations and the surge data from the Tianjin Oceanic Administration, the characteristics of two abnormal increasing water events by the storm surges occurring on Tianjin Harbour in August 2008 were analyzed. The influences of meteorological factors on storm surges were summarized. They can offer valuable information for predicting storm surges. The paper discussed the occurring conditions of storm surge and increasing water on account of the offshore wind (northwest wind). The results show that the extratropical storm surge has the characteristics of highintensity for increasing water (the largest height is 121 cm) and long duration time (for 15 hours). The paper also proposed the differences between the water increased by cyclone and by typhoon. And the reasons for occurring storm surges in a semiclosed and shallow gulf were analyzed based on the propagating theory of Kelvin wave.
2010, 36(5):64-70.
DOI: 10.7519/j.issn.1000-0526.2010.5.009
Abstract:
With the NCEP reanalysis data, the CMA tropical cyclone data and the Scripps temperature data, the climatic background of interdecadal and interannual abnormal year for typhoons in western North Pacfic was analyzed. It is shown that the interdecadal change in the frequency of typhoons is related to the subtropical high and the SST change of the thermocline in the western equatorial Pacific.The interannual change has a close harmonic connection with the subtropical high, monsoon trough, the crossequatorial flow and the SST change of the mixing layer in the eastern and middle equatorial Pacific.
With the NCEP reanalysis data, the CMA tropical cyclone data and the Scripps temperature data, the climatic background of interdecadal and interannual abnormal year for typhoons in western North Pacfic was analyzed. It is shown that the interdecadal change in the frequency of typhoons is related to the subtropical high and the SST change of the thermocline in the western equatorial Pacific.The interannual change has a close harmonic connection with the subtropical high, monsoon trough, the crossequatorial flow and the SST change of the mixing layer in the eastern and middle equatorial Pacific.
2010, 36(5):71-77.
DOI: 10.7519/j.issn.1000-0526.2010.5.010
Abstract:
Observations from aircraft equipped with Particle Measuring System in May-June 2001，surface observations and satellite data have been analyzed to get macro and micro structures of cloud system over Northwest China, including cloud base height, cloud thickness, cloud particle concentration, liquid water content, effective cloud particle radius, and cloud particle spectrum function. The depth of stratiform clouds with precipitation is about 2000 m, The mean value of liquid water content of low clouds with precipitation is about 0.07 g?m-3, The mean value of liquid water content of middle clouds with precipitation is about 0.03 g?m-3. It is found that there are distinct differences between stratiform clouds with and without precipitation, by comparing their macro and microphysics. The effective radius of stratiform cloud with precipitation needs to be as large as 10-16 μm.
Observations from aircraft equipped with Particle Measuring System in May-June 2001，surface observations and satellite data have been analyzed to get macro and micro structures of cloud system over Northwest China, including cloud base height, cloud thickness, cloud particle concentration, liquid water content, effective cloud particle radius, and cloud particle spectrum function. The depth of stratiform clouds with precipitation is about 2000 m, The mean value of liquid water content of low clouds with precipitation is about 0.07 g?m-3, The mean value of liquid water content of middle clouds with precipitation is about 0.03 g?m-3. It is found that there are distinct differences between stratiform clouds with and without precipitation, by comparing their macro and microphysics. The effective radius of stratiform cloud with precipitation needs to be as large as 10-16 μm.
2010, 36(5):78-84.
DOI: 10.7519/j.issn.1000-0526.2010.5.011
Abstract:
Mesoscale numerical model WRF was used to simulate a thunderstorm event occurring in Northeast China on 16 October, 2006. The simulation results show that the rainfall area and amount and radar echo area and intensity are simulated quite well. The high resolution result showed interactions between mesoscale convective system and mountain area circulation.
Mesoscale numerical model WRF was used to simulate a thunderstorm event occurring in Northeast China on 16 October, 2006. The simulation results show that the rainfall area and amount and radar echo area and intensity are simulated quite well. The high resolution result showed interactions between mesoscale convective system and mountain area circulation.
2010, 36(5):85-91.
DOI: 10.7519/j.issn.1000-0526.2010.5.012
Abstract:
Physical mechanism of summer severe climatic high temperature and drought disasters in Sichuan and Chongqing area in 2006 are studied by using NCEP data from years 1970 to 2000 and year 2006. Comparing thermodynamic experiments with control experiments indicates that sensible heating caused the obvious strengthening of geopotential height and temperature rising of the Tibetan Plateau, and also has same effects on the Sichuan and Chongqing Area. Then it induced the plateau high to move eastward, and the subtropical high over the West Pacific to move westward, thus the two highs are strengthened at the same time. Dynamical analysis finds that the dynamic effect of the Tibetan Plateau is only one of the causes to bring about the disaster. The abnormal strong descending flow which controls the disaster area is jointly induced by the subtropical high over the West Pacific, the Tibetan Plateau high and the southward flow over north of the Tibetan Plateau. It is the sensible heat that plays the first important role to result in the disaster to sustain over a long period of time.
Physical mechanism of summer severe climatic high temperature and drought disasters in Sichuan and Chongqing area in 2006 are studied by using NCEP data from years 1970 to 2000 and year 2006. Comparing thermodynamic experiments with control experiments indicates that sensible heating caused the obvious strengthening of geopotential height and temperature rising of the Tibetan Plateau, and also has same effects on the Sichuan and Chongqing Area. Then it induced the plateau high to move eastward, and the subtropical high over the West Pacific to move westward, thus the two highs are strengthened at the same time. Dynamical analysis finds that the dynamic effect of the Tibetan Plateau is only one of the causes to bring about the disaster. The abnormal strong descending flow which controls the disaster area is jointly induced by the subtropical high over the West Pacific, the Tibetan Plateau high and the southward flow over north of the Tibetan Plateau. It is the sensible heat that plays the first important role to result in the disaster to sustain over a long period of time.
2010, 36(5):92-97.
DOI: 10.7519/j.issn.1000-0526.2010.5.013
Abstract:
Freezing rain is a major severe weather in Guizhou winter. The observed data in the past 48 years in Guizhou are used to reveal the frequent freezing rain zone at 27 °N as the central axis of the distribution. To research this phenomenon, a typical case has been found, and the impacts on freezing rain coming from the coldwarm air mass, and moisturetemperature characteristics are discussed. It is pointed out that the frequent freezing rain zone in Guizhou results from the combination of cold and warm air masses and it happens under the background of the quasistationary front; An obvious melting layer and the temperature field with “coldwarmcold” structural features correspond to the strong freezing rain; If without melting layer, the strong advection in the lower atmospheric cooling centers is also able to cause the strong freezing rain. Based on the above analysis, one kind of threedimensional structure for typical freezing rain has been proposed.
Freezing rain is a major severe weather in Guizhou winter. The observed data in the past 48 years in Guizhou are used to reveal the frequent freezing rain zone at 27 °N as the central axis of the distribution. To research this phenomenon, a typical case has been found, and the impacts on freezing rain coming from the coldwarm air mass, and moisturetemperature characteristics are discussed. It is pointed out that the frequent freezing rain zone in Guizhou results from the combination of cold and warm air masses and it happens under the background of the quasistationary front; An obvious melting layer and the temperature field with “coldwarmcold” structural features correspond to the strong freezing rain; If without melting layer, the strong advection in the lower atmospheric cooling centers is also able to cause the strong freezing rain. Based on the above analysis, one kind of threedimensional structure for typical freezing rain has been proposed.
2010, 36(5):98-101.
DOI: 10.7519/j.issn.1000-0526.2010.5.014
Abstract:
With the data of monthly meteorological drought integrated index (Ci) of 40 meteorological stations in the east region of Northwest China from March to May in 1982-2005 and the 500 hPa monthly mean geopotential height field in the corresponding period from the dynamical extended prediction provided by the National Climate Center, the application and test have been done by the MOS method in the aspect of explanation and reanalysis of numerical forecasting products. The result showed that the average accuracy to Ci predicted by the original equation was only 66% in spring, but the corrected average accuracy reached 77%, and increased by 11% according to sequence analysis of 40 stations, with a maximum rise of 15% in March, and a minimum rise of 8% in May. Particularly, the increment of the minimum value was the greatest with a 25% increment in average.
With the data of monthly meteorological drought integrated index (Ci) of 40 meteorological stations in the east region of Northwest China from March to May in 1982-2005 and the 500 hPa monthly mean geopotential height field in the corresponding period from the dynamical extended prediction provided by the National Climate Center, the application and test have been done by the MOS method in the aspect of explanation and reanalysis of numerical forecasting products. The result showed that the average accuracy to Ci predicted by the original equation was only 66% in spring, but the corrected average accuracy reached 77%, and increased by 11% according to sequence analysis of 40 stations, with a maximum rise of 15% in March, and a minimum rise of 8% in May. Particularly, the increment of the minimum value was the greatest with a 25% increment in average.
2010, 36(5):102-107.
DOI: 10.7519/j.issn.1000-0526.2010.5.015
Abstract:
Selecting daily ECMWF (European Center for MediumRange Weather Forecasts) numerical forecast grid field data at 20:00 BT from March 1,2003 to December 31, 2008, the forecast factor database that can reflect the local weather dynamic characteristics is constructed by using such methods as difference method, weather diagnosis and factor combination. And a BP neural network prediction model of the daily highest and minimum temperatures of various months and stations is established by first, roughly checking factors with PRESS (prediction square sum) criteria, second, checking again factors with stepwise regression, and finally, careful checking factors with optimal subset regression, thus the 1-5 day test forecast of maximum and minimum temperatures is done. The result of operational model trial shows that, the BP neural network prediction model has a strong nonlinear processing capability, and can better reflect the changes of daily extreme temperature, thus the average forecast accuracy of 1-5 day maximum and minimum temperatures reaches to higher levels. It is sensitive to warming and cooling processes. The trend and range forecasts of warming and cooling are more correct. It provides an important technical support to the precise town temperature forecast within 1-5 days. Meanwhile, it is a good idea and method of the application of the ECMWF numerical forecast products to temperature forecast.
Selecting daily ECMWF (European Center for MediumRange Weather Forecasts) numerical forecast grid field data at 20:00 BT from March 1,2003 to December 31, 2008, the forecast factor database that can reflect the local weather dynamic characteristics is constructed by using such methods as difference method, weather diagnosis and factor combination. And a BP neural network prediction model of the daily highest and minimum temperatures of various months and stations is established by first, roughly checking factors with PRESS (prediction square sum) criteria, second, checking again factors with stepwise regression, and finally, careful checking factors with optimal subset regression, thus the 1-5 day test forecast of maximum and minimum temperatures is done. The result of operational model trial shows that, the BP neural network prediction model has a strong nonlinear processing capability, and can better reflect the changes of daily extreme temperature, thus the average forecast accuracy of 1-5 day maximum and minimum temperatures reaches to higher levels. It is sensitive to warming and cooling processes. The trend and range forecasts of warming and cooling are more correct. It provides an important technical support to the precise town temperature forecast within 1-5 days. Meanwhile, it is a good idea and method of the application of the ECMWF numerical forecast products to temperature forecast.
2010, 36(5):108-113.
DOI: 10.7519/j.issn.1000-0526.2010.5.016
Abstract:
It was verified and compared that the performance of T639, ECMWF and Japan models about their mediumrange forecasting during Dec. 2009 to Feb. 2010. The results show that the three models have good performance for the evolvement and adjustment of atmospheric circulation situation and the temperature trends of in the lower troposphere in Asian middle and high latitude areas. Compared with the EC model, T639 and JP models have some larger errors for the forecast of trough in the Bay of Bengal. For the high pressure of cold wave, EC model has the best performance for the location and strength of cold anticyclone central， T639 model is better than Japan model in the aspect.
It was verified and compared that the performance of T639, ECMWF and Japan models about their mediumrange forecasting during Dec. 2009 to Feb. 2010. The results show that the three models have good performance for the evolvement and adjustment of atmospheric circulation situation and the temperature trends of in the lower troposphere in Asian middle and high latitude areas. Compared with the EC model, T639 and JP models have some larger errors for the forecast of trough in the Bay of Bengal. For the high pressure of cold wave, EC model has the best performance for the location and strength of cold anticyclone central， T639 model is better than Japan model in the aspect.
2010, 36(5):114-117.
DOI: 10.7519/j.issn.1000-0526.2010.5.017
Abstract:
Using the meteorological data of seven cities in Beijing, Tianjin and Hebei Province, the variation of surface air temperature during the long vacations of International Labor Day and National Day was analyzed to determine the climate effect of “Golden Weeks” beginning from 1999. Results show that mean and maximum temperature significantly change during the long vacations of “Golden Weeks”. An apparent increasing trend of average air temperature is found during the sevenday vacation period of International Labor Day, whereas average air temperature shows a decreasing trend during the seven days of National Day. During the long vacation of International Labor Day, both mean maximum and minimum temperatures significantly increase with a larger increase in maximum temperature. Mean maximum temperature shows weakly change in the vacation of National Day, whereas the minimum temperature significantly decreases during the same period.
Using the meteorological data of seven cities in Beijing, Tianjin and Hebei Province, the variation of surface air temperature during the long vacations of International Labor Day and National Day was analyzed to determine the climate effect of “Golden Weeks” beginning from 1999. Results show that mean and maximum temperature significantly change during the long vacations of “Golden Weeks”. An apparent increasing trend of average air temperature is found during the sevenday vacation period of International Labor Day, whereas average air temperature shows a decreasing trend during the seven days of National Day. During the long vacation of International Labor Day, both mean maximum and minimum temperatures significantly increase with a larger increase in maximum temperature. Mean maximum temperature shows weakly change in the vacation of National Day, whereas the minimum temperature significantly decreases during the same period.
2010, 36(5):118-122.
DOI: 10.7519/j.issn.1000-0526.2010.5.018
Abstract:
The method of horizontal space consistency analysis is put forward.The characteristics of the method consist of the following three steps: (1)The weather stations near the checked station are divided into four groups according to the four directions;(2)The data of the checked station are compared with the data of its surrounding stations;(3) The comparison results are used to judge the data are true or false according to the atmospheric principles. When the cold air and the thunderstorm appear, the physical quantity is distinctly discontinued.Thus, this method can be used to reduce the checking errors, and it is used in the Zhejiang to check the temperature and precipitation data at the 76 automatic weather stations. After a threemonth examination period, it is shown that the method improves the checking capability greatly.
The method of horizontal space consistency analysis is put forward.The characteristics of the method consist of the following three steps: (1)The weather stations near the checked station are divided into four groups according to the four directions;(2)The data of the checked station are compared with the data of its surrounding stations;(3) The comparison results are used to judge the data are true or false according to the atmospheric principles. When the cold air and the thunderstorm appear, the physical quantity is distinctly discontinued.Thus, this method can be used to reduce the checking errors, and it is used in the Zhejiang to check the temperature and precipitation data at the 76 automatic weather stations. After a threemonth examination period, it is shown that the method improves the checking capability greatly.
19 Malfunction Judgment Method of Ground Temperature Sensors by Related Measurement Characteristics
2010, 36(5):123-127.
DOI: 10.7519/j.issn.1000-0526.2010.5.019
Abstract:
Based on the analysis on the related characteristics of enormous ground temperature data at observatories in Jiangsu Province, the general law of the appearing time of the best index point is found. With singlestationed data, the statistical index and empirical index are established and the deviation between estimated value and correct value is compared and analyzed. Conclusion is drawn as follows: In most cases, the deviation between the estimated value and correct value, which are established by the two indexes, would come within a given range which is scientifically rational. This is the important basis for the daily malfunction judgment of ground temperature sensors.
Based on the analysis on the related characteristics of enormous ground temperature data at observatories in Jiangsu Province, the general law of the appearing time of the best index point is found. With singlestationed data, the statistical index and empirical index are established and the deviation between estimated value and correct value is compared and analyzed. Conclusion is drawn as follows: In most cases, the deviation between the estimated value and correct value, which are established by the two indexes, would come within a given range which is scientifically rational. This is the important basis for the daily malfunction judgment of ground temperature sensors.
ZHANG Deshan
,
HAI Yulong
,
FENG Tao
,
WU Zhenling
,
HE Haijun
,
ZHANG Shuli
,
CHU Wei
,
WAN Gongzhan
2010, 36(5):128-132.
DOI: 10.7519/j.issn.1000-0526.2010.5.020
Abstract:
Immune allergy reaction of the sensitive population, which is a common and frequently occurring illness, is induced by the pollen granules floating in the lower atmosphere. The increment of urban afforestation ratio aggravates the disease dramatically during recent years. The prediction model of the pollen concentration for the future 1-4 days of different stations (it is above the 0.01 significance level of Ftest) is established by using the 1999-2005 (1 March to 30 September) daily data of monitoring pollen concentration in the lower atmosphere and the simultaneous surface meteorological data at 7 stations in Beijing and surrounding regions through the orthogonal selection regression method. The model was tested well and it can be used to the environmental meteorological service platform on trial, and provide prediction and prevention services (such as medication in advance) to the sanitary and epidemic institutions in the capital hospital and the patients as well.
Immune allergy reaction of the sensitive population, which is a common and frequently occurring illness, is induced by the pollen granules floating in the lower atmosphere. The increment of urban afforestation ratio aggravates the disease dramatically during recent years. The prediction model of the pollen concentration for the future 1-4 days of different stations (it is above the 0.01 significance level of Ftest) is established by using the 1999-2005 (1 March to 30 September) daily data of monitoring pollen concentration in the lower atmosphere and the simultaneous surface meteorological data at 7 stations in Beijing and surrounding regions through the orthogonal selection regression method. The model was tested well and it can be used to the environmental meteorological service platform on trial, and provide prediction and prevention services (such as medication in advance) to the sanitary and epidemic institutions in the capital hospital and the patients as well.
2010, 36(5):133-137.
DOI: 10.7519/j.issn.1000-0526.2010.5.021
Abstract:
The following are the main characteristics of the atmospheric general circulation in February 2010. There are three polar vortex centers: the Asian polar vortex center is stronger than normal years, the East Asia major trough is weak, and the south branch trough is active in the first ten days of February. This circulation situation causes the north branch frontal zone to be weaker than normal years. The main climatological characteristics in February are as follows. The temperature is higher than normal years. The rainfall in Xinjiang and Zhejiang is more than the other years. The drought in Yunnan, Guizhou, Sichuan and Guangxi becomes more serious。Meanwhile， because of the influence of cold waves during 8-13 February, there are many rainy and snowy days over the large area of China before the Spring Festival of 2010, and it gives high impacts on the traffic in this period.
The following are the main characteristics of the atmospheric general circulation in February 2010. There are three polar vortex centers: the Asian polar vortex center is stronger than normal years, the East Asia major trough is weak, and the south branch trough is active in the first ten days of February. This circulation situation causes the north branch frontal zone to be weaker than normal years. The main climatological characteristics in February are as follows. The temperature is higher than normal years. The rainfall in Xinjiang and Zhejiang is more than the other years. The drought in Yunnan, Guizhou, Sichuan and Guangxi becomes more serious。Meanwhile， because of the influence of cold waves during 8-13 February, there are many rainy and snowy days over the large area of China before the Spring Festival of 2010, and it gives high impacts on the traffic in this period.
2010, 36(5):138-141.
DOI: 10.7519/j.issn.1000-0526.2010.5.022
Abstract:
Based on the analyses of communication need by the remote meteorological stations, to satisfy the above demand the IPSTAR Integrated Communication System is put forward. In the paper We describe the details of the system, and analyze its advantages and disadvantages, as well as the fact that how this project works in some meteorological stations of Xinjiang Autonomous Regional Meteorological Bureau.
Based on the analyses of communication need by the remote meteorological stations, to satisfy the above demand the IPSTAR Integrated Communication System is put forward. In the paper We describe the details of the system, and analyze its advantages and disadvantages, as well as the fact that how this project works in some meteorological stations of Xinjiang Autonomous Regional Meteorological Bureau.
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ISSN:1000-0526 CN:11-2282/P