ISSN 1000-0526
CN 11-2282/P
CN 11-2282/P
Volume 30,Issue 4,2004 Table of Contents
2004, 30(4):3-5.
DOI: 10.7519/j.issn.1000-0526.2004.4.001
Abstract:
The ensemble forecast appeared in 90's of last century. It becomes an important operation of many meteorological centers and an important tool of research. The medium-short range ensemble forecast of the global NWP and limited area NWP models,and two application of ensemble forecast to severe weather are introduced,and related issues are discussed.
The ensemble forecast appeared in 90's of last century. It becomes an important operation of many meteorological centers and an important tool of research. The medium-short range ensemble forecast of the global NWP and limited area NWP models,and two application of ensemble forecast to severe weather are introduced,and related issues are discussed.
2 Sensitivity Research on One-Dimensional Variational Assimilation of Radar-Derived Precipitation Data
2004, 30(4):6-10.
DOI: 10.7519/j.issn.1000-0526.2004.4.002
Abstract:
With limited area meso-scale numerical model under η-coordinate,sensitivity experiments of retrieving model humidity profiles by one-dimensional variational assimilation of digital weather radar-derived precipitation are studied for the abrupt heavy rainfall along the Yangtze River in the east part of Hubei Province. Results show as follows. Different initial values X(0)of humidity profiles have great effects on the decline of the object function, and different initial evaluation schemes of humidity profiles have substantial effects on the results of rainfall variational assimilation under the special condition that model background precipitation equals to zero while observation precipitation does not equal to zero.
With limited area meso-scale numerical model under η-coordinate,sensitivity experiments of retrieving model humidity profiles by one-dimensional variational assimilation of digital weather radar-derived precipitation are studied for the abrupt heavy rainfall along the Yangtze River in the east part of Hubei Province. Results show as follows. Different initial values X(0)of humidity profiles have great effects on the decline of the object function, and different initial evaluation schemes of humidity profiles have substantial effects on the results of rainfall variational assimilation under the special condition that model background precipitation equals to zero while observation precipitation does not equal to zero.
2004, 30(4):11-14.
DOI: 10.7519/j.issn.1000-0526.2004.4.003
Abstract:
Based on NCEP/NCAR reanalysis data(1958-1997) and monthly-mean rainfall data(1951-1998) at 160 stations, the characteristics of summer Eliassen-Palm (E-P) flux in drought/flood years of the Changjiang and Huaihe valley are analyzed. Results indicate that the E-P flux show strong convergence at the regions of 40°N (30°N) in drought (flood) years, which is in well consistent with rainfall distributions. The different distributions of E-P flux in drought/flood years lead to the enhanced upper level westerly jet in the vicinity of 40°N (30°N) in drought(flood) years and further to the enhanced wind field divergence in the upper level and convergence in the lower level at the corresponding region which is favorable to the formation of rainfall and is an important factor for the distributions of rainfall in the Changjiang and Huaihe valley and in China.
Based on NCEP/NCAR reanalysis data(1958-1997) and monthly-mean rainfall data(1951-1998) at 160 stations, the characteristics of summer Eliassen-Palm (E-P) flux in drought/flood years of the Changjiang and Huaihe valley are analyzed. Results indicate that the E-P flux show strong convergence at the regions of 40°N (30°N) in drought (flood) years, which is in well consistent with rainfall distributions. The different distributions of E-P flux in drought/flood years lead to the enhanced upper level westerly jet in the vicinity of 40°N (30°N) in drought(flood) years and further to the enhanced wind field divergence in the upper level and convergence in the lower level at the corresponding region which is favorable to the formation of rainfall and is an important factor for the distributions of rainfall in the Changjiang and Huaihe valley and in China.
2004, 30(4):15-19.
DOI: 10.7519/j.issn.1000-0526.2004.4.004
Abstract:
By using the theory of moist potential vorticity(MPV),the characteristics of MPV are analyzed in the process of two rainstorms caused by typhoon or weaken typhoon circulation in Shandong Province. The results show that the two heavy rain events occurred in the very stiff and dense section of moist isentropes, which can lead to the development of moist slantwise vorticity. MPV1<0 and MPV2>0 in the low troposphere reflect the development of convective and baroclinic instability . The downward spread of high from the upper troposphere is also of an advantage to the release and deposit of instability energy and the results in the amplification of rainstorm.
By using the theory of moist potential vorticity(MPV),the characteristics of MPV are analyzed in the process of two rainstorms caused by typhoon or weaken typhoon circulation in Shandong Province. The results show that the two heavy rain events occurred in the very stiff and dense section of moist isentropes, which can lead to the development of moist slantwise vorticity. MPV1<0 and MPV2>0 in the low troposphere reflect the development of convective and baroclinic instability . The downward spread of high from the upper troposphere is also of an advantage to the release and deposit of instability energy and the results in the amplification of rainstorm.
2004, 30(4):20-24.
DOI: 10.7519/j.issn.1000-0526.2004.4.005
Abstract:
General Circulation features over the Northern Hemisphere in 2003 are analyzed. It's shown that the subtropical high at 500hPa over the western Pacific in the winter of 2002/2003 and the spring and the summer and the autumn of 2003 was stronger than normal.The 500hPa geopotential height anomaly was positive for most of the cases over the Northern Hemisphere in 2003. Both in the summer and autumn,the 500hPa geopotential height anomaly of Tibetan Plateau was positive. The East Asian monsoon was stronger than normal in July and August.The equatorial convergence zone was not more active than nomal.The SSTa in the eastern tropical Pacific was nomal in 2003. The results show that the anomalies of both the tropical Pacific sea temperature and atmospheric circulation would exert a significant impact on the weather and climate in China.
General Circulation features over the Northern Hemisphere in 2003 are analyzed. It's shown that the subtropical high at 500hPa over the western Pacific in the winter of 2002/2003 and the spring and the summer and the autumn of 2003 was stronger than normal.The 500hPa geopotential height anomaly was positive for most of the cases over the Northern Hemisphere in 2003. Both in the summer and autumn,the 500hPa geopotential height anomaly of Tibetan Plateau was positive. The East Asian monsoon was stronger than normal in July and August.The equatorial convergence zone was not more active than nomal.The SSTa in the eastern tropical Pacific was nomal in 2003. The results show that the anomalies of both the tropical Pacific sea temperature and atmospheric circulation would exert a significant impact on the weather and climate in China.
2004, 30(4):25-28.
DOI: 10.7519/j.issn.1000-0526.2004.4.006
Abstract:
Global climate has been warming persistently. The year 2003 becomes the third warmest year since 1860. During the winter, extreme cold and heavy snow weather was experienced in large parts of Europe, South Asia and the United States. Persistent severe hot wave and drought events occurred over South Asia, central and southern Europe and parts of America. Severe forest fires were in these severe drought regions. Serious floods occurred in South Asia, Southeast Asia during the summer monsoon season. Severe tonadoes hit the United States in May. Activities of North Atlantic hurricanes were frequent from June to November and caused serious damage.
Global climate has been warming persistently. The year 2003 becomes the third warmest year since 1860. During the winter, extreme cold and heavy snow weather was experienced in large parts of Europe, South Asia and the United States. Persistent severe hot wave and drought events occurred over South Asia, central and southern Europe and parts of America. Severe forest fires were in these severe drought regions. Serious floods occurred in South Asia, Southeast Asia during the summer monsoon season. Severe tonadoes hit the United States in May. Activities of North Atlantic hurricanes were frequent from June to November and caused serious damage.
2004, 30(4):29-32.
DOI: 10.7519/j.issn.1000-0526.2004.04.007
Abstract:
In 2003 (from December 2002 to November 2003), the characteristics of weather and climate in China were summarized as follows:the annual precipitation was more than normal with higher temperature. The annual precipitation in China was 33.9mm more than normal, but its temporal and spatial distribution were uneven. In North China there was more rainfall, in contrast to the deficient counterpart in southern China. The severe flooding appeared in the Huaihe valley during flooding season (June-Aug.) and in the middle and lower reaches of the Yellow River during the autumn. However, the large-scale drought happened in Northeast China during the spring, and in the South China during the summer and autumn. The annual mean temperature in China was 0.6℃ higher than normal, which was warmer than normal for the seventh successive year. Particularly, the temperatures in the south of China were markedly higher than normal. The areas of South China (south of the Yangtze River) were frequently hit by anomalous hot wave in summer. The meteorological disasters frequently predominated China during 2003. More lose were caused by drought, rainstorm-caused flooding, anomalous high temperature, low temperature with continuing rainfall, and hail.
In 2003 (from December 2002 to November 2003), the characteristics of weather and climate in China were summarized as follows:the annual precipitation was more than normal with higher temperature. The annual precipitation in China was 33.9mm more than normal, but its temporal and spatial distribution were uneven. In North China there was more rainfall, in contrast to the deficient counterpart in southern China. The severe flooding appeared in the Huaihe valley during flooding season (June-Aug.) and in the middle and lower reaches of the Yellow River during the autumn. However, the large-scale drought happened in Northeast China during the spring, and in the South China during the summer and autumn. The annual mean temperature in China was 0.6℃ higher than normal, which was warmer than normal for the seventh successive year. Particularly, the temperatures in the south of China were markedly higher than normal. The areas of South China (south of the Yangtze River) were frequently hit by anomalous hot wave in summer. The meteorological disasters frequently predominated China during 2003. More lose were caused by drought, rainstorm-caused flooding, anomalous high temperature, low temperature with continuing rainfall, and hail.
2004, 30(4):33-35.
DOI: 10.7519/j.issn.1000-0526.2004.4.008
Abstract:
The calculation method and monitoring model of the snow cover information are introduced, by characterizing the short infrared waves and using the remote sensing data of the FY-1D meteorological satellite, which was released by the 9210 meteorological program. In addition, a new method is introduced to monitor the depth and the area of the snow cover by remote sensing, illustrated by the remote sensing monitor of the snow cover in Xinjiang from November 2002 to May 2003. The characteristics of the snow cover and the pattern of the snow cover variation are also analyzed with this method.
The calculation method and monitoring model of the snow cover information are introduced, by characterizing the short infrared waves and using the remote sensing data of the FY-1D meteorological satellite, which was released by the 9210 meteorological program. In addition, a new method is introduced to monitor the depth and the area of the snow cover by remote sensing, illustrated by the remote sensing monitor of the snow cover in Xinjiang from November 2002 to May 2003. The characteristics of the snow cover and the pattern of the snow cover variation are also analyzed with this method.
2004, 30(4):36-38.
DOI: 10.7519/j.issn.1000-0526.2004.04.009
Abstract:
WINDEX is a new index presented by McCann in 1994 for the forecast of the downburst potential. Based on the analysis of a downburst event brought by severe thunderstorm on 2nd July 2001, it is found that WINDEX is a helpful index in some regions and is worthwhile to try farther.
WINDEX is a new index presented by McCann in 1994 for the forecast of the downburst potential. Based on the analysis of a downburst event brought by severe thunderstorm on 2nd July 2001, it is found that WINDEX is a helpful index in some regions and is worthwhile to try farther.
2004, 30(4):39-41.
DOI: 10.7519/j.issn.1000-0526.2004.4.010
Abstract:
A forecast model of sand-storm in China is established by BP artificial neural network. The inputs of the model are the time coefficients of REOF in a few of physical fields, and the outputs are sand-storm or no sand-storm in China. The result shows that combination of these two methods has better effect on forecasting sand-storm.
A forecast model of sand-storm in China is established by BP artificial neural network. The inputs of the model are the time coefficients of REOF in a few of physical fields, and the outputs are sand-storm or no sand-storm in China. The result shows that combination of these two methods has better effect on forecasting sand-storm.
2004, 30(4):42-45.
DOI: 10.7519/j.issn.1000-0526.2004.4.011
Abstract:
A crop yield prediction of Internet-oriented dynamical resolution was proposed the demand of Internet users on dynamic inquiring crop yield into consideration. The results show that it is possible to predict crop yield applying mathematics model based on real-time weather elements and average climatic value in rest period during the growing season, which consist of required temperature, sunshine and precipitation for crops growth. The predicted values tend to approach actual values with the appearance of real-time weather data. The statistical test and validation are acceptable.
A crop yield prediction of Internet-oriented dynamical resolution was proposed the demand of Internet users on dynamic inquiring crop yield into consideration. The results show that it is possible to predict crop yield applying mathematics model based on real-time weather elements and average climatic value in rest period during the growing season, which consist of required temperature, sunshine and precipitation for crops growth. The predicted values tend to approach actual values with the appearance of real-time weather data. The statistical test and validation are acceptable.
2004, 30(4):46-50.
DOI: 10.7519/j.issn.1000-0526.2004.4.012
Abstract:
A sand-storm event occurred on the 6st April 2001 in North China is discussed. The results show, (1) the strong cold wave of the west Siberia and the surface warm and low pressure in southern Xinjiang and Mongolia offered the event dynamic and thermodynamic conditions, therefore the warmness and dryness made topsoil not been frozen, which provided lots of sand to the sandstorm weather. (2) The sandy weather caused serious accident of air pollution and made the air quality in Lanzhou even worse by 2 to 5 time. (3) The sand weather had positive and negative effect on the total solar radiation in Lanzhou. In the daytime, the sandy weather would diminish the absorbability of the surface net radiation and restrain the surface temperature. In the evening, it would diminish the emanation of the net radiation and restrain the surface temperature dropping.
A sand-storm event occurred on the 6st April 2001 in North China is discussed. The results show, (1) the strong cold wave of the west Siberia and the surface warm and low pressure in southern Xinjiang and Mongolia offered the event dynamic and thermodynamic conditions, therefore the warmness and dryness made topsoil not been frozen, which provided lots of sand to the sandstorm weather. (2) The sandy weather caused serious accident of air pollution and made the air quality in Lanzhou even worse by 2 to 5 time. (3) The sand weather had positive and negative effect on the total solar radiation in Lanzhou. In the daytime, the sandy weather would diminish the absorbability of the surface net radiation and restrain the surface temperature. In the evening, it would diminish the emanation of the net radiation and restrain the surface temperature dropping.
2004, 30(4):51-54.
DOI: 10.7519/j.issn.1000-0526.2004.4.013
Abstract:
A statistical analysis of external quality characters, such as ill fruit ratio, 100-grain length, 100-grain weight, and weather conditions of experimental data from 2000 to 2001 is made. Firstly relative coefficients are analyzed to find main meteorological factors affecting external quality characters, and then, the quantitative relationship between external quality character and single meteorological factor is given. Finally, the comprehensive quantitative relationship between external quality characters and meteorological factors is obtained.
A statistical analysis of external quality characters, such as ill fruit ratio, 100-grain length, 100-grain weight, and weather conditions of experimental data from 2000 to 2001 is made. Firstly relative coefficients are analyzed to find main meteorological factors affecting external quality characters, and then, the quantitative relationship between external quality character and single meteorological factor is given. Finally, the comprehensive quantitative relationship between external quality characters and meteorological factors is obtained.
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ISSN:1000-0526 CN:11-2282/P