ISSN 1000-0526
CN 11-2282/P
CN 11-2282/P
Volume 32,Issue 4,2006 Table of Contents
2006, 32(4):3-8.
DOI: 10.7519/j.issn.1000-0526.2006.4.001
Abstract:
Uncertainty is unavoidable in weather and climate prediction, which gives rise to difficulties for societal decision-making, and meanwhile provides opportunity for developing the research of prediction. This note reviews the thoughts that have emerged in recent years towards the future development of the meteorological prediction system. And then it makes up an example to show how the user′s knowledge can be combined with weather forecasting based on decision-making theory. Finally, a conceptual framework of the future prediction system is proposed, which combines the meteorological models and the decision-making processes comprising risk assessments and other knowledge from various users.
Uncertainty is unavoidable in weather and climate prediction, which gives rise to difficulties for societal decision-making, and meanwhile provides opportunity for developing the research of prediction. This note reviews the thoughts that have emerged in recent years towards the future development of the meteorological prediction system. And then it makes up an example to show how the user′s knowledge can be combined with weather forecasting based on decision-making theory. Finally, a conceptual framework of the future prediction system is proposed, which combines the meteorological models and the decision-making processes comprising risk assessments and other knowledge from various users.
2006, 32(4):9-15.
DOI: 10.7519/j.issn.1000-0526.2006.4.002
Abstract:
The appearance of haze has importance indication meaning to air quality, while the fog or light fog has specific weather indication relating to particular weather system. With the rapid development of economic scale and urbanization, the phenomena of haze or haze weather have become increasingly serious. The standard criterion by using relative humidity to distinguish haze or fog in many northeast coastal provinces is generally on the low side, leading to much haze weather recorded as light fog or fog. In the near surface atmosphere there always exists haze, while fog drop hardly exists. Only under the enough supersaturation which is higher than that the maximum of supersaturation can the haze nuclei become fog drop through moisture absorption growing, such a process is not easy to happen. Under non-saturation conditions, not only the insoluble haze nuclei are impossible to transform into fog drop, but also the soluble ones are commonly impossible. The observational data show that the extreme relative humidity is 91% when fog occurred, there is no fog when the relative humidity is lower than 90%. The most important physical process to form fog drop is by falling the temperature to the saturation point. It is hardly impossible to form fog drop through the natural moisture absorption growing of haze nuclei. The distinguishing of fog or haze should be made according to the change of weather system combining with the macro-characteristics. It is rational by using the threshold value of relative humidity 90% as an assistant criterion to distinguish fog or haze.
The appearance of haze has importance indication meaning to air quality, while the fog or light fog has specific weather indication relating to particular weather system. With the rapid development of economic scale and urbanization, the phenomena of haze or haze weather have become increasingly serious. The standard criterion by using relative humidity to distinguish haze or fog in many northeast coastal provinces is generally on the low side, leading to much haze weather recorded as light fog or fog. In the near surface atmosphere there always exists haze, while fog drop hardly exists. Only under the enough supersaturation which is higher than that the maximum of supersaturation can the haze nuclei become fog drop through moisture absorption growing, such a process is not easy to happen. Under non-saturation conditions, not only the insoluble haze nuclei are impossible to transform into fog drop, but also the soluble ones are commonly impossible. The observational data show that the extreme relative humidity is 91% when fog occurred, there is no fog when the relative humidity is lower than 90%. The most important physical process to form fog drop is by falling the temperature to the saturation point. It is hardly impossible to form fog drop through the natural moisture absorption growing of haze nuclei. The distinguishing of fog or haze should be made according to the change of weather system combining with the macro-characteristics. It is rational by using the threshold value of relative humidity 90% as an assistant criterion to distinguish fog or haze.
2006, 32(4):16-23.
DOI: 10.7519/j.issn.1000-0526.2006.4.003
Abstract:
In order to test the forecast capability of MM5, seven combinations of three different physical parameterization schemes are used in simulation tests of precipitation prediction during 2005-flood season over the low latitude plateau. The results show that the combinations of Goddard microphysics parameterization, Grell cumulus parameterization and cloud/RRTM radiation parameterization in the third nested grids are superior to the others, especially the forecast of downfall and rainstorm. There is a certain influence for different scanning radius of interpolation prediction to the observational network. The interpolation result is comparatively ideal when the 20—30km scan radius is used.
In order to test the forecast capability of MM5, seven combinations of three different physical parameterization schemes are used in simulation tests of precipitation prediction during 2005-flood season over the low latitude plateau. The results show that the combinations of Goddard microphysics parameterization, Grell cumulus parameterization and cloud/RRTM radiation parameterization in the third nested grids are superior to the others, especially the forecast of downfall and rainstorm. There is a certain influence for different scanning radius of interpolation prediction to the observational network. The interpolation result is comparatively ideal when the 20—30km scan radius is used.
2006, 32(4):24-28.
DOI: 10.7519/j.issn.1000-0526.2006.04.004
Abstract:
The forecasting effect of convective parameters output by MM5 model is tested with the data of 20 thunderstorm cases. The results show that the model output convective parameters can reflect the difference between the storm and no storm days and can forecast the happening time and area of the storm. The storm can be judged not only through parameter values but also through the changing tendency of convective parameters. At the same time, the model output still need to be improved because the difference is obvious compared to observation data and the different time range outputs is so varied.
The forecasting effect of convective parameters output by MM5 model is tested with the data of 20 thunderstorm cases. The results show that the model output convective parameters can reflect the difference between the storm and no storm days and can forecast the happening time and area of the storm. The storm can be judged not only through parameter values but also through the changing tendency of convective parameters. At the same time, the model output still need to be improved because the difference is obvious compared to observation data and the different time range outputs is so varied.
2006, 32(4):29-33.
DOI: 10.7519/j.issn.1000-0526.2006.4.005
Abstract:
Based on the observational data and NCEP reanalysis data, the heavy rainfall event on 26—28 Aug 2004 in Shandong Province is diagnostically analyzed. The result shows that the event is caused by the interaction between 0418 tropical cyclone trough landed in Fujian Province and a weak cold front in the westerlies, it has obvious interacting characteristics between the two weather systems. The low-level southeast jet accompanying the tropical cyclone transports a plenty of heat and moisture for the event. It plays an important role in stimulating the convection that the weak cold air intrudes the area of the inverted trough, and conduce to warm frontogenesis, thus leading to the heavy storm. The heavy rain mainly distributed in the tongue area of high energy, the total energy is a key index to predict the rainfall area related to distant onland tropical cyclone.
Based on the observational data and NCEP reanalysis data, the heavy rainfall event on 26—28 Aug 2004 in Shandong Province is diagnostically analyzed. The result shows that the event is caused by the interaction between 0418 tropical cyclone trough landed in Fujian Province and a weak cold front in the westerlies, it has obvious interacting characteristics between the two weather systems. The low-level southeast jet accompanying the tropical cyclone transports a plenty of heat and moisture for the event. It plays an important role in stimulating the convection that the weak cold air intrudes the area of the inverted trough, and conduce to warm frontogenesis, thus leading to the heavy storm. The heavy rain mainly distributed in the tongue area of high energy, the total energy is a key index to predict the rainfall area related to distant onland tropical cyclone.
2006, 32(4):34-39.
DOI: 10.7519/j.issn.1000-0526.2006.4.006
Abstract:
Based on the data of 711 radar echo in five years, together with the raindrop size distribution and raingauge data, a statistical analysis of various parameters of stable stratiform clouds is made. The result shows that the precipitation intensity is not only related to the intensity of radar echo but also is affected by the cloud height, warm cloud thickness, etc. A mutiple regression equation is developed to estimate rainfall amount based on the radar echoes.
Based on the data of 711 radar echo in five years, together with the raindrop size distribution and raingauge data, a statistical analysis of various parameters of stable stratiform clouds is made. The result shows that the precipitation intensity is not only related to the intensity of radar echo but also is affected by the cloud height, warm cloud thickness, etc. A mutiple regression equation is developed to estimate rainfall amount based on the radar echoes.
2006, 32(4):40-44.
DOI: 10.7519/j.issn.1000-0526.2006.4.007
Abstract:
Based on the latest 10-year precipitation data, the relationship between the rainstorm areas, frequency etc. from April to September in Anhui Province and the 5840gpm isoline is statistically analyzed. And the comparisons between 20 rainstorm areas and some real-time physical variables during the flood season of the Huaihe River in 2003 are made. It shows that the rainstorm in Anhui Province mainly appears in the period from Meiyu season to July, and both the rain day number and the range of rainstorm basically determine the precipitation amount in flood season and the tendency of flood/drought. The rainstorm areas are concentrated on the 500hPa slope ranging from 5820gpm to 5840gpm while there is seldom rainstorm in the ranges less than 5750gpm and more than 5870gpm. Therefore, the prediction of main rainfall belts during the Meiyu season can refer to the movement of 5840gpm isoline. As to the physical variables, the regions in the north flank of westerly jet and those from the south flank of 500hPa ascending center to the north flank of 850hPa ascending center are favorable for the occurrence and development of rainstorm, whereas the stability in the mid-low troposphere and the 500hPa divergence have no close relationship with rainstorm areas.
Based on the latest 10-year precipitation data, the relationship between the rainstorm areas, frequency etc. from April to September in Anhui Province and the 5840gpm isoline is statistically analyzed. And the comparisons between 20 rainstorm areas and some real-time physical variables during the flood season of the Huaihe River in 2003 are made. It shows that the rainstorm in Anhui Province mainly appears in the period from Meiyu season to July, and both the rain day number and the range of rainstorm basically determine the precipitation amount in flood season and the tendency of flood/drought. The rainstorm areas are concentrated on the 500hPa slope ranging from 5820gpm to 5840gpm while there is seldom rainstorm in the ranges less than 5750gpm and more than 5870gpm. Therefore, the prediction of main rainfall belts during the Meiyu season can refer to the movement of 5840gpm isoline. As to the physical variables, the regions in the north flank of westerly jet and those from the south flank of 500hPa ascending center to the north flank of 850hPa ascending center are favorable for the occurrence and development of rainstorm, whereas the stability in the mid-low troposphere and the 500hPa divergence have no close relationship with rainstorm areas.
2006, 32(4):45-51.
DOI: 10.7519/j.issn.1000-0526.2006.4.008
Abstract:
Storm relative helicity(SRH) reflects eddies in environment wind field and surrounding vorticities inputted into convective cell in an air layer, which is useful to analyze and forecast thunderstorm, tornado, large-area heavy rainfall as well. A method and steps of calculating SRH are presented, first, with Doppler radar vertical wind profile (VWP) product. Then, the SRH of three cases of heavy rain, hail, gale are discussed. Results indicate that the SRH is well corresponding to the intensities of the heavy rain in large area, the change of intensities lags the SRH change about 30 minutes, the time of precipitation strengthening or disappearing, therefore, can be approximately estimated by it. In addition, the SRH has effectivity about 10 to 20 minutes ahead to forecast micro-scale hail and gale, and then the SRH calculated with VWP can be used as a forecast index for strong convective weather such as a heavy rain, hail, gale, etc.
Storm relative helicity(SRH) reflects eddies in environment wind field and surrounding vorticities inputted into convective cell in an air layer, which is useful to analyze and forecast thunderstorm, tornado, large-area heavy rainfall as well. A method and steps of calculating SRH are presented, first, with Doppler radar vertical wind profile (VWP) product. Then, the SRH of three cases of heavy rain, hail, gale are discussed. Results indicate that the SRH is well corresponding to the intensities of the heavy rain in large area, the change of intensities lags the SRH change about 30 minutes, the time of precipitation strengthening or disappearing, therefore, can be approximately estimated by it. In addition, the SRH has effectivity about 10 to 20 minutes ahead to forecast micro-scale hail and gale, and then the SRH calculated with VWP can be used as a forecast index for strong convective weather such as a heavy rain, hail, gale, etc.
2006, 32(4):52-55.
DOI: 10.7519/j.issn.1000-0526.2006.04.009
Abstract:
A weighted area scheme is designed for calculating mean value of a regional meteorological field. The method is used to calculate the mean annual precipitation, the water vapor content of January and July over northwestern China. Compared with arithmetic method, Tyson polygon method as well as grid point interpolation method, the method is regilable to calculate the aerography field hypodispersion in macroscopy area, if there have more sites and these sites are nonuniform distribution. Its advantage is smaller computational complexity and more slight influence of the lacking observation.
A weighted area scheme is designed for calculating mean value of a regional meteorological field. The method is used to calculate the mean annual precipitation, the water vapor content of January and July over northwestern China. Compared with arithmetic method, Tyson polygon method as well as grid point interpolation method, the method is regilable to calculate the aerography field hypodispersion in macroscopy area, if there have more sites and these sites are nonuniform distribution. Its advantage is smaller computational complexity and more slight influence of the lacking observation.
2006, 32(4):56-61.
DOI: 10.7519/j.issn.1000-0526.2006.4.010
Abstract:
Based on the Doppler radar data and the data from twenty-seven automatic weather stations from May to June in 2002 and 2003 in the northern and central Fujian,the statistical analysis of optimization is made to obtain the Z-I relation of different regions.The rainfall amounts in precipitation processes in 2005 are estimated.Using variational method and optimum Kalman filter method (combine Kalman Filter with optimum interpolation), radar estimations are tested with rainfall data of Wuyishan Jiuquxi Valley in the northern Fujian.The accuracies for the methods are compared and analyzed.The results show that mean relative errors are less than 25% with variational method and optimum Kalman Filter method,it is also less than 25% from 0 to 100km with optimization method,however,it increase remarkably from 100 to 200km.Mean relative error is the greatest with the relation of Z=300I1.4.
Based on the Doppler radar data and the data from twenty-seven automatic weather stations from May to June in 2002 and 2003 in the northern and central Fujian,the statistical analysis of optimization is made to obtain the Z-I relation of different regions.The rainfall amounts in precipitation processes in 2005 are estimated.Using variational method and optimum Kalman filter method (combine Kalman Filter with optimum interpolation), radar estimations are tested with rainfall data of Wuyishan Jiuquxi Valley in the northern Fujian.The accuracies for the methods are compared and analyzed.The results show that mean relative errors are less than 25% with variational method and optimum Kalman Filter method,it is also less than 25% from 0 to 100km with optimization method,however,it increase remarkably from 100 to 200km.Mean relative error is the greatest with the relation of Z=300I1.4.
2006, 32(4):62-67.
DOI: 10.7519/j.issn.1000-0526.2006.4.011
Abstract:
In South China, there prevails a proverb “Man can′t cook rice for the firewood is wetted by rainy weather when it encounters two solar terms of Slight Heat and Great Heat in Chinese lunar June”. The proverb is validated and its accuracy is 90%. In terms of physical meaning, it possibly reflects the effect of the annual variability of the relative phase of the moon (MPH) toward the earth on the rainfall in South China early flood season (SCEFS). From that point of view, the proverb is generalized and the correlation fields between MPH and rainfall in SCEFS and the spring persistent rain (SPR) are calculated. It shows highly significant relationships, especially MPH relates to SPR. Running correlation field between MPH and SPR shows high stability of the relationship. Their wavelet transform shows that they have same significant 2—3a periods, indicating their possible internal physical relationship. Therefore, the relationships can be applied to operational predictions as an important reference. But the mechanism is not clear. Maybe it comes from the annual variability of the tide force of moon.
In South China, there prevails a proverb “Man can′t cook rice for the firewood is wetted by rainy weather when it encounters two solar terms of Slight Heat and Great Heat in Chinese lunar June”. The proverb is validated and its accuracy is 90%. In terms of physical meaning, it possibly reflects the effect of the annual variability of the relative phase of the moon (MPH) toward the earth on the rainfall in South China early flood season (SCEFS). From that point of view, the proverb is generalized and the correlation fields between MPH and rainfall in SCEFS and the spring persistent rain (SPR) are calculated. It shows highly significant relationships, especially MPH relates to SPR. Running correlation field between MPH and SPR shows high stability of the relationship. Their wavelet transform shows that they have same significant 2—3a periods, indicating their possible internal physical relationship. Therefore, the relationships can be applied to operational predictions as an important reference. But the mechanism is not clear. Maybe it comes from the annual variability of the tide force of moon.
2006, 32(4):68-73.
DOI: 10.7519/j.issn.1000-0526.2006.4.012
Abstract:
General circulation features over the Northern Hemisphere in 2005 are analyzed. It is shown that the 500hPa subtropical high over the West Pacific is stronger than normal. Its position is westerly and northerly as a whole. Its ridge point is abnormal to the west in spring. At 500hPa, zonal and meridional circulations take place by turn, cold air is stronger than normal during the winter. Monsoon is stronger during the summer, convection activity is weaker during the winter and the spring, and into the summer is stronger in tropics. A warm water process is persisting in the tropical Pacific region in 2005. The anomaly of both the tropical Pacific and atmospheric circulation exerted a significant impact on the weather and climate in China.
General circulation features over the Northern Hemisphere in 2005 are analyzed. It is shown that the 500hPa subtropical high over the West Pacific is stronger than normal. Its position is westerly and northerly as a whole. Its ridge point is abnormal to the west in spring. At 500hPa, zonal and meridional circulations take place by turn, cold air is stronger than normal during the winter. Monsoon is stronger during the summer, convection activity is weaker during the winter and the spring, and into the summer is stronger in tropics. A warm water process is persisting in the tropical Pacific region in 2005. The anomaly of both the tropical Pacific and atmospheric circulation exerted a significant impact on the weather and climate in China.
2006, 32(4):74-77.
DOI: 10.7519/j.issn.1000-0526.2006.4.013
Abstract:
Global climate has been warming up persistently in 2005, and 2005 is the second warmest year on record. During the year, South Asia was hit by hot waves, central-western Europe experienced severe drought and in northern Brazil, drought conditions became the most severe on record. Meanwhile, floods occurred frequently all over the world, while snow storms attacked West Asia, northern South Asia, Center Asia, parts of Japan and China, America and parts of Europe. In this year, disaster from hurricane (typhoon) was disastrous. In the Atlantic Ocean, activity of hurricane was the most active on record, with “Katrina” having become the most destructive hurricane on record in America′s history. Meanwhile, although activity of typhoon was weaker than normal in the northwestern Pacific, landfall typhoons in China exhibited more quantitative, stronger and more destructive than normal.
Global climate has been warming up persistently in 2005, and 2005 is the second warmest year on record. During the year, South Asia was hit by hot waves, central-western Europe experienced severe drought and in northern Brazil, drought conditions became the most severe on record. Meanwhile, floods occurred frequently all over the world, while snow storms attacked West Asia, northern South Asia, Center Asia, parts of Japan and China, America and parts of Europe. In this year, disaster from hurricane (typhoon) was disastrous. In the Atlantic Ocean, activity of hurricane was the most active on record, with “Katrina” having become the most destructive hurricane on record in America′s history. Meanwhile, although activity of typhoon was weaker than normal in the northwestern Pacific, landfall typhoons in China exhibited more quantitative, stronger and more destructive than normal.
2006, 32(4):78-83.
DOI: 10.7519/j.issn.1000-0526.2006.04.014
Abstract:
The annual mean temperature was higher than normal, and the annual mean precipitation was more than normal during 2005. There was no extensive, long-time serious drought, the drought was lighter than normal, except that autumn-winter-spring continuous drought in the southern South China, most serious spring drought in recent 50 years in Yunnan, summer-autumn continuous drought in the northeastern Northwest China and Inner-Mongolia, and autumn significant drought in Jiangxi and the western South China. Rainstorm and flood disasters were more serious than normal year in flood season, e.g. the Xijiang River, the Minjiang River and the Huaihe River watershed and Hubei, Sichuan, Liaoning provinces, serious autumn flood occurred in Weihe River and Hanjiang River watershed. 8 typhoons (including tropical storm) landed on China in 2005, with the characteristics of high intensity, extensity and heavy losses, and it was the second most serious year in losses by typhoon since 1995, only less than that in 1996. Gale and hailstorm, cyclone and thunderstorm, with the serious losses, also frequently occurred in parts of China, by which caused losses were heavier than normal, but lighter than last year. In addition, low temperature chilling and snowstorm occurred in South China at the beginning of the year, and heavy snowstorm hit Shandong Province at the end of the year. The number of spring sand-dust day was the least in recent 50 years.
The annual mean temperature was higher than normal, and the annual mean precipitation was more than normal during 2005. There was no extensive, long-time serious drought, the drought was lighter than normal, except that autumn-winter-spring continuous drought in the southern South China, most serious spring drought in recent 50 years in Yunnan, summer-autumn continuous drought in the northeastern Northwest China and Inner-Mongolia, and autumn significant drought in Jiangxi and the western South China. Rainstorm and flood disasters were more serious than normal year in flood season, e.g. the Xijiang River, the Minjiang River and the Huaihe River watershed and Hubei, Sichuan, Liaoning provinces, serious autumn flood occurred in Weihe River and Hanjiang River watershed. 8 typhoons (including tropical storm) landed on China in 2005, with the characteristics of high intensity, extensity and heavy losses, and it was the second most serious year in losses by typhoon since 1995, only less than that in 1996. Gale and hailstorm, cyclone and thunderstorm, with the serious losses, also frequently occurred in parts of China, by which caused losses were heavier than normal, but lighter than last year. In addition, low temperature chilling and snowstorm occurred in South China at the beginning of the year, and heavy snowstorm hit Shandong Province at the end of the year. The number of spring sand-dust day was the least in recent 50 years.
2006, 32(4):84-90.
DOI: 10.7519/j.issn.1000-0526.2006.4.015
Abstract:
A synthetic analysis of heavy rainfall event of typhoon Tailim depression in Jiangxi Province during 2—4 Sep. 2005 is made with the dense observational data and NCEP re-analysis data. The results show that the weak cold air invading to the typhoon depression led to the strength of energy front in PBL when the typhoon depression is steady in northwest of Jiangxi. The development of continental high in West China retarded the westward moving of typhoon depression. A weak environment stream field provided a good condition to its maintaining long time and staying in northwest of Jiangxi. The sustained vapor transport and divergence of NE cold current from the cold front in meddle latitude and SE warm flow from ocean in low latitude were helpful to the severe torrential rainfall event as the good dynamical and thermal conditions to the typhoon depression in low tropospheric levels. It was demonstrated that the orographic effect contributed greatly to precipitation enhancement due to orographic lifting and convergence with intensified precipitation on the windward slope of the Dabie mountains and Lushan mountain as well as Jiuling mountains.
A synthetic analysis of heavy rainfall event of typhoon Tailim depression in Jiangxi Province during 2—4 Sep. 2005 is made with the dense observational data and NCEP re-analysis data. The results show that the weak cold air invading to the typhoon depression led to the strength of energy front in PBL when the typhoon depression is steady in northwest of Jiangxi. The development of continental high in West China retarded the westward moving of typhoon depression. A weak environment stream field provided a good condition to its maintaining long time and staying in northwest of Jiangxi. The sustained vapor transport and divergence of NE cold current from the cold front in meddle latitude and SE warm flow from ocean in low latitude were helpful to the severe torrential rainfall event as the good dynamical and thermal conditions to the typhoon depression in low tropospheric levels. It was demonstrated that the orographic effect contributed greatly to precipitation enhancement due to orographic lifting and convergence with intensified precipitation on the windward slope of the Dabie mountains and Lushan mountain as well as Jiuling mountains.
2006, 32(4):91-96.
DOI: 10.7519/j.issn.1000-0526.2006.4.016
Abstract:
Based on NCEP reanalysis data and OLR data from NOAA, the characteristics and the causes for the rainband anomaly over the southern China in June 2003 are studied. The results show that exceptional weak ITCZ over the West Pacific Ocean and the fewer tropical cyclones make subtropical high continually stay in the south area; the monsoon circulation is influenced by the convective anomaly over the southern Tibetan Plateau and the low-latitude ocean, thus the moisture is concentrated to the low-latitude area and the southwest monsoon moisture transfer passage is to the south of its normal location; the ridge line of the south Asian high is prevented by the middle and high latitude circulation anomalies at high levels from moving northward, moreover, the west wind front at lower levels is intensified by west wind anomalies at high level through momentum downward transfer. All the facts mentioned above give the reasons for the rainband anomaly.
Based on NCEP reanalysis data and OLR data from NOAA, the characteristics and the causes for the rainband anomaly over the southern China in June 2003 are studied. The results show that exceptional weak ITCZ over the West Pacific Ocean and the fewer tropical cyclones make subtropical high continually stay in the south area; the monsoon circulation is influenced by the convective anomaly over the southern Tibetan Plateau and the low-latitude ocean, thus the moisture is concentrated to the low-latitude area and the southwest monsoon moisture transfer passage is to the south of its normal location; the ridge line of the south Asian high is prevented by the middle and high latitude circulation anomalies at high levels from moving northward, moreover, the west wind front at lower levels is intensified by west wind anomalies at high level through momentum downward transfer. All the facts mentioned above give the reasons for the rainband anomaly.
2006, 32(4):97-100.
DOI: 10.7519/j.issn.1000-0526.2006.4.017
Abstract:
The interdecadal changes of temperature and precipitation over the Hetian river valley are analysed based on the data of temperature and precipitation observed in the Hetian weather station from 1961 to 2000. The results show that the climatic evolvement in the Hetian river valley has obvious both interannual and interdacadal scales. The average temperature and precipitation have upward trend of 0.26℃/10a and 1.56mm/10a respectively. The temperature rising trend is more obvious in 1990s. 1999 is the warmest year in the last 40 years.
The interdecadal changes of temperature and precipitation over the Hetian river valley are analysed based on the data of temperature and precipitation observed in the Hetian weather station from 1961 to 2000. The results show that the climatic evolvement in the Hetian river valley has obvious both interannual and interdacadal scales. The average temperature and precipitation have upward trend of 0.26℃/10a and 1.56mm/10a respectively. The temperature rising trend is more obvious in 1990s. 1999 is the warmest year in the last 40 years.
2006, 32(4):101-105.
DOI: 10.7519/j.issn.1000-0526.2006.4.018
Abstract:
Based on the weather data from year 1988 to 1997, 71 cases of hail weather processes in Chifeng, Inner Mongolia are analyzed, and four circulation patterns for the hail weather process are concluded. And physics parameters about convection are calculated using some recent research results. Subsequently, the prediction factors which have reliable and stable physics are sifted and an integrated prediction method is developed for the local hail process, and the application effect is better.
Based on the weather data from year 1988 to 1997, 71 cases of hail weather processes in Chifeng, Inner Mongolia are analyzed, and four circulation patterns for the hail weather process are concluded. And physics parameters about convection are calculated using some recent research results. Subsequently, the prediction factors which have reliable and stable physics are sifted and an integrated prediction method is developed for the local hail process, and the application effect is better.
2006, 32(4):106-109.
DOI: 10.7519/j.issn.1000-0526.2006.4.019
Abstract:
The intensity change of typhoon Mindulle landing is studied. First, the structure changes during typhoon Mindulle landing at Taiwan and Zhejiang provinces are analyzed with the radar echo data. The result shows that Mindulle seems loose during its first landing but has become more organized during its second landing. The enhancement of Mindulle is proved further by the rain belt distribution and the vorticity distribution on the surface,which are calculated with the data of automatic meteorological stations in Zhejiang Province. At last, the vapor and baroclinic energy conditions during two landings are analyzed with the NCEP reanalysis data. It shows that the main reasons for ‘Mindulle’ to enhance during the second landing are the vapor transport from oceans, and the intrusion of cold air from the north.
The intensity change of typhoon Mindulle landing is studied. First, the structure changes during typhoon Mindulle landing at Taiwan and Zhejiang provinces are analyzed with the radar echo data. The result shows that Mindulle seems loose during its first landing but has become more organized during its second landing. The enhancement of Mindulle is proved further by the rain belt distribution and the vorticity distribution on the surface,which are calculated with the data of automatic meteorological stations in Zhejiang Province. At last, the vapor and baroclinic energy conditions during two landings are analyzed with the NCEP reanalysis data. It shows that the main reasons for ‘Mindulle’ to enhance during the second landing are the vapor transport from oceans, and the intrusion of cold air from the north.
2006, 32(4):110-115.
DOI: 10.7519/j.issn.1000-0526.2006.04.020
Abstract:
The variation of summer precipitation over Huanghuai region is very coordinate. Using SVD technique, the relationship between 100hPa geopotential height over the north Pacific and summer precipitation in the Huanghuai region is studied. The results show that the first mode derived from SVD indicates the key coupled characteristics of the geopotential height and the precipitation field with closely time-space correlation. In the severe summer drought/flood years, the height departure of 100hPa over the north Pacific(40～60°N,160°E～160°W) is remarkably positive/negative. It is the signal of prediction of summer precipitation in the Huanghuai region.
The variation of summer precipitation over Huanghuai region is very coordinate. Using SVD technique, the relationship between 100hPa geopotential height over the north Pacific and summer precipitation in the Huanghuai region is studied. The results show that the first mode derived from SVD indicates the key coupled characteristics of the geopotential height and the precipitation field with closely time-space correlation. In the severe summer drought/flood years, the height departure of 100hPa over the north Pacific(40～60°N,160°E～160°W) is remarkably positive/negative. It is the signal of prediction of summer precipitation in the Huanghuai region.
2006, 32(4):116-120.
DOI: 10.7519/j.issn.1000-0526.2006.4.021
Abstract:
The effect of low temperature, drought, low temperature plus drought on maize growth was imitated in phytotron. The effect of low temperature, drought, low temperature plus drought on the physiological process of maize in the seedling and the heading stage is quantitatively evaluated. The result shows that low temperature and drought stress had negative effect on physiological process and the negative effect was enlarged while low temperature plus drought. A evaluation equation of the effect of the stresses on grain yield is as: y=516.2162+58.72343x1+125.9081x2+114.8233x3. Where, y is the grain yield (kg·hm -2), x1 is the soil humidity (%), x2 is the air temperature at seedling stage (℃) and x3 is the air temperature in the heading stage(℃).
The effect of low temperature, drought, low temperature plus drought on maize growth was imitated in phytotron. The effect of low temperature, drought, low temperature plus drought on the physiological process of maize in the seedling and the heading stage is quantitatively evaluated. The result shows that low temperature and drought stress had negative effect on physiological process and the negative effect was enlarged while low temperature plus drought. A evaluation equation of the effect of the stresses on grain yield is as: y=516.2162+58.72343x1+125.9081x2+114.8233x3. Where, y is the grain yield (kg·hm -2), x1 is the soil humidity (%), x2 is the air temperature at seedling stage (℃) and x3 is the air temperature in the heading stage(℃).
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ISSN:1000-0526 CN:11-2282/P