ISSN 1000-0526
CN 11-2282/P
CN 11-2282/P
Volume 39,Issue 6,2013 Table of Contents
2013, 39(6):665-674.
DOI: 10.7519/j.issn.1000-0526.2013.06.001
Abstract:
The observed geopotential height and temperature in the troposphere stratosphere can be physically decomposed into four components to estimate climatic states and anomalies, namely zonal mean symmetric climate, asymmetric climate, zonal mean instantaneous symmetric anomaly and instantaneous asymmetric anomaly. In this paper, the asymmetric anomaly was extracted from the NCEP/NCAR reanalysis data and used as early signals to indicate the regional heat wave and low temperature events that occurred in North China in June and December 2005, respectively. The result shows that the surface temperature events are some responses to atmospheric disturbances in troposphere and stratosphere. For the heat wave event, its early signals of positive temperature anomaly at 850 hPa and positive height anomaly at 250 hPa can be traced from Europe 7 days ahead, while the early signals of low temperature event are negative temperature anomaly at 850 hPa and negative height anomaly at 300 hPa which are also from Europe with a lead of 13 days. The anomalous synoptic chart provided by this physical decomposition is a useful tool to predict the surface temperature events.
The observed geopotential height and temperature in the troposphere stratosphere can be physically decomposed into four components to estimate climatic states and anomalies, namely zonal mean symmetric climate, asymmetric climate, zonal mean instantaneous symmetric anomaly and instantaneous asymmetric anomaly. In this paper, the asymmetric anomaly was extracted from the NCEP/NCAR reanalysis data and used as early signals to indicate the regional heat wave and low temperature events that occurred in North China in June and December 2005, respectively. The result shows that the surface temperature events are some responses to atmospheric disturbances in troposphere and stratosphere. For the heat wave event, its early signals of positive temperature anomaly at 850 hPa and positive height anomaly at 250 hPa can be traced from Europe 7 days ahead, while the early signals of low temperature event are negative temperature anomaly at 850 hPa and negative height anomaly at 300 hPa which are also from Europe with a lead of 13 days. The anomalous synoptic chart provided by this physical decomposition is a useful tool to predict the surface temperature events.
2013, 39(6):675-680.
DOI: 10.7519/j.issn.1000-0526.2013.06.002
Abstract:
Because of the complexity of underlying surface, satellite radiation data near surface has not been fully developed and used. Infrared hyperspectral data near surface has not been applied on land in our GRAPES model, either, and even on the ocean where the underlying surface is simple relatively, the effect of using infrared spectral data is not very satisfied due to the inaccurate estimation of the sea surface temperature of the GRAPES model’s background. In view of the question that the estimation of the sea surface temperature is inaccurate, this paper uses one dimensional variational (1DVar) method to adjust the background sea surface temperature when the FOV (field of view) of AIRS (The Atmospheric Infrared Sounder) is clear, and utilizes the GRAPES model to do cycle assimilation, then researches the influence of the analytic fields after adjusting the sea surface temperature. The results indicate that using 1DVar to adjust temperature not only makes the simulated brightness temperature in the low level channels better match the observated brightness temperature, but also effectively improves the analytic fields. Besides, the geopotential height fields in the low, middle and upper atmosphere are all improved well, and the humidity fields and the wind fields in the lower atmosphere are also obviously improved.
Because of the complexity of underlying surface, satellite radiation data near surface has not been fully developed and used. Infrared hyperspectral data near surface has not been applied on land in our GRAPES model, either, and even on the ocean where the underlying surface is simple relatively, the effect of using infrared spectral data is not very satisfied due to the inaccurate estimation of the sea surface temperature of the GRAPES model’s background. In view of the question that the estimation of the sea surface temperature is inaccurate, this paper uses one dimensional variational (1DVar) method to adjust the background sea surface temperature when the FOV (field of view) of AIRS (The Atmospheric Infrared Sounder) is clear, and utilizes the GRAPES model to do cycle assimilation, then researches the influence of the analytic fields after adjusting the sea surface temperature. The results indicate that using 1DVar to adjust temperature not only makes the simulated brightness temperature in the low level channels better match the observated brightness temperature, but also effectively improves the analytic fields. Besides, the geopotential height fields in the low, middle and upper atmosphere are all improved well, and the humidity fields and the wind fields in the lower atmosphere are also obviously improved.
2013, 39(6):681-690.
DOI: 10.7519/j.issn.1000-0526.2013.06.003
Abstract:
According to deficiency of the commonly used point based precipitation verification methods in weather forecast operation and model research such as TS scores, the object based verification method developed in near decade is discussed in this paper. In this method, precipitation field is regarded as a combination of many precipitation objects accompanied by several weather systems, and the verification to the position, scale and shape of each object is carried out after these precipitation objects in the observation field and prediction field are identified and matched. So, the method can provide more detailed and quantitative verification information that contains more synoptic meanings. There are three steps in this method: object identification, object pairing and object verification. In addition, this paper introduces the algorithm and processes of the object based verification method in detail and makes some improvements to the operations of the close degree during object identification and the match degree during object pairing. The improved method is applied to the verifications of precipitation of T639, ECMWF and Japan models, and verification products of the position, shape and range of heavy rainfall are created, which can provide quantificational information for the operation of weather forecasting.
According to deficiency of the commonly used point based precipitation verification methods in weather forecast operation and model research such as TS scores, the object based verification method developed in near decade is discussed in this paper. In this method, precipitation field is regarded as a combination of many precipitation objects accompanied by several weather systems, and the verification to the position, scale and shape of each object is carried out after these precipitation objects in the observation field and prediction field are identified and matched. So, the method can provide more detailed and quantitative verification information that contains more synoptic meanings. There are three steps in this method: object identification, object pairing and object verification. In addition, this paper introduces the algorithm and processes of the object based verification method in detail and makes some improvements to the operations of the close degree during object identification and the match degree during object pairing. The improved method is applied to the verifications of precipitation of T639, ECMWF and Japan models, and verification products of the position, shape and range of heavy rainfall are created, which can provide quantificational information for the operation of weather forecasting.
2013, 39(6):691-698.
DOI: 10.7519/j.issn.1000-0526.2013.06.004
Abstract:
Ensemble weight methods based on the Threat Score (TS), the Brier Score (BS) and the Arithmetic Average (AA) were employed to combine the precipitation prediction of four ensemble numerical prediction systems (CMA, ECMWF, NCEP and JMA) from the TIGGE over the southeast of China and its five sub regions. The results of comparison analysis of the four ensemble numerical prediction systems indicated that the super ensemble based on TS weight always provides more skillful performance in any of the four ensemble numerical prediction systems regionally and shows the best prediction performance of rainfall impacted by typhoon landing or not. The grand ensemble based on BS weight and AA weight also shows the better skillful performance. Moreover, verification of super ensemble method in five sub regions showed that the super ensemble precipitation based on TS weight always has a less mean absolute error (MAE) and higher TS score in most sub regions than that based on BS weight and AA weight. The super ensemble precipitation based on TS weight provides the best performance in the southeast of Guangdong and northern Zhejiang and the secondary performance along the coast of Zhejiang and Fujian and the northwest of Guangdong. The skillful performance based on BS weight and AA weight is provided only in the southeast of Guangdong.
Ensemble weight methods based on the Threat Score (TS), the Brier Score (BS) and the Arithmetic Average (AA) were employed to combine the precipitation prediction of four ensemble numerical prediction systems (CMA, ECMWF, NCEP and JMA) from the TIGGE over the southeast of China and its five sub regions. The results of comparison analysis of the four ensemble numerical prediction systems indicated that the super ensemble based on TS weight always provides more skillful performance in any of the four ensemble numerical prediction systems regionally and shows the best prediction performance of rainfall impacted by typhoon landing or not. The grand ensemble based on BS weight and AA weight also shows the better skillful performance. Moreover, verification of super ensemble method in five sub regions showed that the super ensemble precipitation based on TS weight always has a less mean absolute error (MAE) and higher TS score in most sub regions than that based on BS weight and AA weight. The super ensemble precipitation based on TS weight provides the best performance in the southeast of Guangdong and northern Zhejiang and the secondary performance along the coast of Zhejiang and Fujian and the northwest of Guangdong. The skillful performance based on BS weight and AA weight is provided only in the southeast of Guangdong.
2013, 39(6):699-703.
DOI: 10.7519/j.issn.1000-0526.2013.06.005
Abstract:
Hazard area of rainfall in Tongcheng County on June 10 2011 was analyzed according to runoff equilibrium theory. Flood inundated area was simulated by using GIS flood drowned model based on rainfall and DEM data, and the simulation results was tested and analyzed with the disaster results. The result shows that the whole county was inundated by different degrees, and the inundated areas focus in river and low lying areas. The depth inundated areas is between 0.5 and 2 m, accounting for 35% of all the inundated areas. The siumulated inundated area is similar to the actual situation.
Hazard area of rainfall in Tongcheng County on June 10 2011 was analyzed according to runoff equilibrium theory. Flood inundated area was simulated by using GIS flood drowned model based on rainfall and DEM data, and the simulation results was tested and analyzed with the disaster results. The result shows that the whole county was inundated by different degrees, and the inundated areas focus in river and low lying areas. The depth inundated areas is between 0.5 and 2 m, accounting for 35% of all the inundated areas. The siumulated inundated area is similar to the actual situation.
2013, 39(6):704-709.
DOI: 10.7519/j.issn.1000-0526.2013.06.006
Abstract:
Bright band is meaningful for stratus precipitation mechanism research and weather modification. By using the observed data of wind profile radar of different types of precipitation in Beijing from April to September 2010, this paper puts 〖JP2〗forward the bright band recognition algorithm, distinguishing bright band information from precipitation data by the corrected recognition algorithm, and obtaining the height and duration of bright band as well as the comparison of precipitation amount and precipitation type in Yanqing, Beijing. According to the statistical result, the distribution characteristics of the melt layer in Yanqing, Beijing in the summer of 2010 are got. The maximum of echo intensity mainly appears in 36-40 dBz, the thickness of bright band is 1000-1500 m, and the difference of upper and lower boundary velocity is 4-5 m·s-1.〖JP〗
Bright band is meaningful for stratus precipitation mechanism research and weather modification. By using the observed data of wind profile radar of different types of precipitation in Beijing from April to September 2010, this paper puts 〖JP2〗forward the bright band recognition algorithm, distinguishing bright band information from precipitation data by the corrected recognition algorithm, and obtaining the height and duration of bright band as well as the comparison of precipitation amount and precipitation type in Yanqing, Beijing. According to the statistical result, the distribution characteristics of the melt layer in Yanqing, Beijing in the summer of 2010 are got. The maximum of echo intensity mainly appears in 36-40 dBz, the thickness of bright band is 1000-1500 m, and the difference of upper and lower boundary velocity is 4-5 m·s-1.〖JP〗
2013, 39(6):710-718.
DOI: 10.7519/j.issn.1000-0526.2013.06.007
Abstract:
This is an interpretation technique for numerical weather prediction (NWP) products of GFS. In this paper the support vector machine (SVM) was employed to forecast the intensity of offshore and landing tropical cyclones (TC). According to the TC intensity, meteorological environment and topographical factors, we designed related factors and built a forecasting model which was used to forecast the intensities of TC in 12, 24, 36, 48, 60 and 72 hours. The predicting precision by SVM is closer to the forecast by the National Meteorological Centre of CMA and all predictions are superior to that by the method of climate persistence. The trend prediction of TC has obvious advantages and can improve forecast precision by 7%-12%. All these indicate that SVM is a better method and can be applied to TC intensity forecast in operations.
This is an interpretation technique for numerical weather prediction (NWP) products of GFS. In this paper the support vector machine (SVM) was employed to forecast the intensity of offshore and landing tropical cyclones (TC). According to the TC intensity, meteorological environment and topographical factors, we designed related factors and built a forecasting model which was used to forecast the intensities of TC in 12, 24, 36, 48, 60 and 72 hours. The predicting precision by SVM is closer to the forecast by the National Meteorological Centre of CMA and all predictions are superior to that by the method of climate persistence. The trend prediction of TC has obvious advantages and can improve forecast precision by 7%-12%. All these indicate that SVM is a better method and can be applied to TC intensity forecast in operations.
2013, 39(6):719-727.
DOI: 10.7519/j.issn.1000-0526.2013.06.008
Abstract:
The forecast errors and associated surrounding flows of sudden typhoon track changes in the western North Pacific during 2005-2010 are examined in this study. By analyzing the forecasts of National Meteorological Centre of China Meteorological Administration, it is found that the mean 24 h and 48 h forecast errors for the sudden north turning cases are significantly large while the forecasts of sudden west turning cases are close to the average forecasting levels. For the sudden northward change, compared to the average forecast errors, the mean 24 h and 48 h forecast errors are 145.6 km and 317.3 km respectively, increasing by 29.3% and 68.3%. Further composite analysis on the circulations shows that there are clear differences in the westward extension of the low frequency component of the subtropical high and the synoptic scale wind fields associated with the tropical cyclones with sudden track changes.
The forecast errors and associated surrounding flows of sudden typhoon track changes in the western North Pacific during 2005-2010 are examined in this study. By analyzing the forecasts of National Meteorological Centre of China Meteorological Administration, it is found that the mean 24 h and 48 h forecast errors for the sudden north turning cases are significantly large while the forecasts of sudden west turning cases are close to the average forecasting levels. For the sudden northward change, compared to the average forecast errors, the mean 24 h and 48 h forecast errors are 145.6 km and 317.3 km respectively, increasing by 29.3% and 68.3%. Further composite analysis on the circulations shows that there are clear differences in the westward extension of the low frequency component of the subtropical high and the synoptic scale wind fields associated with the tropical cyclones with sudden track changes.
2013, 39(6):728-737.
DOI: 10.7519/j.issn.1000-0526.2013.06.009
Abstract:
Based on FY 2E meteorological satellite images and CINRAD data, this paper analyzes the trigger conditions to the tornado weather seen on 15 May 2010 in the west of Heilongjiang Province. By analyzing the circulation and mesoscale characteristics from satellite images, this article reveals the formation conditions of thunderstorm clouds that generate and trigger the tornado. The characteristics of cloud images and radar echoes of the tornado event is illustrated in detail on the basis of CINRAD data. The main results are as follows: The mesoscale convection process occurs in front of the upper trough and surface cold front, and the α mesoscale convective clouds are developed by multiple small scale convections. Unstable energy of tornado is provided by humidity gradient, water vapor transportion, vertical wind shear and dry intrusion, and the surface cold front provides the trigger mechanism. The thunderstorm clouds constantly generate and dissipate combining with other thunderstorm clouds during the developing process. The tornado is produced when two clouds amalgamate. The characteristics of the radar echoes are very obvious. At the mature stage of the storm, the hook echo and bounded weak echo regions become the largest, the downdraft begins to interact with the inflow producing the outflow boundary and there is a clear gale area in the high, middle and low levels. The tornado occurs in the vicinity of the echo.
Based on FY 2E meteorological satellite images and CINRAD data, this paper analyzes the trigger conditions to the tornado weather seen on 15 May 2010 in the west of Heilongjiang Province. By analyzing the circulation and mesoscale characteristics from satellite images, this article reveals the formation conditions of thunderstorm clouds that generate and trigger the tornado. The characteristics of cloud images and radar echoes of the tornado event is illustrated in detail on the basis of CINRAD data. The main results are as follows: The mesoscale convection process occurs in front of the upper trough and surface cold front, and the α mesoscale convective clouds are developed by multiple small scale convections. Unstable energy of tornado is provided by humidity gradient, water vapor transportion, vertical wind shear and dry intrusion, and the surface cold front provides the trigger mechanism. The thunderstorm clouds constantly generate and dissipate combining with other thunderstorm clouds during the developing process. The tornado is produced when two clouds amalgamate. The characteristics of the radar echoes are very obvious. At the mature stage of the storm, the hook echo and bounded weak echo regions become the largest, the downdraft begins to interact with the inflow producing the outflow boundary and there is a clear gale area in the high, middle and low levels. The tornado occurs in the vicinity of the echo.
2013, 39(6):738-748.
DOI: 10.7519/j.issn.1000-0526.2013.06.010
Abstract:
Based on conventional data and NCEP reanalysis data (1°×1°), 15 strong coldness processes with rain and sonw in late springs in Yunnan have been summarized. The results show that the characteristics of the processes were two trough and one ridge at 500 hPa and north higher than south at 700 hPa. The two different kinds of strong coldness processes in 14-19 March 2011 and 2-6 March 2005 have been emphatically compared and analyzed. Sichuan Yunnan shear line and Kunming quasi stationary front came southward during the processes and Novosibirsk cold air invaded Yunnan from northeast. The main cause of severe surface cooling in the first process was strong cold advection in middle low level and in the second process was strong cold advection in lower level and cold advection sink in higher level. The cold rain and snow weather had deep vertical upward movement or strong rising movement column in middle low level. The Bay of Bengal was the vapor source. Strong upper level and low level jets and their secondary circulation transported water vapor and heat. While heavy snow was falling there were big and strong water vapor flux values and intensity of water vapor convergence without South Branch Trough (SBT), but there was a water vapor flux enhanced process in middle low level with SBT. The cold layer at lower level or strong cold advection near the surface was beneficial to snowing. The convergence of warm and moist southwest airflow which was ahead of the trough or westerly jet on low level and strong cold air strengthened frontogenesis. Ahead of moving front, zero line of frontogenesis function was corresponding to 〖WTHX〗Q〖WTBZ〗 vector convergence line at 850 hPa. The greater horizontal gradient of instability energy was, the more energy accumulated, which means the bigger snowfall ranges were. The isodrosotherm had the Ω characteristic at lower level. Uplifting role of the dew point front triggered dry cold air and warm wet air convergent on wet/dry interface. The top of the Ω isodrosotherm dense zone, the dew point front and location of lower level jet, 〖WTHX〗Q〖WTBZ〗 vector convergence zone had good correlations with snow areas in Yunnan, the magnitude of surface cooling was proportional to the intensity of positive frontogenesis function at 850 hPa.〖HJ〗
Based on conventional data and NCEP reanalysis data (1°×1°), 15 strong coldness processes with rain and sonw in late springs in Yunnan have been summarized. The results show that the characteristics of the processes were two trough and one ridge at 500 hPa and north higher than south at 700 hPa. The two different kinds of strong coldness processes in 14-19 March 2011 and 2-6 March 2005 have been emphatically compared and analyzed. Sichuan Yunnan shear line and Kunming quasi stationary front came southward during the processes and Novosibirsk cold air invaded Yunnan from northeast. The main cause of severe surface cooling in the first process was strong cold advection in middle low level and in the second process was strong cold advection in lower level and cold advection sink in higher level. The cold rain and snow weather had deep vertical upward movement or strong rising movement column in middle low level. The Bay of Bengal was the vapor source. Strong upper level and low level jets and their secondary circulation transported water vapor and heat. While heavy snow was falling there were big and strong water vapor flux values and intensity of water vapor convergence without South Branch Trough (SBT), but there was a water vapor flux enhanced process in middle low level with SBT. The cold layer at lower level or strong cold advection near the surface was beneficial to snowing. The convergence of warm and moist southwest airflow which was ahead of the trough or westerly jet on low level and strong cold air strengthened frontogenesis. Ahead of moving front, zero line of frontogenesis function was corresponding to 〖WTHX〗Q〖WTBZ〗 vector convergence line at 850 hPa. The greater horizontal gradient of instability energy was, the more energy accumulated, which means the bigger snowfall ranges were. The isodrosotherm had the Ω characteristic at lower level. Uplifting role of the dew point front triggered dry cold air and warm wet air convergent on wet/dry interface. The top of the Ω isodrosotherm dense zone, the dew point front and location of lower level jet, 〖WTHX〗Q〖WTBZ〗 vector convergence zone had good correlations with snow areas in Yunnan, the magnitude of surface cooling was proportional to the intensity of positive frontogenesis function at 850 hPa.〖HJ〗
2013, 39(6):749-758.
DOI: 10.7519/j.issn.1000-0526.2013.06.011
Abstract:
Using the GPS low level sounding data obtained in the dam area of Xiluodu Hydropower Station and the reservoir area of Xiangjiaba Hydropower Station in the lower reaches of Jinsha River as well as the synchronous surface observation data, this paper analyzes the variation characteristics of the wind fields in different heights from surface to the 2000 m height of atmospheric boundary layer in spring, summer, autumn and winter. The results indicate that: (1) in spring westerly winds blow in the atmospheric boundary layer over Xiluodu Dam Area mainly while under the height of 1500 m calm and light winds appear more frequently, reaching the maximum values of surface calm and light winds in the four seasons; (2) in summer the occurrence of surface calm and light winds is the least in the four seasons, and west winds and northwest west winds prevail in the middle and lower levels of atmospheric boundary layer; (3) in autumn westerly winds are the major theme in the middle and lower levels over Xiluodu Dam Area but turn to northerly winds gradually in the upper level; (4) in winter wersterlies dominated by west and northwest west winds prevail in the low level whilst in the middle and high levels the directions of winds become west, southwest west, east and northeast east; (5) in autumn and winter the maximum wind speeds of west, northeast north, northeast east in the atmosphere boundary layer over Xiluodu Dam Area all appear in the high level of 2000 m.
Using the GPS low level sounding data obtained in the dam area of Xiluodu Hydropower Station and the reservoir area of Xiangjiaba Hydropower Station in the lower reaches of Jinsha River as well as the synchronous surface observation data, this paper analyzes the variation characteristics of the wind fields in different heights from surface to the 2000 m height of atmospheric boundary layer in spring, summer, autumn and winter. The results indicate that: (1) in spring westerly winds blow in the atmospheric boundary layer over Xiluodu Dam Area mainly while under the height of 1500 m calm and light winds appear more frequently, reaching the maximum values of surface calm and light winds in the four seasons; (2) in summer the occurrence of surface calm and light winds is the least in the four seasons, and west winds and northwest west winds prevail in the middle and lower levels of atmospheric boundary layer; (3) in autumn westerly winds are the major theme in the middle and lower levels over Xiluodu Dam Area but turn to northerly winds gradually in the upper level; (4) in winter wersterlies dominated by west and northwest west winds prevail in the low level whilst in the middle and high levels the directions of winds become west, southwest west, east and northeast east; (5) in autumn and winter the maximum wind speeds of west, northeast north, northeast east in the atmosphere boundary layer over Xiluodu Dam Area all appear in the high level of 2000 m.
2013, 39(6):759-767.
DOI: 10.7519/j.issn.1000-0526.2013.06.012
Abstract:
A study is made by using the data obtained from Panyu Atmospheric Composition Station, Guangzhou, including aerosol particle mass concentration (PM10, PM2.5), black carbon concentration, ozone concentration, surface meteorological data, backward trajectories, vertical velocity, potential temperature and boundary layer. In this study, the causes of a haze process caused by peripheral subsidence of tropical cyclones over the Pearl River Delta region is analyzed. The results show that the peripheral subsidence of tropical cyclones make a stable meteorological condition for this haze process, in which the aerosol particles are mainly from local sources. The PM2.5 and PM10 account for nearly 70% while black carbon and PM10 is nearly 6.0%. The visibility is low in the morning because of the lowest boundary layer and highest relative humidity during a day.
A study is made by using the data obtained from Panyu Atmospheric Composition Station, Guangzhou, including aerosol particle mass concentration (PM10, PM2.5), black carbon concentration, ozone concentration, surface meteorological data, backward trajectories, vertical velocity, potential temperature and boundary layer. In this study, the causes of a haze process caused by peripheral subsidence of tropical cyclones over the Pearl River Delta region is analyzed. The results show that the peripheral subsidence of tropical cyclones make a stable meteorological condition for this haze process, in which the aerosol particles are mainly from local sources. The PM2.5 and PM10 account for nearly 70% while black carbon and PM10 is nearly 6.0%. The visibility is low in the morning because of the lowest boundary layer and highest relative humidity during a day.
13 Exploration to the Method for Determining Diagnostic Indicators of Suitable Climate for Winter Wheat
2013, 39(6):768-773.
DOI: 10.7519/j.issn.1000-0526.2013.06.013
Abstract:
Considering the different effects of soil moisture and precipitation on winter wheat in different growth stages, the calculation method for winter wheat moisture suitability is established in this paper. Then the paper further constructs a climate suitability model of winter wheat combining the calculation models of winter wheat temperature suitability and sunshine suitability. Using the correlations between climatic suitability under different periods and meteorological yields of winter wheat, climate suitable index of winter wheat from sowing to some time in the growing period is established by weighted average. Making use of historical maximum, minimum and average climate suitable index and the observed test data of winter wheat, the diagnostic threshold of climate suitable grade from winter wheat sowing to a growth stage is set up, and then based on this diagnostic threshold, three diagnostic indicators of climate suitable grade in Hebei, Shandong and Henan Provinces are built. The results are significant for improving the quantitative evaluation of agrometeorological service
Considering the different effects of soil moisture and precipitation on winter wheat in different growth stages, the calculation method for winter wheat moisture suitability is established in this paper. Then the paper further constructs a climate suitability model of winter wheat combining the calculation models of winter wheat temperature suitability and sunshine suitability. Using the correlations between climatic suitability under different periods and meteorological yields of winter wheat, climate suitable index of winter wheat from sowing to some time in the growing period is established by weighted average. Making use of historical maximum, minimum and average climate suitable index and the observed test data of winter wheat, the diagnostic threshold of climate suitable grade from winter wheat sowing to a growth stage is set up, and then based on this diagnostic threshold, three diagnostic indicators of climate suitable grade in Hebei, Shandong and Henan Provinces are built. The results are significant for improving the quantitative evaluation of agrometeorological service
2013, 39(6):774-781.
DOI: 10.7519/j.issn.1000-0526.2013.06.014
Abstract:
On the basis of Logistic model, a normalized comprehensive heat injury index that can be accumulated is applied in studying the high temperature events and assessing their impacts on single rice yield. The results show that the northern west part of Yangtze Huaihe River Valley is the critical zone of rice yield loss due to heat injury through the analysis of the relationship between the heat injury index and rice yield loss. In this region, the average loss rate increases notably from 8.9% in 1970s to 17.9% in 2000s with the expanded loss areas. Rice flowering stage concentrates in the period of high temperature, which is the main cause for rice yield loss. Heat injury indexes and affected areas of high temperature reach their maxima respectively in 1960s and 2000s. An abrupt change occurs in 1971 for high temperature covered proportion. Since then high temperature covered proportion increases continuously and gets to 63.6% in 2000s. High temperature events concentrates in the period of 11 July and 15 August every year with 〖JP2〗proportions of more than 20%. With considering comprehensively the end dates of stable temperature above 20℃, concentrated period of high temperature, climate change and the successful experience of avoiding high temperature in the southeastern part of Yangtze Huaihe River Valley, we suggest that late maturing rice be promoted and its sowing date be delayed to May. These measures can ensure the flowering stage to occur in the period between late August and early September, avoiding the high temperature damages.〖JP〗
On the basis of Logistic model, a normalized comprehensive heat injury index that can be accumulated is applied in studying the high temperature events and assessing their impacts on single rice yield. The results show that the northern west part of Yangtze Huaihe River Valley is the critical zone of rice yield loss due to heat injury through the analysis of the relationship between the heat injury index and rice yield loss. In this region, the average loss rate increases notably from 8.9% in 1970s to 17.9% in 2000s with the expanded loss areas. Rice flowering stage concentrates in the period of high temperature, which is the main cause for rice yield loss. Heat injury indexes and affected areas of high temperature reach their maxima respectively in 1960s and 2000s. An abrupt change occurs in 1971 for high temperature covered proportion. Since then high temperature covered proportion increases continuously and gets to 63.6% in 2000s. High temperature events concentrates in the period of 11 July and 15 August every year with 〖JP2〗proportions of more than 20%. With considering comprehensively the end dates of stable temperature above 20℃, concentrated period of high temperature, climate change and the successful experience of avoiding high temperature in the southeastern part of Yangtze Huaihe River Valley, we suggest that late maturing rice be promoted and its sowing date be delayed to May. These measures can ensure the flowering stage to occur in the period between late August and early September, avoiding the high temperature damages.〖JP〗
2013, 39(6):782-788.
DOI: 10.7519/j.issn.1000-0526.2013.06.015
Abstract:
Weather and soil conditions affect the operation quality and production efficiency of maize soil preparation, sowing and harvesting, as well as maize growth, yields and costs. The agricultural meteorological factors in the Northeast of China are soil moisture, soil thawing depth, temperature, precipitation and wind. According to the effect of weather and soil conditions on maize soil preparation, sowing and harvesting, this paper developed the meteorological suitability functions of the farm work by using fuzzy membership function, and defined the agricultural meteorological index, then the comprehensive meteorological suitability evaluation model was constructed by using the weighted sum method. The result of examination showed that the model and index are workable and can be used in the meteorological suitability evaluations on the farm work. On the basis of temperature and precipitation forecasts and other meteorological elements, the model can also be used in the forecast of meteorological suitability of the farm work.
Weather and soil conditions affect the operation quality and production efficiency of maize soil preparation, sowing and harvesting, as well as maize growth, yields and costs. The agricultural meteorological factors in the Northeast of China are soil moisture, soil thawing depth, temperature, precipitation and wind. According to the effect of weather and soil conditions on maize soil preparation, sowing and harvesting, this paper developed the meteorological suitability functions of the farm work by using fuzzy membership function, and defined the agricultural meteorological index, then the comprehensive meteorological suitability evaluation model was constructed by using the weighted sum method. The result of examination showed that the model and index are workable and can be used in the meteorological suitability evaluations on the farm work. On the basis of temperature and precipitation forecasts and other meteorological elements, the model can also be used in the forecast of meteorological suitability of the farm work.
2013, 39(6):789-793.
DOI: 10.7519/j.issn.1000-0526.2013.06.016
Abstract:
Based on the animal experiments, the influence mechanism of cold wave on hypertension was discussed in this paper. The cold wave models were established by statistical downscaling method, and the cold wave processes were simulated in the meteorological environment simulation chamber (TEM1880). At the same time, the SHR and Wister rats were put into simulation chambers divided into low temperature group and return temperature group and subjected to the progresses of cold wave respectively. The following indexes were measured on experimental rats in batches in accordance with the process of cold wave process that occurred in different times: systolic blood pressure (SBP), heart rate (HR), weight, epinephrine (EPI), angiotensinⅡ (AngⅡ) and whole blood viscosity (WBV). The results are as follows: compared with the control group, SBP, HR, EPI, AngⅡ and WBV of the experimental group subjected to cold wave are higher. Except HR, the other physiological indexes of SHR group are more sensitive than the ones of Wister group. The indexes of low temperature group are higher than return temperature group except EPI and WBV. Cold waves can elevate HR, EPI, AngⅡ and WBV which lead to a higher SBP so that it has a great impact on hypertension.
Based on the animal experiments, the influence mechanism of cold wave on hypertension was discussed in this paper. The cold wave models were established by statistical downscaling method, and the cold wave processes were simulated in the meteorological environment simulation chamber (TEM1880). At the same time, the SHR and Wister rats were put into simulation chambers divided into low temperature group and return temperature group and subjected to the progresses of cold wave respectively. The following indexes were measured on experimental rats in batches in accordance with the process of cold wave process that occurred in different times: systolic blood pressure (SBP), heart rate (HR), weight, epinephrine (EPI), angiotensinⅡ (AngⅡ) and whole blood viscosity (WBV). The results are as follows: compared with the control group, SBP, HR, EPI, AngⅡ and WBV of the experimental group subjected to cold wave are higher. Except HR, the other physiological indexes of SHR group are more sensitive than the ones of Wister group. The indexes of low temperature group are higher than return temperature group except EPI and WBV. Cold waves can elevate HR, EPI, AngⅡ and WBV which lead to a higher SBP so that it has a great impact on hypertension.
2013, 39(6):794-800.
DOI: 10.7519/j.issn.1000-0526.2013.06.017
Abstract:
The following are the main characteristics of the general circulation of atmosphere in March 2013. The polar vortex in the Northern Hemisphere lies further south than normal years. It has two centers, located over Europe and Northern Asia, respectively. There are four waves around the earth in middle high latitudes. The south branch trough is slightly weaker than the normal, and the Northwestern Pacific subtropical high is slightly stronger. The average precipitation around 〖JP2〗China is 26.1 mm, 11.5% less than the normal. The monthly mean temperature is 6.3℃, 2.2℃ higher than the normal, which is the 2nd highest value since 1961. There are 5 cold surge processes, during which the largest scale dust weather occurs from 8th to 11th March. Five major rainfall processes are seen in this month, and from 19th to 20th, Jiangnan and South China region experience the largest scale severe convective weather so far in this year.〖JP〗
The following are the main characteristics of the general circulation of atmosphere in March 2013. The polar vortex in the Northern Hemisphere lies further south than normal years. It has two centers, located over Europe and Northern Asia, respectively. There are four waves around the earth in middle high latitudes. The south branch trough is slightly weaker than the normal, and the Northwestern Pacific subtropical high is slightly stronger. The average precipitation around 〖JP2〗China is 26.1 mm, 11.5% less than the normal. The monthly mean temperature is 6.3℃, 2.2℃ higher than the normal, which is the 2nd highest value since 1961. There are 5 cold surge processes, during which the largest scale dust weather occurs from 8th to 11th March. Five major rainfall processes are seen in this month, and from 19th to 20th, Jiangnan and South China region experience the largest scale severe convective weather so far in this year.〖JP〗
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ISSN:1000-0526 CN:11-2282/P