ISSN 1000-0526
CN 11-2282/P
CN 11-2282/P
Volume 37,Issue 1,2011 Table of Contents
2011, 37(1):1-13.
DOI: 10.7519/j.issn.1000-0526.2011.1.001
Abstract:
The variation and improvement of meteorological forecast method are reviewed in a simple and explicit way, based on historical records on meteorological phenomena and a brief development history and status of atmospheric sciences. The present operational prediction skill and main advancements of the relevant researches are summarized as well. Uncertainties in the result of meteorological forecast are discussed from the perspective of numerical forecasting. Moreover, the way for public to understand and utilize ensemble forecast products is also presented by explaining the principles of ensemble forecast in detail.
The variation and improvement of meteorological forecast method are reviewed in a simple and explicit way, based on historical records on meteorological phenomena and a brief development history and status of atmospheric sciences. The present operational prediction skill and main advancements of the relevant researches are summarized as well. Uncertainties in the result of meteorological forecast are discussed from the perspective of numerical forecasting. Moreover, the way for public to understand and utilize ensemble forecast products is also presented by explaining the principles of ensemble forecast in detail.
2011, 37(1):14-20.
DOI: 10.7519/j.issn.1000-0526.2011.1.002
Abstract:
Numerical weather prediction (NWP) techniques and ability are developing constantly and the ensemble prediction is a very important part of NWP. An appropriate interpretation process is needed to convey the mass information provided by ensemble prediction to users, thus the interpretation and application of ensemble prediction products are important to realize their utilitarian value. The 00:00 UTC surface temperature at Wuhan Station is selected as the predictand, and its historical observation data as well as NCEP 120 h ensemble prediction data from TIGGE data during January 2008 are used to establish BPO model for each NCEP ensemble member based on a statistical process technique, which is the Bayesian Processor of Output (BPO). The member Bayesian probabilistic forecast is obtained and the performance difference among members is studied. The member Bayesian probabilistic forecasts are integrated into an integrated Bayesian probabilistic forecast which quantifies the ensemble prediction uncertainty according to the weights depending on member Informativeness Scores. The analysis of initial experiment results shows that the performances of ensemble members are different from each other, so are the member Bayesian probabilistic forecast. This new interpretation scheme based on BPO can quantify the forecasting uncertainty of an ensemble prediction, and then a Bayesian integrated probabilistic forecast can be obtained.
Numerical weather prediction (NWP) techniques and ability are developing constantly and the ensemble prediction is a very important part of NWP. An appropriate interpretation process is needed to convey the mass information provided by ensemble prediction to users, thus the interpretation and application of ensemble prediction products are important to realize their utilitarian value. The 00:00 UTC surface temperature at Wuhan Station is selected as the predictand, and its historical observation data as well as NCEP 120 h ensemble prediction data from TIGGE data during January 2008 are used to establish BPO model for each NCEP ensemble member based on a statistical process technique, which is the Bayesian Processor of Output (BPO). The member Bayesian probabilistic forecast is obtained and the performance difference among members is studied. The member Bayesian probabilistic forecasts are integrated into an integrated Bayesian probabilistic forecast which quantifies the ensemble prediction uncertainty according to the weights depending on member Informativeness Scores. The analysis of initial experiment results shows that the performances of ensemble members are different from each other, so are the member Bayesian probabilistic forecast. This new interpretation scheme based on BPO can quantify the forecasting uncertainty of an ensemble prediction, and then a Bayesian integrated probabilistic forecast can be obtained.
2011, 37(1):21-30.
DOI: 10.7519/j.issn.1000-0526.2011.1.003
Abstract:
The characteristics of summer precipitation diurnal variations in three reanalysis datasets (NCEP，ERA40 and JRA25) over China were analyzed by comparing with those in station rain gauge observations. Results show that the summer precipitation diurnal variations in the three reanalysis products all present obvious deficiencies. Analyzing the percentages of daytime and nighttime rainfall show that the percentage of the daytime (08-20 BT) rainfall to the whole day rainfall is larger than that of nocturnal (20-08 BT) rainfall〖HJ〗 in all reanalysis datasets over the most region of China while comparing with the station gauge data. Further analyses demonstrate that the percentage of the morning (08-14 BT) rainfall is the smallest in the station gauge data, but in NCEP and ERA40 products it is obviously more than that in the station observations. The proportion of the daytime rainfall to nocturnal rainfall in NCEP products over Southwest China is almost reverse to that of station rain gauge data. Generally, the diurnal variations of precipitation amount and frequency in JRA25 products and precipitation intensity in NCEP products are closest to the corresponding components in station data, but the nocturnal rainfall over Southwest China is only partly reproduced by ERA40 products.
The characteristics of summer precipitation diurnal variations in three reanalysis datasets (NCEP，ERA40 and JRA25) over China were analyzed by comparing with those in station rain gauge observations. Results show that the summer precipitation diurnal variations in the three reanalysis products all present obvious deficiencies. Analyzing the percentages of daytime and nighttime rainfall show that the percentage of the daytime (08-20 BT) rainfall to the whole day rainfall is larger than that of nocturnal (20-08 BT) rainfall〖HJ〗 in all reanalysis datasets over the most region of China while comparing with the station gauge data. Further analyses demonstrate that the percentage of the morning (08-14 BT) rainfall is the smallest in the station gauge data, but in NCEP and ERA40 products it is obviously more than that in the station observations. The proportion of the daytime rainfall to nocturnal rainfall in NCEP products over Southwest China is almost reverse to that of station rain gauge data. Generally, the diurnal variations of precipitation amount and frequency in JRA25 products and precipitation intensity in NCEP products are closest to the corresponding components in station data, but the nocturnal rainfall over Southwest China is only partly reproduced by ERA40 products.
2011, 37(1):31-38.
DOI: 10.7519/j.issn.1000-0526.2011.1.004
Abstract:
In view of existence of model systematic error, a study of biascorrection has been done to estimate and reduce systematic error. Onemoment biascorrection has been introduced in this paper. The merit of this method is that quantity of samples needed is smaller, thus estimation and biascorrection could be carried out quickly and economically. Onemoment biascorrection towards T213 global ensemble forecast of 500 hPa height, 850 hPa temperature and 2m temperature has been done. Verification towards raw forecast and biascorrected forecast shows that ensemble member homogeneity and cold bias have been improved, and ensemble mean RMSE and ACC also have been improved, especially bigger systematic error of 2m temperature forecast has been improved obviously.
In view of existence of model systematic error, a study of biascorrection has been done to estimate and reduce systematic error. Onemoment biascorrection has been introduced in this paper. The merit of this method is that quantity of samples needed is smaller, thus estimation and biascorrection could be carried out quickly and economically. Onemoment biascorrection towards T213 global ensemble forecast of 500 hPa height, 850 hPa temperature and 2m temperature has been done. Verification towards raw forecast and biascorrected forecast shows that ensemble member homogeneity and cold bias have been improved, and ensemble mean RMSE and ACC also have been improved, especially bigger systematic error of 2m temperature forecast has been improved obviously.
2011, 37(1):39-47.
DOI: 10.7519/j.issn.1000-0526.2011.1.005
Abstract:
Using the WRF mesoscale numerical model and WRF threedimensional variational data assimilation (3DVar), a combined scheme of cumulus process, microphysical processes and radiation processes for local area is selected based on comparison experiments and the NCEP/GFS data are chosen as background field of the model; the background error covariance over the region centered in Yunnan is computed statistically and replaces the primary background error covariance in 3DVar; At the same time, considering the elevation difference between model bottom layer and surface observing station, the topography in surface data is corrected. Through the above study the localized WRF mesoscale numerical forecast system has been established, which could be better to characterize the dynamic and thermodynamic conditions in the local underlying surface, and has a significant improvement in forecast capability.
Using the WRF mesoscale numerical model and WRF threedimensional variational data assimilation (3DVar), a combined scheme of cumulus process, microphysical processes and radiation processes for local area is selected based on comparison experiments and the NCEP/GFS data are chosen as background field of the model; the background error covariance over the region centered in Yunnan is computed statistically and replaces the primary background error covariance in 3DVar; At the same time, considering the elevation difference between model bottom layer and surface observing station, the topography in surface data is corrected. Through the above study the localized WRF mesoscale numerical forecast system has been established, which could be better to characterize the dynamic and thermodynamic conditions in the local underlying surface, and has a significant improvement in forecast capability.
2011, 37(1):48-58.
DOI: 10.7519/j.issn.1000-0526.2011.1.006
Abstract:
By using conventional observation data, obit meteorological satellite cloud pictures, Doppler weather radar and NCEP data the paper adopted forecast method (ingredients method) based on component to analyze severe convective weather of thunderstorm and gale that happened in the afternoon of June 3, 2008 in east central Henan. Combined with sounding, vapor cloud map and Doppler weather radar echo maps that based on the distribution of temperature, moisture and wind on the 500 hPa, 700 hPa, 850 hPa and surface map in the morning of June 3, 2008 the paper analyzed several severe convective weather components of stratification stability, water vapor, lifting triggered, vertical wind shear and tropospheric dry layer. The results show that Henan convective weather area was in the environment of stronger conditional instability, intense deep layer (from surface to 500 hPa) vertical wind shear and obvious high dry stratospheric layer. The environment was in favor of producing and developing highly organized super cell that leading to thunderstorm, strong wind and hail weather. The combined action of surface front, mesoscale convergence line and subsynoptic scale cold vortex accompanied with positive vorticity advection resulted in rising airflow which made thunderstorm produce first in south central Shanxi. The thunderstorm moved towards southeast from the Taihang Mountain to Henan and developed vigorously in the advantageous environment. Full of using the main thinking of ingredients method the shorttime forecasting of the severe convective process can forecast correctly ahead of several hours which is supported by current observation conditions together with the forecaster’s experiences.
By using conventional observation data, obit meteorological satellite cloud pictures, Doppler weather radar and NCEP data the paper adopted forecast method (ingredients method) based on component to analyze severe convective weather of thunderstorm and gale that happened in the afternoon of June 3, 2008 in east central Henan. Combined with sounding, vapor cloud map and Doppler weather radar echo maps that based on the distribution of temperature, moisture and wind on the 500 hPa, 700 hPa, 850 hPa and surface map in the morning of June 3, 2008 the paper analyzed several severe convective weather components of stratification stability, water vapor, lifting triggered, vertical wind shear and tropospheric dry layer. The results show that Henan convective weather area was in the environment of stronger conditional instability, intense deep layer (from surface to 500 hPa) vertical wind shear and obvious high dry stratospheric layer. The environment was in favor of producing and developing highly organized super cell that leading to thunderstorm, strong wind and hail weather. The combined action of surface front, mesoscale convergence line and subsynoptic scale cold vortex accompanied with positive vorticity advection resulted in rising airflow which made thunderstorm produce first in south central Shanxi. The thunderstorm moved towards southeast from the Taihang Mountain to Henan and developed vigorously in the advantageous environment. Full of using the main thinking of ingredients method the shorttime forecasting of the severe convective process can forecast correctly ahead of several hours which is supported by current observation conditions together with the forecaster’s experiences.
2011, 37(1):59-65.
DOI: 10.7519/j.issn.1000-0526.2011.1.007
Abstract:
Based on the observation data and ECMWF analysis data, the 45 samples of thunderstorm gales occurring during 2006 to 2008 in Guangxi have been statistically analyzed and the influence model is analyzed by using the synoptic meteorology method. The physical significance of stability index and dynamic parameters, and the environment characteristics of the thunderstorm gale occurring area have been discussed in terms of the thunderstorm gale occurrence conditions. The results show: (1) There are 4 weather model types that can cause thunderstorm gales in Guangxi, including the type of plateau trough, the type of typhoon trough, the type of western subtropical high, and the type of North China trough; (2) Thunderstorm gale occurs mostly in July and August especially in the afternoon, whose peak appears at about 16 p.m. (3) The terrain is important for local thunderstorm gale occurring; (4) Before the thunderstorm gale occurring, the unstable energy in the atmospheric stratification congregates in most areas of Guangxi, the moisture convergence in lower layers and the relative humidity are powerful. The vertical ascending movement and the positive vorticity center of the plateau trough type, the western subtropical high type and the North China trough type are located in northern Guangxi, while the type of typhoon trough is located in southeastern Guangxi; (5) The atmospheric stratification is more unstable in the thunderstorm gale occurring, moisture convergence in lower layers and the cyclonic convergence in the middle and lower layers are also stronger.
Based on the observation data and ECMWF analysis data, the 45 samples of thunderstorm gales occurring during 2006 to 2008 in Guangxi have been statistically analyzed and the influence model is analyzed by using the synoptic meteorology method. The physical significance of stability index and dynamic parameters, and the environment characteristics of the thunderstorm gale occurring area have been discussed in terms of the thunderstorm gale occurrence conditions. The results show: (1) There are 4 weather model types that can cause thunderstorm gales in Guangxi, including the type of plateau trough, the type of typhoon trough, the type of western subtropical high, and the type of North China trough; (2) Thunderstorm gale occurs mostly in July and August especially in the afternoon, whose peak appears at about 16 p.m. (3) The terrain is important for local thunderstorm gale occurring; (4) Before the thunderstorm gale occurring, the unstable energy in the atmospheric stratification congregates in most areas of Guangxi, the moisture convergence in lower layers and the relative humidity are powerful. The vertical ascending movement and the positive vorticity center of the plateau trough type, the western subtropical high type and the North China trough type are located in northern Guangxi, while the type of typhoon trough is located in southeastern Guangxi; (5) The atmospheric stratification is more unstable in the thunderstorm gale occurring, moisture convergence in lower layers and the cyclonic convergence in the middle and lower layers are also stronger.
2011, 37(1):66-74.
DOI: 10.7519/j.issn.1000-0526.2011.1.008
Abstract:
The conventional observation data, climatic data, NCEP 2.5°×2.5° reanalysis data and automatic observation data were employed to analyze the 18 severe freezing rain events over the past 50 years in Jiangxi Province. The results show that (1) the favorable influencing systems to the severe freezing rain were cold high, blocking high, subtropical high, trough in lower latitudes, shear line at 850 hPa, surface convergence line (quasistationary front), temperature frontal zone, and jet stream and moist tongue at 700 hPa, and revealed the significant weather system patterns; (2) under favorable weather situations, severe freezing rain process presented characteristics of pentad (dekad) antecedent temperature increase. When the antecedent average maximum temperature and antecedent average temperature surpassed or approached to those in the same time of the past, the severe freezing rain event would occur very likely; (3) temperature inversions appeared between 850-700 hPa during the 18 severe freezing rain events, with 4-5 ℃ average temperature differences, upto a maximum of 10 ℃, and the surface air temperatures were lower than or close to 0 ℃; (4) there were three temperature difference centers between 700-850 hPa, meaning that there were warm and moist currents at 700 hPa and about 89% of the freezing rain events were related to these currents.
The conventional observation data, climatic data, NCEP 2.5°×2.5° reanalysis data and automatic observation data were employed to analyze the 18 severe freezing rain events over the past 50 years in Jiangxi Province. The results show that (1) the favorable influencing systems to the severe freezing rain were cold high, blocking high, subtropical high, trough in lower latitudes, shear line at 850 hPa, surface convergence line (quasistationary front), temperature frontal zone, and jet stream and moist tongue at 700 hPa, and revealed the significant weather system patterns; (2) under favorable weather situations, severe freezing rain process presented characteristics of pentad (dekad) antecedent temperature increase. When the antecedent average maximum temperature and antecedent average temperature surpassed or approached to those in the same time of the past, the severe freezing rain event would occur very likely; (3) temperature inversions appeared between 850-700 hPa during the 18 severe freezing rain events, with 4-5 ℃ average temperature differences, upto a maximum of 10 ℃, and the surface air temperatures were lower than or close to 0 ℃; (4) there were three temperature difference centers between 700-850 hPa, meaning that there were warm and moist currents at 700 hPa and about 89% of the freezing rain events were related to these currents.
2011, 37(1):75-84.
DOI: 10.7519/j.issn.1000-0526.2011.1.009
Abstract:
Based on the nearlytwelveyear hourly geostationary satellite multichannel (IR1,IR2 and water vapor channels) digital infrared image dataset, the distribution and spatiotemporal variations of deep convective clouds over China and its vicinity during the warm season (March-October) from 1996 to 2008 (lacking 2004 data, part data missing) are analyzed, and comparative analysis is conducted on the distribution of thunderstorm days and the density distribution of lightning obtained from loworbit satellites. In this paper, TBir1≤-52 ℃ (Infrared 1channel brightness temperature), TBir1-TBir2＜3 K (Infrared 2channel brightness temperature), and TBir1-TBwv≤8 K (water vapor channel brightness temperature) are used to identify the deep convetive clouds. The results show that: There are four active regions of deep convective clouds during the warm season, i.e., the middleeast of QinghaiTibetan Plateau, South China and Northeast of YunnanGuizhou Plateau, Xinjiang Ili River Valley and its surrounding area, and the most parts of ZhejiangFujianJiangxi regions; Overall, deep convective clouds over summer (June-August) are the most active; in spring (March-May) followed by; the autumn (September-October) are the least; The geographical distribution of deep convective clouds in different seasons is significantly different; The feature of diurnal variations of deep convective clouds has a significantly difference in different seasons and regions; Autumn diurnal variation is the least significant; As spring sunset time is earlier than the summer, in general, the diurnal variation of deep convective clouds in the spring is earlier than the summer peak hours; Deep convective clouds in the middleeast of QinghaiTibetan Plateau, Guangdong and Guangxi hills and the Zhejiang and Fujian hilly regions are of the single peak diurnal variation; At Sichuan Basin, the deep convective clouds often have nocturnal occurrence; In spring and summer, the diurnal variations of deep convective clouds are of bimodal type in Jianghuai region, which may be related to the region more closely related to MαCS; Thermal convections in the eastern part of QinghaiTibetan Plateau are active; In Guangdong and Guangxi hills, Sichuan Basin, and Jianghuai region it is not only very active heat convection, but other weather systems (such as typhoons, Meiyu front, etc.) to trigger and maintain the convection are also very active in summer.
Based on the nearlytwelveyear hourly geostationary satellite multichannel (IR1,IR2 and water vapor channels) digital infrared image dataset, the distribution and spatiotemporal variations of deep convective clouds over China and its vicinity during the warm season (March-October) from 1996 to 2008 (lacking 2004 data, part data missing) are analyzed, and comparative analysis is conducted on the distribution of thunderstorm days and the density distribution of lightning obtained from loworbit satellites. In this paper, TBir1≤-52 ℃ (Infrared 1channel brightness temperature), TBir1-TBir2＜3 K (Infrared 2channel brightness temperature), and TBir1-TBwv≤8 K (water vapor channel brightness temperature) are used to identify the deep convetive clouds. The results show that: There are four active regions of deep convective clouds during the warm season, i.e., the middleeast of QinghaiTibetan Plateau, South China and Northeast of YunnanGuizhou Plateau, Xinjiang Ili River Valley and its surrounding area, and the most parts of ZhejiangFujianJiangxi regions; Overall, deep convective clouds over summer (June-August) are the most active; in spring (March-May) followed by; the autumn (September-October) are the least; The geographical distribution of deep convective clouds in different seasons is significantly different; The feature of diurnal variations of deep convective clouds has a significantly difference in different seasons and regions; Autumn diurnal variation is the least significant; As spring sunset time is earlier than the summer, in general, the diurnal variation of deep convective clouds in the spring is earlier than the summer peak hours; Deep convective clouds in the middleeast of QinghaiTibetan Plateau, Guangdong and Guangxi hills and the Zhejiang and Fujian hilly regions are of the single peak diurnal variation; At Sichuan Basin, the deep convective clouds often have nocturnal occurrence; In spring and summer, the diurnal variations of deep convective clouds are of bimodal type in Jianghuai region, which may be related to the region more closely related to MαCS; Thermal convections in the eastern part of QinghaiTibetan Plateau are active; In Guangdong and Guangxi hills, Sichuan Basin, and Jianghuai region it is not only very active heat convection, but other weather systems (such as typhoons, Meiyu front, etc.) to trigger and maintain the convection are also very active in summer.
WANG Mian
,
LI Wei
,
CHEN Yongqing
,
ZHAO Peitao
,
GUO Qiyun
,
ZHANG Yu
,
HU Heng
,
GUO Yuehong
,
LIU Ling
2011, 37(1):85-91.
DOI: 10.7519/j.issn.1000-0526.2011.1.010
Abstract:
Based on the analysis of wind measurement of operational Lband radar and radiosonde sounding system, it is proposed an improved smoothing algorithm of upperair wind. Firstly, the differences of two smoothing algorithms for upperair winds, which are the operational minute wind and the moving average wind, are compared. Then they are also compared with GPS RS92 wind. The comparative analysis and the results of statistical processing are given, especially are also given several segmented statistical analysis of low elevation, longdistance, low wind and subperiod wind. The last one is regulated by operational rules that use different time intervals to calculate smoothing wind in three periods of an upperair sounding process, i. e., the first 21 minutes, in 22-42 minutes and 43 minutes later. The results show that the vector wind using the most appropriate moving average window has a better consistency with GPS RS92 wind and a small dynamic error. It is suggested that the moving average method of 1 min window or 30 sec window at first 20 minutes and then 1 min window should be used for the future algorithm improvement of upperair wind measured by operational Lband radar and radiosonde sounding system.
Based on the analysis of wind measurement of operational Lband radar and radiosonde sounding system, it is proposed an improved smoothing algorithm of upperair wind. Firstly, the differences of two smoothing algorithms for upperair winds, which are the operational minute wind and the moving average wind, are compared. Then they are also compared with GPS RS92 wind. The comparative analysis and the results of statistical processing are given, especially are also given several segmented statistical analysis of low elevation, longdistance, low wind and subperiod wind. The last one is regulated by operational rules that use different time intervals to calculate smoothing wind in three periods of an upperair sounding process, i. e., the first 21 minutes, in 22-42 minutes and 43 minutes later. The results show that the vector wind using the most appropriate moving average window has a better consistency with GPS RS92 wind and a small dynamic error. It is suggested that the moving average method of 1 min window or 30 sec window at first 20 minutes and then 1 min window should be used for the future algorithm improvement of upperair wind measured by operational Lband radar and radiosonde sounding system.
2011, 37(1):92-98.
DOI: 10.7519/j.issn.1000-0526.2011.1.011
Abstract:
Based on the precipitation data at 13 stations in Tianjin from 1986 to 2008， the precipitation characteristics and the weather modification influence are analyzed in this article. The results show that： the spatial distribution of precipitation is uneven， the difference is small in westeast direction， but large in northsouth direction. The rainfall presents a descending trend from north to south， and the isolines are dense in north while sparse in south. The rate of decreasing rainfall slows down from north to south. The difference is obvious in different season， the rainy days and precipitation amount are mainly concentrated in summer, the precipitation is less in spring and autumn while is least in winter. The weather modification does not change the correlation coefficient of rainfall in Tianjin， and it also has little influence on the spatial distribution. These are related to the characteristics of weather modification in Tianjin. The weather modification operations have influence on probability distribution of the raintype， but the influence is small. After comparing the probability distribution of different raintype in 1986-2001 and 2002-2008， we can find that the probability of lightrain days is relatively low while the probability of moderaterain days is higher after the weather modification operations， but these differences are not significant.
Based on the precipitation data at 13 stations in Tianjin from 1986 to 2008， the precipitation characteristics and the weather modification influence are analyzed in this article. The results show that： the spatial distribution of precipitation is uneven， the difference is small in westeast direction， but large in northsouth direction. The rainfall presents a descending trend from north to south， and the isolines are dense in north while sparse in south. The rate of decreasing rainfall slows down from north to south. The difference is obvious in different season， the rainy days and precipitation amount are mainly concentrated in summer, the precipitation is less in spring and autumn while is least in winter. The weather modification does not change the correlation coefficient of rainfall in Tianjin， and it also has little influence on the spatial distribution. These are related to the characteristics of weather modification in Tianjin. The weather modification operations have influence on probability distribution of the raintype， but the influence is small. After comparing the probability distribution of different raintype in 1986-2001 and 2002-2008， we can find that the probability of lightrain days is relatively low while the probability of moderaterain days is higher after the weather modification operations， but these differences are not significant.
2011, 37(1):99-102.
DOI: 10.7519/j.issn.1000-0526.2011.1.012
Abstract:
By using the model of Xie and the NOAA OLR data in NSMC, the monthly precipitation amount in 1991-2008 was calculated in the area of 10°-60°N, 75°-150°E land with data resolution of 0.5°×0.5° latitudelongitude. Therefore we know that monthly precipitation amount could be calculated out by using monthly OLR anomaly.By comparing the model monthly precipitation with gauge precipitation from NCEP in 1991-2008,we obtained the following results:in winter the relative error in China was 49.14% and the absolute error was 7.97 mm; in spring they were 37.60% and 14.97 mm; in summer they were 27.37% and 31.6 mm; and in autumn they were 37.99% and 16.95 mm. The results were not very good.The main errors were caused by stratus cloud precipitation and continuous cloud cover days without precipitation.By analyzing cloud classification products of FY2C during 2006-2008,we have learned that in winter stratus clouds are common in southern China, and the monthly OLR anomaly there is usually high, and the estimation of precipitation amount obtained from global coefficients A and B is lower than that of ground observation. Therefore, the better way to solve the problem of precipitation underestimation may be in the choice of new coefficients A and B for different areas of China in different seasons.
By using the model of Xie and the NOAA OLR data in NSMC, the monthly precipitation amount in 1991-2008 was calculated in the area of 10°-60°N, 75°-150°E land with data resolution of 0.5°×0.5° latitudelongitude. Therefore we know that monthly precipitation amount could be calculated out by using monthly OLR anomaly.By comparing the model monthly precipitation with gauge precipitation from NCEP in 1991-2008,we obtained the following results:in winter the relative error in China was 49.14% and the absolute error was 7.97 mm; in spring they were 37.60% and 14.97 mm; in summer they were 27.37% and 31.6 mm; and in autumn they were 37.99% and 16.95 mm. The results were not very good.The main errors were caused by stratus cloud precipitation and continuous cloud cover days without precipitation.By analyzing cloud classification products of FY2C during 2006-2008,we have learned that in winter stratus clouds are common in southern China, and the monthly OLR anomaly there is usually high, and the estimation of precipitation amount obtained from global coefficients A and B is lower than that of ground observation. Therefore, the better way to solve the problem of precipitation underestimation may be in the choice of new coefficients A and B for different areas of China in different seasons.
2011, 37(1):103-106.
DOI: 10.7519/j.issn.1000-0526.2011.1.013
Abstract:
In order to study the microscopic features of Beijing’s temperature data, an asymmetrical CARCH model is set up for Beijing’s daily average temperature data, daily minimum temperature data and daily maximum temperature data during 1952-2006. The results show that Beijing’s temperature has a rising trend overall. However, daily maximum temperature and daily average temperature will rise in a limited range, and daily minimum temperature will rise in a larger extent; the changing ranges of daily maximum temperature and daily average temperature will be in a limited extent, but the changing range of daily minimum temperature will be in a larger scope.Temperature warming makes sense to the rising trend on all scopes, but cooling only makes sense to the daily minimum temperature.
In order to study the microscopic features of Beijing’s temperature data, an asymmetrical CARCH model is set up for Beijing’s daily average temperature data, daily minimum temperature data and daily maximum temperature data during 1952-2006. The results show that Beijing’s temperature has a rising trend overall. However, daily maximum temperature and daily average temperature will rise in a limited range, and daily minimum temperature will rise in a larger extent; the changing ranges of daily maximum temperature and daily average temperature will be in a limited extent, but the changing range of daily minimum temperature will be in a larger scope.Temperature warming makes sense to the rising trend on all scopes, but cooling only makes sense to the daily minimum temperature.
2011, 37(1):107-111.
DOI: 10.7519/j.issn.1000-0526.2011.1.014
Abstract:
An 8radar network located at Hefei, Fuyang, Bengbu, Huangshan, Nanjing, Xuzhou, Zhumadian and Jiujiang is used to establish the regional mosaic of Anhui Province. By using GIS and geographical space conversion, the radar echo images at heights of 2-8 km are obtained. According to the rocket trajectory equations, the rocket elevation, azimuth and the ammunition amount used are calculated, and the technique parameters of weather modification are precisely analyzed.
An 8radar network located at Hefei, Fuyang, Bengbu, Huangshan, Nanjing, Xuzhou, Zhumadian and Jiujiang is used to establish the regional mosaic of Anhui Province. By using GIS and geographical space conversion, the radar echo images at heights of 2-8 km are obtained. According to the rocket trajectory equations, the rocket elevation, azimuth and the ammunition amount used are calculated, and the technique parameters of weather modification are precisely analyzed.
2011, 37(1):112-115.
DOI: 10.7519/j.issn.1000-0526.2011.1.015
Abstract:
Many climate feasibility demonstration studies of major energy projects have to involve the designed parameters of dry or wet bulb temperature, but since 2001, according to the request of the China Meteorological Administration, observation stations of Anhui begin to change the observation apparatus to humidity sensors. The new apparatus does not observe wetbulb temperature. To solve this problem about data shortage, we have designed a looping iterative scheme to compute wetbulb temperature and compared the calculated results with data from humidity table. The comparison results show that the errors less than 0.1 ℃ are within 92.84 percent, the errors less than 0.2 ℃ are within 99.80 percent. The method is reliable and is more convenient and fast comparing with the traditional method. Thus it is suitable for becoming the solution of complement wet bulb data series, the scheme meets the requirement of climate feasibility demonstration work and can be widely used in power station designing, also it can be a helpful complementarity for ground historical data checking programs.
Many climate feasibility demonstration studies of major energy projects have to involve the designed parameters of dry or wet bulb temperature, but since 2001, according to the request of the China Meteorological Administration, observation stations of Anhui begin to change the observation apparatus to humidity sensors. The new apparatus does not observe wetbulb temperature. To solve this problem about data shortage, we have designed a looping iterative scheme to compute wetbulb temperature and compared the calculated results with data from humidity table. The comparison results show that the errors less than 0.1 ℃ are within 92.84 percent, the errors less than 0.2 ℃ are within 99.80 percent. The method is reliable and is more convenient and fast comparing with the traditional method. Thus it is suitable for becoming the solution of complement wet bulb data series, the scheme meets the requirement of climate feasibility demonstration work and can be widely used in power station designing, also it can be a helpful complementarity for ground historical data checking programs.
2011, 37(1):116-121.
DOI: 10.7519/j.issn.1000-0526.2011.1.016
Abstract:
By analyzing the impact of precipitation on the crystallization of brine, a conclusion is obtained that the precipitation leading to brine desalination, salt dissolving and pool damage is progressively increased. The precipitation leading to unfreezing salts and the pool damage is much larger than that of plastic film cover. Therefore, the decision makers can consider the plastic film cover precipitation only. By using equivalence principia, the major factors which influence decisionmaking of plastic film cover to precipitation are analyzed. Results show that the influences of plastic film cover cost, rime cistern acreage and changes of salt prices are less, but the plastic film cover precipitation has a positive correlation to the plastic film cover working time, rainfall duration and daily evaporation. When the operating time is constant, the plastic film cover of precipitation is decided by the rainfall duration and daily evaporation. According to the crystal pool of plastic film cover, two projects for decisionmaking of plastic film cover to precipitation are worked out.
By analyzing the impact of precipitation on the crystallization of brine, a conclusion is obtained that the precipitation leading to brine desalination, salt dissolving and pool damage is progressively increased. The precipitation leading to unfreezing salts and the pool damage is much larger than that of plastic film cover. Therefore, the decision makers can consider the plastic film cover precipitation only. By using equivalence principia, the major factors which influence decisionmaking of plastic film cover to precipitation are analyzed. Results show that the influences of plastic film cover cost, rime cistern acreage and changes of salt prices are less, but the plastic film cover precipitation has a positive correlation to the plastic film cover working time, rainfall duration and daily evaporation. When the operating time is constant, the plastic film cover of precipitation is decided by the rainfall duration and daily evaporation. According to the crystal pool of plastic film cover, two projects for decisionmaking of plastic film cover to precipitation are worked out.
2011, 37(1):122-128.
DOI: 10.7519/j.issn.1000-0526.2011.1.017
Abstract:
The following are the main characteristics of the general atmospheric circulation in October 2010. There were two polar vortex centers in the Northern Hemisphere. The circulation presents a fourwave pattern in middlehigh latitudes, in which the strong Ural ridge corresponds to a large 40 gpm positive anomaly area. Strength of the Western Pacific subtropical high is weaker than normal years. The monthly mean temperature (10.1 ℃) is 0.5 ℃ higher than the same period of normal years, and the mean precipitation (42.6 mm) is 15.1% above normal. The major weather events include: 8 precipitation processes occuring, in which a rare heavy rain has struck on Hainan in the first and middle dekad of October; two tropical cyclones generated, with one super typhoon (Chaba, numbered 1013) landed in Fujian; in the last dekad of October, strong cold air outbreak across most areas of China; heavy fog aroused in the central and eastern China.
The following are the main characteristics of the general atmospheric circulation in October 2010. There were two polar vortex centers in the Northern Hemisphere. The circulation presents a fourwave pattern in middlehigh latitudes, in which the strong Ural ridge corresponds to a large 40 gpm positive anomaly area. Strength of the Western Pacific subtropical high is weaker than normal years. The monthly mean temperature (10.1 ℃) is 0.5 ℃ higher than the same period of normal years, and the mean precipitation (42.6 mm) is 15.1% above normal. The major weather events include: 8 precipitation processes occuring, in which a rare heavy rain has struck on Hainan in the first and middle dekad of October; two tropical cyclones generated, with one super typhoon (Chaba, numbered 1013) landed in Fujian; in the last dekad of October, strong cold air outbreak across most areas of China; heavy fog aroused in the central and eastern China.
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ISSN:1000-0526 CN:11-2282/P