ISSN 1000-0526
CN 11-2282/P
CN 11-2282/P
Volume 37,Issue 5,2011 Table of Contents
2011, 37(5):513-521.
DOI: 10.7519/j.issn.1000-0526.2011.5.001
Abstract:
Based on the snow cover data and meteorological element data at 123 meteorological stations in Northeast China during the period of 1960-2006, the spatial and temporal characteristics of snow cover are analyzed by the area weighted method, empirical orthogonal function, Morlet wavelet analysis and power spectral method. The results show that the cumulative snow depth in Northeast China is increasing slowly in the recent 40 years. The cumulative snow depth is no obvious changes in autumn, increasing in winter, and decreasing in spring, in which the increasing cumulative snow depth in winter is the key factor to the increasing annual cumulative snow depth. We hold the opinion that there are three main spatial patterns of cumulative snow depth in Northeast China by using EOF method, of which, the first pattern is consistently more (less) than normal, the second pattern is a seesaw between southern (northern) region and northern (southern) region, and the third pattern is a seesaw between central region (other region) and other region (central region).There is a quasi period of 7 years revealed by Morlet wavelet analysis and power spectral method, its period displays a decreasing trend and has a good response to the global warming.
Based on the snow cover data and meteorological element data at 123 meteorological stations in Northeast China during the period of 1960-2006, the spatial and temporal characteristics of snow cover are analyzed by the area weighted method, empirical orthogonal function, Morlet wavelet analysis and power spectral method. The results show that the cumulative snow depth in Northeast China is increasing slowly in the recent 40 years. The cumulative snow depth is no obvious changes in autumn, increasing in winter, and decreasing in spring, in which the increasing cumulative snow depth in winter is the key factor to the increasing annual cumulative snow depth. We hold the opinion that there are three main spatial patterns of cumulative snow depth in Northeast China by using EOF method, of which, the first pattern is consistently more (less) than normal, the second pattern is a seesaw between southern (northern) region and northern (southern) region, and the third pattern is a seesaw between central region (other region) and other region (central region).There is a quasi period of 7 years revealed by Morlet wavelet analysis and power spectral method, its period displays a decreasing trend and has a good response to the global warming.
2011, 37(5):522-531.
DOI: 10.7519/j.issn.1000-0526.2011.5.002
Abstract:
Three downburst events in Shandong Province were analyzed with Doppler radar data from Jinan, Xuzhou and Linyi. A severe storm with maximum reflectivity between 60-70 dBz, and C-VIL between 41-76 kg·m-2, and cell-top above 10 km, developed in the northeast part of Shandong Province, and produced downburst beyond 4 km across, accompanied by severe hails and heavy precipitation on 27 June 2009 (0627 storm). A severe storm with maximum reflectivity between 56-64 dBz, and C VIL between 26-51 kg·m-2, and cell top above 8 km, developed in the north part of Shandong Province, and produced downburst beyond 4 km across and hails on 25 July 2006 (0725 storm). A storm with maximum reflectivity between 55-59 dBz, and C VIL between 30-48 kg·m-2, and cell top above 10 km, developed in the south part of Shandong Province, and produced downburst as small as 2 km across on 8 July 2009 (0708 storm). The results show that the signatures of upright airflow in three storms were similar, namely cyclonic rotation at mid level, this air flow structure was conducive to the development and maintenance of the severe storm. The downbursts have a pattern of pure diverging or a pattern of anti cyclone diverging Doppler velocities at the surface layer. The dropping markedly of reflectivity factor core or cell top can produce acceleration of downward tilt airflows at middle levels in the storms, this fact can be used to issue downburst warnings. High values of 0-2 km and 0-6 km vertical wind shear, and high CAPE values can produce severe downbursts. The peak average radial velocity above 28 m·s-1 at low levels can lead to strong wind above 25 m·s-1 on the ground.
Three downburst events in Shandong Province were analyzed with Doppler radar data from Jinan, Xuzhou and Linyi. A severe storm with maximum reflectivity between 60-70 dBz, and C-VIL between 41-76 kg·m-2, and cell-top above 10 km, developed in the northeast part of Shandong Province, and produced downburst beyond 4 km across, accompanied by severe hails and heavy precipitation on 27 June 2009 (0627 storm). A severe storm with maximum reflectivity between 56-64 dBz, and C VIL between 26-51 kg·m-2, and cell top above 8 km, developed in the north part of Shandong Province, and produced downburst beyond 4 km across and hails on 25 July 2006 (0725 storm). A storm with maximum reflectivity between 55-59 dBz, and C VIL between 30-48 kg·m-2, and cell top above 10 km, developed in the south part of Shandong Province, and produced downburst as small as 2 km across on 8 July 2009 (0708 storm). The results show that the signatures of upright airflow in three storms were similar, namely cyclonic rotation at mid level, this air flow structure was conducive to the development and maintenance of the severe storm. The downbursts have a pattern of pure diverging or a pattern of anti cyclone diverging Doppler velocities at the surface layer. The dropping markedly of reflectivity factor core or cell top can produce acceleration of downward tilt airflows at middle levels in the storms, this fact can be used to issue downburst warnings. High values of 0-2 km and 0-6 km vertical wind shear, and high CAPE values can produce severe downbursts. The peak average radial velocity above 28 m·s-1 at low levels can lead to strong wind above 25 m·s-1 on the ground.
2011, 37(5):532-539.
DOI: 10.7519/j.issn.1000-0526.2011.5.003
Abstract:
The quality control of automatic rain gauge data is the most fundamental and the most crucial issue in the joint estimation of precipitation using radar and automatic station data. Taking the 891 automatic rainfall stations in Guangdong Province as analysis objects’ and using the conventional automatic rainfall station data for the quality control of themselves, as well as the introduction of radar data, we find the relationship between the ground truth rainfall and radar rainfall estimates by analogy deviation method, and further control over the information on the rainfall stations can formulate a set of automatic station quality control method combined with radar data. The radar echo intensity and the relevance of automatic stations were also studied. Through statistical analysis of large amounts of data we have obtained the following conclusions: being investigated in the 891 automatic rainfall stations, about 2.9% (26) of the automatic rainfall station sites could be identified as wrong, about 3.4% (30) automatic rainfall stations were classified as sites with serious problems, about 25.8% (230) automatic rainfall stations were listed as a general problem with the site. The comprehensive analysis of many cases has proven the feasibility of this method and some limitations of this method are also pointed out.
The quality control of automatic rain gauge data is the most fundamental and the most crucial issue in the joint estimation of precipitation using radar and automatic station data. Taking the 891 automatic rainfall stations in Guangdong Province as analysis objects’ and using the conventional automatic rainfall station data for the quality control of themselves, as well as the introduction of radar data, we find the relationship between the ground truth rainfall and radar rainfall estimates by analogy deviation method, and further control over the information on the rainfall stations can formulate a set of automatic station quality control method combined with radar data. The radar echo intensity and the relevance of automatic stations were also studied. Through statistical analysis of large amounts of data we have obtained the following conclusions: being investigated in the 891 automatic rainfall stations, about 2.9% (26) of the automatic rainfall station sites could be identified as wrong, about 3.4% (30) automatic rainfall stations were classified as sites with serious problems, about 25.8% (230) automatic rainfall stations were listed as a general problem with the site. The comprehensive analysis of many cases has proven the feasibility of this method and some limitations of this method are also pointed out.
2011, 37(5):540-546.
DOI: 10.7519/j.issn.1000-0526.2011.5.004
Abstract:
Collecting the pairs of the numerical weather prediction model daily precipitation forecast results and observed data, the uncertainty index U is set， according to the relative position that the joint entropy exists between maximum joint entropy and minimum joint entropy， so as to analyze the uncertainty of NWM precipitation prediction results quantitatively. Preliminary results show that: U is closely linked with the random deviation error of the model forecast, but has nothing to do with the system deviation error; the uncertainty index of the NWM precipitation forecast is over 60%; it has both reference significance and uncertainty; there is bigger uncertainty to forecast the heavy precipitation. As for the continent wide 24 h precipitation forecast in China, the uncertainty of the Japan model is smaller than the T213. When a 40 to 80 mm precipitation appears in the forecast of Japan Regional Spectral Model (RSM), it has the higher reference value than the T213.
Collecting the pairs of the numerical weather prediction model daily precipitation forecast results and observed data, the uncertainty index U is set， according to the relative position that the joint entropy exists between maximum joint entropy and minimum joint entropy， so as to analyze the uncertainty of NWM precipitation prediction results quantitatively. Preliminary results show that: U is closely linked with the random deviation error of the model forecast, but has nothing to do with the system deviation error; the uncertainty index of the NWM precipitation forecast is over 60%; it has both reference significance and uncertainty; there is bigger uncertainty to forecast the heavy precipitation. As for the continent wide 24 h precipitation forecast in China, the uncertainty of the Japan model is smaller than the T213. When a 40 to 80 mm precipitation appears in the forecast of Japan Regional Spectral Model (RSM), it has the higher reference value than the T213.
2011, 37(5):547-554.
DOI: 10.7519/j.issn.1000-0526.2011.5.005
Abstract:
Using precipitation data in flood period (from June to August) at 160 meteorological stations in China as predictands and 74 circulation characteristic indexes as predictors, a running prediction in flood period was conducted. The significant linear trend between predictands and circulation characteristic indexes was considered, as well as their correlation instability. Using running correlation, stepwise regression and ensemble analysis method, the multiple regression assembling prediction models of precipitation in flood period of 2009 at 160 stations were founded, and the independent swatch forecastings for the last 10 years were tested. It shows that the scores for ACC, PS and TS of the test all were better than those of operation of NCC in the recent years. The outputs through running correlation, stepwise regression and ensemble analysis method all have potential operational applications.
Using precipitation data in flood period (from June to August) at 160 meteorological stations in China as predictands and 74 circulation characteristic indexes as predictors, a running prediction in flood period was conducted. The significant linear trend between predictands and circulation characteristic indexes was considered, as well as their correlation instability. Using running correlation, stepwise regression and ensemble analysis method, the multiple regression assembling prediction models of precipitation in flood period of 2009 at 160 stations were founded, and the independent swatch forecastings for the last 10 years were tested. It shows that the scores for ACC, PS and TS of the test all were better than those of operation of NCC in the recent years. The outputs through running correlation, stepwise regression and ensemble analysis method all have potential operational applications.
2011, 37(5):555-563.
DOI: 10.7519/j.issn.1000-0526.2011.5.006
Abstract:
The cloud detection technology is one of the key steps to implement the application of the assimilation of the Atmospheric Infrared Sounder (AIRS). Mitch Goldberg’s cloud detection is a very fast model based on an empirical combination of 3 tests applied to AIRS channel and co registered AMSUA channels. The cloud detection does not need to apply a channel bias correction. Also, it is relatively independent of atmospheric prior information, except for sea surface temperature. According to the Mitch Goldberg’s thought of cloud detection, the original 3 tests of NESDIS Goldberg cloud detection scheme have been improved to 7， 4 in sea surface and 3 in land surface. The improved cloud detection is conducted to AIRS FOV of the land and sea respectively with the use of GRAPES 3DVAR (Global/ Regional Assimilation and Prediction System). There is a cloud, if every single FOV passed the cloud detection scheme. The NESDIS Goldberg cloud detection scheme and GRAPES Goldberg cloud detection scheme are used to detect the 6 scenes of AIRS on 1 July 2006 respectively. The analysis result shows that, the GRAPES Goldberg cloud detection scheme can effectively find out the FOV contaminated by cloud, and the clear FOV accounts for 10.1% of the total FOV.
The cloud detection technology is one of the key steps to implement the application of the assimilation of the Atmospheric Infrared Sounder (AIRS). Mitch Goldberg’s cloud detection is a very fast model based on an empirical combination of 3 tests applied to AIRS channel and co registered AMSUA channels. The cloud detection does not need to apply a channel bias correction. Also, it is relatively independent of atmospheric prior information, except for sea surface temperature. According to the Mitch Goldberg’s thought of cloud detection, the original 3 tests of NESDIS Goldberg cloud detection scheme have been improved to 7， 4 in sea surface and 3 in land surface. The improved cloud detection is conducted to AIRS FOV of the land and sea respectively with the use of GRAPES 3DVAR (Global/ Regional Assimilation and Prediction System). There is a cloud, if every single FOV passed the cloud detection scheme. The NESDIS Goldberg cloud detection scheme and GRAPES Goldberg cloud detection scheme are used to detect the 6 scenes of AIRS on 1 July 2006 respectively. The analysis result shows that, the GRAPES Goldberg cloud detection scheme can effectively find out the FOV contaminated by cloud, and the clear FOV accounts for 10.1% of the total FOV.
2011, 37(5):564-570.
DOI: 10.7519/j.issn.1000-0526.2011.5.007
Abstract:
Based on the automatic weather stations (AWS) precipitation data, an assessment of multi precipitation products is conducted on the rainfall monitoring of typhoon Morakot in the August of 2009. The results show that, the CPAP (China Precipitation Analysis Product) daily grid precipitation data display an accurate spacial distribution and rain intensity on the land, but not in ocean because of the limitation of station distribution. Compared to the ground gauged rainfall measurements, the method CMORPH can well present an exact spiral rain belt around typhoon eye, and also its evolvement, but the location of maximal rainfall center rooted in the rain belt deviates greatly from the actuality. And the intensity of rainfall in the CMORPH is much weaker than that in gauged. In oceans, FY2C does not perform as good as the CMORPH owing to its discontinued rainfall distribution along the coastal areas. Taking the advantages of the gauged rainfall (accuracy) and the CMORPH (pattern), we may get a high quality precipitation product.
Based on the automatic weather stations (AWS) precipitation data, an assessment of multi precipitation products is conducted on the rainfall monitoring of typhoon Morakot in the August of 2009. The results show that, the CPAP (China Precipitation Analysis Product) daily grid precipitation data display an accurate spacial distribution and rain intensity on the land, but not in ocean because of the limitation of station distribution. Compared to the ground gauged rainfall measurements, the method CMORPH can well present an exact spiral rain belt around typhoon eye, and also its evolvement, but the location of maximal rainfall center rooted in the rain belt deviates greatly from the actuality. And the intensity of rainfall in the CMORPH is much weaker than that in gauged. In oceans, FY2C does not perform as good as the CMORPH owing to its discontinued rainfall distribution along the coastal areas. Taking the advantages of the gauged rainfall (accuracy) and the CMORPH (pattern), we may get a high quality precipitation product.
2011, 37(5):571-575.
DOI: 10.7519/j.issn.1000-0526.2011.5.008
Abstract:
Affected by various factors, there exist certain errors and uncertainties during the retrieval of atmospheric compositions from satellite data. Systematic and comprehensive validation work is very important to obtain accurate and reliable satellite data. The validation of satellite data is mainly related to two parts of contents: one is the validation of the input parameters used in the retrieval algorithm, and the other is the direct validation of satellite retrieval products. In the work, we firstly reviewed the validation demands when obtaining the tropospheric NO2 satellite data and the current status of the atmosphere background observation stations in China, and then discussed the role of the latter might play in satellite data validation. Accurate surface observations at regional background stations and their good regional representations are beneficial for the validation of satellite data. The capability of vertical measurements of atmospheric physical and chemical properties can strengthen the ability for the accurate and quantified validation of satellite data. Therefore, we strongly recommend that some new technologies and technical equipments which can help the validation work should reserve in advance.
Affected by various factors, there exist certain errors and uncertainties during the retrieval of atmospheric compositions from satellite data. Systematic and comprehensive validation work is very important to obtain accurate and reliable satellite data. The validation of satellite data is mainly related to two parts of contents: one is the validation of the input parameters used in the retrieval algorithm, and the other is the direct validation of satellite retrieval products. In the work, we firstly reviewed the validation demands when obtaining the tropospheric NO2 satellite data and the current status of the atmosphere background observation stations in China, and then discussed the role of the latter might play in satellite data validation. Accurate surface observations at regional background stations and their good regional representations are beneficial for the validation of satellite data. The capability of vertical measurements of atmospheric physical and chemical properties can strengthen the ability for the accurate and quantified validation of satellite data. Therefore, we strongly recommend that some new technologies and technical equipments which can help the validation work should reserve in advance.
2011, 37(5):576-582.
DOI: 10.7519/j.issn.1000-0526.2011.5.009
Abstract:
The thunderstorm data from surface observation station from 1960 to 2005 are used to analyze the temporal and spatial characteristics of thunderstorm activities in Henan. According to the activity characteristics and the environmental conditions of the thunderstorm， plenty of the atmospheric dynamical and thermal parameters are calculated based on the numerical products from T213 and T639. Through the diagnostic analyses and correlative analyses， 5 parameters with better relation to the ground flash are picked as forecasting indexes， that is， the convective stability index， the pseudo equivalent potential temperature on 850 hPa， and the vertical wind shear between 400 hPa to 850 hPa and so on. Then， the ADTD ground flash monitoring data and the numerical models T213 and T639 output data， are utilized to establish the model for the lightning potential forecast. The potential forecast method is used in the operation during the flood period from 2008 to 2009， and the assessment result shows that the lightning potential forecasting method based on the numerical data of T213 and T639 can provide objective and quantitative reference and basis for the lightning occurring area forecast of Henan and the forecasting effects for the trough and shear pattern are both good based on models T213 and T639 to different weather patterns.
The thunderstorm data from surface observation station from 1960 to 2005 are used to analyze the temporal and spatial characteristics of thunderstorm activities in Henan. According to the activity characteristics and the environmental conditions of the thunderstorm， plenty of the atmospheric dynamical and thermal parameters are calculated based on the numerical products from T213 and T639. Through the diagnostic analyses and correlative analyses， 5 parameters with better relation to the ground flash are picked as forecasting indexes， that is， the convective stability index， the pseudo equivalent potential temperature on 850 hPa， and the vertical wind shear between 400 hPa to 850 hPa and so on. Then， the ADTD ground flash monitoring data and the numerical models T213 and T639 output data， are utilized to establish the model for the lightning potential forecast. The potential forecast method is used in the operation during the flood period from 2008 to 2009， and the assessment result shows that the lightning potential forecasting method based on the numerical data of T213 and T639 can provide objective and quantitative reference and basis for the lightning occurring area forecast of Henan and the forecasting effects for the trough and shear pattern are both good based on models T213 and T639 to different weather patterns.
2011, 37(5):583-589.
DOI: 10.7519/j.issn.1000-0526.2011.5.010
Abstract:
To explore the causes for snowstorm with lightning in Henan, the weather situation, effects of upper and low level jets and related quantities which reflect dynamic, thermal and water vapor conditions have been analyzed based on the conventional observations, radar data and NCEP 1°×１° reanalysis data per 6 hours. Results show that the height of inversion layer can reach to higher levels than 600 hPa when a snowstorm with lightning happens. When a frontal zone of instability energy appears at the middle layer of troposphere, it is helpful to the development of ascending motion, which makes the height of cloud increase and the lightning occur. Snowstorm with lightning appears in the vigorous period of upper and 〖JP2〗lower level jets. The center of mesoscale instability is near 800 hPa when lightning happens firstly, while it is between 700 and 650 hPa at the second time. Snowstorm appears at the front of high energy tongue and superimposed area of convective instability. Sustained water vapor transport, the accumulation and confrontation at lower layer of two strong cold air currents and the strong symmetrical instability are the causes for the keep of snowstorm.
To explore the causes for snowstorm with lightning in Henan, the weather situation, effects of upper and low level jets and related quantities which reflect dynamic, thermal and water vapor conditions have been analyzed based on the conventional observations, radar data and NCEP 1°×１° reanalysis data per 6 hours. Results show that the height of inversion layer can reach to higher levels than 600 hPa when a snowstorm with lightning happens. When a frontal zone of instability energy appears at the middle layer of troposphere, it is helpful to the development of ascending motion, which makes the height of cloud increase and the lightning occur. Snowstorm with lightning appears in the vigorous period of upper and 〖JP2〗lower level jets. The center of mesoscale instability is near 800 hPa when lightning happens firstly, while it is between 700 and 650 hPa at the second time. Snowstorm appears at the front of high energy tongue and superimposed area of convective instability. Sustained water vapor transport, the accumulation and confrontation at lower layer of two strong cold air currents and the strong symmetrical instability are the causes for the keep of snowstorm.
2011, 37(5):590-598.
DOI: 10.7519/j.issn.1000-0526.2011.5.011
Abstract:
Using the snowmelt flooding disaster data from 1950 to 2006, snowmelt flooding characteristics of the Xinjiang region were analyzed. The results indicate that snowmelt flooding over Xinjiang region usually occurred in the northern slope of Tianshan Mountains, especially in the Ili River Valley and Tacheng area, while snowmelt flooding most easily occurred for the time from mid March to early April. On the basis of it, climate background, weather process, diagnostic analysis were analyzed on the possible weather causes for snowmelt flooding occurring in mid March 2009. Finally we can see the basic condition for snowmelt flooding occurrence that the rainfall in February 2009 was obviously more than the average value in the same period of the past years, and air temperature rapidly and continually increased after the cold air passing through, all these may be the most possible causes for the snowmelt flooding in mid March 2009. During the durative and rapid heating process, the time for mean temperature being higher than 0 ℃, the highest temperature being higher than 5 ℃ as well as warm advection center appearing has the instructive significance to snowmelt flooding forecasting.
Using the snowmelt flooding disaster data from 1950 to 2006, snowmelt flooding characteristics of the Xinjiang region were analyzed. The results indicate that snowmelt flooding over Xinjiang region usually occurred in the northern slope of Tianshan Mountains, especially in the Ili River Valley and Tacheng area, while snowmelt flooding most easily occurred for the time from mid March to early April. On the basis of it, climate background, weather process, diagnostic analysis were analyzed on the possible weather causes for snowmelt flooding occurring in mid March 2009. Finally we can see the basic condition for snowmelt flooding occurrence that the rainfall in February 2009 was obviously more than the average value in the same period of the past years, and air temperature rapidly and continually increased after the cold air passing through, all these may be the most possible causes for the snowmelt flooding in mid March 2009. During the durative and rapid heating process, the time for mean temperature being higher than 0 ℃, the highest temperature being higher than 5 ℃ as well as warm advection center appearing has the instructive significance to snowmelt flooding forecasting.
2011, 37(5):599-606.
DOI: 10.7519/j.issn.1000-0526.2011.5.012
Abstract:
Using the diurnal snow data of 120 meteorological stations in Yunnan Province during 1961-2008, the temporal and spatial distribution characteristics and the trend of climatic change of the annual and monthly snow fall are analyzed. It is pointed out that the total trend of snow frequency and covering stations has been decreasing in Yunnan in the recent 50 years. And the annual snow frequency has declined at a mean rate of 4.5 times per year. The temporal trends of monthly snow frequency and covering stations are all negative. Moreover the reduction of snow frequency in December is the largest in magnitude, therefore, it is the most remarkable. And the reduction of snow stations in April is the largest. As far as the spatial change of the secular trend variation of annual snow frequency is concerned, the reduction of annual snow frequency is larger in Northwest Yunnan than in its northeast and east, where the reduction rate is 0.44 times per year. And the temporal changes of annual snowfall and depth of snow cover are studied, the results show that the secular trends of annual snowfall and the maximum depth of snow cover are all positive. This means that in the nearly 50 years the heavy snow frequency has increased over Yunnan Province.
Using the diurnal snow data of 120 meteorological stations in Yunnan Province during 1961-2008, the temporal and spatial distribution characteristics and the trend of climatic change of the annual and monthly snow fall are analyzed. It is pointed out that the total trend of snow frequency and covering stations has been decreasing in Yunnan in the recent 50 years. And the annual snow frequency has declined at a mean rate of 4.5 times per year. The temporal trends of monthly snow frequency and covering stations are all negative. Moreover the reduction of snow frequency in December is the largest in magnitude, therefore, it is the most remarkable. And the reduction of snow stations in April is the largest. As far as the spatial change of the secular trend variation of annual snow frequency is concerned, the reduction of annual snow frequency is larger in Northwest Yunnan than in its northeast and east, where the reduction rate is 0.44 times per year. And the temporal changes of annual snowfall and depth of snow cover are studied, the results show that the secular trends of annual snowfall and the maximum depth of snow cover are all positive. This means that in the nearly 50 years the heavy snow frequency has increased over Yunnan Province.
2011, 37(5):607-614.
DOI: 10.7519/j.issn.1000-0526.2011.05.013
Abstract:
Based on the surface observation data of 192 meteorological stations during 1961-2008 in South China， the climatic characteristics and variations of haze days and fog days in South China were studied by using statistical diagnostic methods， such as linear regression analysis， Mann Kendall test and the computation of trend coefficients. The results showed that haze days were more in the Pearl River Delta area，northwest areas of Guangdong and northeast areas of Guangxi, the fewest areas of hazes were in Hainan. There were three more fog regions in South China: the middle and western area of Hainan, northeast area of Guangxi and Guangdong, the annual mean fog days showed a decreasing trend from inland to coastal regions. The annual haze days in South China have increased obviously at a mean rate of 5.8 d/10a， it was more than that of the country mean （3.19 d/10a） obviously. There were obvious regional differences in the variable trend of annual haze days in South China， the increasing trends of haze days were obvious in the Pearl River Delta area， northwest areas of Guangdong, the middle and northeast areas of Guangxi, the increasing center was in Shenzhen (38.8 d/10a). The annual fog days in South China have decreased obviously at a mean rate of -0.8 d/10a， it displayed significant regional differences in South China. The fog days have decreased obviously in eastern and southern Guangdong, western and northern Guangxi, most parts of Hainan. The largest decreasing rate was in Baoting of Hainan （-16.8 d/10a）， the largest increasing rate was in Baisha of Hainan (20.7 d/10a). The annual mean haze days had an abrupt change in 1989, fog days had an abrupt change in 1995.
Based on the surface observation data of 192 meteorological stations during 1961-2008 in South China， the climatic characteristics and variations of haze days and fog days in South China were studied by using statistical diagnostic methods， such as linear regression analysis， Mann Kendall test and the computation of trend coefficients. The results showed that haze days were more in the Pearl River Delta area，northwest areas of Guangdong and northeast areas of Guangxi, the fewest areas of hazes were in Hainan. There were three more fog regions in South China: the middle and western area of Hainan, northeast area of Guangxi and Guangdong, the annual mean fog days showed a decreasing trend from inland to coastal regions. The annual haze days in South China have increased obviously at a mean rate of 5.8 d/10a， it was more than that of the country mean （3.19 d/10a） obviously. There were obvious regional differences in the variable trend of annual haze days in South China， the increasing trends of haze days were obvious in the Pearl River Delta area， northwest areas of Guangdong, the middle and northeast areas of Guangxi, the increasing center was in Shenzhen (38.8 d/10a). The annual fog days in South China have decreased obviously at a mean rate of -0.8 d/10a， it displayed significant regional differences in South China. The fog days have decreased obviously in eastern and southern Guangdong, western and northern Guangxi, most parts of Hainan. The largest decreasing rate was in Baoting of Hainan （-16.8 d/10a）， the largest increasing rate was in Baisha of Hainan (20.7 d/10a). The annual mean haze days had an abrupt change in 1989, fog days had an abrupt change in 1995.
2011, 37(5):615-621.
DOI: 10.7519/j.issn.1000-0526.2011.05.014
Abstract:
In order to evaluate the causes and impacts of autumn and winter low temperature and drought from 2008 to 2009 in Suzhou, we have conducted a research by use of the similar regression analysis method and integration regression method, based on the disastrous meteorological data and field disaster survey data from 1953 to 2009, and in combination with the growth law of winter wheat. It is concluded that the main reasons for autumn and winter low temperature and drought from 2008 to 2009 can be attributed to scarce rainfall for long time, loss of moisture in wheat field and the low temperature below 10 ℃ suddenly without a prior cold stress. The drought and frost damages to wheat belong to respectively serious drought and class 2 freeze injury. It occurred twice in 57 years and the return period was 16.5 a as the disaster. Impacts of drought and low temperature on yield were by means of hindering tiller and spiking primordium differentiation.
In order to evaluate the causes and impacts of autumn and winter low temperature and drought from 2008 to 2009 in Suzhou, we have conducted a research by use of the similar regression analysis method and integration regression method, based on the disastrous meteorological data and field disaster survey data from 1953 to 2009, and in combination with the growth law of winter wheat. It is concluded that the main reasons for autumn and winter low temperature and drought from 2008 to 2009 can be attributed to scarce rainfall for long time, loss of moisture in wheat field and the low temperature below 10 ℃ suddenly without a prior cold stress. The drought and frost damages to wheat belong to respectively serious drought and class 2 freeze injury. It occurred twice in 57 years and the return period was 16.5 a as the disaster. Impacts of drought and low temperature on yield were by means of hindering tiller and spiking primordium differentiation.
2011, 37(5):622-625.
DOI: 10.7519/j.issn.1000-0526.2011.05.015
Abstract:
As the uncertainty component introduced by the effect of air density measurement is one of the main compositions of the measurement result uncertainty of the piston pressure gauge, the paper analyzed the effect degree with formula derivation to PG7607 primary piston pressure gauge, the results show that: the effect of the air density to the measurement results of the piston pressure gauge is related to the environmental atmospheric temperature, humidity, pressure status at the using site; related to the measurement result uncertainty of environmental atmospheric temperature, humidity, pressure at using sites. With the laboratory condition, the effect of the air density to measurement results of the piston pressure gauge is in the range from 0.25 ppm to 0.35 ppm in China, the effect of air density to the measurement results of piston pressure gauge is in the range from 0.31 ppm to 0.33 ppm in Beijing. The analysis method in this paper can be applied to other type piston pressure gauges, besides the final computation result differences due to the difference of temperature, humidity and pressure measurement errors.
As the uncertainty component introduced by the effect of air density measurement is one of the main compositions of the measurement result uncertainty of the piston pressure gauge, the paper analyzed the effect degree with formula derivation to PG7607 primary piston pressure gauge, the results show that: the effect of the air density to the measurement results of the piston pressure gauge is related to the environmental atmospheric temperature, humidity, pressure status at the using site; related to the measurement result uncertainty of environmental atmospheric temperature, humidity, pressure at using sites. With the laboratory condition, the effect of the air density to measurement results of the piston pressure gauge is in the range from 0.25 ppm to 0.35 ppm in China, the effect of air density to the measurement results of piston pressure gauge is in the range from 0.31 ppm to 0.33 ppm in Beijing. The analysis method in this paper can be applied to other type piston pressure gauges, besides the final computation result differences due to the difference of temperature, humidity and pressure measurement errors.
2011, 37(5):626-632.
DOI: 10.7519/j.issn.1000-0526.2011.05.016
Abstract:
Study on evaluation method of benefits from pollen forecast and service is significant for understanding public value of special weather forecast and service and potential benefits. Main estimating method used here is that pollen prediction accuracy(Af), time efficiency of service (Tf), percentage of information coverage(Ic)and prevention capability of pollinosis sufferers (P)， which are the important elements influencing how much the benefits is, are firstly designed to be as four factors of service benefits. Secondly， it is necessary to assess them and get four values calculated by monitoring pollen data from 2000 to 2006, pollinosis cases and investigating data coming from 146 questionnaires answered by allergy & clinical immunology experts and pollinosis sufferers in Tianjin. A mathematical estimating model of benefit coefficient, E=Af×Tf×Ic×P, is built based on the relationship between four factors mentioned above. Then the benefit from pollen forecast and service is figured out through the equation. Evaluation result shows that mathematical estimating model is practical and rational. And the value of total social benefits is remarkable.
Study on evaluation method of benefits from pollen forecast and service is significant for understanding public value of special weather forecast and service and potential benefits. Main estimating method used here is that pollen prediction accuracy(Af), time efficiency of service (Tf), percentage of information coverage(Ic)and prevention capability of pollinosis sufferers (P)， which are the important elements influencing how much the benefits is, are firstly designed to be as four factors of service benefits. Secondly， it is necessary to assess them and get four values calculated by monitoring pollen data from 2000 to 2006, pollinosis cases and investigating data coming from 146 questionnaires answered by allergy & clinical immunology experts and pollinosis sufferers in Tianjin. A mathematical estimating model of benefit coefficient, E=Af×Tf×Ic×P, is built based on the relationship between four factors mentioned above. Then the benefit from pollen forecast and service is figured out through the equation. Evaluation result shows that mathematical estimating model is practical and rational. And the value of total social benefits is remarkable.
2011, 37(5):633-638.
DOI: 10.7519/j.issn.1000-0526.2011.05.017
Abstract:
The performance of medium range forecast is verified and compared for the models of T639, ECMWF and Japan from December 2010 to February 2011. The results show that the three models are capable of predicting the variation and adjustment of atmospheric circulation and temperature of 850 hPa successfully. In northern China, EC model has better performance than T639 and JP models in terms of predicting temperature at 850 hPa, whereas in southern China standard deviations for JP model are smallest. In southern China, correlation coefficients between initial fields and forecasts of 850 hPa temperature for the three models are all lower than those in northern China. In forecasting of south branch trough, the forecasts of JP model are stronger than its initial fields and the performance of EC model is the best. The models all predict the weak surface anticyclone, and for T639 and EC models the errors are mainly located in the northwest of the anticyclone.
The performance of medium range forecast is verified and compared for the models of T639, ECMWF and Japan from December 2010 to February 2011. The results show that the three models are capable of predicting the variation and adjustment of atmospheric circulation and temperature of 850 hPa successfully. In northern China, EC model has better performance than T639 and JP models in terms of predicting temperature at 850 hPa, whereas in southern China standard deviations for JP model are smallest. In southern China, correlation coefficients between initial fields and forecasts of 850 hPa temperature for the three models are all lower than those in northern China. In forecasting of south branch trough, the forecasts of JP model are stronger than its initial fields and the performance of EC model is the best. The models all predict the weak surface anticyclone, and for T639 and EC models the errors are mainly located in the northwest of the anticyclone.
2011, 37(5):639-644.
DOI: 10.7519/j.issn.1000-0526.2011.05.018
Abstract:
The following are the main characteristics of the general atmospheric circulation in February 2011. There is a stronger polar vortex center in the Northern Hemisphere than normal years. The circulation presents a four wave pattern in middle high latitudes. The subtropical high is weaker than normal years. The south branch trough is slightly weaker than normal years. The monthly mean precipitation is 11.4 mm, and is 4.9 mm less than normal. Northern China is under control by ridge in early and mid February. In North China and Huang Huai Plain etc., drought increases until the end of the month to get relief. The monthly mean temperature is -1.2 ℃, and is 1.7 ℃ higher than normal. There were two cold air processes affecting most areas of China. Part of the middle and east of China suffered from fog disasters.
The following are the main characteristics of the general atmospheric circulation in February 2011. There is a stronger polar vortex center in the Northern Hemisphere than normal years. The circulation presents a four wave pattern in middle high latitudes. The subtropical high is weaker than normal years. The south branch trough is slightly weaker than normal years. The monthly mean precipitation is 11.4 mm, and is 4.9 mm less than normal. Northern China is under control by ridge in early and mid February. In North China and Huang Huai Plain etc., drought increases until the end of the month to get relief. The monthly mean temperature is -1.2 ℃, and is 1.7 ℃ higher than normal. There were two cold air processes affecting most areas of China. Part of the middle and east of China suffered from fog disasters.
2011, 37(5):645-648.
DOI: 10.7519/j.issn.1000-0526.2011.05.019
Abstract:
In recent years, many problems have been found in provincial quality control data R document at Automatic Weather Station (radiation) in Xinjiang. The causes were analyzed in accordance with the abnormal data of the total radiation by use of “Quality Control Software for Provincial Ground and Radiation Data” and “Quality Control Radiation (R) Document of OSSMO2004 Software for Surface Observation”. By utilizing man computer interface we analyzed and synthesized the complicated and mistaken information automatically produced by software system. Meanwhile we offered the processing method combining with the relevant regulations and problem solution. The real, precise and reliable radiation data will be obtained. Furthermore, the objective and accurate data will be provided for scientific research.
In recent years, many problems have been found in provincial quality control data R document at Automatic Weather Station (radiation) in Xinjiang. The causes were analyzed in accordance with the abnormal data of the total radiation by use of “Quality Control Software for Provincial Ground and Radiation Data” and “Quality Control Radiation (R) Document of OSSMO2004 Software for Surface Observation”. By utilizing man computer interface we analyzed and synthesized the complicated and mistaken information automatically produced by software system. Meanwhile we offered the processing method combining with the relevant regulations and problem solution. The real, precise and reliable radiation data will be obtained. Furthermore, the objective and accurate data will be provided for scientific research.
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ISSN:1000-0526 CN:11-2282/P