Table of Content

30 August 2012, Volume 28 Issue 4 Previous Issue    Next Issue

Articles

Select

A meso-scale diagnostic analysis of torrential rain caused by a southwest  vortex in China GU Xu-zan，XU Ming 2012, 28 (4):  1-7.  Abstract ( 905 )   PDF (2769KB) ( 1061 )   Save Based on the atmospheric data from LAPS (local analysis and prediction system), a torrential rain process caused by a southwest vortex in July 2008 in China was analyzed. The probable precipitation, instable energy of stratification, convective probable precipitation, mean wind speed of water vapor weight, water vapor flux divergence, the total cloud water and cloud ice and its flux divergence, vertical velocity and condensation function precipitation rates and so on were calculated and diagnosed. The results indicate that the torrential rain from “a southwest vortex shear line system” occurs in the ascending areas due to meso-scale wind field convergence between the warm-wet air mass and cold air mass and is located on the side of warm-wet air mass of unstable stratification. The calculation of the meso-scale vertical motion and the field of the condensation function precipitation rate show that the grade of precipitation rate reaches the heavy rain to rainstorm. The calculated precipitation rate of water vapor flux convergence is not entirely consistent with that of the condensation function. The water vapor flux convergence not only produces  meso-scale “rain”, but also  large-scale “cloud”, and cloud moisture and cloud ice flux convergence or divergence is their positive or negative “collection growth” and then forms incremental hydrometeors (precipitation rate), which helps to produce  heavy rain. Thus, the synoptic reasons for the heavy storm in Xiangfan includes the meso-scale and small-scale convective rain mass produced by the field of the condensation function precipitation rate, the water vapor, the flux convergence of cloud moisture and cloud ice, the cloud particle “collection growth”, the energy release from unstable stratification, the   possible “secondary circulation” stimulated by forcing, and the transportation of water vapor, cloud moisture and cloud ice. Related Articles | Metrics

Select

Numerical simulation for a pollution weather process in Shengyang, Liaoning province using MM5 model and NCEP/NCAR data ZOU Xu-dong，YANG Hong-bin，LI Shuai-bin，LIU Yu-che，WANG Hong-yu 2012, 28 (4):  8-15.  Abstract ( 725 )   PDF (3286KB) ( 697 )   Save Based on the NCEP/NCAR reanalysis data and the meso-scale weather model MM5, a pollution weather process in Shengyangfrom 14-19 January 2010 was simulated. Some meteorological elements were analyzed and simulated and these include the ground and upper air pressure fields, the horizontal and vertical wind fields from the ground to the upper level as well as their variation with time, and the vertical temperature profile etc.. The variation of weather system was described in this process, and the meteorological elements causing atmospheric pollution were analyzed. The results indicate that the corresponding ground filed in this process is the Changbai Mountain high pressure and topographic trough circulation type. The upper weather situation is two troughs and one ridge at 500 hPa. The ground wind field is controlled by high pressure divergence airflow. The horizontal wind fields from the ground to the upper all have the southerly wind shear and westerly wind shear, and there is the corresponding downdraft in the vertical wind field. The temperature profile shows a clearly inversion from the ground to the upper level. The above meteorological conditions together cause the persistent pollution weather, while the lasting weather situation with two troughs and one ridge at 500 hPa geopotential height field are the main reason of this process. Related Articles | Metrics

Select

The effect of particulate dry deposition on air pollution simulated by AERMOD model SHOU You-ping，QIAO Jian-zhe，XU Jing 2012, 28 (4):  16-21.  Abstract ( 965 )   PDF (885KB) ( 816 )   Save The AERMOD is a recommended atmospheric simulation model by “a guideline of environment impact assessment: atmospheric environment”. To validate the effect of particulate matter dry deposition on the results of ground concentration predicted by AERMOD model, a coal storage yard in Fuzhou was selected as a non-point source, and the maximum ground concentrations of PM10 and TSP in each grid point within the forecast range were predicted. The results indicate that the ratio of surface TSP concentration with counting dry deposition and without counting dry deposition is 0.13 in all grid points. The same ratio for PM10 is 0.70. The effect of dry deposition is larger on TSP than on PM10. The effect of density on particulate matter dry deposition is significant within the same particle size, while the effect of density increase is larger on dry deposition of inhalable particulate matter than on that of TSP. When the density is higher than 3 g·cm-3, the PM10/TSP ratios of theaverage ground concentrations are all close to 0.98 in all grid points. The particles diameters larger than 10 μm are almost deposited completely. Thus, the decrease of surface concentration in the grid point is caused by PM10 deposition with the increase of density. The ratio of the surface concentration of PM10  to that of TSP  in the grid point  500 m away from the source center is larger than 0.98 when dry deposition is considered in the AERMOD model, coarse particles larger than 10 μm are almost deposited completely. Related Articles | Metrics

Select

The effect of winter air temperature variation on the heating period in Jilin province GAO Feng，YAO Guo-you，ZHU Xiao-fei，TU Gang，SUI Bo 2012, 28 (4):  22-27.  Abstract ( 865 )   PDF (737KB) ( 614 )   Save Based on the mean temperature, the minimum temperature data from 46 weather stations from 1960 to 2009 in Jilin province, heating intensity and heating index were calculated, and the characteristics of temperature variation and rules were analyzed by methods of a tendency analysis and a Mann-Kendall test. The results indicate that the mean and minimum temperatures are the increasing trends in the heating period. The number of days that temperature is lower than -20 ℃ decrease obviously. The mean and minimum temperature tendency rates are 0.24 ℃/decade and 0.42 ℃/decade in the recent 50 years, especially in the recent decade with 0.84℃/decade and 1.25℃/decade respectively, and the increasing tendency of the minimum temperature is obvious. The heating beginning date is in a delaying trend, while the heating ending date is in an advancing trend. Thus, the number of days of the heating period is shortened. The abrupt change of temperature during the heating period occurs in 1985. The heating period is long and the heating intensity is strong before the middle period of 1980s, while the heating period is short and the heating intensity is weak after 1980s. The heating index is mainly positive before the middle period of 1980s, while it is mainly negative after 1980s, especially in 1990s. However, the fluctuant amplitude of the heating index increases in the recent decade. The reasonable heating plans could be carried out according to temperature conditions because of the decreasing heating intensity and the shortening heating days, which can reduce emissions of carbon dioxide, sulfur dioxide and nitrogen dioxide to the atmosphere and it is important to palliation climate warming and improve the quality of atmospheric environment. Related Articles | Metrics

Select

Circulation background of spring soaking rain and its correlation with sea surface temperature in Liaoning province SHEN Yu-min，HU Chun-li，LI Fei，WANG Xiao-tao，LI Ji1 LIN Rong，WEI Wei 2012, 28 (4):  28-32.  Abstract ( 796 )   PDF (2084KB) ( 629 )   Save Based on the daily precipitation data at 14 weather stations during April to May from 1961 to 2008 in Liaoning province, the correlations between the beginning date of the first spring soaking rain and circulation background at 500 hPa as well as sea surface temperature (SST) were analyzed. The results indicate that the date of the first spring soaking rain in Liaoning province has a good correlation with the height field at 500 hPa during September to November last year, and it is of corresponding relation with inter-decadal variations of circulation on the north hemisphere in April of the same year. The date of the first spring soaking rain in Liaoning province is in a significantly negative correlation with the prophase SST in the North Pacific Ocean. The date of the first spring soaking rain occurs early when the prophase SST is high in the North Pacific Ocean, while it delays when the prophase SST is low. Related Articles | Metrics

Select

A case study on a typical environment pollution process in autumn over Tianjin area ZHANG Xiao-yun，GUO Hu，YI Xiao-yuan，ZHU Yu-qiang，ZHANG Guang-quan，WANG Jing 2012, 28 (4):  33-37.  Abstract ( 679 )   PDF (1896KB) ( 591 )   Save  Based on the environmental air quality monitoring data, the conventional meteorological data, the sounding data and the NCEP reanalysis data, a typical pollution process in Tianjin during October 3-12, 2010 was analyzed. The synoptic background field of atmospheric environment, the atmospheric stratification stability and its effect on the pollution process were discussed. The results indicate that the pollution process is closely relative to the upper and lower environmental background fields. During the increasing stage of pollution concentration, the stratification stability increases rapidly, and the upper level situation field at 500 hPa is located in the front of the trough, the surface situation field is in the topographic trough of North China, and the upper and lower wind speed converges. During the stage of pollution concentration summit, the atmospheric stratification and the environmental background are stable, the inversion layer is strong, and the surface wind is weak. During the decreasing stage of pollution concentration, atmospheric stratification becomes unstable quickly| the surface cold front and upper trough pass over Tianjin area, precipitation occurs and the upper and lower north wind are enhanced. Meanwhile, PM10 pollution process is significantly correlated with multiple stratification stability parameters and its correlation coefficient with convective condensation level is 0.84. As a result, the configuration of upper and lower environmental background and the variability of atmospheric stratification are the main reasons causing the PM10 pollution. Related Articles | Metrics

Select

Comparison on quantitative estimation of precipitation using radar based on different calibration methods DONG Gao-hong，LV Jiang-jin 2012, 28 (4):  38-42.  Abstract ( 606 )   PDF (785KB) ( 724 )   Save Based on the observational data from the low-elevation angle radar and precipitation data from intensive automatic weather station, the local Z-I relationships were established by an optimization method according to precipitation feature and the different precipitation types. According to application test, the Z-I relationship of the cumulus clouds mixed precipitation type is more applicable. The results of precipitation estimated using six calibration methods were compared after the Z-I relationships have been modified specifically for Tianjin area. The results indicate that the errors from both the Z-I relationship calibration method and the maximum integrated method are large| they both overestimate rainfall. The estimation accuracy of the optimal interpolation method is the highest among the all methods, and its mean absolute error and root-mean-square error are the smallest. To some extent, the rainfall is overestimated to light rain grade among the all methods. The correlation coefficient between the estimated rainfall from different methods and the observed rainfall are calculated, and it shows that the correlation between the estimated rainfall of variational calibration method and rain gauge rainfall is significant. Related Articles | Metrics

Select

Climatic characteristics of regional snowstorm from 1960 to 2009 in Liaoning province YAN Qi，JIANG Da-kai，CHEN Chuan-lei，CUI Jin，LU Jing-long，SANG Ming-gang 2012, 28 (4):  43-48.  Abstract ( 848 )   PDF (1380KB) ( 749 )   Save  Based on the diurnal precipitation data at 58 weather stations from 1960 to 2009, the climatic characteristics of regional snowstorm were analyzed in Liaoning province. The results indicate that the regional snowstorm mainly occurs from the last ten day of November to March 15 of the next year, especially in February. The number of snowstorm is in an increasing trend in the recent 50 years, and there exist the 9-year, 5-year and 3-year cycles. The 9-year cycle always exists, and its intensity enhances since 1960s, especially from 1970s to 1980s. The 5-year cycle occurs since 1970s and strengthens since the middle of 1970s. The 3-year cycle always exists, and its intensity is the strongest in the middle of 1970s and in 1980s. The number of regional snowstorm and snowstorm amount decrease from the southeast to the northwest, and three centers of snowstorm are located in Shenyang-Fushun-Benxi area, around Anshan area and in Fengcheng area. The falling area of regional snowstorm could be divided into four types, i.e. the middle and east snowstorm, the east snowstorm, the south snowstorm and the west snowstorm. Related Articles | Metrics

Select

Comparative analysis of two heavy rains caused by subtropical high in August 2010 based on Doppler radar data in Dandong XU Lu-lu，LI Hui-lin，SUN Lian-qiang，LI Qian 2012, 28 (4):  49-54.  Abstract ( 774 )   PDF (2444KB) ( 475 )   Save  Based on the basic reflectivity, basic radial velocity and wind profile data from Doppler radar, two heavy rain processes in Dandong area on August 19 and 20, 2010 were analyzed, and their weather situations and radar echo characteristics were discussed. The results indicate that the forces of southward cold air and warm wet air of the rear subtropical high  are compatible  when Dandong is located within subtropical high or near the margin, so it comes into being a typical heavy rain model in Dandong. The VWP (vertical wind profile) has a water vapor accumulation process during the prophase of precipitation, and it shows that upper level jet stream appears and upper momentum transports downward during the short-time heavy rain of two processes. The downward transportation of upper momentum makes lower level jet stream strengthened and the lower level converges, so rain intensity increases obviously. An echo strip with 40 dBz is formed in the precipitation echo areas of two processes, and the echo moving direction is consistent with the echo axial direction, which makes precipitation time prolonged and rainfall intensity increased. The occurrence time of inverse wind area is corresponding with that of the short-time strong rainfall. The corresponding relationship between the location of strong rainfall and strong echo area suggests that the larger the thickness of inverse wind area is, the stronger the corresponding reflectivity factor is, and so rainfall intensity is also strong. Related Articles | Metrics

Select

Optical characteristics of aerosol in autumn of 2010 over Anshan ZHAO Hu-jia， MA Yan-jun，WANG Xu-xin，SU Hong-qiang，ZHU Yi-ming 2012, 28 (4):  55-62.  Abstract ( 824 )   PDF (1032KB) ( 767 )   Save  Based on the observational data with CE-318 sun photometer in Anshan atmospheric composition monitoring station from September to November 2010, the atmospheric aerosol optical depth (AOD) and Angstrom exponent and so on were calculated according to the principles of AOD measurements. The optical feature of aerosol was analyzed in Anshan. The results indicate that AOD value increases with the decrease of wavelength. The mean maximum AOD value occurs in September, then in October, and the minimum one is in November. For the frequency distributions, the mean diurnal AOD values concentrate from 0.4 to 0.6 in September 2010 and from 0.0 to 0.4 in October and November 2010, respectively.  These results suggest that the air is clean from October to November. According to the frequency distributions of Angstrom exponent, atmospheric pollutant is dominated by fine particles in autumn in Anshan. There is a logarithmic relationship between the AOD (500 nm) values  and wavelength exponent, and both correlation coefficients are 0.5145, 0.8412 and 0.2715 in September, October and November, respectively. AOD value is a negative correlation with concentrations of PM10, PM2.5, PM1.0 in September, while it is a positive correlation in October and November. The correlation between AOD value and fine particle of aerosol is significant in October and November. There is a less negative correlation between AOD value and visibility, and it suggests that aerosol particles in upper level have a major impact on aerosol optical depth. Related Articles | Metrics

Select

Relationship between Valsa sordidda nits and meteorological conditions from 2002 to 2008 in Heilongjiang province QU Hui-hui YANG Xiao-qiang LI Shuai JIANG Li-xia JI Yang-hui ZHU Hai-xia 2012, 28 (4):  63-68.  Abstract ( 811 )   PDF (513KB) ( 577 )   Save The relationships between Valsa sordida nits and meteorological conditions were analyzed in order to provide the scientific references for forecasting and controlling the disease. Based on the observational data of Valsa sordida nits and the meteorological data at 14 representative stations from 2002 to 2008, their relationships were discussed by a correlation analysis method. The results indicate that the incidence rates of Valsa sordida nits is in a positive correlation with some meteorological conditions such as air temperature during October of previous  year to April of current year, the temperature-humidity coefficient from May to September, precipitation, the number of precipitation days, the relative humidity from October of previous year to March of current year, the extreme maximum temperature, the diurnal temperature range (DTR), duration of large DTR and the mean wind speed, while it is in a negative correlation with the temperature-humidity coefficient during October of  previous year to April of current year, the mean temperature from May to September, the relative humidity from December of previous year to January of current year, the extreme minimum temperature and sunshine duration. Some climatic conditions such as humidity, warming, cold and the sudden change of cold and warm in winter could strengthen the occurrence and development of Valsa sordida nits, while some others such as abundance sunshine and high summer temperature could restrain the disease. Related Articles | Metrics

Select

Variation of spring corn?water requirement and its relationship with the meteorological factors in Chengde, Hebei province WANG Hong，TAN Guo-ming，SUN Qing-chuan，ZHOU He-ling 2012, 28 (4):  69-72.  Abstract ( 685 )   PDF (447KB) ( 715 )   Save Based on the meteorological data and the corn growth period data from 1961 to 2009 in Chengde of Hebei province, the daily water requirement of spring corn was calculated by using Penman-Monteith formula recommended by the FAO of the United Nation. The changes of spring corn water requirements, the budget in different growth period and its inter-annual variation were analyzed．The effect of meteorological factors on spring corn water requirement was discussed. The results show that the mean total water requirement and its water budget in Chengde are 522.5 mm and 69.4 mm respectively during the growth period of spring corn. The daily water requirement of spring corn firstly increases gradually and then decreases. The spring corn water requirement has a close relation with the meteorological factors. Related Articles | Metrics

Select

Temporal and spatial distributions of thunder and lightning activity and risk division of thunder stroke disaster in Deqing County, Zhejiang province GU Li-hua，CAI Yun-quan，LI Jia-peng，LI Li-song，WAN Kui 2012, 28 (4):  73-78.  Abstract ( 974 )   PDF (1600KB) ( 752 )   Save  Based on the ground lightning data from 2007 to 2010, the density map of ground lightning was drawn by a grid method. The variation of thunderstorm days was analyzed based on the corresponding data in the recent 40 years and risk division of thunder stroke disaster was estimated. The results indicate that the thunderstorm days from 1970s to 1980s are more than those in 1990s and after 2000. The thunderstorm days are in a decreasing trend from 1971 to 2000, while it is in a increasing trend after 2000. There exists thunderstorm in each month except in December, especially in July and August. The thunderstorm occurs mostly in spring and summer, then in autumn, and it is seldom in winter. The thunder and lightning often happens from 12:00 to 13:00 and from 15:00 to 16:00. By 2010, the density of ground lightning is more than 4 times per square kilometer in most areas of Deqing County. The falling areas of dense thunderstorm increases yearly, the high-density area has a diffusion trend to mountain area and the northeast towns. The falling area of thunderstorm has a close relation with topography, and the high-density area is located in the northwest mountain area with the high altitude and in the low slope foothill with the altitude of 50-200 m. The high risk areas of thunder stroke disaster are from Moganshan to Duihekou regions of Deqing County, in the junction of the north of Wukang, Luoshe and Zhongguan and in the southwest of Leidian of Deqing County. Related Articles | Metrics

Select

Characteristics of acid rain and its influencing factors from 2006 to 2010 in Nangong, Hebei province YANG Yun-ling，WANG Cong-mei 2012, 28 (4):  79-83.  Abstract ( 679 )   PDF (664KB) ( 590 )   Save Based on the observational data of acid rain, the ground meteorological data in Nangong from 2006 to 2010, the sounding data and synoptic situation, the characteristics of acid rain and the effect of meteorological conditions on it were analyzed. The results indicate that the mean pH value of precipitation is less than 4.70 in Nangong and acid rain frequency is more than 50%, so it belongs to the serious or more serious acid rain area. The acidity of precipitation is stronger in summer and autumn, while the frequency of acid rain is high in autumn and winter. The conductivity of precipitation is the largest in winter. Acid rain often occurs when the dominant wind is the eastward, calm and north-northwest wind. The frequencies of acid rain and serious acid rain increase with the increase of precipitation grade when upper weather system is a shear line. The intensity of acid rain increases with the increase of relative humidity and inverse temperature. Related Articles | Metrics

Select

An analysis of a typical bow echo LI Sheng-shan，ZHANG Dian-jiang，HU Ling，WU Qiang，YU Li-li 2012, 28 (4):  84-89.  Abstract ( 1015 )   PDF (1705KB) ( 657 )   Save Based on the weather charts, satellite cloud images and the new generation weather radar data, a strong wind process on July 31, 2007 was analyzed. The results indicate that the process is downburst but not tornadoes, and it is produced by the merger process of the bow echo and supercell. The thunder shower and short-time rainstorm occur from the night on July 30 to wee hours on July 31, 2007 during the bow echo moving from southwest to northeast, which affects the six districts and counties of Tianjin. The maximum precipitation intensity reaches 37.6 mm·h-1, while squall, hail and ground gale do not occur in six weather stations. By analyzing the radar data, it shows that the moving bow echo maintaining more than 5 hours merges with a pre-existing supercell in mountain area of Jixian and produces downburst. The weak echo region gap appears in the reflectivity factor chart. At the same time, the bow echo shape is changed and is disconnected above 2.4 ° elevation angle, whose echo intensity reaches 53 dBz. An obvious rear inflow jet occurs early and a mesoscale cyclone generates late companied with the middle and low divergence on the relative radial velocity chart. The strong anti-cyclone features occur in upper level. The height of the storm development is high, and the height of echo top is over 15 km. The nucleus of reflectivity factor drops 3 km rapidly with the occurrence of downburst. Related Articles | Metrics

Select

Spatial analysis method and its application in climate feasibility demonstration of large-scale projects HUANG Shi-cheng，CHENG Ting，CHEN Bin，ZHOU Jia-ling 2012, 28 (4):  90-96.  Abstract ( 674 )   PDF (918KB) ( 919 )   Save The current climate feasibility demonstration report needs more precise assessment conclusions in order to meet the needs of the meteorological disaster prevention and mitigation for the large-scale projects in planning, design and operational phases. Base on the 1:250000 basic geography information, the short-time meteorological observation data accumulated by the climate feasibility demonstration report of some projects such as a major bridge engineering, a nuclear power engineering, a wind power engineering and so on along the lake, river and sea and at inland area, simultaneously observational data and the historical climate data nearby weather stations, the calculation method of the extreme value of climate factors and the effective spatial interpolation scheme of projects were investigated. The meteorological evaluation method of projects and system workflow were established based on the spatial information analysis method. The application results indicate that the climate feasibility demonstration method based on a spatial trend analysis, a spatial correlation analysis and a spatial regression analysis etc. considers the geography information such as the spatial correlation of meteorological elements, topography and underlying surface and so on around the project area and it has a higher calculation resolution compared with the conventional method. Combining with a generalized extreme analysis method, the method could meet the fine needs of meteorological evaluation of a large project. Related Articles | Metrics