Table of Content

28 April 2014, Volume 30 Issue 2 Previous Issue    Next Issue

Articles

Select

Estimation of global and net solar radiation at the Earth surface under clear-sky condition SUN Zhi-an, LIU Jing-miao, ZENG Xian-ning, LIANG Hong 2014, 30 (2):  1-13.  Abstract ( 668 )   PDF (1710KB) ( 523 )   Save  A scheme for estimating global and net solar radiation under clear-sky condition is developed based on an accurate radiation transfer model. Unlike previously used methods, this scheme utilises an idea of radiative band model in the calculations of solar radiation at the earth surface and includes as many atmospheric absorbing and scattering species as possible, which makes the scheme more accurate and globally applicable. The parameterization of aerosol scattering and transmittance proposed by Kokhanovsky et al. is adopted to consider the effects of aerosols on the surface solar radiation. All variables used in the calculations are available in any numerical weather prediction models or they can be obtained from satellite measurements. Therefore, the scheme can be used in a numerical weather prediction model as well as a land-surface model for estimation of solar radiation distribution. The scheme has been tested using the US Atmospheric Radiation Measurements dataset and aerosol data retrieved by the European Space Agency satellites. The results indicate that the scheme is very accurate, the mean relative error is less than 6%, and the root mean square error is 0.3 W •m-2. Related Articles | Metrics

Select

Characteristics of Meiyu and its forming reason in the middle and lower reaches of the Yangtze River in 2011 LOU Xiao-fen,LUO Ling,KONG Zhao-lin 2014, 30 (2):  14-22.  Abstract ( 407 )   PDF (2646KB) ( 431 )   Save  Based on the NCEP/NCAR reanalysis data with the 2.5°×2.5°resolution, the OLR (Outgoing Longwave Radiation) data from the NOAA, the observed precipitation data and the recorded Meiyu index, the evolution characteristics of the South Asia high, the subtropical high, southwest monsoon and convective system in 2011 were analyzed in order to reveal the cause of abnormal precipitation during the Meiyu period. The results show that the abnormal characteristics during the Meiyu period include the advanced beginning and ending dates, the sudden turning from drought to flood, intensive and abnormal abundant precipitation in 2011. The dates of northward jump of the South Asia high and the subtropical high, adjustment of the northern westerly belt circulation at 500 hPa and pushing northward to the Yangtze River valley of southwest monsoon are all earlier than those under the normal conditions, which result in the earlier beginning of Meiyu. The main reason for the earlier ending of Meiyu is that the subtropical high moves northwards and eastwards which is caused by ITCZ (Intertropical Convergence Zone) strengthening and surging northwards with the northward STS (Severe Tropical Storm) “Meari”. The position and intensity of the South Asia high and subtropical high adjust rapidly, so is the circulation of middle-high latitudes. At the same time, the Southwest monsoon and moisture flux transformation are also strengthened. All these factors result in the change from winter monsoon circulation to convergent zone of dry-cold air and warm-wet air in the region of middle and lower reaches of the Yangtze River. The atmospheric stratification is not stable and precipitation intensity is strong during the Meiyu period. Thus, the above-mentioned factors lead to the abrupt change from drought to flood. During the Meiyu period, the subtropical high and the upper westerly jet are stable and strong. The stronger monsoon surge, dry cold air from the middle-high latitudes and propagating eastward convection disturbance over the Tibetan Plateau are favorable to the abnormally abundant precipitation during the Meiyu period in 2011. Related Articles | Metrics

Select

Two methods of initial perturbation generation and both comparison in the GRAPES-EPS system WANG Tai-wei,CHEN De-hui,WU Man-li 2014, 30 (2):  23-30.  Abstract ( 366 )   PDF (3826KB) ( 383 )   Save The basic principles of two methods of a Breeding of growing mode (BGM) and an ensemble transform Kalman filter (ETKF) for the generation of initial perturbation value were introduced and compared with each other. Based on the GRAPES-Meso model, two mecoscale ensemble forecast systems were established, i.e. a GRAPES-BGM and a GRAPES-ETKF. Using the Sepat typhoon event as a case study, the prediction accuracy of two methods for precipitation was compared. The results indicate that two systems can catch the information of precipitation and improve the sever rainfall events. The accuracy of ensemble forecast is higher than that of control forecast, especially for falling area and intensity of the heavy rain to some extent. The talagrand distribution of the ETKF scheme is better than that of the BGM scheme in terms of the poststamps and other verification, while the reverse is true in terms of the TS score of precipitation. Furthermore, the BGM scheme is easy and convenient for weather forecast service. Related Articles | Metrics

Select

Analysis of backflow heavy snowfall weather and its prediction index in Langfang of Hebei province XU Min, LIU Yan-jie, WANG Jie, SUN Yi-tao 2014, 30 (2):  31-37.  Abstract ( 378 )   PDF (2066KB) ( 321 )   Save On the basis of snowfall data from 1990 to 2009, the weather chart, the MICAPS data and the NCEP reanalysis data, backflow heavy snowfall cases in the North China were analyzed and its basic characteristics were summarized. The situation of backflow heavy snowfall and physical features in upper and lower levels at Langfang station and its upstream stations were diagnosed, and some forecast indexes were selected. The results show that the 500 hPa circulation and ground patterns can be respectively divided into two types, i.e. the two troughs and one ridge type and the multi-wave type. It appears “high north and low south” or “northeast high and southwest low” in the east of Asia-Europe on the ground map. The mean intensity at the center of high pressure reaches 1045.5 hPa. The upstream wind direction of ground wind along Langfang is north to East, namely in the west coast of the Bohai sea. The heavy snowfall will happen when the wind speed exceeds 5 m·s-1. Related Articles | Metrics

Select

Study on criteria for winter precipitation phase states in Dandong GAO Song-ying,LI Hui-lin,SONG Li-li,ZHAO Ting-ting,XU Lu-lu 2014, 30 (2):  38-44.  Abstract ( 380 )   PDF (832KB) ( 321 )   Save Based on the daily precipitation data, weather phenomenon, radiosonde data, and the NCEP reanalysis data with resolution of 0.5°×0.5° (part 2.5°×2.5°) during October to April from 1979 to 2012, the climate and atmospheric stratification characteristics of winter precipitation in different phase states were analyzed in Dandong. The typical cases of winter precipitation in the different phase states were discussed. The results show that although Dandong is located in the north of China, winter precipitation phase states are variety. The temperature thresholds for various winter precipitation phase states at each stratification are different in the periods of autumn-winter, winter-spring and winter. Finally the criteria for winter precipitation phase states at the different stratification are determined. The stratification temperature background (especially surface temperature) is important to appearance and conversion of precipitation phase states, which could provide references for the prediction of the dynamic precipitation phase state. Temperature at 850 hPa and below is essential to generation of precipitation phase states. The 0 ℃ line at 850 hPa is the approximate boundary between rain and snow, while that at 925 hPa is between sleet and snow or sleet and rain. Related Articles | Metrics

Select

Characteristics of precipitable water vapor based on ground-based GPS in Dalian HUANG Ting, HUANG Zhen, ZHU Jing, LIANG Hong,ZHANG Jian-guo 2014, 30 (2):  45-50.  Abstract ( 342 )   PDF (1122KB) ( 402 )   Save  Based on the precipitable water vapor (PWV) retrieved from the ground-based GPS observation network in Dalian area, the characteristics of spatial distribution, diurnal variation, monthly variation and the relationship between the PWV and precipitation were analyzed. At the same time, the relationship was fitted between surface temperature and weighted average temperature according to radiosonde data from 2005 to 2011 in Dalian. The results show that the correlation coefficient between the GPS PWV and radiosonde PWV is 0.988 and the root-mean-square error is 2.5 mm. The spatial distribution of the PWV in Dalian is homogeneous. The maximum values of the PWV occur from July to August and minimum values appear in January, and their corresponding monthly averages are 40 mm and 4 mm respectively. The daily variation of the PWV is in a multiple peaks shape with 0.5 mm amplitude range in spring and winter in Dalian, while that in summer and autumn is in a single peak shape with 1.3 mm amplitude range. The PWV increases significantly 8 hours ahead of precipitation, which is of indicative role to the precipitation prediction. Related Articles | Metrics

Select

Characteristics of air quality and its relationship with meteorological factors from 2001 to 2011 in Xi’ning QI Dong-lin,ZHANG Jia-kun,LI Xiao-dong,WEI Hong-ye, WANG Li,MA Ming-liang, KONG Wei-qiang,XIAO Hong-bin,ZHANG Juan 2014, 30 (2):  51-59.  Abstract ( 458 )   PDF (945KB) ( 523 )   Save Based on the daily air quality report and the corresponding meteorological data from 2001 to 2011 in Xi’ning, the characteristic of regional pollution, air quality and its influencing factors were analyzed. The results show that the inhalable particle is the main pollutant and air quality is dominant by excellent and fine grades in Xi’ning. Air quality has a clear seasonal change. It is better in summer, then in autumn and winter, while it is the worst in spring. The air quality is unstable in winter and spring, while it is stable in summer and autumn. The annual air quality changes significantly, and API is higher during winter heating period than during non-heating period. Sand-dust influencing index is in a declining trend in Xi’ning. Air quality is remarkably improved based on analysis of interannual variability. The air pollution is restricted by meteorological factors such as sand-dust days, precipitation, relative humidity and air temperature. Long-range transport of inhalable particulate matters from the northwest of Xinjiang and Gansu provinces, middle and west of Inner Mongolia and Qaidam Basin are important sources of air pollution in spring in Xi’ning. Related Articles | Metrics

Select

Characteristics of visibility during two precipitation processes in Shenyang ZHAO Hu-jia, MA Yan-jun, ZHAO Ming,ZHU Yi-ming,LI Xiao-xiao 2014, 30 (2):  60-66.  Abstract ( 426 )   PDF (1242KB) ( 356 )   Save Using the visibility data on July 29 to 31, August 27 to 29 in Shenyang atmospheric composition monitoring station, the correlation of visibility with meteorological elements such as precipitation, mass concentrations of PM10, PM 2.5 and PM 1.0, wind speed, relative humidity were analyzed. The results show that the features of two precipitation processes on July 29 to 31 (the first process) and August 27 to 29 (the second process) are different. The rainfall amount is greater in a certain time for the former, while it is greater in few continuous hours for the latter. The wet cleaning effect is better to particle matter during the early precipitation for two processes, while the visibility decreases during the later precipitation with the increasing precipitation intensity. The mass concentration of particle matter has a low value about 5 g﹒m-3 because of the action of precipitation and large wind speed together in the first process, while it changes insignificantly because of the stable wind speed in the second process. The correlation of the mean wind speed with mass concentrations of PM10, PM 2.5 and PM 1.0 is negative in two processes. The high relative humidity is favorable to the increase of the particle matter mass concentration. The correlation of the visibility with the ratios of PM 2.5 and PM10, PM 1.0 and PM10 is also negative. The correlation between the particle matter and visibility is gradually increasing with the decreases of the particle size. Related Articles | Metrics

Select

Comparison of aerosol optical properties over source region of sand dust and its downwind region in the East Asia ZHENG Yu-qi, YU Xing-na, XIANG Lei, Dengzengrandeng, Deqingyangzong 2014, 30 (2):  67-73.  Abstract ( 328 )   PDF (1010KB) ( 137 )   Save The aerosol optical properties were compared between source region of sand dust and its downwind region in the East Asia using the observational data from the AERONET site during 2001 to 2011. The results show that the aerosol optical depth is significantly higher over source regions than over its downwind regions during sand dust, while the reverse is true for the Angstr?m exponent and it decreases to zero or even negative when the dust storm appears. The volume spectrum distribution of aerosol particle size is a double peaks shape except in the Dunhuang site. The concentrations of fine particles are extremely higher in Xianghe and Beijing than in the Northwest area, which is caused by the fine particles together with   pollutant aerosols. The averages of aerosol single scattering albedo are 0.93, 0.93 and 0.94 from 440 nm to 1020 nm in China, Korea and Japan. Compared with that in the downwind regions, the real part of refractive index is higher and the imaginary part is lower in the source regions. In general, the average of asymmetry factors at the four wavelengths is 0.70 in the East Asia under sand dust weather condition. Related Articles | Metrics

Select

Characteristic of urban heat island effect in Yangquan, Shanxi province LI Run-chun, CUI Jian-guo,NIU Jun-mei,LI Xing,YUE Kai-jie,WANG Xiao-min 2014, 30 (2):  74-80.  Abstract ( 465 )   PDF (1231KB) ( 499 )   Save Based on the meteorological data at 3 national weather stations from 1972 to 2011 and air temperature data from 36 automatic weather stations in 2011 in Yangquan, the annual, seasonal, monthly and daily urban heat island (UHI) intensity were analyzed. The results indicate that there is the weak heat island effect in Yangquan and the annual average UHI intensity is 0.554 ℃ during 1972 to 2011. The UHI intensity is in a significant upward trend and its increase is mainly due to the increase in summer UHI. The UHI intensity is stronger in winter and autumn and weaker in spring and summer, and the maximum and minimum appear in December and May for the monthly variation, respectively. The minimum UHI intensity appears at 12:00 for the daily variation, and the UHI intensity increases with decreasing of air temperature from the early evening to early morning, and its maximum appears in the morning when temperature drops to the lowest and decreases rapidly after sunrise. The extreme UHI intensity is 7.9 ℃ at 08:00 on January 14, 2010 during 2008 to 2011. In the warming weather, the amplitude of UHI intensity increases in Yangquan and it is easy to form the stronger UHI effect in the morning and the urban cold island effect in the afternoon. In the cooling weather, the amplitude of UHI intensity decreases. It remains the weak UHI effect when temperature changes insignificantly. The major urban development factors in Yangquan are significantly positive correlations with air temperature and the number of hazy days, so urbanization development maybe enable the urban air temperature increase. However, increasing urban green space maybe reduce the UHI effect under the condition of the present economic development in Yangquan. Related Articles | Metrics

Select

Climatic change characteristics over Black Gobi desert region of China XIAN Di,ZHENG Xin-jiang, LI Xue, LI Yong-hua 2014, 30 (2):  81-87.  Abstract ( 441 )   PDF (1317KB) ( 380 )   Save Based on the annual average temperature, precipitation, average wind speed, the number of gale days and dust storm days from 1959 to 2011 at 12 meteorological stations of the Black Gobi desert region, the climatic change?characteristics were analyzed by a climatic trend method and it was compared with that in the desertification region. The results indicate that the annual mean temperature increases and its?rates are 0.34 ℃ and 0.25 ℃ per decade in the Black Gobi desert and desertification regions, so is the annual precipitation and its rates are 1.33 mm and 1.66 mm per decade respectively. The annual mean surface wind speed decreases in the Black Gobi desert region with 0.10 m·s-1 per decade and in the desertification region with 0.14 m·s-1 per decade, so is the number of gale days in Black Gobi desert region with 1.83 d per decade and in the desertification region with 3.44 d per decade. The number of dust storm?days decreases in Black Gobi desert region with 1.83 d per decade and in the desertification region with 1.77 d per decade, respectively. There is only one abrupt change point for most climatic factors except annual precipitation according to a Mann-Kendall test method. The spatial distributions of various climatic factors are different. Related Articles | Metrics

Select

Characteristic of occurrence of rice blast in major rice producing areas of Liaoning province ZHAO Xian-li, LIU Zhi-heng,JI Rui-peng,ZHANG Shu-jie, CAI Fu, CHENG Hai-tao,ZHANG Yu-shu,LIU Ming 2014, 30 (2):  88-92.  Abstract ( 437 )   PDF (1116KB) ( 405 )   Save  Based on the rice blast data at 17 stations in 8 major rice producing areas of Liaoning province from 1999 to 2012, the characteristics of spatial and temporal distribution of rice blast and its tendency were analyzed by a statistical method. The results show that rice yield decreased significantly in 2001, 2003 and 2010 in Liaoning province, and the effect of rice blast on yield is significant. Rice cultivation mainly concentrates in Shenyang, Panjin, Tieling, Liaoyang, Dandong and Yingkou areas, while the rest areas have also a small amount of planting. The most serious rice blast (mainly for panicles blast) occurred in 2001, and the incidence rate is 27.7 %. Rice blast mainly occurred in Xinbin and Qingyuan from 1999 to 2012, and both rates are 17.0 % and 16.4 %, respectively. For the species of the different growing period, the serious rice blast occurs in the mid-early maturity species and the average incidence rate is 10.1 %. For the different planting areas, the serious rice blast occurs in the east of Liaoning province, and the average incidence rate is 11.2 %. Related Articles | Metrics

Select

Analytical analysis of the effect caused by horizontality of antenna pedestals on target-orientation ZHANG Wei-quan, ZHANG Yue, LI Yang,ZHAO Shu-hui, WANG Ji-hong,YUAN Jian, BAN Xian-xiu 2014, 30 (2):  93-100.  Abstract ( 341 )   PDF (825KB) ( 577 )   Save The Practical Coordinate System (PCS) has been originally defined under the condition which the value of the horizontality of the antenna pedestals is nonzero. The analytic relationship between the PCS and the Theoretical Coordinate System (TCS) is also provided strictly. Base on the above relationship and the adoption of rigorous mathematical analysis, the multivariate functional relations of the azimuth-elevation numerical readings of the target which is detected by weather radar between the PCS and the TCS were presented. Additionally, the error-analysis functions of azimuth and elevation are defined, and the analytical analysis on the problem of how the value of the horizontality of antenna pedestals of weather radar affects the target-orientation, has finally been made. The results indicate that the inaccuracy of the target-orientation caused by the horizontality of antenna pedestals of weather radar wouldn’t be greater than the value of the horizontality of antenna pedestals itself when the reading of the elevation is below 45 geometric degrees, while it increases rapidly when the value is above 45 geometric degrees. Particularly, within the vicinal space of the zenithal region, the values could exceed over hundreds of times compared with the value of the horizontality of antenna pedestals itself. Related Articles | Metrics

Scientific Notes

Select

Evaluation methods on the benefit from agricultural meteorological services ZHANG Tai-ren, KUANG Xiao-yan, PAN Shuang-di, FANG Li-qing 2014, 30 (2):  101-106.  Abstract ( 581 )   PDF (537KB) ( 602 )   Save  Scientific and accurate evaluation on the benefit from agricultural meteorological services in China is important to decision makers for government and enterprises and improving disaster prevention and reduction ability of agricultural meteorology. According to the characteristics of agricultural meteorological services and the combined method of a Dose-response analysis and a Delphi technique, an evaluation mode for agricultural meteorological service benefit was established. This evaluation mode takes measurement value of meteorological service contribution rate for typical unit as the reference value, and meteorological service contribution rate in agricultural production was estimated using an expert evaluation method. Based on the above-mentioned method, the benefit value of agricultural meteorological service in He’nan province was evaluated as a case study. The results indicate that the meteorological service contribution rate for farm industry is 6.90 %, followed by husbandry of 4.20%, forestry of 3.93%, and agricultural service of 3.36% and fishing of 2.90%. At the same time, the analysis of the dynamic variation of agricultural meteorological service benefit in He’nan province since 2007 shows that the value of the meteorological service benefit improves with the increasing agricultural production value. The agricultural production value increases from 12.827 billion yuan in 2007 to 19.165 billion yuan in 2010, and annual increased speed reaches 14.32%. Average contribution rate of agricultural meteorological service in He’nan province remains between 5.60% and 5.90%, which is much higher than average of China. It suggests that agricultural meteorological service is important to agricultural production in He’nan province. Related Articles | Metrics

Bulletins

Select

Study on water environmental capacity in the Kouhe river based on aquatic ecological function regionalization WU Song-yu, HU Cheng 2014, 30 (2):  107-111.  Abstract ( 303 )   PDF (664KB) ( 320 )   Save The river water environmental capacity is a theoretical basis for the implementation of total quantity control on pollutant emission, and it is also a scientific basis for river water environmental management. Using a comprehensive identification index method, water pollution situation of the river and the main pollution indicators were identified, and water quality of different aquatic ecological function regionalizations in the Kou River was assessed. The method on aquatic ecological function regionalization was put forward based on the difference of water ecological system. The variation of river water quality was simulated by a one-dimensional water quality model, and water environmental capacity of CODCr and NH4-N in the Kou River upstream higher aquatic ecological function regionalization, the midstream lower aquatic ecological function regionalization, Nanchengzi higher aquatic ecological function regionalization were calculated combining with a linear programming model. The results show that water environmental capacity of CODCr and NH4-N are 852.22 t·a-1 and 47.96 t·a-1 in the Kou River upstream higher aquatic ecological function regionalization, 410.33 t·a-1 and 23.09 t·a-1 in the Kou River midstream lower aquatic ecological function regionalization, 25.23 t·a-1 and 1.58 t·a-1 in the Nanchengzi higher aquatic ecological function regionalization, respectively. Related Articles | Metrics