Table of Content

28 June 2014, Volume 30 Issue 3 Previous Issue    Next Issue

Articles

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Estimation of global and net solar radiation at the Earth surface under cloudy-sky condition SUN Zhi-an, LIU Jing-miao, ZENG Xian-ning,LIANG Hong 2014, 30 (3):  1-9.  Abstract ( 610 )   PDF (1015KB) ( 469 )   Save  Radiation calculations in global numerical weather prediction (NWP) and climate models are usually conducted in 3-hourly time interval in order to reduce the computational cost. Although great reduction in time consuming, this treatment can lead to an incorrect solar radiation at the Earth’s surface which could be one of the error sources in modeled surface energy budget, convection and precipitation. In order to improve the simulation of the diurnal cycle of the solar radiation, a fast scheme has been developed based on detailed radiative transfer calculations for a wide range of atmospheric conditions and can be used to determine the surface solar radiation at each model integration time step with affordable costs. This scheme is divided into components of clear-sky and cloudy-sky conditions. The cloudy-sky component is introduced in this paper. The results indicate that the input variables required by this scheme are all available in NWP and climate models or can be obtained from satellite observations. Therefore, the scheme can be used in a global model to determine the surface solar radiation. It can also be used as an offline scheme to calculate the surface radiation using data from satellite measurements. The scheme has been tested using observations obtained from three Atmospheric Radiation Measurements (ARM) stations established by the U. S. Department of Energy. The results show that a half hourly mean relative error of global solar radiation under all-sky conditions is less than 7%. Related Articles | Metrics

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Analysis of the asymmetric structure of typhoon Damrey SHI De-dao, YI Xiao-yuan,LIU Bin-xian 2014, 30 (3):  10-17.  Abstract ( 607 )   PDF (2867KB) ( 565 )   Save  Based on the surface intensive observed meteorological data, the TBB data from FY-2E satellite and the NCEP 1°×1°reanalysis data, the characteristics of the asymmetric structure of the typhoon Damrey (code 1210) and its forming reason were analyzed. The results indicate that the cloud system structure, precipitation falling area and upper and lower wind fields for the typhoon Damrey are all asymmetric after landfall. The heavy rainstorm mainly appears in the northern and northeastern sides of the center of typhoon Damrey. The evolution of the asymmetric structure could be found obviously by the FY-2E water vapor images. The dark area located in the western side of typhoon cuts off the southwestern transfer of water vapor, which makes advective cloudsystem in the western and southern sides of typhoon center weakened and disappeared, while water vapor plume from the southeast goes into typhoon circulation and provides water vapor and energy for typhoon. At the same time, strong upper divergence, weakly vertical wind shear and evident upward movement are all favorable for enhancement and maintenance of advective cloudsystem to the northeastern side of the typhoon Damrey, which could trigger torrential rain. Cold air brought by upper trough intrudes into inside of typhoon and destroys its warm-core structure, which makes typhoon Damrey disappear on the Bohai Sea. Related Articles | Metrics

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Effects of topography ofthe Taihang mountains and Shandong peninsula on the cold airflow snowstorm LI Jian-hua, CUI Yi-shao,YANG Cheng-fang, XIU Xiao-ying 2014, 30 (3):  18-25.  Abstract ( 657 )   PDF (4371KB) ( 484 )   Save A cold airflow snowstorm process on December 6-7, 2005 in the Shandong peninsula was simulated using a WRF model. By reducing the height of the Taihang mountains down to 10 m and uplifting the height of the Shandong peninsula to 500 m, a sensitivity experiment was performed to analyze the effects of topography of the Taihang mountains and Shandong peninsula on cold airflow snowstorm. The results indicate that the intensity of cold airflow snowstorm in the Shandong peninsula increases because of the existence of the Taihang mountains. The convergence intensity of 10 m wind field in the sensitivity experiment by reducing the height of the Taihang mountains is weakened obviously compared with that in the control experiment, especially in the north of the Shandong peninsula. At the same time, the convergence of flow field in the Shandong peninsula is weakened simultaneously as the stream become diverging. A wave is generated as the northwest wind at 850 hPa crosses over the Taihang mountains, and the vortex in the wave strengthens the local convergence by moving downstream to the Shandong peninsula. As the raising of height of the Shandong peninsula enhances the effects of uplifting and convergence, the cold airflow snowstorm is strengthened consequently. Related Articles | Metrics

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Analysis of aerodynamic roughness in the western coast of the Bohai Sea HUANG He, WU Bin-gui, CAI Zi-ying, WANG Jia, YAN Jun 2014, 30 (3):  26-30.  Abstract ( 509 )   PDF (957KB) ( 382 )   Save  Based on the observed wind speed, wind direction and temperature data from wind energy tower at Dagang in the western coast of the Bohai Sea from December of 2009 to November of 2010, the aerodynamic roughnessZ0 around the wind energy tower was calculated using two methods: a wind-profile and a wind speed standard deviation. The results are analyzed and compared. The applicability of the wind speed standard deviation method and the effect of the inhomogeneous underlying surface on the roughness were discussed. The results show that the average roughnesses on three main wind directions are 0.1319 m (north), 0.0386 m (south-east) and 0.0182 m (south-west), respectively. The roughness calculated using the two methods could be similar if a strictly condition control is carried out. On the same direction, the seasonal differences of the roughness calculated by the two methods using 10-30 m meteorological data are not significant, while those using the 50-70m data are significant. On the same layer, the differences of the roughness between different seasons are significant, which reflects the effect of the seasonal vegetation change on the roughness. Related Articles | Metrics

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Forming reason of flood disaster in summer of 2013 in Heilongjiang province LI Yong-sheng,ZHANG Jian, YU Mei,BAN Jin 2014, 30 (3):  31-37.  Abstract ( 699 )   PDF (2805KB) ( 476 )   Save Based on the daily precipitation and NCEP/NCAR reanalysis data from 1961 to 2013, the forming reasons of flood and summer precipitation anomaly were analyzed in the three rivers valley and their tributaries of Heilongjiang province in 2013. The results show that the overmuch former precipitation is the main reason of flood and leads to high soil humidity and overfull water storage in the valley in 2013. At the same time, the rainstorm frequency is higher in 2013 than in the other years because of abundant and concentrative summer rainfall. The water storage capacity in many large and medium sizes reservoirs undertaking the flood control task exceeds the normal standard, so flood discharge increases in order to protect the safety of reservoir dam. The main reasons cause the more summer precipitation in Heilongjiang province are that the northeast cold vortex is active and its path is north-moving; water vapor transport is sufficient at 850 hPa; the location of the East Asian westerly jet is abnormal at 200 hPa and the East Asian summer monsoon is strong. At 500 hPa, the Eurasian zonal circulation is weak; the west Pacific subtropical high is abnormally north-moving in some stages; the Okhotsk blocking high is obvious; it is controlled by the negative anomaly in midsummer over the Heilongjiang region. Related Articles | Metrics

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Definition of monthly cool summer events over northeast China and interdecadal characteristics of atmospheric circulation LI Shang-feng, YING Shuang,YAO Yao-xian, LIAN Yi 2014, 30 (3):  38-45.  Abstract ( 573 )   PDF (2462KB) ( 326 )   Save Based on the daily temperature data from 150 weather stations in the northeast China during 1960-2009, the monthly cool summer event (MCSE) was defined and it was classified into 5 types. The results indicate that the frequency of MCSEs is the highest during 1960s to 1970s, and then reduces gradually afterwards, especially significantly in 1990s. The Ⅲ type MCSE mainly appears in June and August, and the Ⅱ one is in July. The eddy energy of the Ⅱtype MCSE mainly transports from high to middle latitudes under the cold climate background and from middle to high latitudes under the normal climate background respectively, while the reverse is true for the Ⅲ type MCSE. The transfer direction of the eddy energy under the warming background is the same as that under the cold background for the Ⅱtype MCSE, while that is firstly from lower to upper and then from upper to lower for the Ⅲ type MCSE. In addition, the strong and cold air belt covers over the northeast China under the cold background for the Ⅱ and Ⅲ type MCSEs, while it is obvious northeast cold vortex and Ural blocking (west blocking) under the normal climate background. Under the warming climatic background, the Baikal Lake blocking high (middle blocking), the Okhotsk blocking high (eastern blocking) and cold vortex are all significant for theⅡtype MCSE, while the Baikal Lake blocking high (middle blocking) and cold vortex are obvious for the Ⅲ type MCSE. Related Articles | Metrics

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Characteristics of precipitation change from 1961 to 2011 in southeast Chongqing YANG Bao-gang, Qing Ji-ming,ZHANG Tian-yu,XIE Shi-rong,MA Wen-jie 2014, 30 (3):  46-51.  Abstract ( 696 )   PDF (1935KB) ( 388 )   Save Based on the precipitation data from 6 weather stations in the southeast Chongqing from 1961 to 2011, the precipitation change characteristics were analyzed. The results show that the annual precipitation, spring and autumn precipitation are all in linear decreasing trends, especially for autumn precipitation. Summer and winter precipitation is in linear increasing trends, but these trends are not significant. The cycles of annual and seasonal precipitation are not same, and interdecadel cycles of summer and winter precipitation are significant. The days of annual rainfall, drizzle, moderate rain and heavy rain are in linear decreasing trends, especially for the last two variables. There is not significant change for rainstorm days. For interdecadal change, the increasing number of rainy days mainly appears in 1990s which is mainly from the contribution of the drizzle and rainstorm days, while moderate rain and heavy rain days occur seldom during this period. Rainy days seldom appear in 2000s, especially for drizzle, heavy rain and rainstorm, while moderate rain days are relatively high during this period. Related Articles | Metrics

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Spatial and temporal homogeneity of precipitation events from 1961 to 2010 in northeast China LI Bang-dong, ZHAO Zhong-jun,SHU Li-zhong, WANG Shi-gong, SHANG Ke-zheng 2014, 30 (3):  52-58.  Abstract ( 524 )   PDF (1016KB) ( 480 )   Save Based on the daily precipitation data from 90 weather stations in the northeast China during 1961-2010, the climatic characteristics of precipitation events and its temporal and spatial homogeneity were analyzed. The results indicate that the annual precipitation is in a slightly decreasing trend, while winter and spring precipitation increases significantly. The increase of precipitation in spring and winter is mainly associated with the increase of precipitation intensity, while the decrease of precipitation in summer and autumn is with the decrease of precipitation frequency in terms of the number of precipitating days. Although a linear trend of annual precipitation is not significant, the inhomogeneity of the inter-annual precipitation increases. There is a trend that precipitation tendency is moving towards extreme direction, especially in summer and autumn. The inter-annual precipitation events in various grades are inhomogeneous, especially for snowfall events in the last 20 years. The spatial homogeneity of annual precipitation shows an abrupt change in 1993, while that of annual precipitation days is in 1986.After the abrupt change, the spatial inhomogeneity of the former increases and homogeneity of the latter fluctuates significantly. The variation of precipitation events is likely to increase the risks of flood and drought in the northeast China, so is the events that flood in some regions and drought in other regions occur simultaneously. Related Articles | Metrics

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Temporal-spatial change of temperature and precipitation based on CAST in northeast China SUN Qian-qian, LIU Jing-miao 2014, 30 (3):  59-65.  Abstract ( 626 )   PDF (972KB) ( 630 )   Save  Based on the daily temperature and precipitation data from 81 weather stations during 1961-2010 in the northeast China, the spatial-temporal variations of mean annual temperature and precipitation were analyzed using methods of a rotated principal component analysis (REOF) and a cluster analysis statistic test (CAST). The results show that the warming trend is significant in the northeast China, and the trend differs significantly in the different areas. The ascending trend of temperature is more obvious in the north and east regions than in the west and south regions. On the contrary, the annual precipitation is in a decreasing trend, especially in the western region of northeast China. Related Articles | Metrics

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Characteristics of SO2 , NO2 and O3 in the northern suburb of Nanjing YANG Jun-mei, LI Pei-ren, LI Yi-yu, FENG Qiu-juan,LI Jun-xia, HAN Yong-xiang, ZHU Bin 2014, 30 (3):  66-70.  Abstract ( 652 )   PDF (1023KB) ( 532 )   Save Based on the atmospheric pollutants data from a differential optical absorption spectroscopy (DOAS) system in Nanjing University of Information Science and Technology, the mass concentrations of O3, NO2 and SO2 in the northern suburb of Nanjing from January to November in 2008 were analyzed. The results indicate that the monthly mean mass concentrations of O3 are high in summer, while both mass concentrations of NO2 and SO2 are low in summer. The diurnal variation curve of O3 mass concentrations is mono-modal, while both curves of NO2 and SO2 mass concentrations are bimodal. The correlation between diurnal NO2 and O3 mass concentrations is negative. The SO2 mass concentrations are generally high in this region, and the weekend effect is more apparent for NO2 and SO2thanfor O3 in summer. Related Articles | Metrics

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Climatic characteristics of haze days and its relationship with meteorological conditions over Jiangxi province WU Shan-shan, ZHANG Yi-zhi,HU Ju-fang 2014, 30 (3):  71-77.  Abstract ( 795 )   PDF (1057KB) ( 466 )   Save  Based on the observation data from 83 meteorological stations and radiosounde stations at Nanchang and Ganzhou of Jiangxi province during 1980-2011, the climate characteristics of haze days and its relationship with meteorological elements were analyzed. The results show that the haze days are in an upward trend in the past 32 years and have significant inter-annual and inter-decadal variations. A larger number of haze days occur in autumn and winter with the maximum number in December and smaller number appears in spring and summer with the minimum number in July, respectively. There are significant 4-year and 8-year cycles for annual haze days and 15-year cycle for inter-decadal variation. The spatial distributions of haze days are inhomogeneous in Jiangxi province with a larger number in the north and smaller in the south and mountain area. It is found that the low wind speed, temperature inversion, high pressure, high humidity and less rainfall are favourable conditions to the occurrence of haze. Conversely, the high wind speed, low pressure, low humidity and abundant rainfall are not favourable. Related Articles | Metrics

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Comparison of two methods for determination of empirical coefficients used to estimate total solar radiation in Hebei province YU Chang-wen, XU Qi-hui, QIN Li,LIU Jin-ping 2014, 30 (3):  78-84.  Abstract ( 504 )   PDF (1441KB) ( 592 )   Save  Based on the monthly sunshine percentage and solar radiation data from 8 solar radiation stations surrounding Hebei province, the empirical coefficients of a and b in the climatic formula of total solar radiation were calculated by a least-squares method. These coefficients were then obtained for 142 stations in the whole province using methods of a latitude partition and an inverse distance weighted interpolation. The total solar radiations at four solar radiation observational stations were calculated using the above empirical coefficients and the results were compared with the observation. The comparisons have shown that the accuracies of the two methods are similar. However, the annual total solar radiation calculated using the latitude partition method is closer to the observation. Thus, this method is recommended to use for estimating the total solar radiation in Hebei province. Related Articles | Metrics

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Analysis of hypersensitive meteorological factors of cerebrovascular disease and its prediction model in Panjin 　YANG Wen-yan, YUAN Chao, SUN zhuo,BAI Ru-yu,WANG Bin-fei 2014, 30 (3):  85-90.  Abstract ( 601 )   PDF (877KB) ( 388 )   Save Based on the number of the cerebrovascular patients obtained from Panjin center for disease control and prevention during 2008-2009 and the synchronous meteorological data, the relationship between cerebrovascular disease and meteorological elements, a meteorological forecasting model on the cerebrovascular disease incidence trend was established by methods of a correlative analysis and a stepwise regression. The results indicate that there is a relatively good correlation between the meteorological elements and the moving average of the number of the cerebrovascular patients in the coming three days. The impacts of the meteorological factors on the number of the cerebrovascular patients have the hysteresis and persistency effects. The number of the cerebrovascular patients has obvious correlation with the meteorological elements such as the daily minimum air temperature, average air temperature, the minimum pressure, average wind speed, humidity, and the maximum daily temperature range and so on. The number of the cerebrovascular patients is affected by different hypersensitive meteorological factors in different seasons, and the correlations between them differ greatly. The tests have shown that the accurate rates of the cerebrovascular disease incidence trend model are relatively high. Related Articles | Metrics

Scientific Notes

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Characteristics of climatic potential productivity of vegetables from 1971 to 2010 in Chongqing JI Li,LI Qiang, GOU Si, LI Jia-qi, MA Jun, WANG Zhi-hui, RAN Jing 2014, 30 (3):  91-95.  Abstract ( 436 )   PDF (877KB) ( 311 )   Save Based on the daily meteorological data set at 34 ground weather stations from 1971 to 2010 in Chongqing, the climatic potential productivity of vegetables was anlayzed by methods of a Mann-Kendall and an empirical orthogonal function (EOF) combining the climatic potential productivity model developed by Zhou Guangsheng. The results indicate that the mean annual climatic potential productivity of vegetables is in a decreasing trend and has a significant abrupt change because of decreasing precipitation. The climatic potential productivity of vegetables is higher in the southeast and west-northeast of Chongqing. The climatic potential productivity has obvious local differences. The warm and wet climate is favourable to the growth of vegetables in Chongqing. Related Articles | Metrics

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Influence of climate warming on temperature at the surface and plow layer in the west region of Liaoning province ZHANG Fu-rong, ZHANG Guo-lin,FENG Xue-fei,LIU Zhi-peng, ZHANG Yu-Shu 2014, 30 (3):  96-99.  Abstract ( 593 )   PDF (526KB) ( 440 )   Save The variations of temperatures at the surface and plow layer during 1952-2010 in the west region of Liaoning province were studied by methods of a climate tendency rate, a standard deviation and a baseline year. The results show that the annual mean surface temperature, and the mean temperature of the surface and plow layer in the growing season are in increasing trends, and the climate tendency rates are 0.395 ℃per decade, 0.304 ℃per decade and0.206 ℃per decade respectively. The higher increasing rates occur in winter with 0.535 ℃ per decade and spring with 0.521℃ per decade, and the lower increasing rates are in summer with 0.223 ℃ per decade and autumn with 0.291℃per decade respectively. Warming in the third baseline year is most significant. This study could provide the references for the structural readjustment of agricultural production and the ecological environment improvement, etc. in this region. Related Articles | Metrics

Bulletins

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Application of CFD to studying the effect of building on wind observations at meteorological station YOU Li-jun,ZHANG Xiu-zhi,ZHANG Xiao-dong,BAI Luo-lin 2014, 30 (3):  100-105.  Abstract ( 550 )   PDF (628KB) ( 540 )   Save   Human factors such as urbanization and changes of observing environments cause inhomogeneity of wind speed series at some meteorological stations, so corrections need to be done when using this kind of wind speed data. Using the Dongshan meteorological station as a case study, the influence of buildings on wind speed data was analyzed by a CFD method in terms of five year wind speed data before and after the building erected, and the data of the 10 in tions historical evolution of observing environments. The results indicate that the influence of buildings on wind speed varies with the relative positions of wind measurement mast. The buildings in the north side of the station influences northerly wind speed significantly. According to the influence of buildings on the different wind speed, it can be learnt that the relationship between simulated and observed wind speeds is a linear correlation, so a correction formula of wind is established by this correlation relationship. The influence of buildings on north wind speed is generally eliminated after correction. The other obstacles should be taken into account when revising wind speed of NNE direction because of light influence of buildings on NNE wind. It is proved that CFD could be applied for quantitative evaluations of influence of buildings on wind speed, thus wind speed series of station could be rebuilt. Related Articles | Metrics

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An aquatic ecoregion-based assessment for water ecological security at typical watersheds in the northern areas of Liaoning province WEI Ran, LI Fa-yun, WANG Jin-long, LV Chun-jian 2014, 30 (3):  106-112.  Abstract ( 543 )   PDF (879KB) ( 363 )   Save An aquatic ecoregion-based assessment for water ecological security can offer a premise for the integrated management guidance of watershed ecological with the rule of “by type, by region”. Based on the natural features and social attributes of the spatial differentiation of ecological security pattern in basins on small and medium scales, the typical two tributaries in the northern Liaoning were selected as the study areas, i.e. the Qinghe river and the Fanhe river. On the basis of the third grade  aquatic ecoregion, 6 elements including socio-economic pressure, environmental pressure, urban development indicators, development of resources and environment indicators, investment indicators, governance indicators were anlayzed and 13 indexes were selected according to the pressure-state-response model (PSR). The ecological security is divided into five degrees according to ecological security index by using the comprehensive ecological security index method, and they were specially insecurity, insecurity, basically security, security, special security.At the Qingheriver basin, ecoregion with codes of Ⅳ-5-9,Ⅳ-5-10,Ⅳ-5-11,Ⅳ-5-12,Ⅳ-5-14 are basically security and those with codes of Ⅳ-5-8 and Ⅳ-5-13 belong to insecurity. The ecoregions with codes of Ⅳ-5-1,Ⅳ-5-2,Ⅳ-5-3 of Fanhe river basin belong to basically security, and that with code of Ⅳ-5-4 is security. The results of aquatic ecoregion-based ecological security and grade division offer scientific references for water ecological protection and overall ecological management of Liaohe river basin. Related Articles | Metrics