Table of Content

31 October 2012, Volume 28 Issue 5 Previous Issue    Next Issue

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Establishment of numerical prediction system for Northeast China cold vortex and its operational application ZHOU Xiao-shan CUI Jin WANG Lian-zhong CHEN Li-qiang YANG Sen 2012, 28 (5):  1.  Abstract ( 718 )   PDF (1498KB) ( 696 )   Save Forecast of a heavy rain caused by the Northeast China cold vortex is always difficult but it is important to weather forecasting operation in the northeast China. Based on a number of tests using combination of different physical parameterization schemes, such as radiation, boundary later and cumulus convection schemes available in numerical weather prediction model, the numerical prediction system for the Northeast China cold vortex has been built. The selection of parameterization is based on synoptic verification score that shows improvement in precipitation forecasting. The system includes physical schemes of long wave radiation, Gayno Seaman boundary layer, Grell cumulus parameterization and mixed phase humidity process. The result shows that the forecast accuracy of precipitation caused by the Northeast China cold vortex is higher using this system than using the operational system of meso-scale numerical forecast in the northeast China. At the same time, the influence of forecast products on the forecast capability and systematic error of precipitation caused by the Northeast China cold vortex are evaluated by a synoptic verification method in terms of density, falling areas and moving velocity of precipitation forecast etc.. The evaluation indicates that the forecastprecipitation intensity is stronger than the real; the forecast falling areas moves to west or south; the forecast scope is smaller than the real. These conclusions have been applied to operational forecast and led to better forecasting results. Related Articles | Metrics

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Climate change characteristics and its impacts on water resources in the Liaohe basin from 1961 to 2009 SUN Feng-hua，LI Li-guang，LIANG Hong，YUAN Jian，LU Shuang 2012, 28 (5):  8.  Abstract ( 651 )   PDF (812KB) ( 775 )   Save The Liaohe river basin is one of seven major basins in China, and it has always a serious shortage of water resources. Based on the hydrological and meteorological data from 1961 to 2009, the evolution characteristics were analyzed. The optimal relationship between meteorological elements and hydrological elements were established by the same period and lagged correlation analysis. The results indicate that the warming is obvious in the Liaohe river basin and its amplitude is higher in this basin than in the globe and in China. The variation of precipitation is not obvious in the Liaohe river basin. In general, precipitation is in a slightly decreasing trend. However, there are five obvious fluctuated phases for precipitation variation, i.e. less-more-less-more-less. Evaporation amount is also in a slightly decreasing trend, and so is the runoff in the Liaohe river basin. Evaporation amount is high in spring and summer. There are four fluctuated phases for runoff variations i.e. more-less-more-less. The annual runoff is the least during 1996 to 2009, and the average is only 1.62×108 m3, which is 58% of the mean annual runoff and 32% of  the largest inter-decadal runoff. Runoff concentrates in July and August and amount of which accounts for 50.24% of the amount in whole year. There is a good relationship between precipitation and runoff in the Liaohe river basin. For the annual scale, their correlation coefficients in Tieling and Faku both reach 0.60. For the diurnal scale, the correlation relationship is significant between the current precipitation and runoff on the second day. For all levels, both correlation coefficients exceed 0.70. The highest correlation coefficient could reach 0.85 when the diurnal precipitation is equal or exceeds 25 mm. Related Articles | Metrics

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Application of an ensemble method of quantitative precipitation forecasting YANG Sen，CHEN Li-qiang，ZHOU Xiao-shan 2012, 28 (5):  14.  Abstract ( 529 )   PDF (394KB) ( 597 )   Save An ensemble method based on similar weights (also called "two-step method") was used to integrate the quantitative precipitation forecasts of the 12 numerical prediction models, and put them into the operational application. The results indicate that by comparing the TS scores of 24 hours precipitation forecast from May 1 to October 20, 2009, the accuracy of precipitation forecast by the ensemble method is higher than by each single method of 12 ensemble members and by the ensemble average. Further experiments show that the effects of lag time and expanding grid number on the ensemble forecasts are significant, while that of the each single ensemble member is not significant. The application plan is modified according to these experiments: the expanded grid numbers depends on forecast period validity and precipitation level rather than similarity and if using the newest forecast method of ensemble members. The modified plan is better than the original plan, especially for long forecast period validity and high precipitation level. For Example, TS score of 72 hours forecast period validity for 25 mm precipitation level could increase more than 20%. Related Articles | Metrics

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The characteristics of wind profile radar data in a rainfall process CHEN Nan，HU Ming-bao，XU Fen，SUN Lei，LI Miao-ying 2012, 28 (5):  19.  Abstract ( 784 )   PDF (1052KB) ( 727 )   Save In order to monitor precipitation weather using wind profile radar, the characteristics of wind profiler radar data at the different stages of rainfall including formation, development, and dissipation were discussed and the correlations between vertical velocity, velocity spectrum width detected by the profile radar and rainfall intensity were analyzed according to the comparison and the correlation analysis between the boundary wind profile radar data and the automatic weather station data during a spring precipitation process of 2006 in Nanjing. The results indicate that holes in the horizontal wind profile gradually disappear as rainfall approaches , while holes appear again as rainfall ends, and precipitation increases obviously after low level jet appears. The vertical velocity, velocity spectrum width and refractivity structure constant increase obviously when precipitation appears. The correlation between vertical velocity below the 550 m height level and precipitation is significantly negative, while it is significantly positive between velocity spectrum width from 450 m to 950 m height level and precipitation, namely, rainfall intensity is greatly likely to be stronger when the negativevertical velocity is smaller or spectrum width is bigger. The above results reveal the relationships among wind profile vertical velocity, velocity spectrum width and precipitation intensity, which could be applied to the monitoring of precipitation weather. Related Articles | Metrics

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An analysis of wind field retrieval for typhoon Bilis based on Doppler radar and its improvement DUAN Yun-xia，LI De-qin 2012, 28 (5):  25.  Abstract ( 514 )   PDF (2187KB) ( 779 )   Save A two-step variational method is used to retrieve the “0604” typhoon (called Bilis) of 2006. The retrieval results using the single radar data were compared with that using the dual-Doppler radar data. The results indicate that the two-step variational method can not retrieve well the structure of typhoon using the single radar data. However, this method can retrieve the vortex structure of typhoon at the first step with the dual-Doppler radar data. The Rankine model and the Chen 3 model fit well within and outside the radius of the maximum tangential velocity of typhoon Bilis, respectively. The experiential symmetrical model is added in the two-step variational method in order to determine the moving path of typhoon with the single radar data. The result shows it improves the retrieval ability of the two-step variational method. The retrieval result of wind field is better at the first step by using single radar data after adding the symmetrical model and it is similar to that by using the dual-Doppler radar data. The correlation coefficients of u and v between retrieval results with the single radar data adding the symmetrical model and with the dual-Doppler radar data are both above 0.8, and the mean square errors of u and v at the heights of 2-7 km decrease significantly. Related Articles | Metrics

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The evolution of summer soil moisture from 1981 to 2010 in Heilongjiang province ZHU Hai-xia，GONG Li-juan，QU Hui-hui，LV Jia-jia，WANG Liang-liang，LI Bai-chao，JI Yang-hui，YAN Ping，WANG Qiu-jing，JIANG Li-xia，WANG Ping 2012, 28 (5):  34.  Abstract ( 641 )   PDF (738KB) ( 593 )   Save Based on the soil moisture data at 6 weather stations (Fujin, Longjiang, Shuangcheng, Heihe, Hailun, Ning’an) from 1981 to 2010 in Heilongjiang province, the trend of soil moisture and dry-wet variation of different regions at 0-50 cm soil layer from July to August were analyzed, and the significance of soil moisture variation and its abrupt change were discussed by a Mann-Kendall method. The results indicate that soil moisture from 0 cm to 50 cm soil layer in summer decreases in the recent 30 years in Heihe, Hailun and Longjiang, especially in the west of Longjiang. There is not significant decreasing trend in the east of Fujin, the south of Shuangcheng and Ning’an. There are abrupt changes in Heihe, Hailun and Longjiang by a Mann-Kendall test, and it suggests that drought trend and extent of summer soil moisture become significant in Heihe areas, the west and north of the Songnen plain. The decrease of inter-annual summer soil moisture might be related to the climatic conditions and the deterioration of the soil physical and chemical properties in Heilongjiang province. Related Articles | Metrics

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The risk evaluation and division on rice frost damage in northeast China WANG Liang-liang,YANG Xiao-qiang,LI Shuai ZHU Hai-xia,WANG Ping,JI Yang-hui,JIANG Li-xia 2012, 28 (5):  40.  Abstract ( 553 )   PDF (1093KB) ( 689 )   Save Considering the natural attribute of disaster-causing factor and the social attribute of disaster affected body, a risk evaluation model was established based on a disaster system theory. According to the diurnal minimal temperature data at 182 weather stations from 1961 to 2010, land areas and the social economic data at 172 rice planting areas from 1991 to 2006 in the northeast China, the rice growth period data from 30 agricultural weather stations, the rice frost damage risk was assessed by a traditional method of disaster analysis and a GIS technology. The results indicate that it could be divided into five rice frost damage risk areas in the northeast China, i.e. the highest, the high, the middle, the low and the lowest. The highest risk area is located in the most Heihe area and the west of Yichun in Heilongjiang province, and in the west of Yanbian and the north of Baishan in Jilin province, while the lowest one is in the middle and south of Liaoning province. Related Articles | Metrics

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The relationship between respiratory system diseases mortality and meteorological elements and its prediction in Nanjing LI Xue-yuan,JING Yuan-shu,WU Fan,ZHOU Lian,CHEN Xiao-dong 2012, 28 (5):  46.  Abstract ( 642 )   PDF (483KB) ( 693 )   Save Under the background of global climate change, the impact of climate change on respiratory system diseases can not be ignored. Based on the death surveillance data, demographic data and meteorological data from 2004 to 2010 in Nanjing, the distribution characteristics of respiratory system diseases mortality and its response to meteorological elements in the study area were discussed by a principal component analysis method. A disease mortality prediction model was established. The results show that the patients’ mortalities of respiratory system diseases are the lowest in July and highest in January, and its change amplitude is greater in the first half year than in the second one. The climate is characterized by low pressure, high temperature, and more precipitation in summer half year and by great relative humidity, short duration in winter half year respectively, so the patients’ mortalities of respiratory system diseases are low in the first half year and in an increasing trend in the second one. The fitting coefficients of return test and prediction are 0.755 and 0.795 respectively, and both pass the significance test of 0.01 level. The fitting effect of the principal component regression model is good, which could provide references for the corresponding forecast. Related Articles | Metrics

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An analysis of heating index forecast in winter in Shenyang GUAN Jian-hua,LI Lan,WANG Guan,TANG Ya-ping,LI Dang-hong,MING Hui-qing,SUN Jing,ZHAO Miao,DAI Xin-tong 2012, 28 (5):  49.  Abstract ( 504 )   PDF (598KB) ( 725 )   Save Based on the diurnal meteorological data with 4 hours interval from November 1, 2009 to March 31, 2010 such as temperature, air pressure, relative humidity, precipitation, wind speed, sunshine duration and cloud cover etc. and the simultaneous heating data including temperature of supply water and backwater, a forecast equation was established in Shenyang by a multi-regression method. A heating meteorological forecast index was developed and it could be used to determine the heating load. The results show that the heating meteorological forecast index could be divided into 7 levels if the indoor temperature must reach 18 ℃ . The trends of predicted temperature of supply water and backwater and outdoor air temperature are close, while the trends of the real temperature of supply water and backwater and outdoor air temperature are different. The number of days that the trend of the real temperature of supply water and backwater is similar to that of outdoor air temperature is only 60 days and accounts for 40% of heating period (151 days). The application of the heating meteorological forecast method could improve the quality of heating, control high-energy-consuming and high-emission and provide scientific references for the corresponding department. Related Articles | Metrics

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Radar echo characteristics of a heavy rain process on August 19, 2010 in Fuxin WANG Xian-bin,ZHANG Jian-guo,XIN Yan-hui 2012, 28 (5):  53.  Abstract ( 594 )   PDF (829KB) ( 501 )   Save Based on the Doppler radar data in Yingkou, a heavy rain process in the south of Fuxin on August 19, 2010 was analyzed. The results indicate that a strong echo cell generated in Yixian county moves to the northeast and develops continually and strengthens, which forms a strong echo belt from Yixian county to Haertao of Zhangwu areas. The eastward movement of the strong echo belt is the main reason causing this process. The echo intensity, influencing duration and real precipitation are compared and analyzed. The relationship between the hourly precipitation and echo intensity is discussed. It shows that the hourly precipitation reaches 25 mm and 40 mm when echo intensity is between 35-45 dBz and between 45-50 dBz, respectively. The hourly precipitation can reach 50 mm when echo intensity exceeds 50 dBz, although echo influencing duration is short and less than 3 volume scanning periods. The occurrence and reinforcement of low-level jet provide sufficient water vapor and instability energy for this process and it makes the mesoscale system generation and development, which is the key factor causing the short time rainfall. Related Articles | Metrics

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Diagnostic analysis of a heavy rain process on July 31, 2011 over Heilongjiang province KONG Fan-yan，MA Guo-zhong，YIN Shi-ping 2012, 28 (5):  58.  Abstract ( 590 )   PDF (2777KB) ( 344 )   Save Based on the conventionally observational data, the NCEP reanalysis data and satellite cloud image, the formation reasons of heavy rain weather on July 31, 2011 in the west of Heilongjiang province were diagnosed. The weather system characteristics, atmospheric instable conditions, water vapor condition causing this process and dynamically triggering mechanism were discussed. The results indicate that the heavy rain is caused by the interaction of low vortex, warm-wet airflow in front of low vortex trough and cold air. The strong southerly airflow sets up a water vapor channel where water vapor can be transported rainfall areas. The increase of temperature and humidity in the low level makes atmospheric stratification unstable. The strong northwest airflow converges with the strong southeast warm-wet airflow on low level and generates the strong wind shear, so convergence and ascending motion augment, which provide the dynamic condition for the heavy rain. At the same time, it is favorable to release the unstable energy. Upper divergence and lower convergence go together, which is favorable to the development and maintenance of ascending movement. Mesoscale low pressure and mesoscale convergence line on the ground provide the conditions for the development and maintenance of mesoscale cloud mass. The mesoscale cloud mass still stays about 21 hours in the areas of the heavy rain areas, which is the main reason causing the heavy rain. Related Articles | Metrics

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An analysis of snowstorm and radar echo characteristics from 2001 to 2010 in Dalian WANG Rong-ji，WANG Shu-xiong，JIANG Xiao-wei，LIANG Jun，LIU Xiao-chu 2012, 28 (5):  65.  Abstract ( 690 )   PDF (1850KB) ( 879 )   Save Based on the winter precipitation data at 7 weather stations, the conventionally observational data and the new generation weather radar (CINRAD/SC) data in Dalian from 2001 to 2010, the circulation situations of 8 snowstorm cases occurred during  this period and their radar echoes characteristics were analyzed. The results indicate that the synoptic situation causing snowstorm is related to upper trough formed over north China and stretching towards Huanghuai area before the formation of East Asia trough in 500 hPa. Accordingly, it is related to the eastward or north cyclone (inverted trough) from the south of north China and Jianghuai (Huanghuai) areas and the encounter with southward cold high in Dalian on surface level. The “warm-shear” type is the most in radial velocity field of radar echo and its precipitation intensity increases with the increasing of south and north branches airflows and wind shear, the lifting of shear layer at boundary layer and lower troposphere as well as the occurrence of warm advection, while it decreases with the weakening of southwest airflow at boundary layer and lower troposphere, and the occurrence of cold advection. This study could provide references for snowstorm forecast. Related Articles | Metrics

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Trouble and incident removal of inverse peak current overflowing of CINRAD/SC weather radar transmitting system LI Yang，BAN Xian-xiu，LIU Xiao-dong，ZHANG Wei-quan，WAN Xu-jiang，LU Bing-hong，ZHU Yi-ming 2012, 28 (5):  65.  Abstract ( 565 )   PDF (500KB) ( 542 )   Save The constituents and primary working principles of the modulator in transmitting system of the CINRAD/SC new generation weather radar were introduced. The inspection method of trouble and troubleshooting process were described by using an incident of “inverse peak current overflowing” as a case study, and its reason was analyzed. The results indicate that the main reason of this trouble is pulse transformer turn-to-turn short circuit of transmitting system, which leads to mismatch the modulator, and then inverse peak current overflowing increases rapidly. Thus protection resistance is damaged and makes the current relay working, which comes into being “inverse peak current protection” and high voltage is cut off, finally it results in the trouble of “inverse peak current overflowing”. Replacing the pulse transformer iron core and winding, injecting new No.25 transformer oil, various technical indicators are normal after booting test. The troubleshooting method ensures the normal operation of radar system. Related Articles | Metrics

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Diagnostic analysis of a heavy snow process in November of 2009 in Shijiazhuang LIU Jia-jun，YU Jiang-long，MEI Na，XU Jian 2012, 28 (5):  75.  Abstract ( 742 )   PDF (835KB) ( 440 )   Save Based on the conventionally observational data and the NCEP data, a heavy snow process during November 9-12, 2009 in Shijiazhuang was diagnosed. The results indicate that the heavy snow process is related to upper western trough, southern trough in the south of Hetao area and shear in the middle and lower level. The vertical allocation of the upper and lower level jet is favorable to the strengthening of ascending movement in the heavy snow area. The ascending area is always located in the divergence area on the right side of upper westerly jet and the convergence area in the front of left side of lower southwest jet exit, and the northwest jet in the north of 700 hPa plays a very important role to the strengthening of the heavy snow. The ascending region has a better correlation with the positive vorticity field, and both locations of the strongest ascending region and positive vorticity center are consistent. The better correlation between the ascending motion and humidity field is important to the occurrence and reinforcement of the heavy snow. There exists a high relative humidity (about 90%) column from the surface to 200 hPa over Shijiazhuang. The south warm-wet southwest air airflow from the southwestern and the wetter stream of the Bohai bay from the northeast return streamer are the source of energy and water vapor. Related Articles | Metrics

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Weather conditions of hypertension incidence and its forecast model in Dezhou, Shandong province DAI Yu-tian，YU Feng-ying，CHANG Ping，ZHANG Lin，YANG Yu-xia 2012, 28 (5):  75.  Abstract ( 505 )   PDF (465KB) ( 568 )   Save Based on the hypertension disease data in the people’ hospital of Dezhou and the ground meteorological data from 1999 to 2008 in Dezhou, four liner models according to the relationships between the number of hypertension patients in four seasons and meteorological conditions were established by a step regression method. Considering the life meteorological index and the method of medical meteorology, the hypertension incidence was divided into 4 levels by a clustering analysis method. Accordingly, the incidence in the different seasons could be predicted. The results indicate that the hypertension incidence is related to air pressure and temperature. The heavy fog could influence the hypertension incidence in winter, while its impact is weak in other season. The level of hypertension incidence increases when the heavy fog occurs in winter, especially for continuous heavy fog weather. There is a negative correlation between the level of hypertension incidence and sunshine duration. The level of hypertension incidence increases because of consecutively cloudy weather and little sunshine duration in autumn and winter. Related Articles | Metrics

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An index system and a technical method for the first level aquatic ecoregion in the Liaohe river basin LI Fa-yun， FAN Zhi-ping，ZHANG Bo，WANG Yan-jie，HU Cheng，LIU Su-ping 2012, 28 (5):  83.  Abstract ( 630 )   PDF (1010KB) ( 718 )   Save Aquatic ecoregion of watershed can offer an important foundation for integrated management of water environmental and for changing the management objectives from water quality to aquatic eco-health. Based on the natural attributes of the spatial differentiation of ecological pattern in the Liaohe river basin at a large scale and the progress on ecological environment division in home and abroad, the correlations between the natural factors such as the ratio of annual precipitation to mean annual temperature (P/T), depth of runoff (RD), digital elevation model (DEM), NDVI, hydrological and geologic factors (RP), aquatic environment factors of river and aquatic organism index were analyzed by a canonical correlation analysis (CCA) method. DEM, RD, RP and NDVI were selected as the first level factors of aquatic ecology division, and then an index system and a technical method on aquatic ecoregion were established. The results indicate that it can be divided into 4 first level aquatic ecoregions in the Liaohe river basin, i.e. the mountain and hill area in the upper reaches of west Liaohe river located in the southeast of Daxing’anling and the north of Hebei province, the plain area in the middle and lower reaches of the west Liaohe river, the plain area in the middle of the Liaohe river, the mountain and hill area in the upper reaches of Liaohe-Taizihe river, respectively. All the aquatic ecoregions have the significant relationships with the results of fish species cluster analysis according to historical data and field investigation data. The study offers the technical support for ecological management in the Liaohe river basin and references for the establishment of the technical method of aquatic ecoregion at watershed scale in China. Related Articles | Metrics

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The application of benthic macroinvertebrates in aquatic ecosystem health assessment WANG Yan-jie， LI Fa-yun，FAN Zhi-ping，CHENG Zhi-hui，ZHANG Jian-qi 2012, 28 (5):  90.  Abstract ( 415 )   PDF (747KB) ( 694 )   Save Benthic macroinvertebrates are the main components of the aquatic ecosystem and play a key role in function and health of aquatic ecosystem. With the increasing emphasis on the aquatic ecosystem management based on watershed integrity in China, the studies on aquatic ecosystem health is more and more detailed, thus the study of benthic macroinvertebrates are improved not only in depth but also in breadth. The main study tasks, impacting factors and analytical methods on benthic macroinvertebrates were summarized at home and abroad in recent years. The results indicate that the response of benthic macroinverebrates to the variation of aquatic ecosystem is significant on the spatial scale, so the effects of natural environment, habitat conditions and water quality on benthic animal diversity and its community structure in the different spatial scales were analyzed. The variations of water environment factors caused by the human activities or the damage of habitat could influence directly the species composition and community features of benthic animal according to the integrated analysis of various factors. The analytical methods on benthic animal could be classified as two types, namely, a model analytical method and a biology index assessment method. Which one is selected in the actual application depends on the features of model and index. Related Articles | Metrics