Table of Content

28 February 2014, Volume 30 Issue 1 Previous Issue    Next Issue

Articles

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Numerical simulation on microphysical mechanism of stratiform cloud precipitation in Hebei province WANG Xiu-juan,JIANG Zhong-bao,YANG Jie-fan, XIA Wei, ZHANG Chao 2014, 30 (1):  1-7.  Abstract ( 360 )   PDF (2497KB) ( 402 )   Save Microphysical structures and precipitation process of a stratiform cloud on May 1, 2009 in middle-east of China were analyzed by a one-dimensional stratiform cloud model. The results indicate that this precipitation process is caused by stratiform cloud, and the vertical structure of stratiform cloud is consistent with Koo Chen-Chao’s three-layer cloud conceptual model and “seeder-feeder” cloud mechanism. In the first layer (upper layer from 4.7 km to 7.0 km), there are ice crystal particles and snowflake, and the latter is formed in the way of sublimation and automatical conversion from ice crystal. In the second layer (middle layer from 2.6 km to 4.6 km), there are ice crystal particles,, snowflake, graupel, supercooled water droplets and rain droplets, and they are influenced significantly by the Bergeron process. In the third layer (lower layer from 1.3 km to 2.5 km), there are mainly cloud droplets, rain droplets, the melting snow droplets and graupel droplets from upper layers. The graupel droplets contribute greatly to the formation of rain droplets. When the cloud system develops maturely, there is a certain “seeder-feeder” relationship among the different layers. For example, the first layer supplies snow and ice crystal particles to the top of the second layer and the second layer sends graupel and snow particles to the top of the third layer. Related Articles | Metrics

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Numerical simulation on hail weather caused by meso-scale vortex inside cold vortex over northeastern China FANG Chun-chun, GUAN Chun-ling 2014, 30 (1):  8-14.  Abstract ( 565 )   PDF (2014KB) ( 446 )   Save  Based on the NCEP grid data, a hail weather process on August 21, 2011 in Shenyang region was simulated and its formation mechanism was analyzed using the automatic observation data collected at the airport, Doppler radar data and satellite image. The results show that the hail weather is caused by mesoscale vortex of cold vortex over northeastern China, so is mesoscale cloud cluster on the satellite cloud images. The 0 ℃ and -20 ℃ isothermal lines are located in 600 hPa and near 450 hPa, respectively, and the thickness between them is about 2 km. Before the hail occurs, the maximum ascending speed of obliquely ascending airflow is more than 20 m·s-1 and water vapor accumulation region is located in the layer above 0 ℃, which ensures that the water accumulated area consists of super cooled water droplet. The upper dry cold air invades into the warm-wet air of middle-low level, which is important to convective occurrence and development. The MPV1 in the low level provides the convective instability mechanism for strong convection; the MPV2 in the middle level is for symmetric instability mechanism; two unstable mechanisms coexist in the high level and both contribute to the development of convection. The evolution of convective available potential energy accumulation and release with the time is indicative to hail. At 10:30, the echo intensity increases with the height on Doppler radar map. There is southwest low level jet on the velocity map. Both are favorable to the development of convective. Related Articles | Metrics

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Cause of heavy rain by shear line in the Haihe river basin LU Huan-zhen, LIU Yi-wei, ZHANG Nan 2014, 30 (1):  15-22.  Abstract ( 427 )   PDF (4184KB) ( 410 )   Save  Based on conventional meteorological data from automatic weather stations and intensive stations, FY2C TBB data, Doppler radar data, wind profiler radar data, and the NCEP reanalysis data with 1°×1° resolution, the cause of heavy rain by shear line in the Haihe river basin was analyzed. The result shows that the heavy rain occurs under the favorable configuration condition of the low-level shear line and the upper and lower level jets. The differences of the cold air path and the vertical structure lead to the heavy rain falling in the different areas with different intensity. The banded α-mesoscale convective cloud generates and develops along the shear line, and the β-mesoscale MCS (Mesoscale Convective System) develops, moves, combines, strengthens along the band. The MCC (Mesoscale Convective Complex) will generate within the banded convective cloud system if the vortex is formed along the lower shear line. The position of heavy rainfall is located in the front side of the MCS or MCC moving direction and in the area of the maximum gradient of the TBB contour. The water vapor convergence stretches from the ground to high level before the heavy rainfall. The higher the stretching height of water vapor layer is, the stronger the rainfall is. The center of the heavy rain is corresponding to the two large values of water vapor flux convergence zones in the southwest and east areas where the contours are intensive. The VAD (Velocity Azimuth Display) wind profiles and wind profile radar data show that the low-level jet and ultra low-level jet successively appear which makes the rain intensity strengthened again. Related Articles | Metrics

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Application and verification of sea wave forecast by WAVEWATCH III model in the Bohai Sea of China LI Yan, HUANG Zhen, ZHANG Jun-feng, WU Wen-jie,ZHANG Cai-feng, ZHAO Qian-fei 2014, 30 (1):  23-29.  Abstract ( 475 )   PDF (1313KB) ( 375 )   Save Sea wave was forecasted by the WAVEWATCH III model in the Yellow Sea and the Bohai Sea of Dalian. The products from the sea wave numerical forecast system include sea wave height, sea wave period and sea wave direction every three hours within 48 hours, and all were tested. The results indicate that the sea wave height could be simulated well by the WAVEWATCH III model in the middle of the Bohai Sea and TS (Threat Score) of sea wave height reaches 71.7%, while that is not well near the coast. The analysis of some cases shows that the maximum sea wave height and the trend of sea wave height could be simulated well. The occurrence time of the maximum sea wave height from the model agrees with that of the observation. Moreover, the simulated two sea wave period cases are tested, and the lowest error is 0.17s. The forecast effect of sea wave period by the WAVEWATCH III model is good. Related Articles | Metrics

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Study on quantitative test and forecast index of numerical forecast precipitation products in Yingkou region ZHANG Jing,YAO Wen,HE Xiao-dong,WU Fu-jie,ZHAO Xiao-chuan, WANG Dong 2014, 30 (1):  30-35.  Abstract ( 403 )   PDF (749KB) ( 357 )   Save Based on the numerical forecast precipitation products from the weather online, the Japan facsimile chart, the United States global forecast system (GFS) and the T639 during August of 2010 to July of 2011, precipitation forecast products in Yingkou region were tested by a statistic method and a synoptic method in terms of forecast time validity, forecast precipitation intensity grades and influence system and so on in order to improve the accuracy of forecast. The results show that the accuracy rates of various numerical forecast products decrease generally with the time, while the forecast effect from the weather online and the GFS is good and stable, then from the Japan facsimile chart. The stability of the T639 is the worst among all methods. The simulated value from the various numerical forecast products is lower than the observed value, especially for the heavy rain forecast with poor stability and small precipitation grade. There is obviously false alarm and failed forecast for light rain. There is failed forecast for the upper trough and cold vortex among all numerical forecast products, and most are in the light rain magnitude. Related Articles | Metrics

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Error analysis of hail index and its application to hail cloud identification GUO Xiao-chao, XIAO Lei,LI Ming-yuan,YAO Zheng-lan, YAO Cheng-yong 2014, 30 (1):  36-42.  Abstract ( 407 )   PDF (526KB) ( 308 )   Save The effects of several important factors on the error of hail index were analyzed by a simulation test method. Using the measurement indexes of probability of detection (POD), critical success index (ICS) and false alarm ratio (RFA), the 25 hail storms and 72 non-hail storms among 12 hail processes during March of 2008 to July of 2012 were assessed based on the new generation Doppler weather radar data in Zunyi City. The results indicate that H0, the vertical profile of reflectivity factor and distance between the target and radar have great influence on POSH error, while Hm20 has insignificant influence. There are high RFA and low ICS when POH are used to recognize hail cloud. Identification effect of POSH is better than that of POH. Increasing threshold can enhance ICS and decrease RFA. The POD is low when the threshold is larger. POSH=70 is the best threshold, with which high POD and ICS and low RFA can be obtained. POD has no change when POSH and VIL>20kg·m-2 are used together to identify hail cloud, but lower RFA and higher ICS can be obtained when the threshold of POSH is less than 90. Related Articles | Metrics

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Comparison of PMF and PCA/APCS for VOCs source apportionment in north suburb of Nanjing GAO Meng, AN Jun-lin, HANG Yi-xian,LI Yong-yu 2014, 30 (1):  43-50.  Abstract ( 1264 )   PDF (705KB) ( 1079 )   Save The PMF model and PCA/APCS model were used to apportion atmospheric VOCs qualitatively and quantitatively in Nanjing, and both results were compared. The results show that the simulation result for the different types’ VOCs by the PMF model significantly differs, while it is similar to each other by the PCA/APCS model. The number of sources apportioned by the PMF model is greater than that by the PCA/APCS model. Both source profiles are similar, while the PCA/APCS model fails to distinguish gasoline evaporation and vehicle exhaust emission. The contributions of plant emission and industrial production apportioned by the two models are close, while those of the other sources differ. The contribution of solvent use is greater for the PCA/APCS model than for the PMF model, while the contribution of gasoline evaporation plus vehicle exhaust is greater for the PMF model than for the PCA/APCS. Related Articles | Metrics

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Change of haze day and its forming reason in Hebei province FU Gui-qin,ZHANG Ying-xin, GU Yong-li, ZHANG Yan- heng 2014, 30 (1):  51-56.  Abstract ( 457 )   PDF (1106KB) ( 503 )   Save Based on the observed meteorological data from l981 to 2010 in Hebei province, the temporal and spatial distributions of haze days were analyzed according to the observation and forecast standard of haze. The forming reason was discussed using haze days in Shijiazhuang as a case study. The results indicate that the haze days appear frequently in the east of Taihangshan mountain area. The center of the great frequency haze days expanses with the time, and the frequency is in a increasing trend. The haze days have three changing styles in the representative station, namely, increasing, decreasing and stability. There is a significantly change between stations. The haze days are mainly light haze and its visibility is more than five kilometers in Hebei province. There is a significantly seasonal change for the middle and serious haze days in the representative station. Most haze days appear in autumn and winter and account for 64% of the total. The haze formation is a result of combing effects from many factors. The regional distribution of haze days is related with the geographical environment and climatic factors such as inversion temperature, wind speed, relative humidity, and annual precipitation days. Furthermore, air pollutant emissions caused by the local economy development and the human society action could also lead to the haze. Related Articles | Metrics

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Variation characteristics of winter air temperature in Liaoning province and its relations with East Asia winter monsoon FANG Yi-he1 ZHANG Yun-fu, SHAO Peng-cheng,ZHOU Fang, ZHAO Lian-wei, JIANG Peng, YU Yang 2014, 30 (1):  57-63.  Abstract ( 548 )   PDF (2091KB) ( 376 )   Save  Based on the monthly mean temperature data from 53 observational stations in Liaoning province during 1961 to 2012 and the NCEP/NCAR reanalysis data such as the monthly mean height field, wind field and sea surface pressure, the spatial and temporal features of the winter air temperature were analyzed. The previous definitions of six East Asian winter monsoon indexes were reviewed and calculated, and the relationships of winter air temperature in Liaoning province with the six indexes were compared. The results show that the mean variance of winter air temperature is greater in the eastern region than in the western region during 1961 to 2011, and it is in a significant positive trend in most regions of Liaoning province. The first pattern of EOF shows that winter air temperature in Liaoning province is abnormal high or low. The time coefficient is in a significant increasing trend and the abrupt change occurs in 1977. There are cycles of 4.5 years, 2.0 years and 3.0 years cycles for winter air temperature in Liaoning province. The East monsoon index  defined by Zhu has the best relationship with winter air temperature in Liaoning province regardless of the abrupt change time, periodic characteristics, correlation coefficients and inverting corresponding relations. The relationship can be clearly explained in 850 hPa meridional wind field and sea surface pressure field. Related Articles | Metrics

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Differences anlyasis of historical hourly meteorological data from national basic automatic weather stations due to use of two types of transportation data format ZHANG Zhi-fu,REN Zhi-hua,ZOU Feng-ling 2014, 30 (1):  64-68.  Abstract ( 295 )   PDF (841KB) ( 508 )   Save The hourly data of 6 routine meteorological elements at 2400 national automatic weather stations from 2006 to 2009 were compared, and the data were obtained by A files and Z files (two types of data transport methods). The results indicate that the hourly 2 min and 10 min wind data from two methods are significantly different because of the different artificial decisions for the wind direction when the wind speed is zero, while the other elements from the two methods have relatively small difference. For the different data in two methods, the rates of temperature, air pressure, relative humidity, precipitation, 2 min and 10 min winds within the instrumental error ranges are 23.27 %, 5.4 %, 23.19 %, 65.42 %, 12.93 % and14.16 %, respectively. Related Articles | Metrics

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Characteristics of lightning and it relations with precipitation in Shaoyang region ZHOU Ming-wei,ZHOU Si-qing,PENG Shuang-zi, YIN Zhong-hai, XIAO Wen-an 2014, 30 (1):  69-74.  Abstract ( 306 )   PDF (920KB) ( 328 )   Save Based on the data from a cloud-ground lightning location system and 24 hours precipitation data from the weather stations, the characteristics of lightning in Shaoyang region from 2008 to 2010 were analyzed and its relationship with precipitation was discussed. The results show that most lightning is negative and its large value center is located in the northeast, while its frequency decreases from northeast to southwest. The frequency of cloud-to-ground (CG) lightning has an obvious diurnal change, and the highest frequency usually occurs from 13:00 to 19:00. The cases under 1 mm and 10 mm accumulated precipitation account for 29.63 % and 76.30 % respectively with lightning, while corresponding values are 69.44 % and 96.30 % without lightning. The rainfall events that 24 hours accumulated precipitation is over 20 mm usually occur with lightning, and it is seldom without lightning. The correlation coefficients between CG lightning frequency and convective rainfall are greater than that between CG lightning frequency and the total precipitation, and the former becomes stronger with the increasing of the time-scale. Related Articles | Metrics

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Analysis of residential indoor CO concentration due to coal-burniing during winter in Jilin province XIE Jing-fang, DONG Wei, WANG Ning,CHEN Lei,YANG Jing-hua, JIN Ying-zi, TIAN Zhong-chen 2014, 30 (1):  75-79.  Abstract ( 314 )   PDF (686KB) ( 367 )   Save  The CO and CO2 concentrations and air temperature in the indoor and outdoor were observed and compared using a multi-function radio collector in 10 coal-burning residences in Jilin province during winter. The characteristics of CO and CO2 concentrations and their relationships with the coal-burning route and indoor air temperature were analyzed. The results show that the indoor pollution comes mainly from CO of the coal combustion. The CO pollution in coal-burning residences is prevalent in Jilin province during winter and about 60% residences appear the persistent high pollution with CO concentrations exceeding 125 mg·m-3 among samples in this survey. The monthly change of indoor CO concentration is related with coal consumption, while its diurnal variation is related with the burning method and the process of burning. The CO proportion in the flue gas differs significantly in different seasons, cities, residences, temperature and combustion process. The variation characteristics of CO concentration also differ significantly in different burning stages such as lighting the fire, normal combustion, or putting the coal over the fire and extinguishing the fire, and in the different burning status such as burning strongly, reversing the smoke flowing direction sharply or slowly. Related Articles | Metrics

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Spatial and temporal variation of thermal resources from 1960 to 2010 in North and Northeast China ZHANG Li-bo, JING Yuan-shu,CHEN Chuan-lei 2014, 30 (1):  80-87.  Abstract ( 306 )   PDF (1660KB) ( 542 )   Save  Based on the daily average air temperature data at 165 meteorological stations in North and Northeast China from 1960 to 2010, the temporal and spatial variation characteristics of accumulated temperature steadily above 0 ℃ and 10 ℃, their lasting days, the beginning and ending dates were analyzed using a linear trend estimation method in order to find out the impact of climate warming on the distribution of thermal resources. The results show that the air temperature increases continuously in North and Northeast China, with an increasing trend of annual average air temperature of 0.32 ℃ per decade (P<0.001). It is well correlated with the other thermal resources indexes. The above 0 ℃ and 10 ℃ steady accumulated temperature and its lasting days increase significantly in North and Northeast China with climate warming, and the increasing trends for both are greater than 30 ℃·d per decade and 2 days per decade, respectively. The northern boundaries of subtropical zone and warm temperature zone move northward in North and Northeast China after 2000, especially the former. The northern limit of two-cropping systems moves northward obviously in Shanxi and Liaoning provinces after 1990s, and the mean moved distance exceeds 1.5 latitudes. The widespread increase of the above 0 ℃ and 10 ℃ steady accumulated temperature and their lasting days are influenced by advanced shift of the beginning date and backward shift of the ending date. Furthermore, the influence of the  advanced shift of the beginning date is more significant than that of the backward shift of the ending date for the above 0 ℃ steady accumulated temperature and lasting days, while both have similar influence for the above 10 ℃ steady accumulated temperature and lasting days. Related Articles | Metrics

Scientific Notes

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Temporal and spatial characteristics of number of human comfortable days in Chongqing area JI Li, LI Jia-qi, GOU Si, LI Qiang, WANG Zhi-hui, LI Guang-bing, ZHANG Shuang 2014, 30 (1):  88-94.  Abstract ( 579 )   PDF (1694KB) ( 444 )   Save Based on the diurnal meteorological data from 34 ground weather stations from 1981 to 2010 in Chongqing region, the temporal and spatial characteristics of the number of human comfortable days were analyzed in terms of human comfortable index models and assessment standards of climate impact, and the methods of a linear regression, a M-K mutation, a wavelet theory and an EOF analysis were employed. The results show that the annual mean of the number of human comfortable days are 199 d in Chongqing area. The main comfortable seasons are spring and autumn, and both account for 71% of the year. The inter-annual changes of human comfortable days are significant, and it is in a rising trend in general. There are two periodic oscillations of 4 years and 7-8 years. The hot uncomfortable day is in an ascending trend, while the cold one is in a descending trend. The mean annual human comfortable days and hot uncomfortable days are greater in the southwestern Chongqing and northeastern Chongqing than in the other areas of Chongqing and there are seasonal variations, while the reverse is true for the cold uncomfortable days. Related Articles | Metrics

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Temporal and spatial distribution of direct solar radiation from 1961 to 2010 in Hebei province ZHANG Yi-wei,YUAN Shu-jie,GAO Xu-xu,LI De-jiang, LI Xiao-hong, LIU Zhen-hong, ZHANG Wen-zong 2014, 30 (1):  95-99.  Abstract ( 378 )   PDF (935KB) ( 428 )   Save Based on the observed solar radiation data at 7 stations from 1961 to 2010 in Hebei province, a relatively accurate empirical formula on direct solar radiation was obtained. The temporal and spatial distribution of solar radiation was analyzed in Heibei province. The results indicate that the total annual solar radiation is in a decreasing trend, and the relatively higher and lower decreasing amplitudes are 25% in Shijiazhuang and 11% in Tangshan. The spatial variation of the horizontal direct solar radiation in Hebei province in recent 50 years is quite different. The area with the value less than 2540 MJ·m-2  is mainly in the southern Xingtai, while the that with the value more than 3510 MJ·m-2 is in the northwestern Zhangjiakou. The values of solar radiation are between 2540-3300 MJ·m-2 in most areas of Hebei province. The potential ability for the development and utilization of solar energy resources is great in the dam area of Zhangjiakou in Hebei province. Related Articles | Metrics

Bulletins

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Study of impact factors about willingness to pay for public meteorological service CUI Wei-jun,XIANG Yan,CHEN Ya-lan,LUO Yu,GU Chun-xia 2014, 30 (1):  100-107.  Abstract ( 316 )   PDF (964KB) ( 376 )   Save  Based on survey data in China Meteorological Administration in 2008, the impact factors about willingness to pay (WTP) for public meteorological service were analyzed by the methods of a binary Logistic regression, an optimal scaling regression and a classification regression tree (CRT). The results show that the individual factors such as age and education level have significant influence on WTP including whether to pay (WTP1) and how much to pay (WTP2), while gender has only significant influence on WTP2 but not on WTP1. The income has significant influence to WTP. The four factors including concerning degree for weather forecast, accuracy and timeliness of prediction, overall satisfaction on meteorological service have significant influence on WTP2, while the impact is very small. The individual factors and income have greater impact on WTP compared with the psychological factors. Related Articles | Metrics

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Application of multimedia communication technology to meteorological services in China LIANG Xiao-yu, CHEN Yong-tao,HUANG Xun,JI Jun-yun 2014, 30 (1):  108-112.  Abstract ( 514 )   PDF (1174KB) ( 2040 )   Save Multimedia communication technology, as an advanced technology, had been used to provide remote consultation, meetings, technical trainings and other meteorological services in China Meteorological Administration (CMA). To meet requirements of high quality video transmission, stability of the system, and flexibility of conference organization, a high-definition Weather Conference System (WCS) was established with the advanced multimedia communication technology. The structure of the national high-definition WCS, main function and key technology were introduced. It was compared with the standard definition WCS. The results show that the new system has the advanced technology and stronger function. It is one of the supporting platforms of modern meteorological operational system, and it plays a very important role in meteorological service. Related Articles | Metrics