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Luo Y.,Chinese Academy of Meteorological Sciences | Luo Y.,Nanjing University of Information Science and Technology | Qian W.,Shijiazhuang Meteorological Bureau | Wang H.,Chinese Academy of Meteorological Sciences | And 2 more authors.
Advances in Atmospheric Sciences | Year: 2016

The 3D radar reflectivity produced by a mosaic software system, with measurements from 29 operational weather radars in the Yangtze River–Huaihe River Basins (YRHRB) during the mei-yu season of 2007, is compared to coincident TRMM PR observations in order to evaluate the value of the ground-based radar reflectivity mosaic in characterizing the 3D structures of mei-yu precipitation. Results show reasonable agreement in the composite radar reflectivity between the two datasets, with a correlation coefficient of 0.8 and a mean bias of -1 dB. The radar mosaic data at constant altitudes are reasonably consistent with the TRMM PR observations in the height range of 2–5 km, revealing essentially the same spatial distribution of radar echo and nearly identical histograms of reflectivity. However, at altitudes above 5 km, the mosaic data overestimate reflectivity and have slower decreasing rates with height compared to the TRMM PR observations. The areas of convective and stratiform precipitation, based on the mosaic reflectivity distribution at 3-km altitude, are highly correlated with the corresponding regions in the TRMM products, with correlation coefficients of 0.92 and 0.97 and mean relative differences of -7.9% and -2.5%, respectively. Finally, the usefulness of the mosaic reflectivity at 3-km altitude at 6-min intervals is illustrated using a mesoscale convective system that occurred over the YRHRB. © 2016, Chinese National Committee for International Association of Meteorology and Atmospheric Sciences, Institute of Atmospheric Physics, Science Press and Springer-Verlag Berlin Heidelberg.

Ren G.-Y.,Nanjing University of Information Science and Technology | Ren G.-Y.,National Climate Center | Zhang L.,Nanjing University of Information Science and Technology | Zhang L.,National Climate Center | And 4 more authors.
Chinese Journal of Geophysics (Acta Geophysica Sinica) | Year: 2015

With rapid growth of economy and expansion of cities, urbanization has become a significant factor in affecting the long-term changes of mean and extreme temperature and other key climatic variablesat most urban stations of mainland China. So far, this problem has aroused more and more attentions in urbanization effect on mean temperature trends, but the few analysis of urbanization effect on temperature probability density distribution has been done. This article analyzes the urbanization effect on daily temperature probability density distribution (PDF), daily temperature cumulative probability density distribution (CDF) and the seasonal cycles of daily mean temperature for Shijiazhuang weather station without any relocation before 2011 as an example. This paper uses daily data of Tmean, Tmin and Tmax of an urban weather station, Shijiazhuang station, and a nearby rural weather station, Gaocheng station, from 1962 to 2011. Shijiazhuang station was never moved before 2011.Urbanization effect (ΔTur) is defined as the temperature trends or change in daily temperature PDF and CDF of urban station caused by the changing Urban Heat Island (UHI) intensity and/or the effect of other factors (such as aerosols). The urbanization makes the distribution of annual Tmean, Tmin and Tmax at Shijiazhuang station during 1962-2011 shift to high temperature side. Urbanization effect on the distribution of annual Tmin is very obvious, but the effect on the distribution of annual Tmax is small. Due to the urbanization effect, the increase in Tmin is larger on high value side than on low value side at Shijiazhuang station, resulting in a flatter shape of annual Tmin PDF than that of the rural station; The PDF of Tmean, Tmin and Tmax at Shijiazhuang station all shifts to the higher value side during 1987-2011 compared to 1962-1986, with the largest shift occurring in Tmin. The PDF of Tmin at Shijiazhuang station in the time period 1962-2011 is characterized by a non-normal distribution due to the urbanization effect. The difference of PDF between Shijiazhuang station and Gaocheng station during 1962-2011 is larger and more significant in winter and spring than in summer and autumn, and the largest difference is found for winter Tmin. The urbanization effect in the 1962-2011 series of cold nights and warm nights are respectively -1.13 d/10a and 1.48 d/10a, and the urbanization contribution are respectively 28.32% and 37.76%. The urbanization effects in the Tmin-based extreme temperature indicesare larger for those in the Tmax-based extreme temperature indices at Shijiazhuang station. In each of the seasons of a year, the daily mean Tmin difference between the urban and rural stations is generally more than 1.0℃, with the daily urban heat island intensity, sometimes reaching above 1.5℃, being the largest from the beginning of December to the end of May, and the daily mean Tmax difference between the urban and rural stations is usually less than 0.5℃. The significant urbanization effect on urban station surface air temperature records exists not merely in the linear trends of mean temperature series and extreme temperature indices series, but also in the probability density distribution of daily Tmin and Tmean. It is an important factor in forming the asymmetry changes of diurnal and seasonal temperature cycles for Shijiazhuang station. ©, 2015, Science Press. All right reserved.

Ren G.,National Climate Center | Li J.,National Climate Center | Ren Y.,National Climate Center | Chu Z.,Beijing Municipality Meteorological Bureau | And 7 more authors.
Journal of Applied Meteorology and Climatology | Year: 2015

Trends in surface air temperature (SAT) are a critical indicator for climate change at varied spatial scales. Because of urbanization effects, however, the current SAT records of many urban stations can hardly meet the demands of the studies. Evaluation and adjustment of the urbanization effects on the SAT trends are needed, which requires an objective selection of reference (rural) stations. Based on the station history information from all meteorological stations with long-term records in mainland China, an integrated procedure for determining the reference SAT stations has been developed and is applied in forming a network of reference SAT stations. Historical data from the network are used to assess the urbanization effects on the long-term SAT trends of the stations of the national Reference Climate Network and Basic Meteorological Network (RCN+BMN or national stations), which had been used most frequently in studies of regional climate change throughout the country. This paper describes in detail the integrated procedure and the assessment results of urbanization effects on the SAT trends of the national stations applying the data from the reference station network determined using the procedure. The results showed a highly significant urbanization effect of 0.074°C (10 yr)-1 and urbanization contribution of 24.9% for the national stations of mainland China during the time period 1961-2004, which compared well to results that were reported in previous studies by the authors using the predecessor of the present reference network and the reference stations selected but when applying other methods. The authors are thus confident that the SAT data from the updated China reference station network as reported in this paper best represented the baseline SAT trends nationwide and could be used for evaluating and adjusting the urban biases in the historical data series of the SAT from different observational networks. © 2015 American Meteorological Society.

Sun X.,Nanjing University of Information Science and Technology | Yin Y.,Nanjing University of Information Science and Technology | Sun Y.,Hebei Weather Modification Office | Sun Y.,Shijiazhuang Meteorological Bureau | And 2 more authors.
Atmospheric Environment | Year: 2013

To obtain a representative sampling of aerosol vertical profiles, we performed an extensive airborne characterization of aerosols under different environmental conditions over Shijiazhuang, China. Surface aerosol concentration and aerosol vertical distribution were analyzed using a set of 104 vertical profiles of aerosol number concentration and size distribution ranging from 0.1 to 3μm observed by PCASP-100X. A four modal lognormal size distribution with 10-based logarithm was applied to fit measured aerosol size distributions at different altitudes of three seasons (spring, summer and autumn). It was found that the surface aerosol number concentration had a negative correlation with wind speed. In addition to wet removal of aerosols owing to precipitation in summer, vertical transport of aerosols from the surface to high levels is strongly influenced by convective instability, which contributes to the seasonality of aerosol vertical profiles. The aerosol vertical profiles under a wide range of synoptic conditions can be categorized as "ED" (exhibiting an exponential declining tendency with altitude), "SAL" (aerosol layers existing near surface), and "BAL" (aerosol layers at the boundary layer height). The multi-lognormal fitting captures the total aerosol number size distribution at 0.1-3μm reasonably well. The average scale height of aerosols during spring, summer and autumn is 1.0km, 1.6km and 1.0km, respectively. © 2013 Elsevier Ltd.

Zhou J.-B.,Shijiazhuang Environmental Monitoring Station | Li Z.-G.,Shijiazhuang Environmental Monitoring Station | Lu N.,Shijiazhuang Environmental Monitoring Station | Xu M.,Shijiazhuang Environmental Monitoring Station | And 4 more authors.
Huanjing Kexue/Environmental Science | Year: 2016

Robust measures were taken to ensure a good air quality for the parade on the 70th Victory Memorial Day for the Chinese People's War of Resistance against Japanese Aggression (VM Day). During the period, the source of fine particulate matter in air was analyzed with the single particle aerosol mass spectrometer (SPAMS) located at Shijiazhuang air automatic monitoring station of 20 meter. The results indicated that, on VM Day the primary sources of air pollution were vehicle exhaust emission (20.9%) and coal-generated emissions (20.6%), which were also at lower degrees than those on pre-and post-VM Day. It turned out that these air quality-improving measures, especially the vehicle restriction and coal consumption reduction, had a good effect. Particles from the vehicle exhaust and coal combustion source were mainly based on short-chain elements, carbon, manganese and organic carbon. The particles from the industry source were mainly organic carbon and metal. Particles from the dust source were mainly composed of silicate and calcium. When air quality-improving measures were stopped, the concentration of particulate matter rapidly rose again, and the contribution of dust and vehicle exhaust emission was remarkable. It was believed that the interaction of low-pressure static stability of adverse weather conditions and southeast direction of low altitude transmission was a major cause in the deterioration of air quality. © 2016, Science Press. All right reserved.

Bian T.,Shijiazhuang Meteorological Bureau | Bian T.,National Climate Center | Ren G.,National Climate Center | Zhang B.,Shijiazhuang Meteorological Bureau | And 2 more authors.
Theoretical and Applied Climatology | Year: 2014

Based on daily temperature data from an urban station and four rural stations of Shijiazhuang area in Hebei Province, North China, we analyzed the trends of extreme temperature indices series of the urban station (Shijiazhuang station) and rural stations during 1962-2011 and the urbanization effect on the extreme temperature indices of the urban station. The results showed that the trends of annual extreme temperature indices of the urban station and the rural stations are significantly different in the recent 50 years. Urbanization effect on the long-term trends of hot days, cold days, frost days, diurnal temperature range (DTR), extreme maximum temperature, and extreme minimum temperature at the urban station were all statistically significant, reaching 1.10 days/10 years, -2.30 days/10 years, -2.55 days/10 years, -0.20 °C/10 years, 0.16 °C/10 years, and 0.70 °C/10 years, respectively, with the urbanization contributions to the overall trends reaching 100, 38.0, 42.2, 40.0, 94.1, and 47.0 %, respectively. The urbanization effect on trend of ice days was also significant, reaching -0.47 days/10 years. However, no significant urbanization effect on trends of minimum values of maximum temperature and maximum values of minimum temperature had been detected. The urbanization effects in the DTR and extreme minimum temperature series of Shijiazhuang station in wintertime were highly significant. © 2014 Springer-Verlag Wien.

Luo Y.,Chinese Academy of Meteorological Sciences | Qian W.,Shijiazhuang Meteorological Bureau | Zhang R.,Chinese Academy of Meteorological Sciences | Zhang D.-L.,Chinese Academy of Meteorological Sciences | Zhang D.-L.,University of Maryland College Park
Journal of Hydrometeorology | Year: 2013

Heavy rainfall hit the Yangtze-Huai Rivers basin (YHRB) of east China several times during the prolonged 2007 mei-yu season, causing the worst flood since 1954. There has been an urgent need for attaining and processing high-quality, kilometer-scale, hourly rainfall data in order to understand the mei-yu precipitation processes, especially at the mesob and smaller scales. In this paper, the authors describe the construction of the 0.078-resolution gridded hourly rainfall analysis over the YHRB region during the 2007 mei-yu season that is based on surface reports at 555 national and 6572 regional automated weather stations with an average resolution of about 7 km. The gridded hourly analysis is obtained using a modified Cressman-type objective analysis after applying strict quality control, including not only the commonly used internal temporal and spatial consistency and extreme value checks, but also verifications against mosaic radar reflectivity data. This analysis reveals many convectively generated finescale precipitation structures that could not be seen from the national station reports. A comprehensive quantitative assessment ensures the quality of the gridded hourly precipitation data. A comparison of this dataset with the U.S. Climate Prediction Center morphing technique (CMORPH) dataset on the same resolution suggests the dependence of the latter's performance on different rainfall intensity categories, with substantial underestimation of the magnitude and width of the mei-yu rainband as well as the nocturnal and morning peak rainfall amounts, due mainly to its underestimating the occurrences of heavy rainfall (i.e., .10mmh-1). © 2013 American Meteorological Society.

Chen J.,Shijiazhuang Meteorological Bureau | Zhang Y.-P.,Shijiazhuang Meteorological Bureau | Yang P.,Shijiazhuang Meteorological Bureau | Qian W.-M.,Shijiazhuang Meteorological Bureau | And 2 more authors.
Zhongguo Huanjing Kexue/China Environmental Science | Year: 2016

In order to investigate the properties and variation of dust aerosol transportation, the weather condition and pollutant characteristic that influenced air quality of Shijiazhuang on April 15th, 2015 were analyzed. The HYSPLIT-4model was applied to analyze the back trajectories of dust aerosols. The ground-based micro-pulse Lidar and CE-318sun photometer measurements were used to study the vertical distribution of dust particles and its optical properties variation. In addition, it was compared with another case with strong wind but non dust aerosol deposition. The dust deposition effect on extinction coefficient was discussed. And the contribution of dust deposition to surface PM10 concentration was evaluated. The results indicated that the major factor of rapid increase PM10 concentration in Shijiazhuang was due to the long-distance transportation and deposition of dust particles from Mongolia by the direction of northwest. Dust deposition had an important contribution to both extinction coefficient and PM10 concentration. The rapid dust aerosol disposition was consistent with cold front movement and cold air sinking over Shijiazhuang region. The whole process of dust transportation and disposition had been monitored by the micro-pulse Lidar. It was found that the dust particles mainly distributed on the height of 1500 m to 3000 m before sinking, where the extinction coefficient increased with the altitude. The process from dust transportation to deposition lasted long time, which could be regarded as one strong alarm signal for dust pollution. When the dust particles arrived over Shijiazhuang region, the aerosol optical depth, turbidity, and particle size showed larger values and the visibility decreased exponentially with the aerosol optical depth. © 2016, Chinese Society for Environmental Sciences. All right reserved.

Chen J.,Shijiazhuang Meteorological Bureau | Yang P.,Shijiazhuang Meteorological Bureau | Han J.-C.,Shijiazhuang Meteorological Bureau | Qian W.-M.,Shijiazhuang Meteorological Bureau
Zhongguo Huanjing Kexue/China Environmental Science | Year: 2015

The composition of PM2.5 was on-line monitored using MARGA IC Analyzer ADI 2080 on the top of ShiJiaZhuang meteorology bureau building from August 21 to September 23, 2014 continuously. These on-line data were analyzed conjointly with meteorological data and other routine environmental monitoring data. Sum of concentration of 8 water-soluble ions was in consistent with that contained in PM2.5 in Shijiazhuang, of which SO4 2-, NH4 + and NO3 - accounted for 88.4%, indicating that they are the major components of PM2.5. The proportion of soluble SO4 2- was the largest. Its abundance raised with the increasing temperature and decreasing humidity. On the contrary, the soluble NO3 - raised with the increasing humidity. The proportion of NH4 + was relatively stable. Visibility declined in terms of power function with the increase of the water-soluble ions above. The concentration of SO4 2-, NH4 + and NO3 - were affected by prevailing wind direction, industrial layout and mountain terrain. The largest contribution to the local concentration was northeast wind, while the west contributed the smallest. SOR and NOR of the precursor gas content (SO2, NO2) of SO4 2-, NO3 - increased along with humidity. SOR was more closely associated with humidity. Daily NOR was in unimodal pattern due to daily radiation variation. The concentration of Ca2+, as an indicator of building material, was higher in dry sunny day especially with the influence of west wind, indicating that construction dust should be controlled during that kind of weather. ©, 2015, Chinese Society for Environmental Sciences. All right reserved.

Gao Q.,Shijiazhuang Meteorological Bureau | Chen J.,Shijiazhuang Meteorological Bureau | Yan F.,Shijiazhuang Meteorological Bureau | Zhao W.-L.,Shijiazhuang Meteorological Bureau
Chinese Journal of Ecology | Year: 2012

Based on the herbaceous plants phenological observation data of 8 National agro-meteorological observation stations and the ground observation data of 47 meteorological stations in Hebei Province from 1981 to 2006, and by using EOF and REOF methods, this Paper analyzed the phenological characteristics of herbaceous plants in this Province and the responses of the plants to climate warming. In 1981-2006, the herbaceous plants in the Province had an overall advancing trend in their first leafing date, and the trend was most obvious in the eastern coastal plain, followed by in the central-southern plain, and in the northwest mountain region. The first withering date of the herbaceous plants delayed, and the growth season extended. The air temperature in spring had significant effects on the first leafing date, i. e., when the air temperature increased by 1 °C, the first leafing date was advanced by 4. 1 days. There was a significant positive correlation between the growth season trend and the mean annual air temperature, i. e., the greater the increment of mean annual air temperature, the greater the increment of growth season extension. The phenological characteristics of herbaceous plants and their responses to climate change were similar to those of woody plants. This study would be helpful to the evaluation of the relationships between phenology and climate change in Hebei Province.

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