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Yang J.M.,Weather Modification Office of Shanxi Province
Applied Mechanics and Materials | Year: 2014

Extreme programming and the UNIVAC computer, while unproven in theory, have not until recently been considered private. In this position paper, we argue the study of superblocks, which embodies the essential principles of artificial intelligence. We describe an algorithm for virtual modalities, demonstrating that lambda calculus and local-area networks can interact to answer this challenge. © (2014) Trans Tech Publications, Switzerland.

Li J.,Nanjing University of Information Science and Technology | Yin Y.,Nanjing University of Information Science and Technology | Li P.,Weather Modification Office of Shanxi Province | Li Z.,Beijing Normal University | And 10 more authors.
Atmospheric Research | Year: 2015

For the first time, comprehensive aircraft measurements of atmospheric aerosols and cloud condensation nuclei (CCN) were made over the Loess Plateau in Shanxi, China. Data from six flights in July and August 2013 were analyzed. Fine aerosols were predominant over the region. On the one hazy day, the fraction of fine particles in the total aerosol load was the greatest. Aerosol number concentration decreased exponentially with altitude. Inversion layers caused low-level aerosol accumulation zones. The mean aerosol particle size increased with altitude, and the larger particles were mainly found above 2km. Aerosol number size distributions at different height ranges showed two or three peaks. The aerosol number size distribution from 0.01μm to 20μm can be fitted with three log-normal distribution functions. The number concentration of CCN (NCCN) decreased with altitude. NCCN was linearly related to the CN concentration (NCN). The fraction of CCN to CN (fCCN/CN) at 0.3% SS was half of that at 0.4% SS. The fCCN/CN on the hazy day was lower than on the clear days. Vertical profiles of fCCN/CN and the effective diameter (ED) were similar, although the fCCN/CN increased with altitude. © 2014 Elsevier B.V.

Zhang F.,Beijing Normal University | Li Y.,Beijing Normal University | Li Z.,Beijing Normal University | Li Z.,The Interdisciplinary Center | And 11 more authors.
Atmospheric Chemistry and Physics | Year: 2014

Aerosol hygroscopicity and cloud condensation nuclei (CCN) activity under background conditions and during pollution events are investigated during the Aerosol-CCN-Cloud Closure Experiment (AC3Exp) campaign conducted at Xianghe, China in summer 2013. A gradual increase in size-resolved activation ratio (AR) with particle diameter (Dp) suggests that aerosol particles have different hygroscopicities. During pollution events, the activation diameter (Da) measured at low supersaturation (SS) was significantly increased compared to background conditions. An increase was not observed when SS was > 0.4%. The hygroscopicity parameter (κ) was ∼ 0.31-0.38 for particles in accumulation mode under background conditions. This range in magnitude of κ was ∼ 20%, higher than κ derived under polluted conditions. For particles in nucleation or Aitken mode, κ ranged from 0.20-0.34 for background and polluted cases. Larger particles were on average more hygroscopic than smaller particles. The situation was more complex for heavy pollution particles because of the diversity in particle composition and mixing state. A non-parallel observation CCN closure test showed that uncertainties in CCN number concentration estimates ranged from 30-40%, which are associated with changes in particle composition as well as measurement uncertainties associated with bulk and size-resolved CCN methods. A case study showed that bulk CCN activation ratios increased as total condensation nuclei (CN) number concentrations (NCN) increased on background days. The background case also showed that bulk AR correlated well with the hygroscopicity parameter calculated from chemical volume fractions. On the contrary, bulk AR decreased with increasing total NCN during pollution events, but was closely related to the fraction of the total organic mass signal at m/z 44 (f44), which is usually associated with the particle's organic oxidation level. Our study highlights the importance of chemical composition in determining particle activation properties and underlines the significance of long-term observations of CCN under different atmospheric environments, especially regions with heavy pollution. © Author(s) 2014.

Li J.-X.,Nanjing University of Information Science and Technology | Yin Y.,Nanjing University of Information Science and Technology | Li P.-R.,Weather Modification Office of Shanxi Province | Li R.-J.,Beijing Normal University | And 2 more authors.
Zhongguo Huanjing Kexue/China Environmental Science | Year: 2014

Aircraft Measurements of aerosol spatial distribution properties in the central region of Shanxi Province were carried out in summer, 2013. The vertical distribution characteristics of aerosol number concentration and size were observed and analyzed, and the spectrum properties of aerosol particles in different height were studied. The results show that most aerosol particles were nucleation mode and accumulation mode on non-precipitation days in Shanxi Prov. in summer. Aerosol number concentration on haze day was 2 or 3 times larger than that on clear days. Aerosol number concentration decreased with altitude. A low-level aerosol accumulation zone was present due to the existence of temperature inversion layer. The mean aerosol particle size increased with height with the larger particles mainly distributed above 2500 m. The aerosol particles spectrum usually showed a bimodal or three-modal type. The width of aerosol particles spectrum broadened slightly from ground surface to 5000 m. The air mass back trajectory in observation days showed aerosol particles in high level was transported from north-west China over long distance, and aerosol particles below 3000 m mainly came from the ground emissions.

PubMed | Beijing Normal University, Weather Modification Office of Shanxi Province and Nanjing University of Information Science and Technology
Type: | Journal: Journal of environmental sciences (China) | Year: 2015

Vertical distributions of aerosol optical properties based on aircraft measurements over the Loess Plateau were measured for the first time during a summertime aircraft campaign, 2013 in Shanxi, China. Data from four flights were analyzed. The vertical distributions of aerosol optical properties including aerosol scattering coefficients (sc), absorption coefficients (ab), Angstrm exponent (), single scattering albedo (), backscattering ratio (sc), aerosol mass scattering proficiency (Qsc) and aerosol surface scattering proficiency (Qsc()) were obtained. The mean statistical values of sc were 77.45 Mm(-1) (at 450 nm), 50.72 Mm(-1) (at 550n m), and 32.02 Mm(-1) (at 700 nm). The mean value of ab was 7.62 Mm(-1) (at 550 nm). The mean values of , sc and were 1.93, 0.15, and 0.91, respectively. Aerosol concentration decreased with altitude. Most effective diameters (ED) of aerosols were less than 0.8 m. The vertical profiles of sc,, , sc, Qsc and Qsc() showed that the aerosol scattering properties at lower levels contributed the most to the total aerosol radiative forcing. Both and sc had relatively large values, suggesting that most aerosols in the observational region were small particles. The mean values of sc, , sc, Qsc, Qsc(), ab and at different height ranges showed that most of the parameters decreased with altitude. The forty-eight hour backward trajectories of air masses during the observation days indicated that the majority of aerosols in the lower level contributed the most to the total aerosol loading, and most of these particles originated from local or regional pollution emissions.

Li J.-X.,Weather Modification Office of Shanxi Province | Li J.-X.,Nanjing University of Information Science and Technology | Yin Y.,Nanjing University of Information Science and Technology | Ren G.,Weather Modification Office of Shanxi Province | And 3 more authors.
Zhongguo Huanjing Kexue/China Environmental Science | Year: 2015

Observational data of Cloud Condensation Nuclei (CCN) from January to December 2011 was used to analyze the CCN spatial-temporal distribution properties including the seasonal, monthly and daily distribution in Shanxi Province, and the results were compared with the similar researches in other places of China and abroad. The CCN number concentration (NCCN) showed obvious seasonal variation, the average value of NCCN was highest in Winter and lowest in Summer. The maximum NCCN occurred in January and the lowest value occurred in June. More precipitation days in summertime had strong wet scavenging effect on NCCN. NCCN significantly increased during the local winter heating period. A bimodal pattern was presented in the NCCN diurnal variation. Two peaks appeared at 07:00-11:00 am and 17:00-20:00 pm, respectively. The fitted CCN spectra of four seasons were obtained by using the expression N=CSk. The fitted parameters C were 10983, 2454, 7614 and 16421 for Spring, Summer, Autumn and Winter, and all the values of k were less than 1, which showed the typical continental nuclei spectrum characteristics. The NCCN vertical profiles were acquired based on the airborne measurements of CCN in summertime of Shanxi, 2013.The largest NCCN appeared close to the ground surface, and the NCCN decreased with height. The average magnitude of NCCN was 103 cm-3 below 2000 m height and 102cm-3 above 3000 m height. ©, 2015, Chinese Society for Environmental Sciences. All right reserved.

Hou T.,CAS Institute of Atmospheric Physics | Lei H.,CAS Institute of Atmospheric Physics | Lei H.,Nanjing University of Information Science and Technology | Yang J.,CAS Institute of Atmospheric Physics | And 2 more authors.
Atmospheric Research | Year: 2016

In this study, we investigated stratiform precipitation associated with an upper-level westerly trough and a cold front over northern China between 30 Apr. and 1 May 2009. We employed the Weather Research and Forecasting (WRF) model (version 3.4.1) to perform high-resolution numerical simulations of rainfall. We also conducted simulations with two microphysics schemes and sensitivity experiments without riming of snow and changing cloud droplet number concentrations (CDNCs) to determine the effect of snow riming on cloud structure and precipitation. Then we compared our results with CloudSat, Doppler radar and rain gauge observations. The comparison with the Doppler radar observations suggested that the WRF model was quite successful in capturing the timing and location of the stratiform precipitation region. Further comparisons with the CloudSat retrievals suggested that both microphysics schemes overestimated ice and liquid water contents. The sensitivity experiments without riming of snow suggested that the presence or absence of riming significantly influenced the precipitation distribution, but only slightly affected total accumulated precipitation. Without riming of snow, the changes of updrafts from the two microphysics schemes were different due to a different consideration of ice particle capacitance and latent heat effect of riming on deposition. While sensitivity experiments with three different CDNC values of 100, 250 and 1000 cm-3 suggested variations in snow riming rates, changing CDNC had little impact on precipitation. © 2016 Elsevier B.V.

Li W.,Shandong University | Li W.,CAS Institute of Atmospheric Physics | Shi Z.,University of Birmingham | Zhang D.,Prefectural University of Kumamoto | And 5 more authors.
Journal of Geophysical Research: Atmospheres | Year: 2012

Heavy haze frequently occurs in winter over a coal-burning region, the Taiyuan Basin, in the eastern China Loess Plateau, which is the upstream area of the North China Plain. We participated in three research flights to collect aerosol particles and to monitor SO2 concentration in hazes from the ground (780m asl) up to ∼4000m during 17-18 December, 2010. Meteorological records reveal that the whole haze column (ground to 4000m) was stable and could be further divided into three sub-layers depending on the sampling altitude, which are characterized by two shifts of the lapse rate of virtual potential temperature and water vapor mixing ratio: Layer-1, surface to 1500m; Layer-2, 1500∼3000m on 17 December, and 1500∼2500m on 18 December; Layer-3, above 3000m on 17 December and above 2500m on 18 December. SO2 concentration was 16-116ppb with an average of 58ppb in the Layer-1, 2-45ppb with an average of 10ppb in the Layer-2, and 1-10ppb with an average of 4ppb in the Layer-3. The accumulation of SO2 in the Layer-1 was due to the stable meteorological conditions and the strong anthropogenic emissions in addition to the possible valley topography. Analyses of the collected particles using a transmission electron microscope revealed the dominance of organic particles and fly ash in the Layer-1 and Layer-2 and sulfate particles in the Layer-3. The organic aerosols frequently contained certain amounts of Si and Cl. Fly ash particles consisted of O and Si with minor Fe, Mn, Zn, Ti, Pb, As, Co, and Cr. These two types of aerosol particles are typically emitted from coal burning. These results indicate that the haze particles were characterized in principle by aerosols from primary emissions of coal burning, which are different from those over the North China Plain where secondary sulfate particles are the dominant component. © 2012 American Geophysical Union. All Rights Reserved.

Li W.,Shandong University | Li W.,China University of Mining and Technology | Li P.,Weather Modification Office of Shanxi Province | Sun G.,Weather Modification Office of Shanxi Province | And 3 more authors.
Atmospheric Environment | Year: 2011

Most studies of aerosol-cloud interactions have been conducted in remote locations; few have investigated the characterization of cloud condensation nuclei (CCN) over highly polluted urban and industrial areas. The present work, based on samples collected at Mt. Tai, a site in northern China affected by nearby urban and industrial air pollutant emissions, illuminates CCN properties in a polluted atmosphere. High-resolution transmission electron microscopy (TEM) was used to obtain the size, composition, and mixing state of individual cloud residues and interstitial aerosols. Most of the cloud residues displayed distinct rims which were found to consist of soluble organic matter (OM). Nearly all (91.7%) cloud residues were attributed to sulfate-related salts (the remainder was mostly coarse crustal dust particles with nitrate coatings). Half the salt particles were internally mixed with two or more refractory particles (e.g., soot, fly ash, crustal dust, CaSO4, and OM). A comparison between cloud residues and interstitial particles shows that the former contained more salts and were of larger particle size than the latter. In addition, a somewhat high number scavenging ratio of 0.54 was observed during cloud formation. Therefore, the mixtures of salts with OMs account for most of the cloud-nucleating ability of the entire aerosol population in the polluted air of northern China. We advocate that both size and composition - the two influential, controlling factors for aerosol activation - should be built into all regional climate models of China. © 2011.

Sun H.-P.,Weather Modification Office of Shanxi Province | Li P.-R.,Weather Modification Office of Shanxi Province | Sheng D.-D.,Weather Modification Office of Shanxi Province | Yang J.-M.,Weather Modification Office of Shanxi Province
Zhongguo Huanjing Kexue/China Environmental Science | Year: 2016

In August 2013, We used Y-12aircraft to carry out the experiment, which was equipped with PCASP, SMPS, AMS, CCN200, TSI-3563 type integral turbidity meter, and MAAP-5012 type Multi-angle absorption spectrophotometer from the United States and so on. For the first time, on the loess plateau that atmospheric aerosol joint observation data was obtained, in order to find the aerosol vertical distribution characteristics and optical properties. Results show that aerosol physical properties was stable, but scattering coefficient still fluctuate along with the change of meteorological conditions. the average backward scattering field of three band ratio was 0.13, the aerosol is given priority to with fine particles. Three wavelength scattering coefficient change trend was very consistent, can be thought aerosol micro physical properties basically remain unchanged in the process of detecting, but merely concentration was changed. The change tendency of the scattering coefficient and the volume concentration have almost the same change trend. The obvious positive correlation have been find between the high value area and the atmospheric humidity. Backward trajectory analysis show most of the aerosol particles originated from high altitude, from Mongolia, Inner Mongolia, Gansu and Shanxi transmitted over a long distance. © 2016, Editorial Board of China Environmental Science. All right reserved.

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