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Liu L.,CAS Institute of Atmospheric Physics | Hu F.,CAS Institute of Atmospheric Physics | Cheng X.-L.,CAS Institute of Atmospheric Physics | Song L.-L.,Guangzhou Institute of Tropical and Marine Meteorology
Boundary-Layer Meteorology | Year: 2010

The probability density functions (pdf's) of the wind increments are measured under different weather conditions in the atmospheric boundary layer, including the extreme weather of a typhoon and sand storm. It is found that in each case the measured pdf's with respect to different time lags coincide by suitable scaling transformation. This property is similar to that of the stable distributions. However, fitting results show that the tails of the stable distributions are generally heavier than that of the measured ones. Beside, the stable distributions (except for the Gaussian distribution) have infinite variance, which implies infinite average kinetic energy. In fact, it can be proved that if the tails of the pdf's are heavy enough, the variance will be infinite. Therefore, the tail-truncated stable distributions with finite variances are introduced to fit the data and the fitting results are excellent. © Springer Science+Business Media B.V. 2009. Source

Yu H.,Hong Kong University of Science and Technology | Wu C.,Hong Kong University of Science and Technology | Wu C.,U.S. National Center for Atmospheric Research | Wu D.,Guangzhou Institute of Tropical and Marine Meteorology | Yu J.Z.,Hong Kong University of Science and Technology
Atmospheric Chemistry and Physics | Year: 2010

Elemental carbon (EC) in size-segregated aerosol samples were determined at five urban, one suburban, and one rural locations in the Pearl River Delta region in South China during 2006-2008 period. The size modal characteristics of EC were different at the urban and suburban/rural locations. The urban EC had a dominant condensation mode with a mass median aerodynamic diameter (MMAD) in the 0.36-0.43 μm range and a slightly less abundant mode in the droplet mode size (MMAD: 0.8-1.1 μm), while the suburban/rural EC had a prominent mode in the droplet mode size (MMAD: 0.7-1.1 μm) and a minor condensation mode (MMAD: 0.22-0.33 μm). Calculations using Mie theory and the measured size distributions of EC, organic carbon, and major inorganic ions indicate that EC-containing particles contributed 76±20% of the observed light extinction at the urban sites. Among the EC-containing particles, EC mass alone contributed 21±11% of the observed light extinction while non-EC materials on the EC particles (i.e., organic matter, ammonium sulfate, and water) contributed 55±15%. At the suburban/rural locations, EC-containing particles contributed 37g-48% of the measured light extinction, with EC mass contributing 4-10% and non-EC coating materials contributing the remaining light extinction. Our results suggest that EC-containing particles were important to the overall light extinction in the urban atmospheres due to their more abundant presence from vehicular emissions. The EC-containing particles in the suburban/rural locations had a reduced but still significant contribution to light extinction budget. © Author(s) 2010. Source

He C.,Guangzhou Institute of Tropical and Marine Meteorology | Zhou T.,CAS Institute of Atmospheric Physics
Atmospheric Science Letters | Year: 2015

A decadal change has occurred on the relationship between the summertime western North Pacific subtropical High (WNPSH) and the tropical Sea Surface Temperature anomalies (SSTA) in the early 1990s. After this decadal change, the interannual variability of the WNPSH is more strongly regulated by the SSTA over the equatorial central Pacific and the maritime continent. The earlier decay of ElNiño in strong WNPSH years and the earlier development of ElNiño in weak WNPSH years both contributed to this change. Such decadal change is found in the pre-industrial control simulation of a coupled model, suggesting it is probably an internal variability of the climate system. © 2014 Royal Meteorological Society. Source

Wu M.,Sun Yat Sen University | Wu D.,Sun Yat Sen University | Wu D.,Guangzhou Institute of Tropical and Marine Meteorology | Fan Q.,Sun Yat Sen University | And 3 more authors.
Atmospheric Chemistry and Physics | Year: 2013

The structure of the atmospheric boundary layer (ABL) and its influence on regional air quality over the Pearl River Delta (PRD) were examined through two intensive observations in October 2004 and July 2006. Analytical results show the presence of two types of typical weather conditions associated with poor air quality over the PRD. The first is the warm period before a cold front (WPBCF) and the second is the subsidence period controlled by a tropical cyclone (SPCTC). Two typical low air quality situations, which are affected by WPBCF and SPCTC, and one high air quality situation were analysed in detail. Results showed that continuously low or calm ground winds resulted in the accumulation of pollutants, and sea-land breezes had. © 2013 Author(s). Source

Wu D.,Guangzhou Institute of Tropical and Marine Meteorology | Wu D.,Sun Yat Sen University
Huanjing Kexue Xuebao/Acta Scientiae Circumstantiae | Year: 2012

Systematic research on haze in China has been on-going for a decade. The rapid economic expansion and urbanization has led to worsening particulate matter (PM) pollution and more frequent poor visibility events. A rapid increase in the number of hazy days has been seen over eastern China. The culprit of hazy weather is fine PM pollution. Hazy weather is often associated with photochemical pollution and composition of aerosols responsible for haze is rather complicated. In recent years, hazy weather, due to its significant environmental impacts and climatic effects, has become a hot topic, attracting wide attention from scientific community, government departments and the public. This paper surveys the literature in Chinese in the recent decade to provide a review on the process of understanding haze and research progress in hazy weather. Future research directions are also discussed. Source

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