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Liu C.,CAS Beijing Institute of Geographic Sciences and Nature Resources Research | Liu C.,Beijing Normal University | Liu X.,CAS Beijing Institute of Geographic Sciences and Nature Resources Research | Liu X.,University of Chinese Academy of Sciences | And 2 more authors.
Journal of Geographical Sciences | Year: 2010

Solar radiation is an important driving force for the formation and evolution of climate system. Analysis of change in solar radiation is helpful in understanding mechanism of climate change. In this study, the temporal and spatial variations of solar radiation and the cause of the change in solar radiation have been analyzed based on meteorological data from 46 national meteorological stations and aerosol index data from TOMS over the Haihe River Basin and surrounding areas. The results have shown that solar radiation and direct radiation significantly decreased, while scattered radiation increased during the period 1957-2008. Spatially, the decreasing trend of solar radiation was more and more significant from low population density areas to high population density areas. The spatial distribution of increase in aerosol index is consistent with that of decrease in solar radiation. The increase in aerosols resulting from human activities was an important reason for the decrease in solar radiation. © 2010 Science in China Press and Springer-Verlag Berlin Heidelberg. Source

Li N.,Nanjing University of Information Science and Technology | Wei M.,Nanjing University of Information Science and Technology | Niu B.,Wuhan Central Meteorological Observatory | Mu X.,Jiangsu Institute of Meteorological science
Meteorological Applications | Year: 2012

A new storm identification and warning technique is proposed which exclusively uses radar data as input. The new identification method assembles contiguous storm points to constitute 2D storm components and improve the vertical association of storm components to construct 3D storms, which can overcome the deficiencies existing in traditional identification methods. Based on the evolution properties and characteristic distributions, strong storms and general storms are specified to train support vector machines (SVMs) which then can be used to discriminate storms. The performance of the SVM shows that it can indicate the intensity and development of a storm, providing an important aid in severe weather warning. © 2011 Royal Meteorological Society. Source

He J.,Nanjing University of Information Science and Technology | Fan S.,Nanjing University of Information Science and Technology | Meng Q.,Nanjing University of Information Science and Technology | Sun Y.,Nanjing University of Information Science and Technology | And 2 more authors.
Atmospheric Environment | Year: 2014

A study of 16 polycyclic aromatic hydrocarbons (PAHs) associated with fine particulate matters at suburban and urban sites in Nanjing was carried out each season from November 2009 to July 2010. At the suburban and urban sites, the concentrations of total PAHs (T-PAHs) were in the ranges of 30.76-102.26ng/m3 and 25.92-90.80ng/m3, respectively. This paper elucidates the distributions, sources of PAHs and meteorological influences: 1) PAHs concentrations at the two sites were close to each other and similarity between PAHs profiles of the two sites indicated they had common sources, which were attributed to the combined effect of regional transport and local emission. 2) At both sites, the profiles displayed obvious seasonal variations, as a result of the seasonality of sources and meteorological influences. The T-PAHs concentrations were in the order of winter>spring>autumn>summer. 3) Source apportionment showed vehicle exhaust (72.93-87.24%) was the greatest contributor in all seasons. The coal combustion and coke production (coal/coke) (10.02-18.63%) were identified in all but summer seasons, because of the low collection efficiency of PAHs markers of coal/coke under high temperature. For autumn, biomass burning (10.58%) was an extra contributor. 4) Regarding meteorological parameters, a negative effect of temperature over PAHs was confirmed, with a correlation coefficient of-0.51 (p<0.05). Precipitation could remove PAHs to some extent. Both positive and negative correlations between PAHs concentration and wind speed in each season were analyzed in combination with air mass back-trajectories so as to evaluate the effects of regional air transport. The results showed that polluted air from ENE-S and NNW-NE brought in outside sources to the study area and played a major role in the accumulation of fine-particulate PAHs in spring and winter respectively, while clean air from southwest contributed to the dilution in summer. © 2014 Elsevier Ltd. Source

Die H.,Lanzhou Institute of Arid Meteorology | Lei Z.,Lanzhou University | Hongbin W.,Jiangsu Institute of Meteorological science
IOP Conference Series: Earth and Environmental Science | Year: 2014

In this study, Aerosol Optical Depth (AOD) at 550nm from the MODIS sensor on board the Terra/Aqua satellites were compared with sun photometer (CE-318) measurements from 11 AERONET stations in China. The average correlation coefficient (R) value from the AOD product, using the Aqua-MODIS Deep Blue algorithm, in the Hexi Corridor was 0.67. The MODIS Dark Target algorithm AOD product is superior to Deep Blue algorithm AOD products in SACOL of the Semi-arid regions of the Loess Plateau. These two kinds of algorithm are not applicable to sites in Lanzhou city. The average R value of Dark Target algorithm AOD MODIS products is 0.91 for Terra and 0.88 for Aqua in the eastern part of China. According to the analysis of spatial and temporal characteristics of the two MODIS AOD products in China, high value areas are mainly distributed in the southern part of Xinjiang (0.5∼0.8), Sichuan Basin (0.8∼0.9), North China (0.6∼0.8) and the middle and lower reaches of the Changjiang River (0.8∼1.0). The Deep Blue algorithm for Aqua-MODIS is a good supplement for the retrieval of AOD above bright surfaces of deserts in Northwest China. Source

Xie Z.Q.,Jiangsu Institute of Meteorological science | Du Y.,Nanjing University of Information Science and Technology | Zeng Y.,Jiangsu Institute of Meteorological science | Yan M.L.,Jiangsu Institute of Meteorological science | Zhu C.Y.,Jiangsu Institute of Meteorological science
Quaternary International | Year: 2010

A zigzag city belt along the Yangtze River and Hangzhou rim has formed in the Yangtze River Delta in China due to the accelerated development of human activities and urbanization. Local climate change in the belt has affected the spatial patterns of surface air temperature (SAT). (1) There exist six major warmer centers with increasing rates of SAT from 0.28 to 0.54°C per decade during 1961-2006 along the belt, namely Yangzhou, Nanjing, Jiangyin, Shanghai, Hangzhou and Ningbo. As the greatest areas of human activities and rapid urbanization in the Yangtze River Delta, Shanghai metropolitan areas have the maximum rates of increases in annual and seasonal mean SAT, which range from 0.23 to 0.50°C per decade, and the strongest urban heat island effects, which are increasing at rates in the range of 0.11-0.15°C per decade. (2) Local warming and urban heat island effects have created the largest and warmest SAT core in the Shanghai metropolitan areas, contributing to spatial pattern changes in SAT over the Yangtze River Delta. The spatial patterns of SAT for 2001-2006 and 1971-2000 significantly differ in the typical latitudinal pattern for 1971-2000 that has changed, mainly in Shanghai metropolitan areas. (3) The annual mean of the regional SAT will increase from 15.4°C in 1961-1990 to 18.5°C in 2071-2100 due to global warming and urban heat island effects according to the IPCC SRES A2 Scenario. This increase is notably higher than the increment of 2.5°C from 15.4°C to 17.9°C due to global warming alone. The spatial distribution of the projected SAT with global warming and urban heat island effects is markedly different from that for global warming alone. In 2071-2100, the Shanghai metropolitan areas will have summer average temperatures of about 30.0-30.5°C, which are higher than summer average temperatures of about 28.7°C that would be expected from global warming alone. Higher average temperatures can have negative implications for energy and water consumption, human health and local ecosystems. The development and implementation of adaptation strategies are important and required by the policy makers from local government and city planning departments. © 2010 Elsevier Ltd and INQUA. Source

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