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Man-Ting Cheng Wei-Chun Chou Chia-Pin Chio Shih-Chieh Hsu Yi-Ru Su Pei-Hsuan Kuo Ben-Jei Tsuang Shuen-Hsin Lin Charles C.-K. Chou 《Journal of Atmospheric Chemistry》2008,61(2):155-173
A study has been carried out on water soluble ions, trace elements, as well as PM2.5 and PM2.5–10 elemental and organic carbon samples collected daily from Central Taiwan over a one year period in 2005. A source apportionment
study was performed, employing a Gaussian trajectory transfer coefficient model (GTx) to the results from 141 sets of PM2.5 and PM2.5–10 samples. Two different types of PM10 episodes, local pollution (LOP) and Asian dust storm (ADS) were observed in this study. The results revealed that relative
high concentrations of secondary aerosols (NO3−, SO42− and NH4+) and the elements Cu, Zn, Cd, Pb and As were observed in PM2.5 during LOP periods. However, sea salt species (Na+ and Cl−) and crustal elements (e.g., Al, Fe, Mg, K, Ca and Ti) of PM2.5–10 showed a sharp increase during ADS periods. Anthropogenic source metals, Cu, Zn, Cd, Pb and As, as well as coarse nitrate
also increased with ADS episodes. Moreover, reconstruction of aerosol compositions revealed that soil of PM2.5–10 elevated approximately 12–14% in ADS periods than LOP and Clear periods. A significantly high ratio of non-sea salt sulfate
to elemental carbon (NSS-SO42−/EC) of PM2.5–10 during ADS periods was associated with higher concentrations of non-sea-salt sulfates from the industrial regions of China.
Source apportionment analysis showed that 39% of PM10, 25% of PM2.5, 50% of PM2.5–10, 42% of sulfate and 30% of nitrate were attributable to the long range transport during ADS periods, respectively. 相似文献
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Ben-Jei Tsuang Chia-Ying Tu Jeng-Lin Tsai John A. Dracup Klaus Arpe Tilden Meyers 《Climate Dynamics》2009,32(2-3):251-272
The theoretical framework of the vertical discretization of a ground column for calculating Earth’s skin temperature is presented. The suggested discretization is derived from the evenly heat-content discretization with the optimal effective thickness for layer-temperature simulation. For the same level number, the suggested discretization is more accurate in skin temperature as well as surface ground heat flux simulations than those used in some state-of-the-art models. A proposed scheme (“op(3,2,0)”) can reduce the normalized root–mean–square error (or RMSE/STD ratio) of the calculated surface ground heat flux of a cropland site significantly to 2% (or 0.9 W m?2), from 11% (or 5 W m?2) by a 5-layer scheme used in ECMWF, from 19% (or 8 W m?2) by a 5-layer scheme used in ECHAM, and from 74% (or 32 W m?2) by a single-layer scheme used in the UCLA GCM. Better accuracy can be achieved by including more layers to the vertical discretization. Similar improvements are expected for other locations with different land types since the numerical error is inherited into the models for all the land types. The proposed scheme can be easily implemented into state-of-the-art climate models for the temperature simulation of snow, ice and soil. 相似文献
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W.-L. Cheng J.-L. Pai B.-J. Tsuang C.-L. Chen 《Meteorology and Atmospheric Physics》2001,78(1-2):11-21
Summary
Recent studies have shown that regional orography and synoptic patterns greatly affect ozone concentrations. The orography
of certain locations is unfavorable for pollutant dispersion, and specific synoptic patterns in these locations lead to serious
air pollution episodes. Frequent ozone episodes (defined as hourly ozone ≥ 120 ppbv) in west-central Taiwan during recent
years have generated much concern. High ozone days (defined as hourly ozone ≥ 80 ppbv) are also occurring more frequently.
High ozone days occur mainly during autumn, but there has been no clear linear relationship demonstrated between any single
meteorological variable and pollutant concentration. In this study, statistical data from 1997–1999 has shown that high ozone
levels occur with two types of synoptic patterns. The first type consists of a continental anticyclone emanating from mainland
China which is swept towards Taiwan. The second is a tropical low pressure system moving northwards closer to Taiwan.
West-central Taiwan is located in the lee of the Central Ranges (altitude of 2500 ∼ 3500 m). These synoptic patterns are unfavorable
for pollutant dispersion and cause high ozone days.
Received October 14, 2000/Revised January 5, 2001 相似文献
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