Modeling Study of Taiwan'S Riverbed Dust Emissions and Its Comparison with Asian Dust Emissions(I)

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Project title

Code/計畫編號

MOST107-2111-M019-002

Translated Name/計畫中文名

台灣河床揚塵的影響及與大陸沙塵的比對模擬分析(I)

Project Coordinator/計畫主持人

Fu-Jung Tsai

Funding Organization/主管機關

National Science and Technology Council

Department/Unit

Department of Marine Environmental Informatics

Website

https://www.grb.gov.tw/search/planDetail?id=12674164

Year

2018

Start date/計畫起

01-08-2018

Expected Completion/計畫迄

31-07-2019

Co-Investigator(s)

Yao-Tsai Lo

Bugetid/研究經費

685千元

ResearchField/研究領域

大氣科學

在亞洲地區，大陸的沙塵事件為影響空氣品質的重要因素之一，特別是在東北季風期間，常會有沙塵事件發生，帶來高濃度的懸浮微粒，除了影響到大氣之外，也對海洋浮游植物提供了營養鹽。根據環保署的沙塵事件統計，台灣每年平均會有2-3次左右的主要沙塵事件，平均對北台灣貢獻了15 μg m-3的沙塵顆粒，大約是24-30%的大氣懸浮微粒濃度。而在重大沙塵事件的時候，懸浮微粒每小時的濃度值可超過1000‭ ‬g m-3，更會嚴重影響能見度。除了大陸的沙塵事件之外，台灣的河床也常有揚沙，造成漫天的揚塵瀰漫著周圍地區。台灣的河川如大安溪，大甲溪，大肚溪，濁水溪，高屏溪，蘭陽溪，卑南溪，在強風下每小時平均濃度可達400-500 μg m-3，嚴重影響附近的大氣濃度。在東北季風期間，大陸沙塵事件與台灣的河床揚塵也常常相伴發生，以致於常常無法釐清沙塵顆粒的來源及其影響。‭ ‬‭ ‬為了了解台灣河床揚塵的影響，並與大陸沙塵做比較，本計劃擬於區域性的大陸沙塵模式中加入台灣河床揚塵的排放量，以評估其影響。工作包括將各河川流域網格點化，參數化台灣7條主要河床起沙的風速、溼度，以及起沙量，並藉此推估整條河道的沙塵濃度。結果將與觀測值比對並修改參數，最後將評估河床揚塵的影響，並與大陸沙塵的影響做一比較，釐清大氣中沙塵的來源。本計劃預計以兩年時間完成，此為第一年的計劃內容。 "In Asia, dust event from China is one of the main factors that affect air quality. Especially during northeasterlies when dust events often occur, the high aerosol concentrations not only affect the atmosphere, but also impact the marine phytoplankton by supplying the necessary nutrients. According to the Environmental Protection Administration's statistics, Taiwan has two or three times of major dust events each year, providing an average of 15 μg m-3 of aerosol concentrations to northern Taiwan, which accounting for about 24-30% of aerosol concentration. During the severe dust events, hourly aerosol concentrations can even reach as high as 1000 g m-3, and significantly affect the visibility. In addition to Asian dust events, Taiwan's riverbeds also generate dust emissions, and the concentrations often cover the downwind areas with dust aerosol. Taiwan's major rivers, such as Daan, Dajia, Dadu, Zhuoshuei, Gaoping, Lanyang, and Peinan emit dust concentrations as high as 400-500 μg m-3 during strong winds, and severely affect the local and downwind areas. During the northeasterly winds, both Asian and Taiwan's dust emissions can occur simultaneously, resulting in difficulty in distinguishing between their impacts. In order to understand Taiwan's riverbed emissions and compare with Asian dust emissions, this project intend to add Taiwan's riverbed emissions into the regional Asian dust model. This includes to add the watershed of the rivers into model grid points, parameterize the wind speeds, humidity, and the emissions of the major seven riverbeds. The calculated dust concentrations of the major riverbeds will be compared with observations and the model will be adjusted accordingly. Finally, the impacts of Taiwan's riverbed emissions will be quantified and compared with Asian dust emissions, and the dust concentrations from which sources will be clarified. This project intends to be completed in two year, and this is the content of the first year."

Keyword(s)

河床揚塵
懸浮微粒
模式
大陸沙塵
riverbed emissions‭
aerosol‭
model‭
Asian dust

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Modeling Study of Taiwan'S Riverbed Dust Emissions and Its Comparison with Asian Dust Emissions(I)

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