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Please use this identifier to cite or link to this item: http://ntour.ntou.edu.tw:8080/ir/handle/987654321/46425

Title: 2010年3月19-23日大陸沙塵個案對海洋影響模擬分析
Model simulation of an Asian dust event in March 2010 and its impacts on ocean
Authors: Chen, Xu-Yi
陳旭儀
Contributors: 國立臺灣海洋大學:海洋環境資訊系
Keywords: 東亞沙塵;基礎生產力;葉綠素甲
asia dust storm;basic productivity;chlorophyll-A;TAQM-Dust
Date: 2016
Issue Date: 2018-05-16T08:49:40Z
Abstract: 近年來全球氣候變遷導致降雨分配不均,沙塵暴的發生頻率及強度也都受到影響,鄰近中國的臺灣及附近海面也受到大陸沙塵暴變化的影響。臺灣近20年來最嚴重的一次大陸沙塵事件,影響時間為2010年3月21日至23日,觀測資料顯示該個案影響範圍近乎遍及臺灣全島。在此之前影響臺灣的沙塵暴其PM10濃度多低於300~400 μm m-3,但在2010年的個案PM10濃度高達1228 μm m-3,為破紀錄的沙塵個案。 為瞭解此個案對臺灣懸浮微粒濃度變化及東亞周圍海域(東海和南海)生態影響,本研究使用區域沙塵模式TAQM-Dust模擬此沙塵個案揚起與傳輸過程及對海洋的影響,為了準確模擬此個案,也參考衛星資料的地形分布修正沙塵暴源地如戈壁沙漠、黃土高原與河西走廊等地區的地貌分布與排放權重,輔以衛星資料(Modis)海洋水色產品、實際測站觀測資料(大陸API指數、臺灣環保署)等來了解沙塵的時空分布,及定量這些營養鹽對東海和南海海域的葉綠素甲的影響。 根據模式計算結果,可溶性鐵與磷的濕沉降約為乾沉降的兩倍多,東海在沙塵影響的時間內,可溶性鐵的乾濕沉降量總和約0.29 mg m-2day-1,可溶性磷的沉降量總和約0.044 mg m-2day-1。由於沙塵個案侷限於臺灣附近,南海沉降量比東海少了100倍,可溶性鐵的沉降量總和約2.7 µg m-2 day-1,可溶性磷的沉降量總和約0.4 µg m-2day-1。依據Redfield ratio的估算,可溶性鐵與磷沉降入海面後,可以生成碳的數量,在東海分別為6307 mg m-2day-1與1.88 mg m-2day-1;南海則分別可產生57 mg m-2day-1與0.02 mg m-2day-1。若按照前人研究,磷為東海的限制性營養鹽的話,則產生的基礎生產力為0.04 mg Chl-a m-2day-1 將衛星觀測所得葉綠素甲衛星資料經由經驗式轉換海洋基礎生產力,得沙塵落入東海後第二週平均每日增長30 mg m-2day-1,而經模式計算出可溶性磷東海的沉降量可產生的基礎生產力為0.04 mg m-2day-1,因此此沙塵事件所落下的沙塵中的磷對於基礎生產力增長量約占0.1%。因此推論除了沙塵中的磷外,尚有其他營養鹽或海洋混合等因素造成在沙塵事件時海洋基礎生產力的增加 。
In recent years, the global climate change results in the uneven distribution of the rainfall, leading to the change of dust storm frequency and its intensity. The change of the Asian dust storm will affect the downwind area, such as Taiwan and the marginal seas of East Asia. The severest Asian dust storm in the recent two decades occurred on March 21-23, 2010. According to the observation, the dust storm affected the whole Taiwan island. Normally, a severe dust storm with aerosol concentrations below 300-400 µg m-3 were observed in Taiwan, but this is not the case for the dust event in March 2010, when the aerosol concentration was far above 1228 µg m-3. In order to understand the impacts of this dust event on the aerosol concentrations of Taiwan and the marginal sea of East Asia, this study apply regional dust model – TAQM-Dust to simulate the dust emissions, transport, and their impacts on the ocean. For better simulate this dust event, the satellite data of land cover was used to modified the emission weighting and the dust sources areas, such as the Gobi Deserts, Loess Plateau, and the Hexi Corridor. By incorporating satellite’s ocean cover data and station dust observations, the dust distributions can be better estimated, and the nutrient depositions to the East China Sea and the South China Sea can be quantified. According to the model calculation, the amount of iron and phosphate wet deposition is twice more than their dry deposition. During the dust event, the wet and dry deposition of dissolved iron in the East China Sea accounts for 0.29 mg m-2day-1 and the dissolved phosphate accounts for 0.044 mg m-2day-1. Since the dust event mainly affects the Taiwan area, the deposition in the South China Sea is two order less than in the East China Sea. The wet and dry depositions of dissolved iron sums up to 2.7 µg m-2 day-1, while the dissolved phosphate sums up to 0.4 µg m-2day-1. According to Redfield ratio, the dissolved iron and phosphate depositions will lead to the production of carbon mass of 6307 mg m-2day-1 and 1.88 mg m-2day-1 in the East China Sea, and 57 mg m-2 day-1 and 0.02 mg m-2day-1 in the South China Sea. If phosphate is the limited nutrient in the East China Sea, based on previous studies, the basic productivity will be 0.04 mg Chl-a m-2day-1 in the East China Sea. By applying the satellite observed chlorophyll-A data in an empirical equation, the basic productivity of the ocean can be calculated. The obtained basic productivity for the East China Sea was 30 mg m-2day-1 at the second week of the dust event. The model calculated basic productivity was 0.04 mg m-2day-1 based on phosphate deposition. Based on the above calculation, the phosphate in the dust particles had contributed 1% of basic productivity. According to the above calculation, there might be other nutrient sources or marine surface mixing that provide the nutrient for the basic productivity.
URI: http://ethesys.lib.ntou.edu.tw/cgi-bin/gs32/gsweb.cgi?o=dstdcdr&s=G0010181002.id
http://ntour.ntou.edu.tw:8080/ir/handle/987654321/46425
Appears in Collections:[海洋環境資訊系] 博碩士論文

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