研究生: |
李名翔 Li, Ming-Siang |
---|---|
論文名稱: |
臺灣北部梅雨季極端降水個案之系集分析與可預報度研究 Ensemble-based Analysis and Predictability of An Extreme-precipitation Event over Northern Taiwan in the Mei-yu Season |
指導教授: |
王重傑
Wang, Chung-Chieh |
學位類別: |
碩士 Master |
系所名稱: |
地球科學系 Department of Earth Sciences |
論文出版年: | 2020 |
畢業學年度: | 108 |
語文別: | 中文 |
論文頁數: | 190 |
中文關鍵詞: | 梅雨鋒面 、臺灣北部極端降雨 、技術得分 、系集敏感度分析 、可預報度 |
DOI URL: | http://doi.org/10.6345/NTNU202001022 |
論文種類: | 學術論文 |
相關次數: | 點閱:169 下載:45 |
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本研究針對2017年6月初的梅雨個案,並著重於6月2日當日北部地區的極端降雨事件,進行系集敏感度分析(ensemble sensitivity analysis, ESA)與可預報度的探討。該事件在短短12小時的最大累積雨量就達到641毫米的驚人雨量,並造成北部地區多處產生積、淹水現象。但在事件發生前,多數的數值模式都無法很好掌握北部地區的極端降雨,嚴重低估雨量,不利於事前的防災準備。
本研究採用45個成員的系集預報,透過5種技術得分(TS、BS、POD、FAR、FSS)的計算,來評估各成員的表現。結果顯示相較於24小時累積雨量,12小時累積雨量的得分都較低,且北部地區BS得分大多小於1(預報不足),顯示模式對於北部的短時強降雨較難以掌握,可預報度偏低。
而在系集敏感度分析方面,選取北部地區(東經120.9-122.1度,北緯25.0-25.5度)的平均6小時累積降雨量(6月2日0300-0900 LST)當作反應函數(response function)的結果顯示,影響北部地區降雨的因子主要有(1)鋒面位置和移速(2)鋒面強度(3)環境水氣含量(4)低壓擾動(5)中低層槽線,而這些因子彼此之間也互相影響。中低層槽線的位置與移速會影響到地面鋒面的位置和移速,進而導致主要降雨位置的差異,而低壓擾動的生成與發展又與對流密切相關,當低壓擾動生成後,除了會改變降雨位置的分布,也有助於將鋒後冷空氣帶至較南邊的位置,若鋒面因此南移至臺灣西北近海一帶,再配合地形阻擋使得海峽西南風增強,讓此區域的輻合作用增強,此區域恰好為北部地區降雨的上游位置,加上因輻合而加強的鋒生作用,使鋒面強度增強,而鋒生作用又會影響到鋒面的移動速度,使鋒面移動速度較慢並增強對流發展,造成北部地區產生較多的降雨。
透過高解析度實驗,顯示了提高模式的解析度是有助於改善此極端降雨事件的預報結果。另外,初始與邊界條件的品質好壞對於模式結果也有重大影響。當初始與邊界條件能較好地反映真實大氣的情況時,模式才較有機會能預報出較好的結果,進而提高可預報度。
陳泰然,1988:東亞梅雨鋒面之綜觀氣候特徵研究。大氣科學,16,435–446。
陳泰然,2007:最近之梅雨研究回顧。大氣科學,35,261-286。
莊璧瑜,2014:雲解析模式對臺灣梅雨季豪大雨定量降水預報技術之評估研究。國立臺灣師範大學地球科學系碩士學位論文。
謝竣安,2019:不同梅雨鋒面走向與移速對臺灣北部地區降雨影響之理想模擬研究。國立臺灣師範大學地球科學系碩士學位論文。
Ancell, B., and G. J. Hakim, 2007: Comparing adjoint- and ensemble-sensitivity analysis with applications to observation targeting. Mon. Wea. Rev., 135, 4117–4134.
Bednarczyk, C. N., and B. C. Ancell, 2015: Ensemble sensitivity analysis applied to a southern plains convective event. Mon. Wea. Rev., 143, 230–249.
Chen, G. T.-J., and C. C. Yu, 1988: Study of low-level jet and extremely heavy rainfall over northern Taiwan in the Mei-Yu season. Mon. Wea. Rev.,116, 884–891.
Chen, G. T. J., C.‐C. Wang, and D. T. W. Lin, 2005: Characteristics of low‐level jets over northern Taiwan in Mei‐Yu season and their relationship to heavy rain events, Mon. Weather Rev., 133, 20–43.
Hakim, G. J., and R. D. Torn, 2008: Ensemble synoptic analysis. Synoptic-Dynamic Meteorology and Weather Analysis and Forecasting: A Tribute to Fred Sanders, Meteor. Monogr., No. 55., Amer. Meteor. Soc., 147–161.
Hill, J. A., C. C. Weiss, and B. C. Ancell, 2016: Ensemble sensitivity analysis for mesoscale forecasts of dryline convection initiation. Mon. Wea. Rev., 144, 4161–4182.
Hohenegger, C., and C. Schär, 2007: Atmospheric predictability at synoptic versus cloud-resolving scales. Bull. Amer. Meteor. Soc., 88, 1783–1793.
Lorenz, E. N., 1969: The predictability of a flow which possesses many scales of motion. Tellus, 21, 289–307.
Lorenz, E. N., 1996: Predictability—A problem partly solved. Proc. Seminar on Predictability, Vol. I, Reading, United Kingdom, ECMWF, 1–19.
Roberts, N. M., and H. W. Lean, 2008: Scale‐selective verification of rainfall accumulations from high‐resolution forecasts of convective events, Mon. Weather Rev., 136, 78–97.
Torn, R. D. and G. J. Hakim, 2009: Initial condition sensitivity of western Pacific extratropical transitions determined using ensemble-based sensitivity analysis. Mon. Wea. Rev., 137, 3388–3406
Tsuboki, K., and A. Sakakibara, 2002: Large-scale parallel computing of cloud resolving storm simulator. High Performance Computing, H. P. Zima et al., Eds., Springer, 243–259.
Tsuboki, K., and A. Sakakibara, 2007: Numerical Prediction of High-Impact Weather Systems: The Textbook for the Seventeenth IHP Training Course in 2007. Hydrospheric Atmospheric Research Center, Nagoya University, and UNESCO, 273 pp.
Wang, C.-C., B.-K. Chiou, G. T.-J. Chen, H.-C. Kuo, and C.-H. Liu, 2016a: A numerical study of back-building process in a quasistationary rainband with extreme rainfall over northern Taiwan during 11–12 June 2012. Atmos. Chem. Phys., 16, 12359–12382
Wilks, Daniel S., 2011: Statistical methods in the atmospheric sciences (3rd ed.). Elsevier Inc., chapter 8.
Yeh, H. C., and Y. L. Chen, 2003: Numerical simulations of the barrier jet over northwestern Taiwan during the Mei-Yu Season. Mon. Wea. Rev., 131, 1396–1407.
Zhang, F., C. Snyder, and R. Rotunno, 2002: Mesoscale predictability of the “surprise” snowstorm of 24–25 January 2000. Mon. Wea. Rev., 130, 1617–1632.
Zhang, F., C. Snyder, and R. Rotunno, 2003: Effects of moist convection on mesoscale predictability. J. Atmos. Sci., 60, 1173–1185.
Zhang, F., A. Odins, and J. W. Nielsen-Gammon, 2006: Mesoscale predictability of an extreme warm-season rainfall event. Wea. Forecasting, 21, 149–166.