| DC 欄位 |
值 |
語言 |
| DC.contributor | 大氣科學學系 | zh_TW |
| DC.creator | 楊斯惟 | zh_TW |
| DC.creator | Szu-Wei Yang | en_US |
| dc.date.accessioned | 2020-7-28T07:39:07Z | |
| dc.date.available | 2020-7-28T07:39:07Z | |
| dc.date.issued | 2020 | |
| dc.identifier.uri | http://ir.lib.ncu.edu.tw:88/thesis/view_etd.asp?URN=107621009 | |
| dc.contributor.department | 大氣科學學系 | zh_TW |
| DC.description | 國立中央大學 | zh_TW |
| DC.description | National Central University | en_US |
| dc.description.abstract | 前人研究結果顯示，在全球暖化的情境下，Madden Julian Oscillation (MJO)會增強且其時間週期會傾向縮短。因此為了更加瞭解 MJO在全球暖化下變化的情形，本篇研究使用 pseudo global warming method 以及雲解析模式針對單一強MJO個案進行模擬分析。此實驗中採用WRF3.9.1版本進行模擬，其中有兩組實驗分別為控制組以及全球暖化情境的實驗組。在控制組實驗中，使用兩層巢狀網格，其分別為 27公里以及 9公里，並以 ERA-interim再分析資料作為模擬的初始及邊界條件。實驗組則是利用CMIP5中26組系集模式的RCP8.5暖化情境資料，將氣候變異值加在控制組的初始及邊界條件上，並將做完動力降尺度的結果，視為全球暖化的情境。
模擬結果顯示，在全球暖化下， 該 MJO事件 在降雨強度上有顯著的增強，此外對流結構也更傾向深對流發展。相速方面，全球暖化影響MJO的相速增快 。上述現象與 Gross Moist Stability (GMS)增加有密切的關係，透過 Chou et al. (2013)的方法，並針對動力部分做進一步的分析，我們發現其增加來自於，全球暖化下乾靜能 梯度變化效應、水氣梯度變化效應、對流結構改變以及雲頂效應所相互造成。其中乾靜能梯度變化由溫度梯度變化所主導，溫度垂直梯度變小會使 GMS加大，進而 讓 大氣更加穩定；至於水氣的垂直梯度，豐沛的底層水氣而有所增加，
增 強 的水氣垂直 梯度使環境趨向不穩定。在水氣與溫度 變化效應 互相抗衡之下，動力效應顯得格 外 重要，對流結構的加深以及對流層頂的升高使環境輸出濕靜能的效率增強GMS加大。除此之外，本研究並使用NGMS plane來探討局部地區 MJO水文循環在全球暖化情境下的變化，獲得相似的結果。 | zh_TW |
| dc.description.abstract | The Madden Julian Oscillation (MJO) is expected to become stronger while its period tends to be shorter with a higher temperature. To know how an MJO event might change under global warming, we use the pseudo global warming approach with a cloud-resolving model to simulate a super MJO event in this study. The Weather Research and Forecasting (WRF) model with two layers of nested domains, with a horizontal resolution of 27 km and 9 km, respectively, is utilized. Initial and boundary conditions are taken from the ERA-Interim reanalysis data. Changes in atmospheric variables under global warming are calculated from the multi-model ensemble means of twenty-four CMIP5 models under the RCP8.5 scenario, and the global warming conditions are produced by adding these changes to the control simulation’s initial and boundary conditions.
The simulation results show that MJO becomes much more intense under global warming, featured by enhanced surface precipitation and stronger deep (top-heavy) convection, along with a faster MJO phase speed. The above features are associated with a greater gross moist stability (GMS) of the atmosphere. By decomposing the change in GMS into the change of gross dry stability (GDS), the change of gross moisture condensation (GMC), the change of the convection structure and the cloud top effects, we find that changes in GDS, convection structure and convective depth are responsible for a greater GMS. Furthermore, the GMS plane analysis is employed to elucidate the physical implications for a faster hydrological cycle of MJO under global warming. | en_US |
| DC.subject | 馬登－朱利安振盪 | zh_TW |
| DC.subject | Madden Julian Oscillation | en_US |
| DC.title | Impacts of Global Warming on a Super Madden Julian Oscillation Event in the WRF Simulation | en_US |
| dc.language.iso | en_US | en_US |
| DC.type | 博碩士論文 | zh_TW |
| DC.type | thesis | en_US |
| DC.publisher | National Central University | en_US |