DSpace collection: 研究計畫
http://ir.lib.ncu.edu.tw/handle/987654321/24090
The collection's search engineSearch the Channels
http://ir.lib.ncu.edu.tw/simple-search
中央氣象局FV3GFS全球天氣預報系統應用混合增益系集—變分資料同化方法之評估研究(2/3);Evaluation of the hybrid gain ensemble-variational data assimilation method applied to Central Weather Bureau’s FV3GFS global weather prediction system (2/3)
http://ir.lib.ncu.edu.tw/handle/987654321/88565
title: 中央氣象局FV3GFS全球天氣預報系統應用混合增益系集—變分資料同化方法之評估研究(2/3);Evaluation of the hybrid gain ensemble-variational data assimilation method applied to Central Weather Bureau’s FV3GFS global weather prediction system (2/3) abstract: 本研究計畫將於中央氣象局未來作業用全球模式系統(FV3GFS)架構下,進行混成資料同化(HGDA)系統的建置與開發,強化具氣象局特色之全球預報系統。計畫第一年已藉由氣象局的FV3GFS-GSI資料同化系統為基礎,利用單點觀測同化實驗測試FV3GFS-GSI內子同化系統的特性。由於HGDA在實作上有兩種同化策略,故亦分就各同化策略進行結合權重的測試與探討,理解結合權重在不同策略中的貢獻。本年度將基於單點觀測實驗的經驗,進行FV3GFS-HGDA的循環同化實驗,並測試出各同化策略的最佳結合權重,評估最合適氣象局的同化策略。第三年將致力於QR-HGDA同化系統的建置,並將正交向量診斷應用於FV3GFS-GSI同化系統,期待可釐清EnVAR同化系統的修正特性。此三年期研究計畫成果預期可完成FV3GFS-HGDA系統的建置與效益評估,並可培養國內自主研發與強化全球模式的維護能力。 ;CWB has advanced its global operational system toward the next-generation system, the FV3GFS, coupled with a Gridpoint Statistical Interpolation (GSI) hybrid ensemble-variational (EnVar) data assimilation system (FV3GFS-GSI). This system is planned to be operational in 2021. Different from hybridizing the background error covariance in EnVar, a three-year project is planned to explore a different possibility of hybrid data assimilation and aims to develop the hybrid gain data assimilation (HGDA) system using the ensemble and variational DA components from the FV3GFS-GSI system. In the first year, single observation experiment had been conducted to investigate the properties of each DA system, including the FV3GFS-GSI, the FV3GFS-HGDA and its component DA systems. In this year, cycling experiments will be conducted to examine the applicability and feasibility for the FV3GFS-HGDA under a semi-operational environment. Since the HGDA has two scenarios for implementation, a series of sensitivity tests are necessary to justify the optimal combination weight for both scenarios. Except for a single weight value, an altitude-dependent combination weight would be a potential option for improving the hybrids if needed. In the last year of this three-year study, we will focus on implementing the QR-HGDA algorithm to evaluate the possibility of removing the ad-hoc determined combination weight in hybrids. The newly derived orthogonal analysis increment through QR-factorization can be used to understand the characteristics of the increments in the current FV3GFS-GSI system. Through the three-year study, we are able to develop a hybrid DA system and such experiences can feedback to the FV3GFS-GSI development. The optimal goal of this study is to enhance CWB’s ability in DA research and global forecast system in Taiwan.
<br>中央氣象局FV3GFS全球天氣預報系統應用混合增益系集—變分資料同化方法之評估研究(1/3);Evaluation of the hybrid gain ensemble-variational data assimilation method applied to Central Weather Bureau’s FV3GFS global weather prediction system (1/3)
http://ir.lib.ncu.edu.tw/handle/987654321/85160
title: 中央氣象局FV3GFS全球天氣預報系統應用混合增益系集—變分資料同化方法之評估研究(1/3);Evaluation of the hybrid gain ensemble-variational data assimilation method applied to Central Weather Bureau’s FV3GFS global weather prediction system (1/3) abstract: 本研究計畫將於中央氣象局未來作業用全球模式系統(FV3GFS)架構下,進行混成資料同化系統的建置與開發,強化具氣象局特色之全球預報系統。計畫第一年將以氣象局的GSI資料同化系統為基礎,開發混成增益矩陣資料同化系統(HGDA),並以單點觀測實驗比較各同化系統特性,藉此評估同化系統開發所需之參數及適合作業用的同化策略。第二年將藉由循環分析實驗,以敏感度實驗測試最佳化結合權重,並評估建立隨波譜特性調整最佳結合權重之迫切性。第三年將致力於QR-HGDA同化系統的建置,並將修正量的正交向量診斷應用於FV3GFS-GSI同化系統,釐清EnVAR同化系統的修正特性。此三年期研究計畫成果預期可完成FV3GFS-HGDA系統的建置與效益評估,並可培養國內自主研發與強化全球模式的維護能力。 ;CWB has advanced its global operational system toward the next-generation system, the FV3GFS, coupled with a Gridpoint Statistical Interpolation (GSI) hybrid ensemble-variational (EnVar) data assimilation system (FV3GFS-GSI). This system is planned to be operational in 2021. Different from hybridizing the background error covariance in EnVar, a three-year project is planned to explore a different possibility of hybrid data assimilation and aims to develop the hybrid gain data assimilation (HGDA) system using the ensemble and variational DA components from the FV3GFS-GSI system. In the first year, the major task is to implement the HGDA system, including the feasible steps to combine the sub-DA components of the FV3GFS-GSI system. A single observation experiment will be conducted to investigate the properties of each DA system, including the FV3GFS-GSI, the FV3GFS-HGDA and its component DA systems. The results of a single observation experiment would help evaluate the assimilation strategy and optimize the setup of the HGDA system. For the second year, cycling experiments will be conducted to examine the applicability and feasibility for the FV3GFS-HGDA under a semi-operational environment. A series of sensitivity tests are necessary to justify the optimal combination weight. Except for a single weight value, a spectrum-dependent combination weight would be a potential option for improving the hybrids if needed. In the third year, we will focus on implementing the QR-HGDA algorithm to evaluate the possibility of removing the ad-hoc determined combination weight in hybrids. The newly derived orthogonal analysis increment through QR-factorization can be used to understand the characteristics of the increments in the current FV3GFS-GSI system. Through the three-year study, we are able to develop a hybrid DA system and such experiences can feedback to the FV3GFS-GSI development. The optimal goal of this study is to enhance CWB’s ability in DA research and global forecast system in Taiwan.
<br>桃竹苗地區受地形影響之梅雨系統氣象雷達加強觀測計畫
http://ir.lib.ncu.edu.tw/handle/987654321/69826
title: 桃竹苗地區受地形影響之梅雨系統氣象雷達加強觀測計畫 abstract: 台灣桃竹苗地區是台灣梅雨季強降水發生的高頻率地區,而新竹苗栗缺乏足夠的雷達觀測資料,強降水又多發生在雪霸山區,雨量站很稀少。本計畫擬在梅雨季節對於該地區進行加強觀測。本計畫將針對桃竹苗地區挑選三個觀測點(平地、丘陵及山區) 以3公分的移動式偏極化雷達與中央大學CPOL雷達及清泉崗都卜勒雷達,進行氣象雷達聯合加強觀測,填補該區域低層資料,提升該區定量降水估計能力。另外可利用五分山雙偏極化雷達校驗中央大學CPOL雷達及移動式偏極化雷達之資料品質處理校驗。同時亦可使用移動式雷達以RHI做高時空解析度的掃瞄,以得;Heavy rainfall events in Mei-Yu season often occur near the Shei-Pa National Park in the mountain area of TaoYuan, HsinChu and Miaoli county. The convergence near the Mei-Yu front and the interaction with the unique topography of this region induce torren;研究期間:10403~10412
<br>中央氣象局全球系集颱風預報系統作業研究
http://ir.lib.ncu.edu.tw/handle/987654321/69824
title: 中央氣象局全球系集颱風預報系統作業研究 abstract: 經歷103年度的計畫研究,共蒐集2104年至計畫書繳交前所有颱風個案及2013年8個個案。所建置的颱風路徑系集系統已將粗具規模,雖說系集的分佈和實際均方根誤差仍有一段落差,但是系集成員表現穩定,沒有大好大壞的情形。同時,系集平均略好於單一模式預報,但不致於和單一模式預報成南轅北轍的結果。這樣的結果說明:(1)單一模式的準確率有提升的必要:(2)系集系統散佈可再增加。 氣象局全球模式預計2015年9月上線新物理過程及較高解析度T511L60的模式,將有助於 路徑預報。另一方面,系集散佈的增加可採用不同的方法;In 2014 project, we collected all west pacific typhoon cases during the period from 1 Jan. to 25 Nov, 2014. We also analyzed 8 cases in 2013. The prototype of global ensemble prediction system for typhoon-track has established. The system performs very st;研究期間:10401~10412
<br>