気象集誌. 第2輯
Online ISSN : 2186-9057
Print ISSN : 0026-1165
ISSN-L : 0026-1165
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20件中1~20件の論文を表示しています
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  • 2024-020
    Development of a Temperature Prediction Method Combining Deep Neural Networks and a Kalman Filter もっと読む
    編集者のコメント

    This paper that described an advanced post-processing method for output from numerical weather forecast models by combining the Kalman Filter and machine learning. This study combined the CNN-based bias correction scheme with the JMA’s operational KF algorithm. ŸVerification results showed that our method outperformed both the DNN and the JMA's operational temperature guidance forecast. Ÿ   The KF has advantages of online learning that the DNN does not have. The verification demonstrated that the KF was able to follow the bias changes for NWP model updates.

  • 2024-010
    Global Historical Reanalysis with a 60-km AGCM and Surface Pressure Observations: OCADA もっと読む
    編集者のコメント

    This paper presents the development of a historical atmospheric reanalysis OCADA along with its validations and applications. Surface pressure observations in East and Southeast Asia, which are newly archived and used in this study, account for 15 % of the database in the early 20th century. OCADA is superior in representing the intensities of observed tropical cyclones in 1979-2015. OCADA reproduces several extreme precipitation events in Japan before World War II.

  • 2024-004
    The JRA-3Q Reanalysis もっと読む
    編集者のコメント

    This paper describes a new global atmospheric reanalysis JRA-3Q developed by Japan Meteorological Agency, focusing on the improvements from the previous reanalysis. The large upward imbalance in the global mean net energy flux at the top of the atmosphere and at the surface, one of the major problems of JRA-55, has been significantly reduced. The artificial decrease in the detection of tropical cyclones seen in JRA-55 has been resolved by the use of a tropical cyclone bogus generation method based on the JMA operational system. For the pre-1957 period, which is first included in Japanese reanalyses, major typhoons, such as Typhoon Kathleen and Typhoon Marie, are clearly represented in the mean sea level pressure field of JRA-3Q, and the pressure fields are generally consistent with the original weather map analyzed at that time.

  • 2024-003
    Geometry of Rainfall Ensemble Means: From Arithmetic Averages to Gaussian-Hellinger Barycenters in Unbalanced Optimal Transport もっと読む
    編集者のコメント

    This paper proposed new ensemble means of rainfall based on the theory of unbalanced optimal transport. Ensemble forecast results are usually announced using ensemble means. However, for the rainfall variable, ensemble means are rarely used in practice due to the diffusion effect resulting from the averaging operator, which smooths rainfall significantly. A method to calculate more meaningful ensemble means of rainfall is proposed based on the theory of unbalanced optimal transport. The new ensemble means are interpreted as barycenters of rainfall distributions with respect to a new geometric distance called the Gaussian-Hellinger distance. The new ensemble means avoid the diffusion effect as observed in the case of arithmetic means, and open a way to reintroduce ensemble means of rainfall back to numerical weather prediction.

  • 2023-025
    The 30-year (1987-2016) Trend of Strong Typhoons and Genesis Locations Found in the Japan Meteorological Agency's Dvorak Reanalysis Data もっと読む
  • 2023-015
    Particle Filtering and Gaussian Mixtures―On a Localized Mixture Coefficients Particle Filter (LMCPF) for Global NWP もっと読む
    編集者のコメント

    This paper describes a particle filter in the global NWP at Deutscher Wetterdienst (DWD).  A particle filter (PF) in the global NWP at DWD is proposed and evaluated its skills in comparison with the operational system. To alleviate the degeneration, which is the largest issue in PFs with high-dimensional systems, several approaches are effectively incorporated such as localization, Gaussian mixture approximation in the prior distribution, adaptive resampling, and so on (See Section 2.3). Since comprehensive formulations in this system are described, the readers can totally understand its theoretical aspects.

  • 2023-009
    Japan Meteorological Agency/Meteorological Research Institute Coupled Prediction System Version 3 (JMA/MRI-CPS3) もっと読む
    編集者のコメント

    This paper describe a newly developed operational seasonal forecast system, JMA/MRI-CPS3. Ocean 4D-Var and sea ice 3D-Var data assimilation methods are newly introduced. The errors in the ocean analysis are now represented in the initial perturbations. Updated physical processes and increased resolution of the atmospheric model contribute to the improved climate reproducibility of the MJO and North Atlantic blocking highs. The introduction of a 0.25-degree-resolution ocean model provides a realistic representation of tropical instability waves and contributes to improved ENSO pattern.

  • 2023-004
    Effects of Dry Vegetation Coverage Estimated from the MODIS Soil Tillage Index on Dust Occurrence: Verification by Surface Synoptic Observations もっと読む
    編集者のコメント

    This paper proposed a machine learning method as an observation operator for satellite radiances within a data assimilation system. Model forecast and satellite microwave radiance observations are used to train machine learning models to obtain the observation operator for satellite data assimilation.Data assimilation experiments using the machine learning-based observation operator show promising results without a separate bias correction procedure.The machine learning-based observation operator can potentially accelerate the development of using new satellite observations in numerical weather prediction.

  • 2023-005
    A Machine Learning Approach to the Observation Operator for Satellite Radiance Data Assimilation もっと読む
    編集者のコメント

    This paper proposed a new method calculating the threshold wind speed for dust occurrence. A new method to obtain threshold wind speed that takes account of the interannual variations of dry vegetation cover is proposed. Dry vegetation coverage is a key factor determining interannual variations in the April dust occurrence. Other land surface factors such as soil freeze-thaw and snow cover should be considered to explain dust occurrence variations in March.

  • 100 巻 (2022) 2 号 p. 445-469
    プリミティブ方程式系の3次元スペクトルモデルの定式化 もっと読む
  • 100 巻 (2022) 2 号 p. 321-341
    北西太平洋の台風通過に伴って生じる気象庁準リアルタイム版全球海面水温解析のバイアス もっと読む
  • 99 巻 (2021) 2 号 p. 287-308
    9月の発達した低気圧によるシベリアから北極域への黒色炭素エアロゾル輸送に対するモデル分解能の影響 もっと読む
  • 98 巻 (2020) 6 号 p. 1163-1182
    京コンピュータを用いた豪雨の広域・超高解像度実験:Part 2 2014年8月の広島豪雨事例と対流コアのモデルの解像度依存性 もっと読む
  • 99 巻 (2021) 2 号 p. 309-337
    石油・ガス、炭鉱、畜産部門からの排出による過去30年間のメタン濃度の増加 もっと読む
  • 99 巻 (2021) 2 号 p. 205-237
    全球降水観測計画二周波降水レーダ(GPM/DPR)の降水強度推定アルゴリズム もっと読む
  • 98 巻 (2020) 4 号 p. 755-773
    衛星搭載二周波降水レーダによる全球雨滴粒径分布の4年気候値とその季節変動 もっと読む
  • 98 巻 (2020) 4 号 p. 775-786
    東京に接近する台風の1980年以降の増加 もっと読む
    編集者のコメント

    Yamaguchi and Maeda (2020) The above paper was press released. (25 Aug. 2020)
    Press release document (in Japanese)

  • 98 巻 (2020) 4 号 p. 821-833
    マルチアンサンブルを用いた台風進路予報における予報楕円 もっと読む
    編集者のコメント

    Kawabata and Yamaguchi (2020): The above paper was chosen as a JMSJ Editor's Highlight. (13 Jul. 2020)
    Description of this paper 

  • 98 巻 (2020) 2 号 p. 395-435
    雲と降水をシミュレートするためのラージエディモデルとストーム解像モデルの付加価値 もっと読む
    編集者のコメント

    Stevens et al. (2020): The above paper was chosen as a JMSJ Editor's Highlight. (5 Mar. 2020)
    Description of the paper

  • 98 巻 (2020) 1 号 p. 169-187
    盛夏期におけるアジアジェットに沿う準定常ロスビー波束伝播と 太平洋・日本パターンとの力学的関連性 もっと読む
    編集者のコメント

    Takemura and Mukougawa (2020): The above paper was chosen as a JMSJ Editor's Highlight. (4 Jan. 2020)
    Description of this paper

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