未分類」カテゴリーアーカイブ

Data Assimilation Seminar – Professor Serge Guillas [UCL]

We held the 59th Data Assimilation Seminar at RIKEN Center for Computational Science (R-CCS) on 31 May.

The talk was given by Professor Serge Guillas who was visiting us from University College London (UCL). Professor Guillas spoke about current solutions to investigating uncertainties in tsunami impacts, including investigating the potential for landslides as a source of tsunamis in the Western Indian Ocean and the risk of tsunamis from the Makran subduction zone. Part of his research was using very high resolution models to simulate potential tsunamis in these regions and predict seabed deformations and landslide velocities. We wish Professor Guillas well in the future with his research on this very important topic and hope that he will return again soon to R-CCS to update us on his progress. Thank you!

For more information about this and all our DA seminars at RIKEN R-CCS, please see the DA seminar page:

http://www.data-assimilation.riken.jp/en/events/da_seminar/index.html

Data Assimilation Seminar – Prof. Ming-Cheng Shiue

We held the 58th Data Assimilation Seminar at RIKEN Center for Computational Science (R-CCS) on 7 May.

The seminar was given by Professor Ming-Cheng Shiue from the National Chiao Tung University, Taiwan. He spoke about his research on hybrid, nonlinear continuous data assimilation algorithms for Lorenz systems. He presented his work showing that approximate solutions converge to reference solutions over time provided that only first and second variables of Lorenz systems are synchronized. He also presented research on two continuous and discrete DA algorithms for 2D Navier-Stokes equations, showing how present and past observations at each time step provide a way that new methods could outperform old ones.

We are very grateful to Professor Shiue for visiting us at RIKEN and hope to see him again soon.

For more information about this and all our DA seminars at RIKEN R-CCS, please see the DA seminar page:

http://www.data-assimilation.riken.jp/en/events/da_seminar/index.html

Data Assimilation Seminar – Dr Atsushi Okazaki [R-CCS]

We held the 57th Data Assimilation Seminar at RIKEN Center for Computational Science (R-CCS) on 25 April.

The talk was given by our very own Dr. Atsushi Okazaki from the Data Assimilation team at RIKEN R-CCS. Dr Okazaki presented his research on testing the feasibility of a a new type of geostationary satellite that would be able to provide continuous space borne precipitation radar observations, similar to those of Tropical Rainfall Measuring Mission (TRMM) and Global Precipitation Measurement (GPM). Dr. Okazaki has been testing the impact of such observation on numerical weather prediction for a tropical cyclone case. His results showed promising impact on track and intensity forecasts with the assimilation of such observations.

Dr Okazaki has been member of the Data Assimilation team for 3 years but will leave next month to start a new position in the United States . We are very sad to see him leave but wish him all the best in the future and hopefully see him again very soon. Good luck Atsushi!

For more information about this and all our DA seminars at RIKEN R-CCS, please see the DA seminar page:

http://www.data-assimilation.riken.jp/en/events/da_seminar/index.html

データ同化手法を活用した観測システムの影響評価に関する研究会(4/18-19)のご案内

海洋研究開発機構(JAMSTEC) アプリケーションラボおよびR-CCS データ同化研究チームの共催による「データ同化手法を活用した観測システムの影響評価に関する研究会」が、
来週4月18日(木)、19日(金)にJAMSTEC横浜研究所にて行われます。
開催概要は以下の通りです。

日時 2019年4月18日(木)-4月19日(金)
場所 海洋研究開発機構 横浜研究所 交流棟2F小会議室
神奈川県横浜市金沢区昭和町3173番25
対象 主に大気・海洋分野の観測・シミュレーション・データ同化研究者
言語 日本語
参加費 無料

詳しいプログラムおよび参加申し込みは以下をご参照ください。
http://www.data-assimilation.riken.jp/jp/events/oreda_2019spring/index.html

The 56th Data Assimilation Seminar

We held the 56th Data Assimilation Seminar at RIKEN Center for Computational Science (R-CCS) on 1 February.

The talk was given by Dr. Tie Dai from State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics (LASG), Institute of Atmospheric Physics at the Chinese Academy of Sciences.

Dr Dai talked about his work developing an aerosol data assimilation system based on the NICAM model and LETKF. He showed how he has been able to successfully assimilate observations from both the MODIS satellite and Himawari 8 satellite to produce an aerosol analysis for the improvement of short-range aerosol forecasting over Eastern Asia.

We would like to thank Dr Dai very much for visiting us here in Kobe and for the lively discussion about his work! We wish him well with his research in the future.

For more information about this and all our DA seminars at RIKEN R-CCS, please see the DA seminar page:

http://www.data-assimilation.riken.jp/en/events/da_seminar/index.html

The 54th and 55th Data Assimilation Seminar

We held the 54th and 55th Data Assimilation Seminars at RIKEN Center for Computational Science (R-CCS) on January 28.

The first talk was given by Dr. Alison Fowler from the University of Reading (UK), who spoke about observation error correlations and how we might apply data compression techniques that retain maximum information content of the observations, allowing us to use more observations in our data assimilation.

The second talk was given by Jemima Tabeart, also from the University of Reading. She spoke about available reconditioning methods that can be used to improve the condition number of correlated matrices. She found that she could improve the convergence by introducing correlated observation error covariance matrices with only small changes to retrieved variables.

We would like to thank Alison and Jemima for visiting us here at RIKEN R-CCS and giving two very interesting talks on observation error covariance matrix estimation – a very important topic in this era of Big Data!  

For details, please see the following DA seminar page:

http://www.data-assimilation.riken.jp/en/events/da_seminar/index.html

53rd DA Seminar – Dr Eugenia Kalnay

We held the 53rd Data Assimilation Seminar at RIKEN Center for Computational Science (R-CCS) on January 18. The seminar talk was given by Dr Eugenia Kalnay from the University of Maryland.

Dr Kalnay spoke about how wind and solar farms may lead to unintended climate changes caused by changes to land surface properties. She showed using a climate model how a large scale installation of wind and solar farms across the Sahara would lead to a local temperature increase and precipitation increase, which could have a positive impact on vegetation.

We would like to thank Dr Kalnay very much for visiting us again in Kobe and for the many great discussions we had with her during her stay. We look forward to welcoming her again to R-CCS soon!

52nd Data Assimilation Seminar – Dr. Tetsuo Nakazawa

We held the 52nd Data Assimilation Seminar at RIKEN Center for Computational Science (R-CCS) on December 19. The seminar talk was given by Dr Tetsuo Nakazawa from Meteorological Research Institute (MRI), Japan Meteorological Agency (JMA).

Dr Nakazawa spoke about his research on tropical cyclone frequency under a warmer climate scenario and why it may be expected that the annual number of tropical cyclones may decrease in the future.

We would like to thank Dr Nakazawa very much for visiting us at RIKEN. We look forward to his next visit!

51st Data Assimilation Seminar – Prof. Roland Potthast

We held the 51st Data Assimilation Seminar at RIKEN Center for Computational Science (R-CCS) on November 13. The seminar talk was given by Professor Roland Potthast from Deutscher Wetterdienst (DWD), the German National Meteorological Service, and University of Reading.

Prof. Potthast spoke about the ICON global and mesoscale model under development at DWD and alongside COSMO partners.

We would like to thank Prof. Potthast very much for visiting us at RIKEN and providing us with a good overview of all the interesting research happening at DWD. We look forward to his next visit to RIKEN.

For details on upcoming DA seminars, please see the following DA seminar page:
http://www.data-assimilation.riken.jp/en/events/da_seminar/index.html.

第51回データ同化セミナー (11月13日)のご案内

11/13のデータ同化セミナーについてのご案内です。
今回のセミナーでは、
Prof. Roland Potthast (DWD/U of Reading)
よりご講演頂きます。

※どなたでもご参加いただけますが、入館に手続きが必要なため、
事前に下記までご連絡をお願い致します。
da-seminar(please remove here)@riken.jp

以下URLに随時情報を更新しています。
http://data-assimilation.riken.jp/en/events/da_seminar/

以下、詳細です。

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Date: *Tuesday 13 November 2018, 10:30-12:00 *
Place: Room – R104-2 at R-CCS
Language: English
Speaker: Prof. Roland Potthast (DWD/U of Reading)

*Title: New Observations and Algorithmic Developments for Convective Scale
Ensemble Data Assimilation*

*Abstract: *
We first present the setup of the ensemble data assimilation (EDA) and
forecasting systems (EPS) which have been developed and are under
development at the German Weather Service DWD and its COSMO partners. This
is first the ICON global+mesoscale model (two-way nested), 13km/6.5km
resolution, with its hybrid ensemble variational data assimilation
(LETKF+EnVAR) run on a 3h cycle,and the ensemble prediction system ICON
EPS. Second, this system drives the high-resolution ensemble data
assimilation system COSMO-KENDA (Kilometer Scale Ensemble Data
Assimilation) with 2.2km operational resolution at DWD and up to 1km
resolution at further members of the COSMO consortium (Germany,
Switzerland, Italy, Russia, Poland, Romania, Greece and Israel) to provide
initial conditions for the high-resolution ensemble forecasting systems,
e.g. the operational COSMO-D2-EPS or experimental ICON-LAM EPS. The system
is also successfully run on GPU based supercomputers.

The core task of the talk is to discuss recent and current developments on
new observations and on new algorithmic developments on the convective
scale, but many of them relevant for global NWP as well. We discuss recent
insight into the importance of quality control, report on the large success
and positive impact of Mode-S data assimilation, discuss the assimilation
of RADAR radial winds and reflectivity with an ensemble Kalman filter and
finally report on some initial tests on the assimilation of visible
channels SEVIRI VIS on the convective scale.

Second, we will discuss new algorithmical developments, in particular
aspects of 4D-LETKF versus 3D-LETKF and initial tests on the ICON-LAM data
assimilation with the KENDA system. Then, we present the particle filter
for global or convective scale EDA as well as ultra-rapid data assimilation
(URDA) on a scale of minutes imbedded into an operational rapid update
cycle (RUC) of a convection resolving model.

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