Events / Media

Data Assimilation Seminar Series

Registration: da-seminar(at)

Registration deadline: September 25, 2017

Next Seminar

Date & Time 15:30-16:30, Sep. 26 2017 (2017-13(38th))
Place & Contact 6F Auditorium
RIKEN Advanced Institute for Computational Science
7-1-26 Minatojima-minami-machi, Chuo-ku, Kobe, 650-0047, Japan
Click here for directions.
To enter the AICS building, please contact the following address in advance.
Language English
Speaker [Intership student]
Mr. Cheng Da
(University of Maryland / AICS HR development intern)

Dr. Guo-Yuan Lien
Title [Internship report] Assimilation of the GSMaP Precipitation Data with the SCALE-LETKF System
Abstract Past studies with the variational data assimilation systems have shown that assimilating precipitation observations improves the analysis, while the model quickly "forgets" their impacts, and the resulting forecasts are not substantially improved after a few hours. By introducing the Gaussian transformation to the precipitation data, and directly modifying the dynamical variables through an Ensemble Kalman Filter system, Lien et al. (2013) showed with the SPEEDY model that assimilating precipitation can improve both the analysis and medium-range forecast for almost all variables. Consistent positive results were then observed in the follow-up studies using more realistic global models and observations (GFS-LETKF/TMPA, Lien et al. 2016a, 2016b; NICAM-LETKF/GSMaP, Kotsuki et al. 2017). However, it is still unclear whether this methodology is applicable to the mesoscale regional model. Therefore, it is of our interest to investigate whether precipitation assimilation can provide additional forecast benefits to the regional model. During this internship, we implement the precipitation assimilation with the SCALE-LETKF regional data assimilation system, and conduct experiments on Typhoon Chan-hom and Nangka in 2015. The preliminary results show that with the GSMaP precipitation assimilation, the sea level pressure analysis of the typhoon center is more close to the best track data. In addition to the dynamical adjustments, the hydrometeor fields around the typhoon center are also improved when verified against the cloud liquid water and ice water path retrievals from the GPM Microwave Imager. The forecast experiments show that additional precipitation assimilation improves both the track and intensity forecasts.

Upcoming Seminars

Date & Time 15:30-16:30, Oct. 12 2017 (2017-14(39th))
Place & Contact Room - R104-2
RIKEN Advanced Institute for Computational Science
7-1-26 Minatojima-minami-machi, Chuo-ku, Kobe, 650-0047, Japan
Click here for directions.
To enter the AICS building, please contact the following address in advance.

Language English
Speaker [Intership student] Mr. Krishnamoorthy Chandramouli
(Indian Institute of Technology Madras)

[Supervisor] Dr. Koji Terasaki
Title [Internship report] Impact of assimilating humidity sounder radiances with the NICAM-LETKF system
Abstract TBD
Date & Time 15:30-16:30, Nov. 17 2017 (2017-15(40th))
Place & Contact Room - C107
RIKEN Advanced Institute for Computational Science
7-1-26 Minatojima-minami-machi, Chuo-ku, Kobe, 650-0047, Japan
Click here for directions.
To enter the AICS building, please contact the following address in advance.

Language English
Speaker Dr. Yusuke Uchiyama
(Department of Civil Engineering, Kobe University)
Title Challenges and issues in forward regional ocean modeling: Eddies, terrestrial influences, and surface gravity waves
Abstract TBD


Number Date Speaker Title (crick the title to see abstract & PDF)
2017-12(37th) Aug 16, 2017 Ms. Paula Maldonado
(CONICET-U of Buenos Aires)
Radar Data Assimilation in a Case of Deep Convection in Argentina
2017-11(36th) Aug 16, 2017 Mr. Sam Hatfield
(Oxford U)
How low can you go? Reducing the precision of data assimilation to improve forecast skill
2017-10(35th) Aug 4, 2017 Dr. Chih-Chien Tsai
(TTFRI, Taiwan)
Preliminary Experimental Results of Polarimetric Radar Data Assimilation in the Case of Typhoon Soudelor (2015)
2017-09(34th) Jun 26, 2017 Dr. Toshio Iguchi
Radar Measurement of Precipitation from Space: TRMM/PR and GPM/DPR rain retrieval algorithms data
2017-08(33rd) May 18, 2017 Dr. Guo-Yuan Lien
30-second-cycle convection-resolving data assimilation of dense phased array weather radar data
2017-07(32nd) Mar 7, 2017 Dr. Alison Fowler
(U of Reading)
On the interaction of observation and a-priori error correlations in data assimilation
2017-06(31st) Mar 7, 2017 Dr. Joanne A. Waller
(U of Reading)
Diagnosing observation error statistics for numerical weather prediction
2017-05(30th) Mar 7, 2017 Prof. Nancy K. Nichols
(U of Reading)
New applications and challenges in data assimilation
2017-04(29th) Mar 6, 2017 Prof. Steven J. Greybush
(Penn State U)
Ensembles, Data Assimilation, and Predictability for Winter Storms
2017-03(28th) Mar 6, 2017 Prof. Eugenia Kalnay
(U of Maryland)
Modeling Sustainability: Coupling Earth and Human System Models
2017-02(27th) Feb 7, 2017 Prof. Hiromichi Nagao
(U of Tokyo)
Promises and Challenges in Assimilation of Infrared and Microwave All-sky Satellite Radiances for Convection-Permitting Analysis and Prediction
2017-01(26th) Jan 13, 2017 Prof. Fuqing Zhang
(Penn State U)
Data assimilation for massive autonomous systems based on a second-order adjoint method
2016-09(25th) Dec 22, 2016 Dr. Takahiro Nishimichi
(Kavli IPMU, U of Tokyo)
Dark Emulator: cosmic large-scale structures and parameter estimate
2016-08(24th) Dec 21, 2016 Dr. Takumi Honda
Assimilating All-Sky Himawari-8 Satellite Infrared Radiances: Preliminary Case Studies
2016-07(23rd) Nov 24, 2016 Mr. Yasumitsu Maejima
Impacts of dense and frequent surface observations on a sudden severe rainstorm forecast: A case of an isolated convective system
2016-06(22nd) June 13, 2016 Mr. Yasutaka Ikuta
Assimilation of GPM/DPR at JMA
2016-05(21st) Apr 14, 2016 Dr. Yohei Sawada
Advancing land data assimilation science to monitor terrestrial water and vegetation dynamics
2016-04(20th) Mar 16, 2016 Dr. Juan Ruiz
(U Buenos Aires (CIMA)/RIKEN AICS)
Implementation and evaluation of a regional data assimilation system based on WRF-LETKF
2016-03(19th) Mar 7, 2016 Prof. Roland Potthast
(DWD/U of Reading)
On Ensemble and Particle Filters for Large-Scale Data Assimilation
2016-02(18th) Mar 2, 2016 Ms. Chang Yaping
Dr. Shunji Kotsuki
Ensemble data assimilation of MODIS surface temperature into land surface model
2016-01(17th) Feb 17, 2016 Mr. Sho Yokota
Comparison between LETKF and EnVAR with observation localization
2015-10(16th) Dec 25, 2015 Dr. Shunji Kotsuki
Ensemble Data Assimilation of GSMaP precipitation into the nonhydrostatic global atmospheric model NICAM
2015-09(15th) Dec 15, 2015 Dr. Kozo Okamoto
Assimilation of cloud-affected infrared radiances
2015-08(14th) Oct 21, 2015 Prof. Kosuke Ito
(U of the Ryukyus)
Advanced data assimilation techniques for predicting tropical cyclone intensities
2015-07(13th) Sep 16, 2015 Mr. Shumpei Terauchi
(U of Tsukuba)
Dr. Guo-Yuan Lien
Verification of the near-real-time weather forecasts and study on 2015 typhoon Nangka with the SCALE-LETKF system
2015-06(12th) Sep 2, 2015 Dr. Daisuke Hotta
Diagnostic methods for ensemble data assimilation
2015-05(11th) Jun 25, 2015 Dr. Koji Terasaki
Applying the Local Transform Ensemble Kalman Filter to the non-hydrostatic atmospheric model NICAM
2015-04(10th) Jun 5, 2015 Prof. S. Lakshmivarahan
(U of Oklahoma)
Nonlinear dynamics and Predicitability
2015-03(9th) Apr 17, 2015 Prof. Takeshi Enomoto
Assimilation and forecast experiments using bright band heights
2015-02(8th) Mar 24, 2015 Dr. Shigenori Otsuka
Towards 100-m resolution prediction of local convective storms: predictability and nowcasting
2015-01(7th) Jan 20, 2015 Dr. Nobumasa Komori
Development of an ensemble-based data assimilation system with a coupled atmosphere-ocean GCM
2014-06(6th) Dec 26, 2014 Dr. Keiichi Kondo
The 10,240-member ensemble Kalman filtering with an intermediate AGCM without localization
2014-05(5th) Nov 26, 2014 Prof. Shin-ichiro Shima
(U of Hyogo/RIKEN AICS)
Data assimilation experiments of the dynamic global vegetation model SEIB-DGVM with simulated GPP observations
2014-04(4th) Nov 26, 2014 Prof. Takeshi Ise
(Kyoto U)
Simulating terrestrial ecosystems: current progress and future perspectives
2014-03(3rd) Oct 31, 2014 Prof. Masayuki Yokozawa
(Shizuoka U)
Evaluating the productivities of major crops at the global scale using process-based crop model
2014-02(2nd) Sep 10, 2014 Dr. Guo-Yuan Lien
Ensemble Assimilation of Global Large-scale Precipitation
2014-01(1st) July 23, 2014 Dr. Juan Ruiz
(U of Buenos Aires (CIMA)/RIKEN AICS)
Efficient parameter estimation for numerical weather prediction models using data assimilation