Report from GIFS-TIGGE working group Richard Swinbank, and Masayuki Kyouda, with thanks to the GIFS-TIGGE working group, THORPEX IPO and other colleagues Presentation for THORPEX ICSC-10, October 2012

TIGGE and GIFS Working Group changes TIGGE GIFS TIGGE research TIGGE archive status GEOWOW project GIFS using TIGGE for developing forecast products linking with CBS & SWFDP TIGGE research Recent studies Research focus of working group Looking forward – after 2014

TIGGE working group Membership and proposed changes Co-chairs: Richard Swinbank, Met Office Members: Philippe Arbogast, Météo-France Jiandong Gong, CMA Seung-Woo Lee, KMA Osvaldo Moraes, CPTEC Mike Naughton, BoM Masayuki Kyouda, JMA Tiziana Paccagnella, ARPA-SIM David Richardson, ECMWF Doug Schuster, NCAR Laurie Wilson, EC Yuejian Zhu, NCEP

GIFS-TIGGE WG meeting, Boulder

TIGGE project Since 2006, TIGGE has been collecting ensemble predictions from 10 of the leading global forecast centres. TIGGE data are made available after a 48-hour delay, to support research on probabilistic forecasting methods, predictability and dynamical processes. Over 60 TIGGE articles published in scientific literature.

TIGGE Archive Data volume now exceeds 600 terabytes, >1TB added every week. Around 100 users access TIGGE data every month; >1600 users registered at ECMWF.

TIGGE-LAM: TIGGE for limited-area models The TIGGE-LAM panel, chaired by Tiziana Paccagnella works closely with the GIFS-TIGGE working group to supports the coordinated development of Limited Area Model Ensemble Prediction Systems. The panel facilitates the interoperability of the different modelling systems and coordinates the archiving of limited-area ensemble forecasts – the three TIGGE archive centres have agreed to host a sub-set of high priority data. With the increasing emphasis on convective-scale ensembles, TIGGE-LAM works closely with the WWRP Mesoscale Weather Forecasting Research group, as well as GIFS-TIGGE. The TIGGE LAM Panel now structured in regional sub-groups to facilitate the focus on regional activities, with links to THORPEX regional committees. More information is available from the TIGGE-LAM website http://www.smr.arpa.emr.it/tiggelam/. We are unconvinced by call from WWRP/JSC to linkTIGGE-LAM with Mesoscale WG rather than GIFS-TIGGE.

The Weather component (WP4) includes: GEOWOW (GEOSS interoperability for Weather, Ocean and Water) is a 3-year EU-funded FP7 project started September 2011. The Weather component (WP4) includes: improving access to TIGGE data at ECMWF; archiving of TIGGE-LAM data; developing and demonstrating forecast products. Weather participants: ECMWF, Met Office, Météo-France, KIT Involve other TIGGE partners in planning development & demonstration of products in conjunction with SWFDP. GIFS-TIGGE 31 August - 2 September 2011

Towards a Global Interactive Forecast System (GIFS) Our objective is to realise the benefits of THORPEX research by developing and evaluating probabilistic products. Focus on risks of high-impact weather events – unlikely but potentially catastrophic. First step: exchange of real-time tropical cyclone predictions using “Cyclone XML” format. Followed by development of products based on gridded forecasts of heavy precipitation & strong wind.

Tropical cyclone products from MRI/JMA http://tparc. mri-jma. go Tetsuo Nakazawa

Engaging with SWFDP Invite SWFDP SG representatives to GIFS-TIGGE WG meetings, and vice versa. Document of prototype products based on TIGGE data Seek feedback from RSMCs coordinating SWFDP regional subprojects Develop real-time products for SWFDP based on preferred prototypes Provide training on new products via SWFDP Subjective and objective evaluation of GIFS products

Links with SWFDP - questionnaire Explore requirements of forecasters in SWFDP with questionnaire – key findings: Most important forecast requirements: Tropical cyclones Heavy rainfall Strong winds State of sea (and large inland lakes) Forecast range: primary interest short-range (1st few days) TIGGE products with 48h delay not useful

TC ensemble products Now developing multi-model version of TC track / strike probability products, based on CXML data exchange. To be delivered to SWFDP regional centres starting this autumn. Piers Buchanan, Met Office

Near-real time severe weather products Survey results confirm need for near real-time version of severe weather products developed by MRI Joint proposal being developed by Met Office, JMA, MRI. Agreement sought to enable real-time JMA data to be used in addition to ECMWF, NCEP & Met Office.

TIGGE Research: Ensemble combination & calibration A range of papers based on TIGGE forecasts have demonstrated benefits of multi-model grand ensembles, in particular for surface air temperature, rainfall, tropical cyclone tracks, e.g.: Matsueda & Tanaka (2008), Johnson & Swinbank (2009), Yamaguchi (2012) Other papers have also compared multi-model ensembles with use of reforecasts to correct systematic errors – with similar benefits, e.g.: Hagedorn et al (2012), Hamill (2012)

Thanks to Tom Hamill

TIGGE Research: Dynamics & Predictability Most of the published studies using TIGGE data are focused on predictability & dynamical processes Examples: Prediction of SH cyclones (Froude, 2011) Prediction of MJO (Matsueda & Endo, 2011) Impact of ET transition of cyclones (Keller et al, 2011) Planned paper reviewing TIGGE research, in conjunction with PDP WG.

Differences in Uncertainty – Standard devation of 500 hPa gph Characteristics of TIGGE in forecasting ET events - explore the benefit of multi-model approach Differences in Uncertainty – Standard devation of 500 hPa gph Sample case: Fcst during ET of Hurricane Ike, initialized 10 Sep 2008, 12 UTC gpm 10 20 30 40 50 60 70 80 90 100 110 120 130 140 Time longitude longitude TIGGE (8 EPSs) First overview of variability in the different EPS and TIGGE is given by a Hovmoeller diagram for the 500 hPa geopotential height standard deviation (shaded). Black dots mark position of Ike, red dot marks analysed position of Ike at ET time, black line marks investigation time. Differences in regions and strength of uncertainty in the several data sets are clearly obvious. Surface position of Ike in members Analysis position of Ike at ET time Courtesy Julia Keller

TIGGE Research focus Following the successful establishment of the TIGGE dataset, the main focus of the GIFS-TIGGE working group has shifted towards research on ensemble forecasting. Initial emphasis: Calibration and combination methods Bias correction, downscaling Multi-model ensembles; reforecasts Development of probabilistic forecast products – GIFS development Tropical cyclones (CXML-based) Gridded data: heavy precipitation; strong winds Focus has been on downstream application of ensembles, rather than on improving EPSs

TIGGE Research needs & priorities But other important areas for EPSs include Initial conditions – link with ensemble data assimilation (DAOS) Representing model error – stochastic physics (PDP, WGNE) Verification of ensemble forecasts (JWGFVR) Seamless forecasting – links with sub-seasonal forecasting (new S2S project) Convective-scale ensembles (TIGGE-LAM, MWFR) These areas, particularly first two, are important for improving EPS skill and products. TIGGE is an excellent resource for comparing EPS techniques.

Virtuous Circle Develop, Improve Evaluate, Diagnose Ensemble Forecasts To improve EPSs we need to develop a virtuous circle – best with a single group with focus on ensemble prediction

Evolution of TIGGE & GIFS TIGGE development Calibration, combination, products EPS improvement Time GIFS-TIGGE should also be a forum to focus on R&D directed at improving our EPS systems, to help us develop a “virtuous circle”. We introduced a section of the WG meeting for discussing ensemble initial conditions, stochastic physics & other aspects of improving our EPSs. We also need to maintain an interest in ensemble verification & links with convective-scale EPS and the new sub-seasonal to seasonal group.

Looking forward - A proposed new working group The logical evolution of an increased focus on research would be the creation of a Predictability & Ensemble Forecasting working group, combining much of the current GIFS-TIGGE and PDP groups. This new group would provide a centre of scientific expertise on dynamics, predictability and ensemble forecasting that is currently lacking in the core WWRP programme.

Future of TIGGE archive The GIFS-TIGGE working group strongly supports the continuation of the TIGGE archive TIGGE is increasingly accepted as an invaluable data set for research, especially on predictability and dynamics. TIGGE is a major resource for forecast verification & validation, and comparison of models & EPS methods. TIGGE has been very useful for development of products for forecasting severe weather. TIGGE has attracted additional EU funding for enhancement of the ECMWF portal, archiving of TIGGE-LAM and making data available to a wider community. We recognises the key role played by TIGGE partners, and that continuation of TIGGE will require the active support from at least one of the archive centres, and most of the data providers.

Other recommendations We recommend that the proposed Predictability and Ensembles group become a WWRP working group The ongoing management of the TIGGE archive could be accomplished by setting up a liaison group, under the auspices of the P&EF group. One established, the S2S project could be managed in a similar manner. It is not so clear what how to manage ongoing GIFS product development. We suggest that product development could be covered primarily by CBS.

TIGGE website: http://tigge.ecmwf.int Summary Since October 2006, the TIGGE archive has been accumulating regular ensemble forecasts from leading global NWP centres. Progress is being made towards starting to deliver “GIFS products” to the SWFDP regional websites, first for tropical cyclone tracks and later focused on heavy rain and strong winds. We will collaborate with SWFDP on evaluating the products. Looking forward to the post-THORPEX period, we recommend the establishment of a Predictability and Ensemble group which would oversee the TIGGE archive, and with a scientific focus on dynamics, ensemble forecasting & predictability. TIGGE website: http://tigge.ecmwf.int