Event

03 JAN 2017

S2S, Workshops

First Workshop on Subseasonal to Seasonal Prediction for Southeast Asia (S2S-SEA I)

Date: 27 FEB 2017 - 02 MAR 2017

Venue: Concorde Hotel, Singapore

Exploring the potential of subseasonal predictions for Southeast Asia

Background

The Subseasonal-to-Seasonal (S2S) Project was jointly set up by the World Meteorological Organization’s (WMO) WWRP /THORPEX -WCRP in 2013 to promote research in the subseasonal to seasonal timescale and with a focus on high impact weather events. The objectives of S2S are to improve forecast skill and understanding on the timescale that falls between the 2-week (medium range) and 3-month (seasonal) periods, and also to promote uptake of the initiative by operational centres and the applications community. These are achieved by making the most of the expertise of the weather and climate research communities to address issues raised by the Global Framework of Climate Services (GFCS) pertaining to this timescale (Vitart, et al., 2012).

Motivation

Seamless weather-to-climate forecasts have the potential to be significantly beneficial to society. As part of the Regional Climate Outlook Forum (RCOF) process for the ASEAN region, ASEANCOF, a survey of all National Meteorological and Hydrological Services (NMHSs) in the ASEAN region showed that the development of a regional capability in the use of sub-seasonal forecasts was a high priority. Weeks’ ahead is a particularly important planning timescale and, if some indication of the likelihood of extreme weather conditions can be provided at that lead-time, it can be especially useful for contingency planning.

Planning and management activities in the agricultural and food, disaster-risk reduction, health and water resources often require lead-time that fall into this subseasonal to seasonal time range. These include anticipating hazards arising from early or late onsets of rainy seasons that may lead to major droughts and floods, or hazards from extreme hot and cold conditions impacting the local population. Being ready for such contingencies, through judicious use of the forecasts by operational centres, can potentially minimise the losses from weather and climate-related disasters. For example, the seasonal outlook for Jun-Sep 2015 provided ample warning of a significantly drier than-normal boreal summer monsoon season in the southern ASEAN region due to the El Niño, thereby increasing the likelihood of a prolonged and severe haze episode in the region. However, there was then no easily accessible information on the intra-seasonal (week-to-week) variability of the wind and rainfall outlook for the region. Clearly, more refined risk assessments of such events can benefit from better understanding of the potential applications of model outlook on the S2S timescale.

WMO initiatives have provided an excellent database of S2S forecasts for use in research applications. Real time forecasts will also be made available in the future (Park, et al., 2016). Although such forecasts have been used extensively in most developed countries for some time, there is little expertise in either the accessing or interpretation of such forecasts in many parts of Southeast Asia. For the region as a whole, to make best use of what is now becoming available, a capability-building programme focused on the understanding and regional application of S2S forecasts is required.

Objectives of S2S-SEA 

A S2S Multi-model Ensemble Prediction System (MEPS) database was set up to host the model outputs from the WMO’s Global Producing Centres (GPCs), which consist of ensembles of subseasonal forecasts up to 60 days. The MEPS also provides an extensive set of reforecasts (hindcasts) dataset from the different modelling centres. The forecast products, at the moment, lag by 3 weeks, and hence cannot yet be used operationally, but access to the reforecasts dataset would allow operational centres to preview and assess their potential benefits and limitations.

In preparation for the eventual release of operational products from the S2S, this S2S-SEA demonstration project aims to familiarise the participants with the database, improve their understanding on the mechanisms of subseasonal-to-seasonal predictability, and equip the participants with the knowledge to investigate the skill and usefulness of the subseasonal forecasts in applications. This project also aims to provide training to participants in generating products tailored for risk- and impact-based predictions on the S2S timescale.

The Southeast Asian region, in particular the Maritime Continent, has the potential to benefit substantially from this database more than other parts of the world as the model skill over this region has been found to be relatively good (Li & Robertson, 2015). S2S-SEA activities aim to build capacity and enhance collaboration among the NMHSs in the region.

S2S-SEA Programme 

The proposed programme will be spread over 4 years, split into 2 phases and with 2 workshops in each phase. Activities in Phase 1 will focus on familiarisation of the S2S concept and database, as well as extensive skill assessment of the models available on the database. Activities in Phase 2 will focus on training in developing products for risk- and impact-based predictions on the S2S timescale. As the operational, real-time forecast information from S2S database is estimated to be available at least 2-3 years from now (Park, et al., 2016), the proposed schedule of the programme is timely.

First S2S-SEA Workshop

A 5-day workshop on Subseasonal to Seasonal Prediction for Southeast Asia (S2S-SEA I) will be conducted in Singapore from 27 February to 2 March 2017. This workshop is organised by the Meteorological Service Singapore (MSS) as host of the ASEAN Specialised Meteorological Centre and supported by World Meteorological Organization’s (WMO) Subseasonal to Seasonal Prediction (S2S) Project. The workshop is part of the multi-year S2S-SEA Capability Building Programme proposed by ASMC to enhance regional capacity and collaboration in this area among the National Meteorological and Hydrological Services (NMHSs).

1. The first set of activities proposed is to introduce the S2S database to the participants, accompanied by hands-on sessions to download the data and process them for analyses. Given the varying configurations of models that contribute to the MEPS database, this activity in itself covers a broad range of skill sets.
2. The second set of activities is to get the participants to assess model performance on weekly means or extremes of temperature and rainfall for example; either using their own countries’ station data or suitable gridded observation data. Given the introductory level of the first workshop, case-studies type of assessment is appropriate. More extensive skill assessment over the hindcast period of models should be the focus of the second and subsequent workshops.

On the final day of the workshop, participants will present preliminary results to consolidate the workshop outcomes. Participants will follow up with the analyses in their home countries and submit the findings for consolidation into a preliminary technical report. Subsequent workshops will build upon the activities of the preceding workshop. To ensure continuity, it is therefore emphasised that the participants identified by NMHSs for the first workshop are able to commit to the project over the entire duration of the project.

Participation

Each of the 10 ASEAN NMHSs will be represented by up to 2 participants (meteorologists or research scientists) who are actively involved in the operational/research activities of their centres related to seasonal and subseasonal timescales. The First Workshop will be facilitated by 2 experts from the S2S project who will provide lectures and conduct hands-on training sessions.

Proposed Structure for the First S2S-SEA Workshop

References