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Advisory workshop on Enhancing forecasting capabilities for North Indian Ocean Storm Surges

Event Type Workshop
Date(s)(yyyy-mm-dd) Start: 2009-07-14 - End: 2009-07-17
Location Indian Institute of Technology Delhi, Indian Institute of Technology Delhi Hauz Khan, New Delhi, India
Summary The Meeting of the Advisory Group on enhancing the forecasting capabilities for North Indian Ocean Storm Surges (IIT-D storm surge model upgrade) was held in India at Indian Institute of Technology Delhi (IIT Delhi) during 14-17 July 2009, under the co-chairmanship of Dr Boram Lee (IOC of UNESCO) and Dr Val Swail (JCOMM). The international experts reviewed current status/performance of operational storm surge forecasting model (IIT-D Model) in the North Indian Ocean (NIO) region and addressed requirements for upgrading and improving model performance, considering the needs of the region following the recommendations made at the first JCOMM Scientific and Technical Symposium on Storm Surges held during 2-6 October 2007 at Seoul, Korea Republic (JCOMM2007SSS, http://www.surgesymposium.org). Experts also deliberated on setting up the medium-term and long-term technical workplan for the project on improving storm surge forecasting capabilities. This Workshop was planned and conducted under the framework of the UNESCO extrabudgetary project on “Enhancing regional capabilities for Coastal Hazards Forecasting and Data Portal Systems”, funded by extrabudgetary contribution from Republic of Korea. The India Ministry of Earth Science (MoES) provided in-kind support, and linkage with its national projects. Highlights and recommendations from the workshop are the following: While the storm surge prediction capability of India and further the North Indian Ocean region was generally satisfactory, the forecast was presently given only at the district level - the immediate goal was to provide forecasting with finer spatial resolution (small geographical regions) with better predictability. Experts agreed that, to be able to do this, the numerical models as well as the observational networks have to be improved. Additional research needs to be done on how to incorporate into operational use, some other important processes that presently were not included in the forecast models. With these goals in mind, the workshop has highlighted the requirements under observational data, categorized into meteorological, boundary, hydrological and location specific. The experts group stressed the importance of the storm surge forecasting in probabilistic terms, somewhat akin to the routine weather forecasts at present. This is a more realistic approach, since it is scientifically unsound to issue definitive diagnostic forecasts, when there is so much uncertainty in the input data to the numerical models. It has been shown clearly that tide-surge interaction could change the value of the Total Water Level Envelope (TWLE) as well as the timing of the occurrence of the peak surge. Hence it is important the numerical models include the non-linear interactions between tide and storm surge. At present the only meteorological data input to the storm surge models of IIT Delhi are the pressure drop and the radius of maximum winds, in addition to the cyclone track. Since observed wind fields are now becoming more and more routinely available in real time, the numerical models should incorporate data assimilation techniques such as Kalman Filter to include observed wind data. At present the wind wave model is not part of the storm surge model. An operational wind wave model should be dynamically coupled to the storm surge model. For the cyclone season of 2010 and beyond, the coupled model (surge plus tide plus wind wave) should be first tested in a hindcast mode, and once it is established that the model performance is satisfactory. it can then be used operationally. One of the key recommendations on data was on bathymetric data. 100 m horizontal resolution over the continental shelf is recommended in order to enable high resolution modelling. This data set should be updated every five years over the shelf, and every three years in the river delta regions such as the Meghna, Hooghly, Godavari, Krishna, Ayeyarawady etc. Another important requirement was to have an optimum network of tide gauges in the vulnerable coastal areas with a temporal resolution of one minute averaged sea level data. At present the existing and the planned tidal network together is generally satisfactory for India, with a wish list of a few more gauges located at the head of the Bay of Bengal. It was recommended to install at least two more gauges in Bangladesh and three more gauges in Myanmar, for the storm surge modelling and monitoring purpose. The two most important meteorological parameters were again emphasized by the Experts to be more accurately monitored during the events, in addition to location of the cyclone landfall - the pressure drop and the radius of maximum sustained winds. Aircraft reconnaissance and dropsonde data may enhance the quality of the input data. On the Hydrological side, we need data on area-weighted rainfall in river catchments as well as station data. In addition to this, for Hydrological input to surge models, we need to enhance the existing river gauge network for data on river runoff. A most useful product will be storm surge data dossiers, which include all data from post-event surveys and also detailed data on road network, escape routes, nearby high ground (hills and mountains) and coastal infrastructure. For the computation of inundation, we need data on shore topography, with a resolution of 5 m in the horizontal and 0.5 m in the vertical, with updates done preferably every decade. The use of crest gauges as well as chemically treated ribbons for mapping the extent of horizontal inundation and depth should be considered. For improvements to cyclone track prediction, the Multi Model Ensemble (MME) should be enhanced through improvements in the meso-scale Numerical Weather Prediction (NWP) model, and nowcasting assimilation of the remote sensing (satellite and radar) and in-situ (buoy and ship) based data. With regard to the capacity development and outreach, it was suggested to continue training on IIT-D model development and operation, in collaboration with ongoing programmes by WMO and IOC. Based on advisory input as described above, the 3-year workplan was agreed by the Expert group and IIT Delhi expert team, to improve the predictability of the IIT-D Storm Surge model. Priorities were set up and agreed in view of enhancing storm surge predictability through the IIT-D Storm Surge Model, taking into account; 1) ongoing plans and activities in the North Indian Ocean region; 2) timeline and workplan for IIT model upgrade, and; 3) feasibility of each recommendation.

Web site http://www.jcomm.info/SSindia
Keywords SPA JCOMM services ETWS storm surge, SSS, coastal disaster

Event Entered By Boram LEE
Organisers Shishir DUBE
Boram LEE
Staff Boram LEE



Group(s): IOC , GOOS , JCOMM
Created: 2008-04-18 12:17:12
Last Updated: 2011-09-20 16:27:32