Details of Award
NERC Reference : NE/L00853X/1
Urban gust estimates for insurance portfolio loss.
Training Grant Award
- Lead Supervisor:
- Professor CSB Grimmond, University of Reading, Meteorology
- Grant held at:
- University of Reading, Meteorology
- Science Area:
- Atmospheric
- Terrestrial
- Overall Classification:
- Atmospheric
- ENRIs:
- Environmental Risks and Hazards
- Global Change
- Pollution and Waste
- Science Topics:
- None
- Abstract:
- This project is concerned with extreme wind hazard in urban areas. Demand for the research comes from the CASE partner, RMS, a world business leader in catastrophe risk modeling. RMS develops mathematical models to assess the potential damage to properties from natural disasters. Several of these models focus on extreme wind hazard (e.g. European windstorms, US hurricanes or Japanese typhoons) and are used by insurance and re-insurance companies (among others) to quantify the risk to their portfolios (much is focused on mega cities). Critical to all wind hazard models is the conversion of mean wind estimates modeled over oceans to gust values representative of areas where losses might occur. This has to account for two contrasting impacts (1) as the winds flows over rougher surfaces (e.g. cities), its mean component is slowed down; but (2) the turbulent contribution to the flow increases. Getting the resulting gust estimates (and their variability) consistently over the exposed areas is critical to assess portfolio losses. The quantification of these two contributions relies on an accurate description of the land cover in terms of its roughness and a framework to model the impact on the wind flow. The methodology used by RMS, based on Deaves & Harris (in Cook 1997), relies on an estimate of roughness characteristics for a range of land cover categories, mapped from high resolution land cover databases/satellite imagery at scales 1-5 km2 (neighborhoods). Past work has shown that models can be improved significantly by using observed gust data to empirically correct some of the assumptions made. Simple corrections have been developed using stations with distinct local roughness (e.g. residential vs parks), with regression relations to predict the ratio of the observed gusts as a function of the site characteristics. However, this methodology has been developed with limited data and needs to be more extensively evaluated/recalibrated. The two main aims of the project are: (1) To better characterize surface roughness variability within cities, at neighborhood scale, within the RMS modeling framework. This involves updating the way land use is characterised (e.g. the definition/ number of categories, or a move from the concept of categories altogether) and identification of key parameters that best characterize the roughness impact (e.g. height, spacing and variability of roughness elements). The procedures to select optimum values for each of these key inputs will be carefully studied, along with an assessment on model sensitivity. (2) To gather and analyze relevant gust observations from cities under strong wind conditions to improve the original Deaves & Harris model. Differences between typical urban settings in (and within) Europe, US and Asia will be linked to their impact on observed roughness. After an initial evaluation of the current RMS model with these data, empirical gust corrections will be adjusted to improve model performance. Other weaknesses identified from the model evaluation also will be studied and addressed where applicable. The research will draw on recent turbulence measurements in key areas of risk (Europe, US, Asia) and the latest developments in the estimation of neighborhood roughness (building on Grimmond's earlier work). Given the expertise of Grimmond and Barlow in urban/ boundary layer meteorology, Meteorology at Reading is an excellent environment for the student to develop the skills required for this project (particularly understanding of methods to model and monitor momentum exchange in cities). RMS, as a business leader, is the ideal industrial partner. The main outcome of this project for RMS will be a more robust view of the land cover impact on extreme damaging winds, which will be embedded in RMS' modeling scheme. This will have broader implications for building design/wind engineering too. Cook NJ 1997: Deaves & Harris ABL model. J Wind Eng Ind Aero 197-214
- NERC Reference:
- NE/L00853X/1
- Grant Stage:
- Completed
- Scheme:
- DTG - directed
- Grant Status:
- Closed
- Programme:
- Industrial CASE
This training grant award has a total value of £83,515
FDAB - Financial Details (Award breakdown by headings)
| Total - Fees | Total - Student Stipend | Total - RTSG |
|---|---|---|
| £16,225 | £56,290 | £11,001 |
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