Upper tail dependence in rainfall extremes: would we know it if we saw it?
Author(s): Francesco Serinaldi, András Bárdossy, Chris G. Kilsby
Field(s): Upper tail dependence Extreme events Binary correlation Binary entropy Rainfall Peak over threshold analysis Collective spatial risk
Summary: The simultaneous occurrence of extreme events, such as simultaneous storms and floods at different locations, has a serious impact on risk assessment and mitigation strategies. The joint occurrence of extreme events can be measured by the so-called upper tail dependence (UTD) coefficient λ U.
Dismissing return periods!
Author(s): Francesco Serinaldi
Field(s): Return period Nonstationary frequency analysis Multivariate frequency analysis Copulas Risk of failure Design values Design life
Summary: The concept of return period in stationary univariate frequency analysis is prone to misconceptions and misuses that are well known but still widespread...
Groundwater fluxes in a shallow seasonal wetland pond: The effect of bathymetric uncertainty on predicted water and solute balances
Author(s): Mark A. Trigg, Peter G. Cook, Philip Brunner
Summary: The successful management of groundwater dependent shallow seasonal wetlands requires a sound understanding of groundwater fluxes. However, such fluxes are hard to quantify. Water volume and solute mass balance models can be used in order to derive an estimate of groundwater fluxes within such systems. This approach is particularly attractive, as it can be undertaken using measurable environmental variables, such as; rainfall, evaporation, pond level and salinity. Groundwater fluxes estimated from such an approach are subject to uncertainty in the measured variables as well as in the process representation and in parameters within the model. However, the shallow nature of seasonal wetland ponds means water volume and surface area can change rapidly and non-linearly with depth, requiring an accurate representation of the wetland pond bathymetry. Unfortunately, detailed bathymetry is rarely available and simplifying assumptions regarding the bathymetry have to be made. However, the implications of these assumptions are typically not quantified.
Forecast cooling of the Atlantic subpolar gyre and associated impacts
Author(s): Hermanson et al.
Field(s): Climate dynamics, Impacts of global change
Summary: Decadal variability in the North Atlantic and its subpolar gyre (SPG) has been shown to be predictable in climate models initialized with the concurrent ocean state. Numerous impacts over ocean and land have also been identified.
Integrating Natural Disaster Risks & Resilience into the Financial System
Author(s): Rowan Douglas
Field(s): Willis Research Network
Summary: Integrating disaster risk and resilience into the financial system provides the structural and proportionate means of saving millions of lives and livelihoods in the coming decades and protecting US$ billions in homes, assets and property in a cost effective and rational way when weighed against competing priorities.
The impact of uncertain precipitation data on insurance loss estimates using a flood catastrophe model
Author(s): C. C. Sampson, T. J. Fewtrell, F. O’Loughlin, F. Pappenberger, P. B. Bates, J. E. Freer, and H. L. Cloke
Field(s): Climate Change, Atmospheric science
Summary: Catastrophe risk models used by the insurance industry are likely subject to significant uncertainty, but due to their proprietary nature and strict licensing conditions they are not available for experimentation. In addition, even if such experiments were conducted, these would not be repeatable by other researchers because commercial confidentiality issues prevent the details of proprietary catastrophe model structures from being described in public domain documents. However, such experimentation is urgently required to improve decision making in both insurance and reinsurance markets.
A new physically based stochastic event catalog for hail in Europe
Author(s): H. J. Punge • K. M. Bedka • M. Kunz • A. Werner
Field(s): Hail ! Climatology ! Overshooting top ! Europe
Summary: Hailstorms represent one of the major sources of damage and insurance loss to residential, commercial, and agricultural assets in several parts of Central Europe. However, there is little knowledge of hail risk across Europe beyond local historical damage reports due to the relative rarity of severe hail events and the lack of uniform detection methods. Here we present a new stochastic catalog of hailstorms for Europe.
The poleward migration of the location of tropical cyclone maximum intensity
Author(s): James P. Kossin, Kerry A. Emanuel, & Gabriel A. Vecchi
Field(s): Climate Change, Atmospheric science
Summary: Attempts to monitor changes in tropical cyclone activity have been hampered by inconsistencies in global data sets, such as measures of frequency, storm duration and intensity. Jim Kossin and colleagues by-pass this long-standing problem by instead focusing on the latitude at which tropical cyclones reached their lifetime maximum intensity, a far more robust measurement. They find that during the past 30 years the position of peak intensity has migrated steadily poleward, at a rate of about 60 km per decade. This shift appears to be associated with changes in vertical wind shear and potential intensity, which the authors suggest may be associated with recent increases in the width of the tropical belt associated with global warming.
The Impact on Workers' Compensation Insurance Markets of Allowing the Terrorism Risk Insurance Act to Expire
Author(s): Michael Dworsky, Lloyd Dixon
Summary: Congress enacted the Terrorism Risk Insurance Act (TRIA) in 2002, in response to terrorism insurance becoming unavailable or, when offered, extremely costly in the wake of the 9/11 attacks. The law provides a government reinsurance backstop in the case of a terrorist attack by providing mechanisms for avoiding an immediate drawdown of capital for insured losses or possibly covering the most extreme losses. Extended first in 2005 and again in 2007, TRIA is set to expire at the end of 2014, and Congress is again reconsidering the appropriate government role in terrorism insurance markets.
Development of the Global Width Database for Large Rivers
Author(s): Dai Yamazaki, Fiachra O’Loughlin, Mark A. Trigg, Zachary F. Miller, Tamlin M. Pavelsky, and Paul D. Bates
Summary: River width is a fundamental parameter of river hydrodynamic simulations, but no global-scale river width database based on observed water bodies has yet been developed. Here we present a new algorithm that automatically calculates river width from satellite-based water masks and flow direction maps.
Skillful long-range prediction of European and North American winters
Author(s): Scaife et al.
Field(s): Climate dynamics, Climate variability, Coupled models of the climate system, Global climate models
Summary: Until recently, long-range forecast systems showed only modest levels of skill in predicting surface winter climate around the Atlantic Basin and associated fluctuations in the North Atlantic Oscillation at seasonal lead times. Here we use a new forecast system to assess seasonal predictability of winter North Atlantic climate
The Impact on Federal Spending of Allowing the Terrorism Risk Insurance Act to Expire
Author(s): Tom LaTourrette, Noreen Clancy
Summary: Congress enacted the Terrorism Risk Insurance Act (TRIA) in 2002, in response to terrorism insurance becoming unavailable or, when offered, extremely costly in the wake of the 9/11 attacks. The law creates an incentive for a functioning private terrorism insurance market by providing a government reinsurance backstop for catastrophic terrorist attack losses. Extended first in 2005 and again in 2007, TRIA is set to expire at the end of 2014, and Congress is again considering the appropriate government role in terrorism insurance markets.
Technology: Fight floods on a global scale
Author(s): Guy J.-P. Schumann, Paul D. Bates, Jeffrey C. Neal & Konstantinos M. Andreadis
Summary: Bristol and NASA issue call for international co-operation on global-scale flood model
National Security Perspectives on Terrorism Risk Insurance in the United States
Author(s): Henry H. Willis, Omar Al-Shahery
Field(s): Community Resilience, Terrorism Risk Insurance Act Of 2002, Terrorism Risk Management, United State
Summary: Congress enacted the Terrorism Risk Insurance Act (TRIA) in 2002, in response to terrorism insurance becoming unavailable or, when offered, extremely costly in the wake of the 9/11 attacks. The law provides a government reinsurance backstop in the case of a terrorist attack by providing mechanisms for avoiding an immediate drawdown of capital for insured losses or possibly covering the most extreme losses. Extended first in 2005 and again in 2007, TRIA is set to expire at the end of 2014, and Congress is again reconsidering the appropriate government role in terrorism insurance markets. This policy brief examines the potential national security implications of allowing TRIA to expire. Examining the history of terrorism in the United States since the passage of TRIA and reviewing counterterrorism studies, the authors find that terrorism remains a real national security threat, but one that is very difficult for insurers to model the risk of. They also find that terrorism risk insurance can contribute to making communities more resilient to terrorism events, so, to the extent that terrorism insurance is more available with TRIA than without it, renewing the legislation would contribute to improved national security.
Estimating seepage flux from ephemeral stream channels using surface water and groundwater level data
Author(s): Saskia L. Noorduijn, Margaret Shanafield, Mark A. Trigg, Glenn A. Harrington, Peter G. Cook and L. Peeters
Summary: Seepage flux from ephemeral streams can be an important component of the water balance in arid and semiarid regions. An emerging technique for quantifying this flux involves the measurement and simulation of a flood wave as it moves along an initially dry channel.
Social Vulnerability and Integrated Risk Project
Author(s): Bijan Khazai, Christopher Burton, Christopher Power and James E. Daniell
Summary: Central to the Global Earthquake Model (GEM) is the development of state-of-the-art modeling capabilities that can be used worldwide for the assessment and communication of seismic risk. For a holistic evaluation of the consequences of earthquake impacts and loss, the Social Vulnerability and Integrated Risk Project is focusing on the development of metrics, methods, and OpenSource software tools for the assessment of seismic risk and impact potential beyond the estimation of direct physical impacts and loss of life.
High resolution global climate modelling; the UPSCALE project, a large simulation campaign
Author(s): M. S. Mizielinski, M. J. Roberts, P. L. Vidale, R. Schiemann, M.-E. Demory, J. Strachan, et al.
Field(s): Hurricanes, Tropical cyclones, Climate change, Climate models, Coupled models
Summary: The UPSCALE (UK on PRACE: weather-resolving Simulations of Climate for globAL Environmental risk) project constructed and ran an ensemble of HadGEM3 (Hadley centre Global Environment Model 3) atmosphere-only global climate simulations over the period 1985–2011, at resolutions of N512 (25 km), N216 (60 km) and N96 (130 km) as used in current global weather forecasting, seasonal prediction and climate modelling respectively. Alongside these present climate simulations a parallel ensemble looking at extremes of future climate was run, using a time-slice methodology to consider conditions at the end of this century.
Improved evaporative flux partitioning and carbon flux in the land surface model JULES: Impact on the simulation of land surface processes in temperate Europe
Author(s): Catherine Van den Hoof, Pier Luigi Vidale, Anne Verhoef, Caroline Vincke
Field(s): Eddy fluxes measurements; Europe; Evaporative flux partitioning; Land surface model; 2003 heat wave
Summary: The primary role of land surface models embedded in climate models is to partition surface available energy into upwards, radiative, sensible and latent heat fluxes. Partitioning of evapotranspiration, ET, is of fundamental importance: as a major component of the total surface latent heat flux, ET affects the simulated surface water balance, and related energy balance, and consequently the feedbacks with the atmosphere. In this context it is also crucial to credibly represent the CO2 exchange between ecosystems and their environment. In this study, JULES, the land surface model used in UK weather and climate models, has been evaluated for temperate Europe. Compared to eddy covariance flux measurements, the CO2 uptake by the ecosystem is underestimated and the ET overestimated
Spatial and temporal modeling of radar rainfall uncertainties
Author(s): Gabriele Villarini, Bong-Chul Seo, Francesco Serinaldi, Witold F. Krajewskia
Field(s): Weather radar; Rainfall; Uncertainty; Space–time modeling; NEXRAD
Summary: It is widely acknowledged that radar-based estimates of rainfall are affected by uncertainties (e.g., mis-calibration, beam blockage, anomalous propagation, and ground clutter) which are both systematic and random in nature. Improving the characterization of these errors would yield better understanding and interpretations of results from studies in which these estimates are used as inputs (e.g., hydrologic modeling) or initial conditions (e.g., rainfall forecasting).
The sensitivity of the tropical circulation and Maritime Continent precipitation to climate model resolution
Author(s): R. Schiemann, M.-E. Demory, M. S. Mizielinski, M. J. Roberts, L. C. Shaffrey, J. Strachan, P. L. Vidale
Field(s): Precipitation Climate model bias Resolution GCM Boundary conditions Maritime Continent Walker circulation Coastal tiling
Summary: The dependence of the annual mean tropical precipitation on horizontal resolution is investigated in the atmospheric version of the Hadley Centre General Environment Model. Reducing the grid spacing from about 350 km to about 110 km improves the precipitation distribution in most of the tropics. In particular, characteristic dry biases over South and Southeast Asia including the Maritime Continent as well as wet biases over the western tropical oceans are reduced. The annual-mean precipitation bias is reduced by about one third over the Maritime Continent and the neighbouring ocean basins associated with it via the Walker circulation.