Gilbert Brunet

Gilbert Brunet
Bureau of Meteorology · Science and Innovation

34.02
 · 
PhD in Meteorology

About

84
Publications
13,311
Reads
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2,457
Citations
Introduction
I am Group Executive and Chief Scientist at the Bureau of Meteorology, Australia.
Research Experience
October 2012 - March 2015
Met Office
Position
  • Deputy Director
January 2007 - present
Environment and Climate Change Canada
Position
  • Director Meteorological Research Division
August 1993 - December 2006
Environment and Climate Change Canada
Position
  • Research Scientist
Education
September 1984 - September 1989
McGill University
Field of study
  • Meteorology
September 1980 - September 1982
Université de Montréal
Field of study
  • Mathematical physics

Publications

Publications (84)
Article
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Tropical Cyclone (TC) formation regions are analysed in twelve CMIP5 models using a recently developed diagnostic that provides a model-performance summary in a single image for the mid-summer TC season. A subjective assessment provides an indication of how well the models perform in each TC basin throughout the globe, and which basins can be used...
Article
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The WMO convened the “Science Summit on Seamless Research for Weather, Climate, Water, and Environment” to guide the Commission for Atmospheric Sciences (CAS-17) on future scientific research needs and requirements. Whether on an urban or planetary scale, covering timescales of a few minutes or a few decades, the societal need for more accurate wea...
Article
Over the past 100 years, the collaborative effort of the international science community, including government weather services and the media, along with the associated proliferation of environmental observations, improved scientific understanding, and growth of technology, has radically transformed weather forecasting into an effective global and...
Article
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EON-ROSE (Earth-System Observing Network-Réseau d’Observation du Système terrestrE) is a new initiative for a pan-Canadian research collaboration to holistically examine Earth systems from the ionosphere into the core. The Canadian Cordillera Array (CC Array) is the pilot phase, and will extend across the Cordillera from the Beaufort Sea to the U.S...
Article
Previous studies have shown that the Madden-Julian oscillation (MJO) has a global impact that may provide an important source of skill for subseasonal predictions. The extratropical response was found to be the strongest when the tropical diabatic heating has a dipole structure with convection anomaly centers of opposite sign in the eastern Indian...
Article
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The UK experienced record average rainfall in winter 2013–14, leading to widespread and prolonged flooding. The immediate cause of this exceptional rainfall was a very strong and persistent cyclonic atmospheric circulation over the North East Atlantic Ocean. This was related to a very strong North Atlantic jet stream which resulted in numerous dama...
Article
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Recently Asaadi et al. found that an easterly wave (EW) train over the Atlantic and eastern Pacific is oriented in a southeast–northwest direction because of the observed tilt in the easterly jet. This tilt results in only one out of four (~25%) waves to be located at the cyclonic critical layer south of the jet axis in a comoving frame, and they s...
Article
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The Observing System Research and Predictability Experiment (THORPEX) was a 10-yr, international research program organized by the World Meteorological Organization’s World Weather Research Program. THORPEX was motivated by the need to accelerate the rate of improvement in the accuracy of 1-day to 2-week forecasts of high-impact weather for the ben...
Article
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A shallow-water model is used to study the role of critical layers in tropical cyclogenesis. Forced and unforced problems of disturbances on a parabolic jet associated with weak basic-state meridional potential vorticity (PV) gradients, leading to Kelvin cat's-eye formation around the jet axis, are first investigated. Numerical simulations with var...
Article
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Motivated by Dunkerton et al., a climatological study of 54 developing easterly waves in 1998-2001 was performed. Time-lagged composites in a translating reference frame following the disturbances indicate a weak meridional potential vorticity (PV) gradient of the easterly jet and a cyclonic critical layer located slightly to the south of the weak...
Article
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Advances in numerical weather prediction represent a quiet revolution because they have resulted from a steady accumulation of scientific knowledge and technological advances over many years that, with only a few exceptions, have not been associated with the aura of fundamental physics breakthroughs. Nonetheless, the impact of numerical weather pre...
Article
Interannual variability of the Madden-Julian Oscillation (MJO) and its influence on the extratropical teleconnection are analyzed. It is found that there is an interannual shift of the MJO activity between the Indian Ocean and the western-central Pacific. This is reflected by the year-to-year changes in the occurrence frequency of individual MJO ph...
Chapter
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We are entering a new era in technological innovation and in use and integration of different sources of information for improving well-being and the ability to cope with multi-hazards. New predictive tools able to detail weather conditions to neighbourhood level, to provide early warnings a month ahead, and to forecast weather-related impacts such...
Article
As the societal impacts of hazardous weather and other environmental pressures grow, the need for integrated predictions that can represent the numerous feedbacks and linkages between sub-systems is greater than ever. This was well illustrated during winter 2013/2014 when a prolonged series of deep Atlantic depressions over a 3 month period resulte...
Technical Report
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The Arctic is recognized as one of the key areas of the globe, both in terms of its sensitivity to climate change, and by the increasing economic activity that is expected with the opening up of Arctic areas in a warming climate. In addition, Arctic weather can have important influences in winter cold outbreaks of air which can affect Northern Hemi...
Article
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This white paper is a synthesis of several recent workshops, reports and published literature on monthly to decadal climate prediction. The intent is to document: (i) the scientific basis for prediction from weeks to decades; (ii) current capabilities; and (iii) outstanding challenges. In terms of the scientific basis we described the various sourc...
Article
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Anovel statistical technique called space-time empirical normal mode (ST-ENM) is applied in a diagnostic study of the genesis of a secondary eyewall in a simulated hurricane using the nonhydrostatic, high-resolution fifth-generation Pennsylvania State University (PSU)-National Center for Atmospheric Research (NCAR) Mesoscale Model (MM5). The bases...
Article
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Using the output of the intraseasonal hindcast experiment conducted with the Global Environmental Multiscale (GEM) atmospheric model during 24 extended winters, the association between the forecast skill of the Madden-Julian Oscillation (MJO) and the amplitude of the North Atlantic Oscillation (NAO) in the initial condition is investigated. It is f...
Article
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While Hippocrates recognized that health is influenced by the external environment, it is only recently that the relationship between health and climate has become a focus of community and public health services. Advances in understanding of weather and climate sciences on the one hand and human health on the other are providing new opportunities f...
Article
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Despite the fact that asymmetries in hurricanes, such as spiral rainbands, polygonal eyewalls, and mesovortices, have long been observed in radar and satellite imagery, many aspects of their origin, space–time structure, and dynamics still remain unsolved, particularly their role on the vortex intensification. The underlying inner-core dynamics nee...
Article
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Some scientists have proposed the Earth-System Prediction Initiative (EPI) at the 2007 GEO Summit in Cape Town, South Africa. EPI will draw upon coordination between international programs for Earth system observations, prediction, and warning, such as the WCRP, WWRP, GCOS, and hence contribute to GEO and the GEOSS. It will link with international...
Article
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Despite the fact that asymmetries in hurricanes (e.g., spiral rainbands, polygonal eyewalls, and mesovortices) have long been observed in radar and satellite imagery, many aspects of their dynamics remain unsolved, particularly in the formation of the secondary eyewall. The underlying associated dynamical processes need to be better understood to a...
Article
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Progress in long-range prediction depends on coordination of research in multimodel ensembles, in tropical convection and its interaction with the global circulation, in data assimilation, and in socio-economic applications. The four main areas of the World Weather Research Program-World Climate Research Program (WWRP-WCRP) collaboration includes s...
Article
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This paper highlights the role of the Earth-system biosphere and illustrates the complex: biosphere-atmosphere interactions in the Amazon Basin, changes in nitrogen cycling, ocean chemistry, and land use. It introduces three important requirements for accelerating the development and use of Earth system information. The first requirement is to deve...
Article
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Based on the adjusted daily total precipitation data at Canadian stations and the Climate Prediction Center Merged Analysis of Precipitation (CMAP) data during the most recent 30 Northern Hemisphere winters, the connection between the tropical convection of the Madden-Julian oscillation (MJO) and the intraseasonal variability of precipitation in Ca...
Article
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Using the output of the intraseasonal hindcast experiment conducted with the GEM global atmospheric model during 24 extended winters, the association between the forecast skill of the NAO and the amplitude and phase of the MJO in the initial condition is investigated. It is found that with a lead time up to about one month the NAO forecast skill is...
Article
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Using the homogenized Canadian historical daily surface air temperature (SAT) for 210 relatively evenly distributed stations across Canada, the lagged composites and probability of the above- and below-normal SATin Canada for different phases of the Madden-Julian oscillation (MJO) in the winter season are analyzed. Significant positive SAT anomalie...
Article
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Based on the bivariate Madden-Julian oscillation (MJO) index defined by Wheeler and Hendon and 25 yr (1979-2004) of pentad data, the association between the North Atlantic Oscillation (NAO) and the MJO on the intraseasonal time scale during the Northern Hemisphere winter season is analyzed. Time-lagged composites and probability analysis of the NAO...
Article
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The output of two global atmospheric models participating in the second phase of the Canadian Historical Forecasting Project (HFP2) is utilized to assess the forecast skill of the Madden–Julian oscillation (MJO). The two models are the third generation of the general circulation model (GCM3) of the Canadian Centre for Climate Modeling and Analysis...
Article
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In the second phase of the Canadian Historical Forecasting Project (HFP2), four global atmospheric general circulation models (GCMs) were used to perform seasonal forecasts over the period of 1969-2003. Little predictive skill was found from the uncalibrated GCM ensemble seasonal predictions for the Canadian winter precipitation. This study is an e...
Article
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Ensemble integrations using a primitive-equation dry atmospheric model were performed to investigate the atmospheric transient response to tropical thermal forcings that resemble El Ni (n) over tildeo and La Ni (n) over tildea. The response develops in the North Pacific within 1 week after the integration. The signal in the North Atlantic and Europ...
Article
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A long integration of a primitive equation dry atmospheric model with time-independent forcing under boreal winter conditions is analyzed. A variety of techniques such as time filtering, space–time spectral analysis, and lag regressions are used to identify tropical waves. It is evident that oscillations with intraseasonal time scales and a Kelvin...
Article
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The Large Atmospheric Computation on the Earth Simulator (LACES) project is a joint initiative between Canadian and Japanese meteorological services and academic institutions that focuses on the high resolution simulation of Hurricane Earl (1998). The unique aspect of this effort is the extent of the computational domain, which covers all of North...
Article
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The North American Ensemble Forecast System (NAEFS, see Fig. 1) combines state of the art weather forecast tools, called ensemble forecasts, developed at the Meteorological Service of Canada (MSC), and at the US National Weather Service (NWS). When combined, these tools (a) provide weather forecast guidance for the 1-14 day period that is of higher...
Article
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A statistical approach to correct ensemble seasonal forecasts is formulated based on the regression of the forecast model's leading forced singular value decomposition (SVD) patterns and the observed 500 hPa geopotential height. This technique is applied to the winter forecasts from two general circulation models (GCMs). The performance of the corr...
Conference Paper
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Modern weather prediction is one of the best tools available to reduce the losses of life and property due to extreme weather events at sea, in the air, and on land. The success rate attained by modern forecasting systems is the result of more than 100 years of complex and often dramatic developments linking the technology with the advancements in...
Article
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A primitive equation dry atmospheric model is used to perform ensemble seasonal predictions. The predictions are done for 51 winter seasons [December–January–February (DJF)] from 1948 to 1998. Ensembles of 24 forecasts are produced, with initial conditions of 1 December plus small perturbations. The model uses a forcing field that is calculated emp...
Article
Using the NCEP/NCAR global reanalysis data for 51 boreal winters, a convective index (CI) for the tropical Pacific is constructed. It is found that the extreme positive and negative events of the CI are connected to the positive phases of the two dominant modes of the extratropical atmospheric variability, i.e., the PNA and the NAO, respectively. T...
Article
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Introduction A long-term collaborative effort between scientists from the Earth Simulator Center (ESC), McGill University and Recherche en Prvision Numrique (RPN) is now focusing on simulating the full life cycle of hurricane Earl (September 1998) with the Canadian MC2 Community Model. In this regional simulation, cumulus convection is explicitly r...
Article
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The theory of empirical normal modes (ENMs) was applied in a diagnostic study of the inner spiral bands formed in a simulated hurricane using the high-resolution Pennsylvania State University-National Center for Atmospheric Research (PSU-NCAR) nonhydrostatic mesoscale model version 5 (MM5). The ENM method has the capability to decompose simultaneou...
Article
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A diagnostic algorithm, based on the empirical normal mode decomposition technique, is proposed as a diagnostic tool in studies of the atmospheric variability. It begins by analyzing the transient eddies in terms of empirical modes that are orthogonal with respect to wave activities. Time-dependent amplitudes together with wave activity spectra are...
Article
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An algorithm based on the empirical normal mode analysis is used in a comparative study of the climatology and variability in dynamical-core experiments of the Global Environmental Multiscale model. The algorithm is proposed as a means to assess properties of the model's dynamical core and to establish objective criteria for model intercomparison s...
Article
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Idealized linear and nonlinear numerical experiments are carried out to test the predictions of the theory developed in Brunet and Montgomery [Vortex Rossby Waves on Smooth Circular Vortices Part I: Theory (pages 153–177, this issue)]. For a monopolar tropical cyclone-like vortex whose strength lies between a tropical depression and tropical storm,...
Article
A complete theory of the linear initial-value problem for Rossby waves on a class of smooth circular vortices in both f-plane and polar-region geometries is presented in the limit of small and large Rossby deformation radius. Although restricted to the interior region of barotropically stable circular vortices possessing a single extrema in tangent...
Article
A new solution to the linear initial-value problem for shallow water Rossby waves on a class of smooth circular vortices is presented in the limit of small and large Rossby deformation radius. The nondimensional evolution equation for perturbation poten- tial vorticity is shown to depend on only one parameter, G, involving the azimuthal wavenumber,...
Article
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Two dynamical models are used to perform a series of seasonal predictions. One model, referred to as GCM2, was designed as a general circulation model for climate studies, while the second one, SEF, was designed for numerical weather prediction. The seasonal predictions cover the 26-year period 1969–1994. For each of the four seasons, ensembles of...
Article
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Data for 39 winters are used to compute the potential vorticity (PV) budget on the θ = 315 K isentropic surface over the Northern Hemisphere. The object is to compare the mechanisms that maintain the PV balance during normal winters with those that maintain the balance during winters with anomalies of the North Atlantic Oscillation (NAO) and Pacifi...
Article
The structure of the self-trapped exciton (STE) in alkali chlorides has been obtained from a calculation in which the electron state and the lattice relaxation are determined simultaneously in a consistent way. The excited electron of the STE is treated with the extended-ion model and the lattice is represented by a pair potential. The results show...
Article
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Observations show the presence of localized regions in the atmosphere with diminished potential vorticity gradients, an example being the tropical upper troposphere where convective heating plays an important role. The present work investigates the effect of forcing on the evolution of Rossby waves in a zero potential vorticity gradient environment...
Article
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The theory of empirical normal modes (ENMs) is adapted to diagnose gravity waves generated by a relatively high-resolution numerical model solving the primitive equations. The ENM approach is based on the principal component analysis (which consists of finding the most efficient basis explaining the variance of a time series), except that it takes...
Article
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The statistical model proposed by Vautard et al. is applied to the seasonal prediction of surface air temperatures over North America (Canada and the United States). This model is based on sea surface temperature predictors filtered by multichannel singular spectrum analysis (MSSA), which is equivalent here to a nonseasonal version of extended EOF...
Article
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We present a diagnostic study of the maintenance of the potential vorticity (PV) on isentropic surfaces, in the troposphere to the lower stratosphere, using ten years of analyses produced by the European Centre for Medium-Range Weather Forecasts. After a brief three-dimensional description of the general circulation in isentropic coordinates, we ex...
Article
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The theory of empirical normal modes (ENMs) for a shallow water fluid is developed. ENMs are basis functions that both have the statistical properties of empirical orthogonal functions (EOFs) and the dynamical properties of normal modes. In fact, ENMs are obtained in a similar manner as EOFs but with the use of a quadratic form instead of the Eucli...
Article
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The nonlinear reflection of an isolated Rossby wave train at a low-latitude wave-breaking region is contrasted with the more familiar longitudinally periodic case. General theoretical arguments for nonlinear reflection based on absorptivity bounds do not carry over to the case of an isolated wave train, and detailed investigation is needed to deter...
Article
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A 25-year dataset of potential vorticity on the 315-K isentropic surface is built from the National Meteorological Center (NMC) final analysis archive. Potential vorticity is calculated from the nonlinear gradient wind balance using temperature and geopotential fields, since the wind field is not available in the early part of the archive. The vali...