Recent Changes

Friday, January 18

  1. page BIRS Workshop Papers edited ... Alexis Hannart: Approaching D&A as an inverse problem: data Assimilation in a toy model of…
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    Alexis Hannart: Approaching D&A as an inverse problem: data Assimilation in a toy model of stratospheric cooling
    D&A can be seen as an inverse problem. An interest of taking this perspective is that it gives access to many methods that are not currently used in D&A. With that said, is there anything in the inverse problem toolbox that is valuable to tackle the present challenges of D&A ? We start exploring this question by implementing a Kalman filter inversion of an idealized radiative atmospheric model. We show that such a data assimilation procedure is able to reconstruct the contributions of the different radiative forcings from climate observations. We discuss further possible extensions of this data assimilation approach of D&A ('DADA').
    {poster_banff_2.pdf}
    Jara Imbers: Sensitivity of detection and attribution to simulated internal variability
    The IPCC very likely statement that anthropogenic emissions are affecting climate is based on a statistical detection and attribution methodology, heavily dependent on the characterisation of internal climate variability. In this paper, we ask how robust is the IPCC statement in the event of varying the representation of such variability? We do this conceptually with a simple energy balance model of the climate system forced with dierent natural and anthropogenic forcings, a stochastic short memory process (AR1), and a stochastic long memory process, (FD). We nd that independently of the representation the greenhouse gas signal in particular remains statistically signicant. We present this paper as additional evidence that the IPCC statement is robust but also, we claim the need to update the methodologies to assess GCMs simulations compared to the observed record.
    (view changes)
    1:10 pm
  2. 1:08 pm

Monday, June 18

  1. page BIRS Workshop Papers edited ... Nathan Gillett: An introduction to climate change detection and attribution. This presentatio…
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    Nathan Gillett: An introduction to climate change detection and attribution.
    This presentation will build on the first introductory lecture on climate change detection to consider studies which explicitly separate the responses to multiple climate forcings, for example anthropogenic forcings and natural forcings. Such studies typically relate observed changes in a variable of interest to simulated responses to a set of forcings using a multiple linear regression equation. Rather than assuming that the response to each set of forcings consists of a linear trend, such studies often use spatio-temporal patterns of response in order to better differentiate between the responses to different forcings. This talk will introduce regression-based approaches to detection and attribution, consider signal-to-noise opimisation, approaches which account for uncertainty in the simulated response patterns, multi-model approaches, the use of results to constrain projections, and other innovations in methodology. Applications to a range of variables will be discussed, including recent attribution results for surface temperature change and sea level pressure change derived using CMIP5 simulations. The limitations of such approaches will also be discussed.
    Presentation: [to follow] {gillett_birs_talk2.pdf}
    Video link: Gillett video
    Chris Paciorek (for Francesca Domenici): Human health impacts of climate change
    (view changes)
    5:41 am

Thursday, June 7

  1. page BIRS Workshop Papers edited ... Ben Shaby: Bayesian spatial extreme value analysis to assess the changing risk of widespread c…
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    Ben Shaby: Bayesian spatial extreme value analysis to assess the changing risk of widespread crop failure in Europe
    There is strong evidence that extremely high temperatures are detrimental to the yield and quality of many economically and socially critical crops. Fortunately, the most deleterious conditions for agriculture occur rarely. We wish to assess the risk of the catastrophic scenario in which large areas of croplands simultaneously experience extreme heat stress. Applying a hierarchical Bayesian spatial extreme value model that allows the distribution of extreme temperatures to change in time both marginally and in spatial coherence, we examine whether the risk of widespread crop failure due to high temperatures has increased in Europe over the last century.
    Poster: {crops_banff_poster_01.pdf}
    Ying Sun: Function Median Polish with Climate Applications
    We propose functional median polish, an extension of univariate median polish, for one-way and two-way functional analysis of variance (ANOVA). The functional median polish estimates the functional grand effect and functional main factor effects based on functional medians in an additive functional ANOVA model assuming no interaction among factors. A functional rank test is used to assess whether the functional main factor effects are significant. The robustness of the functional median polish is demonstrated by comparing its performance with the traditional functional ANOVA fitted by means under different outlier models in simulation studies. The functional median polish is illustrated on various applications in climate science, including one-way and two-way ANOVA when functional data are either curves or images. Specifically, U.S. precipitation observations and outputs of global and regional climate models are considered.
    (view changes)
    10:46 am
  2. 10:45 am
  3. 10:44 am

Saturday, June 2

  1. page BIRS Workshop Papers edited ... Video link: Gillett video Chris Paciorek (for Francesca Domenici): Human health impacts of cl…
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    Video link: Gillett video
    Chris Paciorek (for Francesca Domenici): Human health impacts of climate change
    Presentation: {paciorek.pptx}
    Video link: Paciorek video:
    Tuesday
    (view changes)
    9:27 am

Friday, June 1

Thursday, May 31

  1. page BIRS Workshop Papers edited ... Panel discussion: theory and methodology (Guttorp et al.): Video link Randall Dole: Event Att…
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    Panel discussion: theory and methodology (Guttorp et al.): Video link
    Randall Dole: Event Attribution: Physical-Diagnostic Approach
    Presentation: Part 1 {2012-06-01 BIRS_Dole_attribution part1.pdf} . Part 2: {2012-06-01 BIRS_Dole_attribution part 2.pdf}
    Video link: Dole video
    Notes from breakout discussion on extremes and impacts (T. Greasby): ExtremeImpacts_breakoutnotes.pdf {ExtremeImpacts_breakoutnotes.pdf}
    (view changes)
    9:47 pm

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