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Empirical Statistical Downscaling Evaluations

NOTEWORTHY JOURNAL PUBLICATION & CONFERENCE PRESENTATIONS:

Lanzante, JR, KW Dixon, MJ Nath, CE Whitlock, D Adams-Smith, (2018) Some Pitfalls in Statistical Downscaling of Future Climate. Bulletin of the American Meteorological Society, doi:10.1175/BAMS-D-17-0046.1.

Dixon KW, JR Lanzante, D Adams-Smith, (2017) Examining the Performance of Statistical Downscaling Methods: Toward Matching Applications to Data Products, Poster PA43B-0321. presented at 2017 Fall Meeting American Geophysical Union, New Orleans, La, 11-15 Dec. [PDF of Poster]


Our Statistical Downscaling Research Team’s efforts

Overview:

Here at NOAA GFDL, we view our Empirical Statistical Downscaling (ESD) team’s research efforts as potentially filling a niche akin to that of a Consumer Reports® for statistical downscaling and bias correction techniques that are used to refine climate forecasts and projections. Our primary aim is not to build a the most advanced, state-of-the-art statistical downscaling method ourselves, but rather our main goal is to do evaluations and share the results so that others can make better informed decisions about the suitability of different statistical downscaling methods for various applications relevant to decision-making and adaptation planning. We view our team’s efforts to systematically evaluate the performance characteristics of statistical downscaling methods (both using a “perfect model experimental design” and via “sensitivity studies”) as being relevant and valuable to three different communities interested in climate variability and change. They are…

Applied Science Researchers & Decision-Makers

For many climate impacts studies, large-scale dynamical climate model output is viewed as having inadequate spatial resolution and/or unacceptably large biases that make it unsuitable for direct use in applications of interest. When used in climate impacts analyses that support planning and decision-making, statistically downscaled climate projections typically are viewed as being value-added products that address climate model biases and provide finer spatial scale detail. Our research can benefit users of ESD products in two main ways. First, our “perfect model” experimental design research and sensitivity analyses increase our knowledge about the performance of different ESD methods when applied to changing climatic conditions. Our analyses are uncovering and documenting how ESD performance varies geographically, by time of year, variable of interest, amount of climate change, and is dependent upon the ESD method used. Knowledge gained by this work can provide valuable guidance regarding some aspects of the confidence one should attribute to different statistically downscaled climate projections used in decision-support. Additionally, information gleaned from our studies can be used to help applied researchers who employ ESD data products as input to their studies to better match their applications’ needs and sensitivities to the performance characteristics of different ESD techniques.  Also, as outlined below, our efforts contribute to improving the GCMs and the ESD techniques used to generate the downscaled climate projection data sets that in turn are used as input to impacts analyses.

Empirical-Statistical Downscaling Community

Lacking observations of the future, it is difficult to assess whether and to what extent the skill of ESD techniques may degrade when applied to future climate projections. (Here “skill” broadly refers to the ability of an ESD method to account for GCM biases and to add meaningful fine-scale detail to the raw GCM output.)  A “perfect model experimental design” developed at NOAA GFDL allows us to conduct rigorous quantitative assessments of ESD skill both for the contemporary climate and for future projections. The results of our analyses already have proven useful in isolating weakness in some ESD methods, and have led to ESD method improvements.

Global Climate Modeling Community

Empirical Statistical Downscaling can be thought of as an additional post-processing step applied to Global Climate Model (GCM) output. In effect, an ESD method challenges GCM results with observations as it seeks to address shortcomings in the GCM-simulated climate based on information gleaned from the observational record. Our team’s efforts can promote GCM development at NOAA GFDL by helping identify GCM weaknesses and strengths, with an emphasis on surface climate variables of particular value to adaptation planners, resource managers, and other decision-makers.

PEOPLE

Team members & collaborators


PROJECTS & LINKAGES

Committees, programs, and organizations with whom we interact, as well as entities funding some of our work.

Projects & linkages page


NEWS, PRESENTATIONS & PAPERS

ESD Team news, conference presentations & manuscripts available online.

SELECT JOURNAL PUBLICATIONS:

  • Lanzante, JR, KW Dixon, MJ Nath, CE Whitlock, D Adams-Smith, (2018) Some Pitfalls in Statistical Downscaling of Future Climate. Bulletin of the American Meteorological Society, doi:10.1175/BAMS-D-17-0046.1.
  • Dixon KW, JR Lanzante, MJ Nath MJ, K Hayhoe, A Stoner, A Radhakrishnan, V Balaji, CF Gaitán (2016) Evaluating the stationarity assumption in statistically downscaled climate projections: is past performance an indicator of future results? Climatic Change. doi:10.1007/s10584-016-1598-0

AGU Poster: (Dec. 2017)

  • Dixon KW, JR Lanzante, D Adams-Smith, (2017) Examining the Performance of Statistical Downscaling Methods: Toward Matching Applications to Data Products, Poster PA43B-0321. presented at 2017 Fall Meeting American Geophysical Union, New Orleans, La, 11-15 Dec. [PDF of Poster]