Claudia Tebaldi

	Claudia Tebaldi

Claudia Tebaldi is mainly working on analyzing climate model output with the goal of characterizing future projections and their uncertainty.

Her main focus has so far been on probabilistic projections of temperature and precipitation at regional scales, and on changes in indices of climate extremes.

Characterizing uncertainties in climate change projections

Probabilistic projections of average temperature and precipitation change at regional scales are important pieces of information for any impact study. Accordingly, Claudia has the chance of hearing from very different projects, and at times participate in them by providing ad hoc projections, and translating them into local changes through downscaling techniques.

Among the projects she has been involved in lately, she has been working with Barry Keim (LSU) and Virginia Burkett (USGS) on a study of the impact of climate change on the Gulf Coast transportation infrastructure; with Hayley Fowler (U. of Newcastle, UK) on impacts on hydrologic systems in Europe; with Bob Harriss and Jim Norwine on the future climate of South Texas; with Dave Yates (RAP) and Dave Groves (RAND) on water resource impacts in California. After a while it became clear that the demand for this kind of product was ever increasing and warranted the development of a web-based interface that eventually will provide ad-hoc regional climate change projections automatically on request. Claudia has been working with Seth McGinnis (ISSE) on this project. From the methodological point of view Claudia worked with Ana Lopez (Oxford U., UK) to compare the method that she originally developed with Richard L. Smith (UNC), Doug Nychka and Linda Mearns (NCAR) to another well established method for probabilistic projections developed by Myles Allen (Oxford U.) and colleagues. Together with the original co-authors she has worked on a variation of the Bayesian statistical model that borrows strength in the estimation of the probabilities across regions.

Currently, she's working on developing joint projections of temperature and precipitation by an extension of the Bayesian approach already developed, with Bruno Sanso' of UCSC. The work on probabilistic projections has led to take up the writing of a small but controversial methodological section in the chapter on regional projections of the next IPCC report, the AR4. The "uncertainty" section was written under the guidance of Linda Mearns, and involved a lot of literature searching and reviewing and e-discussions across the continents with other IPCC AR4 authors, on the nature and hidden assumptions of statistical modeling and uncertainty quantification.

Indices of climate extremes

The work on climate extremes is an on-going collaboration with Jerry Meehl and Julie Arblaster (CGD). THe IPCC asked for the computation and storage of a suite of pre-defined indices of temperature and precipitation extremes, and 9 out of 23 modeling groups actually complied. Claudia, Jerry, Julie and Katherine Hayhoe wrote a paper on the results gleaned from the GCMs, as an overview of the entire suite of indices, and focused on precipitation intensity in another paper. There is a never ending series of studies that can be done on the basis of these datasets, and papers are in progress comparing modeled and observed indices and determining the indices dependence on ENSO phases.

Publications

Tebaldi, C., K. Hayhoe , J.M. Arblaster, and G.A. Meehl (2006), Going to the extremes: An intercomparison of model-simulated historical and future changes in extreme events. Climatic Change, forthcoming.

Lopez, A., C. Tebaldi, M. New, D. Stainforth, M. Allen and J. Kettleborough (2005), Two approaches to quantifying uncertainty in global temperature changes. J. of Climate, forthcoming.

G.A. Meehl, J.M. Arblaster and C. Tebaldi, (2005). Understanding future patterns of increased precipitation intensity in climate models. Geophys. Res. Letters, v.32.

Smith, R.L., C. Tebaldi, D. Nychka and L.O.Mearns (2006), Bayesian modeling of uncertainty in ensembles of climate models. Submitted.

Fowler,H.J., Blenkinshop, S. and C. Tebaldi (2006) Linking climate change modelling to impacts studies: recent advances in downscaling techniques for hydrological modelling. Submitted.

Funding Sources

These activities are supported by funding from The National Science Foundation through its support of NCAR and, in particular, ISSE, CGD and IMAGe.