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Hello stranger,

I am a climate dynamicist working at the University of Southern California. Broadly speaking, my research is concerned with the role of the Tropics in long term climate variability. The central actor of this game is of course the El Niño-Southern Oscillation (ENSO) phenomenon, whose behavior I strive to understand on decadal to millennial timescales. My current research interests include :

1) Reconstructing surface conditions over the past 2 millennia

This work is at the interface between applied mathematics and climatology, with a joint emphasis on proxy quality and the development of adequate statistical and timeseries analysis methods. Here is the general idea: consider the picture painted in the tropical Pacific by the instrumental record of the past 150 years. The temperature field varies as a function of time, latitude and longitude, but we can fold latitude and longitude into a single location index (362 points, each corresponding to a 5 by 5 degree box). The following picture is such a represensation of Kaplan SST over the tropical Pacific, smoothed with a 10-year lowpass filter to highlight slowly evolving phenomena.

SSTtapestry

As you can see, this looks rather like a tapestry. The question is: how can we weave this climate tapestry back in time ? And how reliable would be such a reconstruction? To answer these questions, I used the coarse threads provided by multiple proxies from around the tropics, and a statistical method called RegEM. The proxies are geological objects (corals, ice cores, stalagmites, sediment cores, tree rings) that sensitively record climate information like temperature and precipitation perturbations, generated by ENSO even in remote regions of the Tropics. By making use of the correlation matrix estimated over the period of overlap between instrumental meansurements and proxy measurements, we can fill in the holes in the tapestry. This does introduce errors and biases, however, so it is just as critical to represent those as fairly as possible.

2) Understanding and representing uncertainties in climate proxy records

Forward modeling the geological processes giving rise to such geochemical timeseries. This (incipient) work is at the interface between biogeochemistry and climatology.

3) Modelling tropical climate over the past millennium

using an array of climate models with varying degrees of complexity, one can investigate physical mechanisms of natural climate change in the recent past. Such models currently include:

And are run at USC's High Performance Computing Center .

I am particularly interested in the climate sensitivity to natural (solar and volcanic) forcing and what it teaches us (or not) about climate sensitivity to anthropogenic greenhouse gas emissions.

4) Dynamical ocean response to geothermal heatflow.

This work makes use of numerical models of the ocean (NEMO) and geochemical tracers that help constrain the patterns and intensity of the deep circulation, and its potential impact on millennial-scale climate change.

Student Opportunities: I am looking for original thinkers for a numbers exciting projects at the intersection of paleoclimatology, biogeochemistry, and climate modeling.

Post-doctoral Opportunities: I am looking for a statistician (especially a Bayesian) with interest in geosciences to develop and expand climate reconstruction methods.

Please contact me if you have questions