Session: Glacial Climates (LGM, Last deglaciation, Ice sheet uncertainties, Glacial-interglacial cycles)
Author: James Annan / email@example.com / Blue Skies Research
Co-author: Julia Hargreaves, Blue Skies Research;
Ruza Ivanovic, University of Leeds;
Lauren Gregoire, University of Leeds;
Paul Valdes, University of Bristol;
Bette Otto-Bliesner, NCAR;
Using data assimilation techniques for climate reanalysis should provide the best description of how and why our climate has changed through the past and up to the present. Due to both computational and data limitations, previous paleoclimate reanalyses of the authors and others have typically focussed either on time slices (such as the Last Glacial Maximum or mid-Pliocene Warm Period) or the relatively short transient of the last millennium, using a wide variety of methods. The forthcoming PMIP6 simulations of the last deglaciation, together with recently published compilations of core data, should provide us a new opportunity to reconstruct the fully global transient evolution of the climate state over this period with more detail and accuracy than previously achieved.
Here we present some initial investigations and results using transient simulations which have been produced by the FAMOUS model (low-resolution HadCM3) and CCSM3, which builds on our previous work in state (LGM) reconstruction. We show that in principle it is possible to blend the data and model simulations in order to give a realistic reconstruction of the full deglatiation. Future challenges include handling errors in the timing and magnitude of forcing time series used to drive the models, and also in the chronologies of proxy data.