Keywords

Milankovitch theory, astronomical theory, palaeoclimate, 2D climate model, Quaternary and Future climate

Research Interest

Marie-France Loutre's major research deals with the study of the different astronomical parameters leading to the computation of the insolation. The purpose of her research is to better explain how changes of the Earth orbital and rotational parameters can induce long-term climatic changes over the Earth. Since the late 80's, she contributes in improving the accuracy of the orbital paramaters and in calculating the long-term variations of the astronomically forced insolation. In addition to the seasonal and latitudinal distribution of the solar energy received at the top of the atmosphere, other kinds of insolation are also defined and calculated such as the insolation over longer time intervals during the year (astronomical and meteorological seasons, for example), over parts of the day, over zonal belts, over an hemisphere or over the whole year. She is tries to see which of these insolations is integrating most of the processes responsible for glaciations and deglaciations.

As far as climatic modelling is concerned she uses the LLN 2-D climate model, designed to test the Milankovitch theory over the last glacial-interglacial, to assess the role of the different forcings and feedbacks in the model, in particular those related to the atmospheric CO2 concentration, albedo and water-vapor. These studies underline the existence of insolation and CO2 thresholds in the response of the climate system to the astronomical forcing. She focuses on the interglacial during the Quaternary, in particular MIS11, in order to gain further knowledge on the future climate of the next glacial interglacial cycle. She is also involved in the extension of the model validity to time scales of the order of hundreds to thousands of years, i.e. time scales intermediate to the instrumental and astronomical time scales, and of particular interest to CLIVAR (An interdisciplinary research effort within the WCRP). She was also involved in the PMIP project comparing the results of different 3D-simulation, in particular for the monsoon changes point of view. On a shorter time scale she uses the LOVECLIM model to assess the modelling uncertainties in long-term climate and sea level projections and to improve projections of climate and sea-level changes over the current century and this millennium, to identify the likelihood of abrupt changes, and to better understand their causes and mechanisms. In this context, she became interested in the climate of the last interglacial.

From the experience gained in performing these experiments related to the past, she looks for the future of our climate, using different CO2 forcing scenarios to better understand the role of the 'natural' and of the anthropogenically-perturbed conditions. These experiments are amongst the very few performed in the world and are used in many countries, in particular in research related to the nuclear waste disposal repositories. An exceptional long present interglacial and a possible significant influence of man's activities over the XX and XXI centuries on the astronomically forced long-term climatic changes are original results of her research in this field.

She also contributes to the frequency analysis of proxy data to analyse whether these proxies have recorded orbitally induced cimatic changes. Confrontation between the modeling results of the astronomical theory and the proxy record is a fundamental step towards a better understanding of climatic changes and improvements in time scale, data interpretation and modeling. It also allows he to become involved in the development of new methods of dating long glacial-interglacial ice core records.