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Institut d’Astronomie et de Géophysique G. Lemaître Chemin du Cyclotron, 2 1348 Louvain-la-Neuve. Paramètres Astronomiques : le métronome des changements climatiques. A. Berger et M.F. Loutre.
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Institut d’Astronomie et de Géophysique G. Lemaître Chemin du Cyclotron, 2 1348 Louvain-la-Neuve Paramètres Astronomiques : le métronome des changements climatiques A. Berger et M.F. Loutre Ecole Eté de Physique sur la Physique de notre Planète : la Terre et son Climat, E2PHY, Université de Bordeaux I, 25-28 août 2003
Last Glacial Maximum 21kyr BP Today LGM DT=-5°C Dsea level = –130m Dice volume = +52 106km3 CO2 = 200 ppmv Pre-industrial CO2 = 280 ppmv 2000 AD CO2 = 370 ppmv (Joussaume, 1993)
ASTRONOMICAL SOLUTION • MATHEMATICS OF INSOLATION • MODELLING THE PAST • MODELLING THE FUTURE • MAN’S IMPACTS ON CLIMATE/ • ASTRONOMICAL TIME SCALE
14 kyrBP 0.0167 • | ~80kyr SS Aphelion • SS Perihelion 9 kyrBP | • 23°4 } High insolation Lat. MAX NH in summer } D lat in summer D season in high lat NH e large SS Perihelion (v=270°; e sin v min) MAX
ASTRONOMICAL SOLUTION • MATHEMATICS OF INSOLATION • MODELLING THE PAST • MODELLING THE FUTURE • MAN’S IMPACTS ON CLIMATE/ • ASTRONOMICAL TIME SCALE
Present day departure from the last 400kyr average of insolation
105 Wm-2 11 kyr BP 25 Wm-2 9 kyr AP
24h mean irradiance (Wm-2) Mid-month June
Insolation (Wm-2) Deviation from present day value 115 kyr BP 125 kyr BP
10kyrBP departure from the last 400kyr average of insolation
ASTRONOMICAL SOLUTION • MATHEMATICS OF INSOLATION • MODELLING THE PAST • MODELLING THE FUTURE • MAN’S IMPACTS ON CLIMATE/ • ASTRONOMICAL TIME SCALE
ASTRONOMICAL SOLUTION • MATHEMATICS OF INSOLATION • MODELLING THE PAST • MODELLING THE FUTURE • MAN’S IMPACTS ON CLIMATE/ • ASTRONOMICAL TIME SCALE
The EXCEPTIONAL astronomical forcing over the next 50 kyr
14 kyrBP 0.0167 • | ~80kyr SS Aphelion • SS Perihelion 9 kyrBP | • 23°4 } High insolation Lat. MAX NH in summer } D lat in summer D season in high lat NH e large SS Perihelion (v=270°; e sin v min) MAX
105 Wm-2 11 kyr BP 25 Wm-2 9 kyr AP
24h mean irradiance (Wm-2) Mid-month June
STAGE 11 / STAGE 1 and its Future
MIS11 : an analogue for the future Ref : Petit et al., 1999
MIS11 : an analogue for the future CO2 = Vostok
MIS11 : other CO2 scenarios Stage 11 is replaced by stage 9 or stage 5 Stage 11 is made older by 10 kyr or by 20 kyr
ASTRONOMICAL SOLUTION • MATHEMATICS OF INSOLATION • MODELLING THE PAST • MODELLING THE FUTURE • MAN’S IMPACTS ON CLIMATE/ • ASTRONOMICAL TIME SCALE