East Asian Monsoon and paleoclimatic data analysis: a vegetation point of view
J. Guiot 1, Hai Bin Wu
2,3
, Wen Ying Jiang
4
, and Yun Li Luo
5
1
CEREGE, CNRS/Universit´e Paul C´ezanne UMR 6635, BP 80, 13545 Aix-en-Provence cedex France
2
SKLL, Institute of Earth Environment, Chinese Academy of Sciences, Xian 710075, China
3
Institut des Sciences de l'Environnement, UQAM, Montreal PQ, H3C 3P8 Canada
4
Key Laboratory of Cenozoic Geology and Environment, Institute of Geology and Geophysics, Chinese Academy of
Sciences, 100029 Beijing, China
5
Institute of Botany, Chinese Academy of Sciences, 100093, Beijing, China
An open access article from Clim. Past, 4, 137-145, 2008.
Abstract. First we review several syntheses of paleodata
(pollen, lake-levels) showing the climate variations in China
and Mongolia from the last glacial maximum to Present and
in particular the precipitation increase at mid Holocene re-
lated to enhanced monsoon. All these results concur to a
much enhanced monsoon on most of China during the first
half of the Holocene. Second we present, in some details, a
temporal study of a core (Lake Bayanchagan, Inner Mongo-
lia) located in an arid region at the edge of the present East
Asian Monsoon (EAM) influence and then sensitive to cli-
matic change. This study involves pollen data together with
other macro-remains and stable isotope curve to obtain a ro-
bust climate reconstruction. This study shows a long wet pe-
riod between 11 000 and 5000 years BP divided in two parts,
a warmer one from 11 000 and 8000 (marked by large evap-
otranspiration) and a cooler one more favourable to forest
expansion. Third, we present a spatial study based on pollen
data only and covering all China and Mongolia at 6000 years
BP, but using a mechanistic modelling approach, in an in-
verse mode. It has the advantage to take into account en-
vironmental context different from the present one (lower
atmospheric CO
2
, different seasonality). This study shows
temperature generally cooler than present one in southern
China, but a significant warming was found over Mongolia,
and a slightly higher in northeast China. Precipitation was
generally higher than today in southern, northeast China, and
northern Mongolia, but lower or similar to today in northwest
China and north China. Enhanced EAM was then found in
the southern half of China and in northeast China.