Geoscience Reference
In-Depth Information
Tibetan Plateau is very sensitive to climate change. The model results reveal that
besides precipitation also temperature has to be considered as a driving mechanism
for vegetation in monsoon-in
uenced regions.
On average, the biome simulations show a 15 % reduction of forest and a 20 %
increase of desert in the monsoon-westerly wind transition zone from mid-Holocene
to pre-industrial, but the amplitude of this signal strongly depends on the prescribed
climate forcing. The desert-steppe margin is located further westward by approx.
5
in the different simulations. The forest biomes
extend further north-westward by approx. 2
at 6k, ranging from 1
to 10
°
°
°
.
Role of vegetation-atmosphere interaction: Most of the temperature and
precipitation changes in the Asian monsoon region can be attributed to the direct
response of the atmosphere to the Holocene insolation forcing. However, this direct
signal is strongly modi
, ranging from 0
to 4
°
°
°
ed by the ocean-atmosphere interaction (Dallmeyer et al.
2010
). In India, the interactive ocean strongly increases the Indian summer
monsoon precipitation (0.68 mm/day) and can even overcompensate the decreased
precipitation calculated in the atmosphere-only run (
0.22 mm/day) for the
mid-Holocene. The East Asian monsoon weakens due to the atmosphere-ocean
interaction, particularly above the ocean. The vegetation-atmosphere interaction
generally has a minor effect on the Holocene climate change in our simulations.
However, the idealized sensitivity simulations reveal that large-scale forest decline
in East and South Asia leads to heavy losses in precipitation at a regional level
(Dallmeyer and Claussen
2011
). For instance, in the area along the yellow river,
which was one of the major settlement areas of prehistoric cultures in Asia,
the simulated precipitation change related to forest decrease is half as large as the
insolation induced signal and may therefore have strongly contributed to the
attenuating Asian summer monsoon precipitation known from reconstructions.
−
References
Cao X, Ni J, Herzschuh U, Wang Y, Zhao Y (2013) A late Quaternary pollen dataset from eastern
continental Asia for vegetation and climate reconstructions: set up and evaluation. Rev
Palaeobot Palyno 194:21
-
37
Dallmeyer A, Claussen M (2011) The in
uence of land cover change in the Asian monsoon region
on present-day and mid-Holocene climate. Biogeosciences 8:1499
-
1519
Dallmeyer A, Claussen M, Otto J (2010) Contribution of oceanic and vegetation feedbacks to
Holocene climate change in monsoonal Asia. Clim Past 6:195
-
218
Dallmeyer A, Claussen M, Herzschuh U, Fischer N (2011) Holocene vegetation and biomass
changes on the Tibetan Plateau - a model-pollen data comparison. Clim Past 7:881
901
Dallmeyer A, Claussen M, Wang Y, Herzschuh U (2013) Spatial variability of Holocene changes
in the annual precipitation pattern: a model-data synthesis for the Asian monsoon region. Clim
Dyn 40(11):2919
-
2936
Fischer N, Jungclaus JH (2011) Evolution of the seasonal temperature cycle in a transient
Holocene simulation: orbital forcing and sea-ice. Clim Past 7:1139
-
1148
Herzschuh U, Birks HJB, Ni J, Zhao Y, Liu H, Liu X, Grosse G (2010) Holocene land-cover
changes on the Tibetan Plateau. Holocene 20:91
-
104
-
Search WWH ::
Custom Search