Permafrost

plains between 4200 m and 4300 m ASL, subsurface low resistivities (30–140 Ωm) indicate the
absence of permafrost below the groundwater level detected by intermediate P-wave velocities
(1.5–1.7 km s −1 ). The presence of permafrost is unclear at the other four sites between 4200 m
and 4300 m by the resistivity sounding alone. A geocryological map edited in early 1990s
included the whole plain area in a permafrost region, with exceptions of lakes, streams and
nearby swamps. Recent climatic warming, however, would have induced significant deepening
of permafrost table or even completely melted permafrost. Thus, the source area of the Yellow
river currently faces a rapid loss of the permafrost area, since the elevations mostly belong to a
transitional condition between permafrost and seasonal frost environments. Such rapid
permafrost degradation may also significantly affect the groundwater circulation within the
source area.
Key words: Permafrost, global warming, ground temperature, geophysical soundings, Tibet
160
Monitoring and modeling the permafrost dynamics
under climate changes
A.V.Pavlov 1 , G.Z.Perlshtein 2*
(1.Institute of the Earth Cryosphere, SB RAS; 2.Institute of Environmental Geoscience, RAS)
Abstract: Monitoring of cryolithozone behavior under climate changes requires a rise in
precision, duration and completeness of the ground temperature and cryogenic processes
observations.
The monitoring net in Russia has 15-20 permafrost stations (Vorkuta, Marre-Sale, Nadym
et al.) with observational series duration upward of 20-30 years. Obtained data together with the
results of meteorological observations are used for estimating cryolithozone thermal state and
forecasting its dynamics in XXI century.
In the Russian North contemporary rise in the air temperature has started since the middle
sixties of past century. It averages 1.1 ºC whereas the global one is essentially less, about 0.5 ºC.
The climate warming is pronounced in the continental regions of cryolithozone where it may be
as much as 1.4-2.5 ºC. Over Arctic plains the climate warming does not exceed 0.5-0.7 ºC. The
maximum warming rate was observed in 1980-ies. The values of the air temperatures’ local
trends range from 0.01 to 0.08 ºC/year. The climate warming rate reduces since the middle of
1990-ies.
The permafrost thermal state is usually considered as a sensible detector of contemporary
climate changes. According to monitoring data rise in the ground temperature was observed in a
number of northern regions of Russia between late seventies and middle nineties. For example,
in the north of Western Siberia the rise in frozen ground temperature can be estimated as 0.9 ºC
for continuous cryolithozone and 0.9-1.4 ºC for the regions with discontinuous and sporadic
permafrost. In Central Yakutia, in spite of high climate warming, the increasing of ground
temperature manifests poorly and far from everywhere. If the rase in frozen ground temperature
(at the depth of 3-10 m) occurred its relation to the rise of the air temperature ranged from 0.3
to 0.75.