Permafrost

throughout the whole frozen part, showing “zero curtain”. This is the most sensitive condition for
permafrost to respond the surface warming, and numerical experiments showed that such
permafrost could degrade in the time scale of ten to several tens of years. Considering the time
scale of the global warming, there is a high possibility that the relict permafrost (perennially
frozen part beneath the supra-permafrost talik) has widely degraded during 1990s, which is
considered to be related with the desertification of the grassland or lowering of the ground water
level. Further analysis of borehole temperature data may provide more constraints for ground
surface temperature history.
Keywords: Permafrost, global warming, ground temperature, numerical modelling, Tibet
200
Permafrost distribution in the vicinity of Esso, central Kamchatka,
Russia
T. SONE 1 , K. YAMAGATA 2 , Y. OTSUKI 3 , K. FUKUI 4 , Y. SAWADA 1
V.P.Vetrova 5 , M.Vyatkina 5 , and V.A.Bakalin. 5
(1. Institute of Low Temperature Science, Hokkaido Univ.; 2. Joetsu Univ. of Education; 3. Tohoku Univ.; 4.
National Institute of Polar Research; 5. Kamchatka Branch of Pacific Institute of Geography)
Abstract: It has been reported that the limit of discontinuous permafrost lies in the Kamchatka
Peninsula, Russia. However, the information on permafrost in Kamchatka is very limited. We
conducted the year round ground temperature measurements in the vicinity of Esso village,
central Kamchatka.
Esso village is situated at 158°40’E, 55°56’N, 500 m above sea level and is surrounded by
lava plateaus of around 1000m a.s.l. We measured the ground temperatures of 0-2m deep at
1-hour interval with thermistor temperature recorders (T and D corp., Tr.52) along the Uksichan
River. The river is one of tributary of the Bystraya River and flows west of Esso village. MAAT
in Esso is around –2°C.
Larch trees (Larix cajanderi) and creeping pines (Pinus pumila) are developing mainly on
the right bank of the Uksichan River (north-facing slope). An intact forest of larch trees
upstream looks like a “drunken forest”, suggesting the existence of permafrost. Permafrost
occurs in the larch forest with a thick litter layer. A forest fire occurred on moraines near the
village in 1995. Permafrost develops even in a burned place under the sphagnum layer. A slope
failure occurred on the right side slope of the Uksichan River in 1997. It is possibly related to
the forest fire and climatic warming. Permafrost does not develop on the place with thin litter
layer or without sphagnum.
There are several mounds of 60-80 cm high and 2 to 10 m wide on the burned gentle slope
of 2-3° (650 m a.s.l.). The shape of the mounds is oval to circular. They consist of peat layer.
Around the mound the peat layer become thin and the thickness of the seasonal thaw layer
become larger. The frozen mounds are covered with the peat layer of 40-60 cm thick. The peat
layer is underlain by humus layer of 10cm thick, which overlies the volcanic ash soil. They are
defined as degradation palsas. The temperature profiles show that the thickness of permafrost
seems to be only several meters.