Intensity of Cryogenic Processes in Central Yakutia
in the context of GAME-Siberia Study
Fedorov Alexander*Permafrost Institute of Siberian Branch of Russian Academy of Sciences, Yakutsk, Russian Federation* Permafrost Institute SB RAS, Merzlotnaya 1, Yakutsk-10, 677010, Yakutsk, Russian Federatione-mail: fedorov@mpi.ysn.ru
Abstract
This paper illustrates the peculiarities of permafrost processes manifestation in various landscapes during the intense
GAME observations in Central Yakutia. Observation results that were achieved at the Spasskaya Pad station nearYakutsk within the frameworks of the GAME-Siberia project and at Permafrost Institute stations are used in this paper.
Keyword: permafrost, landscape, process, stress, succession.
The period of intensive GAME-Siberia observations

Permafrost Institute's sites Neleger, Yukechi and(1996-2000) in Central Yakutia coincided in time with

Umaibyt located near Yakutsk are used in this analysis.

climatic and cryoecological stresses in permafrost andEarlier we analyzed the retrospective schemes ofin the environment as a whole. Thus the environmental

changes

inair

temperature,

precipitation,

soil

investigations during this period were most effective

temperature and seasonal thaw depth for Central

for the study of critical situations in permafrost and its

Yakutia (Fedorov, 2001).

sensitivity.

GAME-Siberia observations (1996-2000) coincided inThe period of intensive

The results of observations at the Spasskaya Pad

time with a considerable increase in mean annual air

study area of the GAME-Siberia Project and thetemperature (Fig. 1) and in thawing index, and  <4;:
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"$#"$%%#%%&('&() *'-/.(0(1 2*)+'+),',)'Fig. 1. Variability of mean annual air temperature in Yakutsk (thin blue line – actual data,
thick red line – 5-year mean)a decrease in precipitation. These changes resulted in

the landscapes (Fedorov, 1996).

warming of soil temperatures in Central Yakutia in theField observations of thermokarst-related surface

late 1990s, which caused the activation of cryogenic

subsidence in Central Yakutia show that settlements

processes and notably modified the permafrost-occurred at flat locations of the forest-free inter-alasslandscape conditions. Thawing of the upper layers ofareas, which had not been subject to thermokarst earlier

ground ice in disturbed and forest-free areas of the(Fig.2). In small thermokarst depressions, settlement

inter-alass landscapes triggered thermokarst. We

rates of up to 10-15 cm/yr were measured during thisrelated it to the development of cryoecological stress inperiod (Fig.3).

KL
IAJGHhiF ECEE
BDC(E=?>A@MON/NP

Q RR/SjTOUU/VkWOXXZY[O\/\]l^ __/`mn;o/oaObbZc aOb/b/bm/nqpfr

dfee/em/n;s/t

dfeegFig. 2. Surface subsidence of flat inter-alas areas, site 2.
A, B, C – markers on flat inter-alas areas; bc22, bc40, bc56 – markers near small thermokarst depression.

xyyuxy

u zyyu zxyuwvyyuwvxy{}| | ~}  } O}  }  } /((  }  }       

Fig. 3. Surface subsidence in thermokarst depression, Yukechi, site 2.
C – check point, undisturbed inter-alas area; D – incipient thaw depression; 1-3 – centers of polygons
within thaw depression.

The rates of cryogenic processes are primarily

summer of 1999, when soil thawing was deepest. In

dependent on soil hydrologic regime. We estimated thethis season, thaw depth values of 1.4-1.5 m occurred in

effect of active-layer moisture on the permafrost

52.3% of the map area and moisture contents above

landscapes.

20% occurred in 49.5% of the area.

Y.I.Torgovkin

constructed

GIS-basedspatial models of active-layer thickness and moisture

At present, both permafrost warming and cooling

content variability over the period of intensive GAME-

are observed in Central Yakutia. A decrease ofSiberia observations for the area adjoining thepermafrost temperature is primarily related, along with

Spasskaya Pad study area. In spatial interpretations, weother factors, to the recovery of forest vegetation atused a landscape map of a 10 x 12 km area where 45

successional stands after anthropogenic disturbance.

terrain units at a patch ('urochische') level were

Successional stands following fires and tree cutting

identified. The number of landscape contours was 704

occupy significant areas. They cover about 30% of theunits. Analysis of the maps shows that active layer

Spasskaya Pad area. We established the general

thickness and soil moisture content strongly vary frompatterns in vegetation succession in Central Yakutia.

year to year. However, the general patterns ofInvestigations at the Umaibyt site show that the periodvariations are practically identical for the patch types.

of complete vegetation recovery is 130 years (Fig.4).

The wettest conditions were observed in 1997 andWe estimated the effect of vegetation succession on the1999. Cryogenic processes were most intensive in thepermafrost thermal regime and active-layer thickness.

Fig.4. A succession scheme of landscape evolution at Umaibyt site (a), variability of groundtemperature (Kt), seasonal thaw depth (Kξ) – (b) and protective thickness (Kp) – (c).

Ground temperatures in the recovering birch andbirch-larch forests have cooled by 0.3-0.5°C over theperiod from 1980 to 2000. Based on this model, both
retrospective and predictive models of permafrost canbe developed.
Observations indicate that the GAME-Siberia study
period fell on the time of cryoecological stresses in theCentral-Yakutian landscapes. The data obtained during
the GAME-Siberia Project will provide a basis forunderstanding the development of critical situations inpermafrost landscapes and for determining permafrost
sensitivity criteria.

Reference

Fedorov, A.N. Effects of resent climate change on
permafrost landscapes in Central Sakha //Polar Geography, 1996, 20, 2, pp.99-108.
Fedorov A. The period of intensive observation in theGAME study area, the vicinity of Yakutsk, inthe Trade Center, Nagoya, Japan. 3-5 October
2001, pp. 48-51.