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Objectives for the study of largescale snow cover features

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Objectives for the study of large-scale snow cover features ... In Volga and Yenisey basin, the increase of snow accumulation and hence runoff ... – PowerPoint PPT presentation

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Title: Objectives for the study of largescale snow cover features


1
Objectives for the study of large-scale snow
cover features
  • To study macro-scale peculiarities of the spatial
    distribution of snow accumulation parameters over
    the Northern Eurasia
  • To reveal the changes in snow cover parameters
    connected to the warming.

2
Data Snow depth (cm) and snow water equivalent
(and evaluated density) over the former USSR
territory (Russia Institute of Hydrometeorological
Information RIHMI), for the end of February,
derived from the measuring snow courses and
compiled in (Russia Institute of
Hydrometeorological Information RIHMI), 682
stations from 1966 till 2000.
3
Variations of winter air surface temperature
anomalies, averaged over the FSU territory, and
winter NAO index. Winter warming in Northern
Eurasia is connected to more active cyclonic
circulation, quantified by NAO index. The coldest
years since 1966 are 1966-77, the warmest
1989-2000.
4
Surface air temperature anomalies in winter, Co,
averaged for the period 1989-2001, compared with
the mean for 1951-1980Shmakin and Popova, 2004
Recent winter warming over the Northern
Eurasia
5
Mean snow depth (cm, upper panel), and SWE (mm)
in 1966-2000, (lower panel)
6
Correlation coefficients between interannual
variations of snow depth and SWE during 1966-2000
The correlation has its minimum in the
south-west, where warm waves (melting events)
during winter are typical.
7
Anomalies of snow depth (upper panel) and SWE
(lower panel) during the warmest period 1989-2000
() in relation to the coldest 1966-1977
Increase of the snow depth and SWE are typical
for the regions where the winter warming is most
pronounced. Their decrease is observed in the
regions where there is no significant warming.
8
Mean snow density (kg/m3 10-2 ) (upper panel)
and its anomalies (lower panel) during the
warmest period 1989-2000 () in relation to
coldest 1966-1977
Distribution of average snow density demonstrates
its dependence on a) winter melting frequency,
and b) wind velocity and heavy precipitation (the
latter two being typical for intensive cyclonic
activity). The same factors are responsible for
the change of snow density under contemporary
winter warming.
9
Studies of snow-runoff relationships in 4 large
river basins In Volga and Yenisey basin, the
increase of snow accumulation and hence runoff
increase is related to the same origin as the
contemporary warming the cyclonic activity. In
Ob and Lena basins, the long-term variations of
runoff and snow accumulation are not related to
each other (possibly, due to summer
precipitation).
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