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Characteristics of soil moisture in permafrost observed in East Siberian taiga with stable isotopes of water
Author(s) -
Sugimoto A.,
Naito D.,
Yanagisawa N.,
Ichiyanagi K.,
Kurita N.,
Kubota J.,
Kotake T.,
Ohata T.,
Maximov T. C.,
Fedorov A. N.
Publication year - 2002
Publication title -
hydrological processes
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.222
H-Index - 161
eISSN - 1099-1085
pISSN - 0885-6087
DOI - 10.1002/hyp.1180
Subject(s) - water content , environmental science , meltwater , infiltration (hvac) , soil water , snowmelt , snow , udic moisture regime , hydrology (agriculture) , evapotranspiration , permafrost , moisture , field capacity , soil science , geology , chemistry , geomorphology , oceanography , ecology , physics , geotechnical engineering , organic chemistry , biology , loam , thermodynamics
Soil moisture and its isotopic composition were observed at Spasskaya Pad experimental forest near Yakutsk, Russia, during summer in 1998, 1999, and 2000. The amount of soil water (plus ice) was estimated from volumetric soil water content obtained with time domain reflectometry. Soil moisture and its δ 18 O showed large interannual variation depending on the amount of summer rainfall. The soil water δ 18 O decreased with soil moisture during a dry summer (1998), indicating that ice meltwater from a deeper soil layer was transported upward. On the other hand, during a wet summer (1999), the δ 18 O of soil water increased due to percolation of summer rain with high δ 18 O values. Infiltration after spring snowmelt can be traced down to 15 cm by the increase in the amount of soil water and decrease in the δ 18 O because of the low δ 18 O of deposited snow. About half of the snow water equivalent (about 50 mm) recharged the surface soil. The pulse of the snow meltwater was, however, less important than the amount of summer rainfall for intra‐annual variation of soil moisture. Excess water at the time just before soil freezing, which is controlled by the amount of summer rainfall, was stored as ice during winter. This water storage stabilizes the rate of evapotranspiration. Soil water stored in the upper part of the active layer (surface to about 120 cm) can be a water source for transpiration in the following summer. On the other hand, once water was stored in the lower part of the active layer (deeper than about 120 cm), it would not be used by plants in the following summer, because the lower part of the active layer thaws in late summer after the plant growing season is over. Copyright © 2002 John Wiley & Sons, Ltd.