Snowmelt and the hydrological interaction of forest-grassland ecosystems in Central Yakutia, eastern Siberia

Abstract

Abstract:In the last two decades the major focus of study in forest water and carbon balances in eastern Siberia has been on the effect of rain during the growing season. Little attention has been paid to the contribution of snowmelt water. The results of the present study indicate that weather conditions during the snowmelt period as well as the soil moisture conditions carried from the previous year's growing season strongly determined the water availability for the forest ecosystem at the beginning of the next growing season. In the forest-grassland intermingled ecosystem of lowland Central Yakutia, gradual snowmelt water flow from the forest into the adjacent grassland depressions increased when soil moisture was high and air temperature was low, whereas low soil moisture and high air temperatures accelerated soil thawing and consequently snowmelt water infiltration into the forest soil. We found that snow depth did not determine the volume of snowmelt water moving to the grassland depression since the thermokarst lake water level in the adjacent grassland was about 25 cm lower in 2005 than in May 2006, even though maximum snow depth reached 57 cm and 43 cm in the winter of 2004-05 and 2005-06, respectively. The contribution of snowmelt water to forest growth as well as the flow of water from the forest to the grasslands showed a strong annual variability. We conclude that warmer springs and high variability in precipitation regimes as a result of climate change will result in more snowmelt water infiltration into the forest soil when the previous year's precipitation is low while more snowmelt water will flow into the thermokarst lake when the previous year's precipitation is high.

Estimates of Global Surface Hydrology and Heat Fluxes from the Community Land Model (CLM4.5) with Four Atmospheric Forcing Datasets

“…Toure et al (2016) evaluated offline CLM4-simulated snow using in situ observed snow depth and satellite snow cover data and found that the model underestimated the snow depth and showed early snowmelt. We compared the SWE monthly climatology from four simulations for 1980-2009 over eastern Siberia and the western United States (figure not shown) and found that SWE peaked in April and February, respectively, which were much earlier than in the observations (e.g., Lopez Caceres et al 2015). This explains the model runoff peak in May (vs observed peak in June) over eastern Siberia and the model runoff peak in March (vs observed peak in May) over the western United States in Fig.…”

Variations of Microwave Scattering Properties by Seasonal Freeze/Thaw Transition in the Permafrost Active Layer Observed by ALOS PALSAR Polarimetric Data

“…However, some polarimetric parameters, including the dominant eigenvalue and co-polarization coherences exhibit characteristic differences between two ground sites only in frozen conditions. According to the literature [23][24][25][26][27], soils and active layers in forested areas are distinctive from those in open areas by the thermal condition, active layer thickness, infiltration and evaporation rates, salinity and thickness of the shielding layer. Consequently, although the causal mechanisms about these characteristic scattering properties cannot be confirmed at this stage, polarimetric scattering analysis also reveals the possibility of obtaining a spatially-detailed distribution of the surficial features.…”

“…In this study, a small part of the area showing distinctive differences in the radar-derived spring transition date is selected for further investigation of microwave scattering properties. The permafrost characteristics in the Yakutsk area have been relatively well studied as compared to other high-latitude regions [23][24][25][26][27]. This region is covered with forests, grasslands and thermokarst features underlain by continuous permafrost.…”

“…According to the QuikScat snowmelt time product, the second PALSAR data were acquired about six days after the end of snowmelt. Since soil thawing starts as soon as snow disappears [27], it is possible to assume that the second PALSAR data (16 May) was acquired under thawed ground conditions. An optical image taken on a cloud-free day (8 September 2007) by the Landsat TM sensor is also obtained to support the interpretation of SAR data.…”

Effects of extreme drought and wet events for tree mortality: Insights from tree‐ring width and carbon isotope ratio in a Siberian larch forest

“…In this region, the August SWE usually has a greater influence on the tree-ring parameters than the June or July SWE (Tei, Sugimoto, Yonenobu, Hoshino, et al, 2013;Tei, Sugimoto, Yonenobu, Yamazaki, et al, 2013). In June, more water is usually available for plants because of infiltration of snowmelt water (Sugimoto et al, 2002Lopez et al, 2015), which then gradually decreases from July to August. Table 2).…”