- E_ACG38-P09 -
[A-CG38]
[ACG38-P09]
©Japan Geoscience Union 
Japan Geoscience Union Japan Geoscience Union Meeting 2018 
[EJ] Evening  Poster | A (Atmospheric and Hydrospheric Sciences) | A-CG Complex & General
Science in the Arctic Region
convener:Shun Tsutaki(The University of Tokyo), NAOYA KANNA(Arctic Research Center, Hokkaido
University), Shunsuke Tei(北海道大学 北極域研究センター, 共同), Tetsu Nakamura(Faculty of Environmental
Earth Science, Hokkaido University)Thu. May 24, 2018 5:15 PM - 6:30 PM  Poster Hall (International Exhibition Hall7, Makuhari Messe)
The Arctic and circumpolar region is the key area for the study of global change because the anthropogenic
impact is projected to be the largest in this area due to the complicated feedback processes of the nature. A
number of international and interdisciplinary research projects have been conducted for the studies on the
land-atmosphere-ocean system. In order to understand the feedback processes occurring in the Arctic and to
project the global warming in the future, we need to establish the intense observational network and to
exchange the knowledge and information by combining the different scientific communities under the
common interest of the Arctic. The objectives of this session are 1) to exchange our knowledge on the
observational facts and integrated modelling and 2) to deepen our understanding on wide range of natural
sciences related to the Arctic and the circumpolar region. Studies on humanities, social sciences, and
interdisciplinary fields are also welcomed. 
Variation of seasonal thaw depth at permafrost larch forest
in eastern Siberia
*Ayumi Kotani1, Takeshi Ohta1, Tetsuya Hiyama2, Taro Nakai2, Yoshihiro Iijima3, Trofim Maximov4 (1.Graduate
School of Bioagricultural Sciences, Nagoya University, 2.Institute for Space-Earth Environmental Research,
Nagoya University, 3.Graduate School of Bioresources, Mie University, 4.Institute for Biological Problems of
Chryolithozone, SB RAS)
Keywords:seasonal thaw depth, larch forest, soil water 
This study investigated temporal and spatial variability of seasonal thaw depth at larch-dominated forests in
the middle part of the Lena basin, eastern Siberia. We compared temporal and spatial variability of thaw
depth at two larch-dominated forests mixed with birch and willow, in the southern and middle parts of the
Lena basin. Difference in precipitation both of rain and snow and soil properties such as soil texture relate to
difference in seasonal thawing speed and soil water content of the two forests. Field measurements of thaw
depth using handheld dynamic cone penetrometer were repeated in each site in June&ndash;July (first half
of summer) and September (before soil freezing). Although averages of thaw depth observed in the same
season was not differ, their spatial variability showed contrast in two sites. Thaw depth relates to vertical
mean penetration resistance in summer, while it relates to upper canopy and floor plant coverage in autumn
observation.