Hiroaki Kawase, Masayuki Hara, Takao Yoshikane,
Noriko Ishizaki, and Fujio Kimura, Japan Agency for Marine-Earth Science and
Technology, Japan
We focus on the dramatic
decrease in the snow cover on the Japan Sea side of Central Japan in the late
20th Century. The WRF-ARW model accurately simulated the interannual variation
of maximum snow depth (SNDmax) and the dramatic decrease in SNDmax between the
1980s and the 1990s. We then conducted a Pseudo Climate Simulation (PCS) in the
1990s, which assumes the mean atmospheric fields in the 1990s and the
perturbation from the mean atmospheric fields in the 1980s. The PCS method is
expected to evaluate the impacts of changes in the mean atmospheric fields on
the snow cover changes. The PCS simulates the decreases in SNDmax over the
coastal area, which are comparable to the changes in SNDmax simulated by the
hindcast experiment. On the other hand, the PCS simulates the slight decreases
in SNDmax over the mountainous area, where the slight increases in SNDmax are
simulated by the CTL. Therefore, the changes in the mean atmospheric fields are
main factors of the snow cover decrease over the coastal area, while both
changes in the mean atmospheric fields and the perturbation contribute to the
snow cover changes over the mountainous area.