Wednesday, October 2, 2019

New Paper on Japan's "Gosetsu Chitai"

Sento Nakai and I have a new paper out in the Bulletin of the American Meteorological Society examining the remarkable snow climate on the Japanese Islands of Honshu and Hokkaido near the Sea of Japan.  The paper, entitled Perspectives on Sea- and Lake-Effect Precipitation from Japan's "Gosetsu Chitai", is available in early online release (click here), which is a preliminary version made available by the journal while they are preparing it for publication.  Gosetsu Chitai translates to heavy snow region. 

Sento is an atmospheric scientist at the Snow and Ice Research Center in Nagaoka, Japan, which is operated by the Japanese National Research Institute for Earth Science and Disaster Resilience.  One of the great things about science is having the opportunity to collaborate with people from all over the world, and we have really enjoyed working with Sento and his colleagues. 

Yours truly (left), Sento Nakai (center), and Peter Veals (right) in the mountains above Nagaoka.
I have had a "thing" for Japanese snow for some time.  Early in my career, to help prepare for the 2002 Olympic Winter Games, I traveled to Nagano to learn about weather support for the 1998 Olympic Winter Games.  During that same period, we were conducting research on lake effect generated by the Great Salt Lake.  Much of what I knew about lake effect at the time was based on studies of the Great Lakes of North America, but I learned quickly that there was a rich Japanese literature examining sea-effect precipitation generated by the Sea of Japan.  Not only was this work very applicable to lake effect in North America, it was also very applicable to Utah where lake effect, like sea effect in Japan, interacts with major topographic barriers.  I've also been told there is good skiing in Japan ;-).

Ski touring in the Hida Mountains, Honshu, Japan
Collaborations between Japanese and North American scientists to study sea- and lake-effect precipitation (they are essentially the same phenomenon generated by the flow of cold air over a warm water body) have, however, been historically limited.  Thus, our objectives in writing the article were to expose North American meteorologists to the remarkable snow climate of Japan and encourage greater collaboration in the study of sea- and lake-effect precipitation.  It is a review article written for a broad meteorological audience that synthesizes and describes prior research rather than presenting new material.

Readers of this blog might be most interested in the figure below, which summarizes the climatology in the Sea of Japan region using precipitation observations [liquid precipitation equivalent (LPE) and/or snowfall) from observing sites in Korea, Russia, and Japan.  Japan's remarkable snow climate is driven by frequent cold air outbreaks over the Sea of Japan during the East Asian Winter Monsoon.  Although winter is quite dry in mainland Asia, these outbreaks, which occur most frequently from December to February, result in a very pronounced maximum in snowfall in mean monthly snowfall in January at sites on the Japanese Islands of Honshu and Hokkaido near the Sea of Japan.

Source: Steenburgh and Nakai (2019)
Although Hokkaido has a huge reputation for powder, it snows a ton on Honshu as well.  At Tsunan in the Echigo Mountains of central Honshu, the mean annual snowfall is 1349 cm (531 inches), with a monthly maximum of 443 cm (174 inches) in January.  Let me repeat that.  The mean monthly snowfall in January is 174 inches! Further north, Sukayu Onsen in the Hakkoda Mountains of northern Honshu has a mean annual snowfall of 1764 cm (694 inches), including a peak of 459 cm (180 inches) in January.   This is why I say there is no surer bet for deep powder skiing than the mountains of Honshu and Hokkaido near the Sea of Japan in January. 

Just another January day in the mountains of Honshu near the Sea of Japan.
To put those numbers into perspective, the mean monthly snowfall at Alta in January is 83 inches.  

If you are so inclined, I hope you enjoy the read. 

1 comment:

  1. Thanks for the paper Jim, good read. It was interesting to hear that they can receive a lot of graupel in mid-winter especially closer to the coast. I doubt I'll ever go, but if I do I'd tour more inland. I've seen surprisingly wide slab propagations of quite soft slab densities with warm heavy storms and graupel.