雪氷チーム

Snow and Ice Research Team

気象変動の影響による雪氷環境の変化に関する研究
Changes in Snow and Ice Environments Associated with Climate Change
地球規模の温暖化の影響により、日本国内の降積雪や気温の変動が予測されています。積雪寒冷地では、暖冬による少雪傾向、降雪の少ないとされてきた地域への大雪、局地的な豪雪など、今までとは異なった姿が想定されます。本研究では、近年の雪氷環境の変化傾向について調査を行っています。
Global warming is forecasted to drastically alter snowfall and temperature trends in Japan. The cold, snowy
regions of this country are expected to have winters with unprecedented changes, such as warm winters withlittle snowfall, heavy snowfall in areas that have typically had little snowfall, and localized intense snowfall.
This study surveys the trends in the snow and ice environments for recent years.

2008年4月1〜2日に発生した北海道東部での災害
Snow disaster in Eastern Hokkaido on April 1 and 2, 2008

近年の降雪・積雪の変動傾向
Changes in snowfall and snow cover in recent years

新潟県以北のアメダス141箇所を対象に、調査期間(1983〜2008年度、11月〜4月）における各冬期の最深積雪や累積降雪量の変化傾向を調べました。冬期の最深積雪は、北海道では日本海側の小樽以北、内陸部、オホー
ツク海側および太平洋側東部で、本州では北部太平洋側で増加傾向にあります。
冬期累積降雪量は、対象地域の大部分で減少傾向にあります。

（cm/ 冬期）(cm/winter)

The trends of change in the seasonal maximum snow depth and the seasonal
snowfall from November to April in the years 1983 to 2008 were surveyed using thedata from 141 AMeDAS stations in Northern Japan, including stations in Niigata
Prefecture. Areas with increasing seasonal maximum snow depth are found in
Hokkaido and Honshu: Those in Hokkaido include the northern part of the JapanSea coast, including Otaru; the inland areas; areas on the Okhotsk coast; and thePacific east coast areas. The areas in Honshu are on the Pacific northern coast. Theseasonal snowfall has tended to decrease in most of the surveyed areas.

（cm/ 冬期）(cm/winter)

増加
Increasing

増加
Increasing

減少
Decreasing

減少
Decreasing▲最深積雪の変化傾向

Trends of change in seasonal maximum snow depth▲冬期累積降雪量の変化傾向

Trends of change in seasonal snowfall

近年の大雪や暴風雪時の低気圧の位置と移動経路について

The locations and routes of low-pressure systems at the time of heavy snowfall events and snowstorms in recent years
1985〜2014年度冬期において、北海道で発生した大雪および暴風雪時の地上天気図に着目し、低気圧や前線の移動経路、気圧配置について特長を調べました。
その結果、下の表に示すA〜Dの4パターンが、全事例の約60%を占める事が分かりました。
（右図）
A〜Dそれぞれのパターンについて10冬期ごとの出現頻度を求め、表にしました。数字は出現頻度を示しています。
なお、括弧内の数字は北海道付近で急速に発達した低気圧（24時間で中心気圧が19hPaより低下）によるものを意味しています。
近年の特長として、二つの低気圧が北海道付近で一つになり、急激に発達するパターン（パターンD）が増加する傾向がある事が分かりました。
（下表）
The characteristics of the locations and routes of low-pressure areas and their fronts,
and pressure patterns were investigated by referring to surface weather charts at thetime of heavy snowfall and snowstorms in Hokkaido from FY 1985 to the winter of
FY 2014. It was found that about 60% of the cases fall under the patterns of A to D
shown below. (Figure at right)
The occurrence frequency for each pattern (A to D) for 10 winters was obtained andis shown in the table.The numbers show the occurrence frequencies. Parentheses
indicate the occurrence of a low-pressure system that rapidly developed (thepressure at the center decreased by 19 hPa or more in 24 hours) near Hokkaido.
It was found that one characteristic pattern, Pattern D, has tended to increase inrecent years. In Pattern D, two low-pressure systems combine near Hokkaido andrapidly develop. (Table below)
期間Period低気圧

Low-pressure system

天気図パターン
Weather chart pattern1985

1995

2005

1994

2004

2014

||

|

計
Total

A

津軽海峡を通過 Passes over the Tsugaru Strait.

3(1)

6(3)

0(0)

9(4)

B

三陸沖を北東進 Moves northeast-ward off the coast of Sanriku.

5(1)

3(1)

4(2)

12(4)

C

二つ玉各々通過 Two low-pressure areas pass.

3(3)

4(3)

5(2)

12(8)

D

二つ玉併合

3(2)

5(2)

11(7)

19(11)

14(7)

18(9)

20(11)

52(27)

Two low-pressure areas combine.
計Total▲大雪や暴風雪の発生頻度

B低低

低気圧が日本海中部から東進して津軽海峡を通過

低気圧が三陸沖を北東進する

A low-pressure system moves eastward from the central
Japan Sea and passes over the Tsugaru Strait.

A low-pressure system moves northeast-ward off
the coast of Sanriku.

CD低低低低二つ玉低気圧が北海道を挟むように北東進

二つ玉低気圧の一方が他方の低気圧に吸収

Two low-pressure systems move northeast-ward on
both sides of Hokkaido.

One of the two low-pressure systems isabsorbed by the other.

▲大雪や暴風雪をもたらしやすい低気圧のパターン
Patterns of low-pressure systems that tend to result in heavy snowfall or snowstorms

Frequency of heavy snowfalls and snowstorms (for each 10 winters)

安全・快適A

北の道Safe, pleasant driving on Northern Roads

国立研究開発法人土木研究所 寒地土木研究所

National Research and Development Agency Public Works Research Institute Civil Engineering Research Institute for Cold Region

Low-pressure system