著者

Sho Kawazoe Masaru Inatsu Tomohito J. Yamada Tsuyoshi Hoshino

出版者

Meteorological Society of Japan

雑誌

SOLA (ISSN:13496476)

巻号頁・発行日

pp.2020-039, (Released:2020-10-28)

被引用文献数

11

---

Synoptic circulation patterns associated with heavy snowfall events in Sapporo are examined using large ensemble simulation with 60-km global climate experiments. For snowfall, a 5-km dynamically downscaled model from the 20-km regional simulation is utilized. To identify synoptic circulation patterns, self-organizing maps (SOMs) are applied, and their response to a warming climate is examined. The authors find that heavy snow events predominantly occur due to low pressure anomalies to the north/east of Hokkaido or over central Japan, and by high pressure anomalies over the Siberian continent. The 4 K warming climate shows robust decreases in heavy snowfall amounts associated with low pressure anomalies over central Japan and increases in heavy snowfall amounts under patterns with high pressure anomalies over Siberia. This is attributed to surface air temperature characteristics in future climates, as precipitation in the former with surface winds transporting warm, moist air from the south and east, develops predominantly above 0°C in the +4 K climate, while the latter, often resulting in intense snow band events, continues to be dominated by temperatures near or below zero.

著者

Yuka Kanamori Masaru Inatsu Ryoichi Tsurumaki Naoki Matsuoka Tsuyoshi Hoshino Tomohito J. Yamada

出版者

公益社団法人 日本気象学会

雑誌

SOLA (ISSN:13496476)

巻号頁・発行日

vol.18, pp.249-253, 2022 (Released:2022-11-26)

参考文献数

23

被引用文献数

1

---

A set of hydrological experiments for a flooding event on 11 September 2014 at Motsukisamu River in Sapporo were performed. Dynamical downscaling to 5-km resolution of a large-ensemble global simulation allowed us to estimate that a 99%-tile hourly precipitation in Sapporo would increase by 70% in a future climate, when the global-mean temperature increases by 4 K compared with the present climate. After developing a three-tank model of which parameters were optimized on the basis of the in-situ observation at the Motsukisamu River during the event period, the model was forced by hypothetical hyetographs of the event that would occur under the future climate. The results of this experiment suggested that the peak flow rate would increase by 75%. However, it was also revealed that an upstream aqueduct tunnel, just completed in autumn 2021, would effectively reduce the peak flow rate and mitigate the flooding risk even in extreme precipitation under the future climate.

著者

Yuka Kanamori Masaru Inatsu Ryoichi Tsurumaki Naoki Matsuoka Tsuyoshi Hoshino Tomohito J. Yamada

出版者

公益社団法人 日本気象学会

雑誌

SOLA (ISSN:13496476)

巻号頁・発行日

pp.2022-040, (Released:2022-11-11)

被引用文献数

1

---

A set of hydrological experiments for a flooding event on September 11, 2014 at Motsukisamu River in Sapporo were performed. Dynamical downscaling to 5-km resolution of a large-ensemble global simulation allowed us to estimate that a 99%-tile hourly precipitation in Sapporo would increase by 70% in a future climate, when the global-mean temperature increases by 4 K compared with the present climate. After developing a three-tank model of which parameters were optimized on the basis of the in-situ observation at the Motsukisamu River during the event period, the model was forced by hypothetical hyetographs of the event that would occur under the future climate. The results of this experiment suggested that the peak flow rate would increase by 75%. However, it was also revealed that an upstream aqueduct tunnel, just completed in autumn 2021, would effectively reduce the peak flow rate and mitigate the flooding risk even in extreme precipitation under the future climate.

著者

Sho Kawazoe Masaru Inatsu Tomohito J. Yamada Tsuyoshi Hoshino

出版者

Meteorological Society of Japan

雑誌

SOLA (ISSN:13496476)

巻号頁・発行日

vol.16, pp.233-239, 2020 (Released:2020-12-05)

参考文献数

30

被引用文献数

11

---

Synoptic circulation patterns associated with heavy snowfall events in Sapporo are examined using large ensemble simulation with 60-km global climate experiments. For snowfall, a 5-km dynamically downscaled model from the 20-km regional simulation is utilized. To identify synoptic circulation patterns, self-organizing maps (SOMs) are applied, and their response to a warming climate is examined. The authors find that heavy snow events predominantly occur due to low pressure anomalies to the north/east of Hokkaido or over central Japan, and by high pressure anomalies over the Siberian continent. The 4 K warming climate shows robust decreases in heavy snowfall amounts associated with low pressure anomalies over central Japan and increases in heavy snowfall amounts under patterns with high pressure anomalies over Siberia. This is attributed to surface air temperature characteristics in future climates, as precipitation in the former with surface winds transporting warm, moist air from the south and east, develops predominantly above 0°C in the +4 K climate, while the latter, often resulting in intense snow band events, continues to be dominated by temperatures near or below zero.