04/06/2026
【研究室セミナーのお知らせ】Seminar (16:30-, Jun. 4, C204-1)
1. Haruka Kobayashi
Title: Paper review of “Predictability of Heavy Snowfall Days in Western Hokkaido from JMA Operational 1-Month Ensemble Predictions Using Self-Organizing Maps”.
2. Mai Nakazawa
Title: Overview of Pyrocumulonimbus (PyroCb) Research
3. Yuji Oda
Title: Investigating the temporal evolution of the structure of polar mesocyclones using the cyclone phase space
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1. Haruka Kobayashi
Title: Paper review of “Predictability of Heavy Snowfall Days in Western Hokkaido from JMA Operational 1-Month Ensemble Predictions Using Self-Organizing Maps”.
Abstract: Providing accurate, long-lead heavy snowfall forecasts is crucial, but sub-seasonal prediction of these events remains challenging. This study investigated the sub-seasonal predictability of heavy snowfall events in Iwamizawa, Hokkaido, using the JMA’s 1-month ensemble predictions and the self-organizing map (SOM) technique. By identifying multiple weather patterns and projecting them onto the prediction model, forecast accuracy was improved up to approximately 10 days for both the 2019 and 2020 winters. These results highlight the potential benefit of incorporating multiple weather patterns to forecast heavy snowfall.
[Paper Information]
Kawazoe, S. and Inatsu, M., 2022: Predictability of Heavy Snowfall Days in Western Hokkaido from JMA Operational 1-Month Ensemble Predictions Using Self-Organizing Maps. SOLA, 18, 147-153, DOI:10.2151/sola.2022-024
2. Mai Nakazawa
Title: Overview of Pyrocumulonimbus (PyroCb) Research
Abstract: While studying fire whirls associated with wildfires, I became interested in the phenomenon known as pyrocumulonimbus (PyroCb). PyroCb is a cumulonimbus cloud generated by intense wildfire activity and is known to produce various hazardous phenomena, including rapid fire spread, downbursts, lightning-induced new fires, hail, and fire tornadoes. In addition, PyroCb can transport large amounts of smoke and aerosols from the upper troposphere into the lower stratosphere, potentially causing large-scale smoke transport and climatic impacts. I was attracted to this topic because PyroCb research is a relatively new field with many unresolved questions. This presentation begins with the introduction of the formation processes of PyroCb, followed by the review of PyroCb researches from early satellite-based observational studies to recent machine learning approaches for prediction.
3. Yuji Oda
Title: Investigating the temporal evolution of the structure of polar mesocyclones using the cyclone phase space
Abstract: Polar mesocyclones developing over the sea west of Hokkaido occasionally cause severe snowfall, such as a 24-hour snowfall total of 53 cm, the largest on record for January, observed from 24 to 25 January 2026. These mesocyclones exhibit a variety of physical structures, and thus their development mechanisms are complex. This study focuses on a case in January 2024 to investigate the structural evolution of a polar mesocyclone using cyclone phase space analysis. The results suggest that the structure of the polar mesocyclone may evolve from an extratropical-cyclone-like structure to a tropical-cyclone-like structure during its lifetime. Given that SST in the Sea of Japan has increased in recent years, future work is expected to investigate how SST affects the structure of polar mesocyclones through the analysis of more cases.
