著者

Michiya Hayashi Hideo Shiogama

出版者

Meteorological Society of Japan

雑誌

SOLA (ISSN:13496476)

巻号頁・発行日

pp.2022-016, (Released:2022-03-28)

被引用文献数

4

---

The technique for composing a small subset of global climate models is critical to provide climate scenarios for impact and adaptation studies of regional climate changes. A recent study developed a novel statistical method for selecting a mini-ensemble of five climate models from the Coupled Model Intercomparison Project Phase 6 for widely capturing different future projections of Japanese climate across eight atmospheric variables at the surface. However, it remains unclear which mini-ensemble model contributes to efficiently covering the full projection ranges. Here, we rank each mini-ensemble projection around Japan among a full ensemble, showing that the selected five models capture the full ranges without systematic biases, except for relative humidity. Furthermore, we find that the widespread global warming level contributes to covering well the projection uncertainties in the daily-mean, maximum and minimum air temperatures and downward longwave radiation but not in precipitation, solar radiation, relative humidity, or wind speed. As the last four variables are sensitive to various factors, such as large-scale circulation and aerosol-forcing changes, rather than global-mean temperature changes, the model selection method featured here is preferable for capturing the wide future projection ranges in Japan.

著者

Michiya Hayashi Hideo Shiogama

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.96-103, 2022 (Released:2022-05-17)

参考文献数

47

被引用文献数

4

---

The technique for composing a small subset of global climate models is critical to provide climate scenarios for impact and adaptation studies of regional climate changes. A recent study developed a novel statistical method for selecting a mini-ensemble of five climate models from the Coupled Model Intercomparison Project Phase 6 for widely capturing different future projections of Japanese climate across eight atmospheric variables at the surface. However, it remains unclear which mini-ensemble model contributes to efficiently covering the full projection ranges. Here, we rank each mini-ensemble projection around Japan among a full ensemble, showing that the selected five models capture the full ranges without systematic biases, except for relative humidity. Furthermore, we find that the widespread global warming level contributes to covering well the projection uncertainties in the daily-mean, maximum and minimum air temperatures and downward longwave radiation but not in precipitation, solar radiation, relative humidity, or wind speed. As the last four variables are sensitive to various factors, such as large-scale circulation and aerosol-forcing changes, rather than global-mean temperature changes, the model selection method featured here is preferable for capturing the wide future projection ranges in Japan.

著者

Michiya Hayashi Masahiro Watanabe

出版者

(公社)日本気象学会

雑誌

SOLA (ISSN:13496476)

巻号頁・発行日

vol.12, pp.42-45, 2016 (Released:2016-02-25)

参考文献数

36

被引用文献数

1 2

---

Westerly (WWEs) and easterly (EWEs) wind events, short-lived anomalous westerly and easterly surface winds, are known to occur with unusual large magnitude over the equatorial Pacific. As their relative frequency of occurrence and dependence on background conditions are yet to be fully clarified, we analyzed daily surface winds for 1982-2013 from which WWEs and EWEs are detected. Both types of events appear over the Pacific warm pool, where sea surface temperature (SST) is sufficiently high for active deep convection, and favorably occur with increasing Niño4 SST. However, the frequency of occurrence of EWEs is less than that of WWEs, resulting in asymmetry in wind amplitude. Local and remote anomalous convections are equally important in exciting these events, but different local development processes cause the asymmetry in the frequency of occurrence. These results can also be seen in wind stress anomalies, albeit obscured due to nonlinearity therein.