[M-ZZ48] Renewable energy and earth science

[MZZ48-P07] Climatology of Dark Doldrums in Japan

*Masamichi Ohba¹, Yuki Kanno¹, Daisuke Nohara¹ (1.Central Research Institute of Electric Power Industry)

Keywords:Variable renewable energy, Dark doldrums, Self-organizing maps, Synoptic circulation, Energy transition, Windless-Sunless

“Windless and sunless” weather durations, so-called “dark doldrums,” can cause energy supply disruptions when the penetration of variable renewable energy (wind and solar) is high. Dark doldrums, defined as periods during which the sum of solar and wind power is less than 10% of the rated output capacity, are most common during the summers in East Japan. This study investigated the synoptic-scale summer weather patterns associated with dark doldrums by applying self-organizing maps to characterize atmospheric circulations using surface wind data derived from atmospheric reanalysis data over the Tohoku region of Japan. Frequent occurrences of dark doldrums were linked to four typical weather patterns associated with the enhancement of the monsoon rain front and the Okhotsk high-pressure system. The frequency of dark doldrum events also showed considerable interannual variability that is strongly connected to climate variations in the tropical Indo-western Pacific. Further research on climate variability and its relationship with dark doldrums in East Asia is warranted.