Our understanding of the sun’s effect of Earth’s weather is so immature
Remarkably, some Japanese families kept weather record diaries in the 1700 and 1800s, and some for as long as 150 years. The connections they reveal are tantalizing but so incomplete. We are trying to fish out primitive signals from murky water. The Sun turns around on itself every 27 days, so these researchers are looking for repeating patterns in lightning that fit, but the poles of the sun spin slower than the equator and the sun spots can take their own time. Hence, it’s not a neat “27” days.
During periods of high solar activity, they found regular peaks in lightning activity with the right timing, from May to September when the cold Siberian air mass is not so influential.
Other studies we’ve discussed here have investigated long solar cycles on the 11 year or 200 year scales. But here, the researchers are thinking of day to day weather, and looking for a solar influence on timeframe that might improve weather forecasting. Obviously there is a long way to go. As for mechanisms they suspect that it’s the solar wind that is influential, but they don’t know, when sun spots peak there’s also an increase in ultraviolet rays and decrease in energetic particles.
In a paper last year they found the 27 day cycle in modern Japanese records from 1989-2015. Now they have found it in much older and longer records.
The Sun affects Earth in so many ways, through magnetic and electric fields, charged particles at Mach 2000, and wild swings in UV radiation. Climate models treat it as if it were just a ball of light. Imagine if we had spent $100 billion looking at solar influences on the climate. We might have models that worked….
From Miyahara 2017
How the sun’s rotation affects lightning activity: Records dating back to the 1700s reveal new clues on the nature of storms
Daily Mail
Diary entries dating back to the 1700s could help scientists understand the link between lightning activity on Earth, and the rotational cycle of the sun.
Researchers in Japan have turned to detailed logs kept by farm families and government officials hundreds of years ago, looking for mentions of thunder and lightning events. The study shows this activity lined up with the time it takes sunspots to make a complete rotation, suggesting the cycle plays a ‘very important role,’ in daily weather.
According to the team, this is the same window for a sunspot rotation, and was seen to be especially strong in years with a high number of sunspots.
“It is well known that long-term — centennial to millennial-scale — variations of solar activity influences terrestrial climate,” said Hiroko Miyahara, first author on the paper, and an associate professor of Humanities and Sciences/Museum Careers at Musashino Art University in Tokyo, Japan. “However, it is not well established whether the sun influences the daily or monthly weather.”
From the intro to the 2018 paper — this effect also occurs in England and possibly in tropical clouds:
Thunderstorm activity sometimes shows a period of approximately 27 days, which is comparable to the solar rotational period. The 27-day period has been detected in thunder and lightning activity, for example, in the records in England for AD 2000–2005 (Scott et al., 2014) and AD 2000–2007 (Owens et al., 2015) and in Japan for AD 1991–1992 and AD 1999–2001 (Muraki et al., 2004). A relatively longer record of thunder and lightning activity since AD 1989 in Japan has also shown a signal of solar rotational period near the maxima of the solar decadal cycle (Miyahara et al., 2017a). It has also been suggested that cloud activities in tropical areas had a similar periodicity at the solar cycle maxima during the period of AD 1980–2003 (Takahashi et al., 2010; Hong et al., 2011); this may also be related to the solar rotation. The amplitudes of the Schumann resonance, which are excited by lightning activity, also exhibit a solar rotational period.
The Mechanism?
The mechanisms for a solar influence on the climate and weather are not certain; however, possible explanations are given based on the forcing of solar radiation (Foukal, 2004, 2006; Hood, 1986; Shindell, 1999; Kodera and Kuroda, 2002; Zhou and Tung, 2013), galactic cosmic rays (Svensmark and Friis-Christensen, 1997; Marsh and Svensmark, 2000; Yamaguchi et al., 2010; Svensmark et al., 2016), solar energetic particles (Jackman et al., 2009; Scott et al., 2014), and from the changes in the atmospheric electric circuit (Tinsley, 1996; Owens et al., 2015). The variations of solar-related parameters associated with solar rotations are quasi-periodic. For example, solar radiative outputs vary in time with a period of 24–31 days due to the migration of sunspots and faculae on the solar surface. Due to the occurrence of coronal mass ejections or the passage of co-rotating interaction regions on Earth, the flux of galactic cosmic rays shows an anomaly of a few days every 26–31 days.
Give that these are daily weather records from so long ago, it is impressive they can find any pattern. Modern records electronically record thunderclaps so these older records will not have anything like that rigor.
(c) Periodicity of lightning during solar maxima. (d) Same but for solar minima. Again from the 2017 paper.
Both papers are freely available.
REFERENCES
- Hiroko Miyahara, Ryuho Kataoka, Takehiko Mikami, Masumi Zaiki, Junpei Hirano, Minoru Yoshimura, Yasuyuki Aono, Kiyomi Iwahashi. (2018) Solar rotational cycle in lightning activity in Japan during the 18–19th centuries. Annales Geophysicae, 2018; 36 (2): 633 DOI: 10.5194/angeo-36-633-2018
- Hiroko Miyahara1 , Yasuyuki Aono2 , and Ryuho Kataoka3 (2017) Searching for the 27-day solar rotational cycle in lightning events recorded in old diaries in Kyoto from the 17th to 18th century, Ann. Geophys., 36, 633–640, 2018 https://doi.org/10.5194/angeo-36-633-2018