My best friend Bo Ribbing and I were camping on the island of Gotland in the Baltic in anticipation of the total solar eclipse that was to take place on June 30, 1954. We had bicycled from Stockholm to Nynäshamn to take the overnight boat ride to Visby, the capital of Gotland. Not sure, but I think we arrived on Saturday June 26. We had planned to get supplies upon arrival, but all the stores were closed. The reason was Friday was Midsummer eve. Saturday was a holiday, and in those days holidays were holidays. We stopped by my uncle Folke who was vacationing in the city and he helped us out so we could start our bicycle trip around the island.
This was Bo’s first visit to Gotland, but thanks to many family visits to the island I knew it fairly well. As we bicycled south (totality would be longest at the southern tip) we stopped by the many medieval churches that dotted the countryside. They were built in the 1200s when the island was extremely wealthy thanks to its strategic location in the Baltic. The evening before the eclipse we camped near Burgsvik not far from Hoburgen, the southern tip of the island. My notebook tells me that when we woke up the next morning the sky was at first clear but soon became gray from horizon to horizon with altocumulus. Damn! But we decided nonetheless to bicycle to Hoburgen to check things out, we were likely to see a lot of people.
Amazingly, roughly an hour before totality the clouds evaporated, and the sky became clear. We stationed ourselves up on a cliff overlooking the Baltic to the west. As the eclipse advanced, it was striking how cold it became. We began to shiver – we weren’t dressed for this, only a week after summer solstice! It was striking how the bird life turned quiet as the light turned thinner and thinner. Although faint, it was light up until the very last moment when the eclipse became total. Then it turned dark, I mean it turned into night! Wow, what a change. I had my camera ready on a tripod and took several good pictures (sadly now lost). The eclipse lasted a couple of minutes, that’s all. But the sensation is so intense it stays with you for life. I tell anyone who will listen that if you have half a chance to see a total eclipse, don’t hesitate. The altocumulus clouds reappeared an hour later. The way they vanished before and then came back after the eclipse makes me imagine going to the theater where the curtains open for the show and close when it is over. What a show it was!
Addendum: We noticed high level cirrus clouds during Monday’s eclipse (reached 90%), but they were so thin they weren’t a problem at all. In reading the many accounts of the eclipse in the newspapers I noticed many entries talked about sunset conditions during totality. I haven’t seen any comments on this, but I assume this brightness on the horizon comes from illumination of high-level clouds outside the umbra. I certainly don’t recall a bright horizon during the eclipse I saw in Sweden. I am quite confident that there were no cirrus clouds prior to totality. Interestingly, cirrus clouds are excellent greenhouse clouds. They admit shortwave radiation (it got cold during the eclipse!) but tend to block longwave radiation.
The reason I bring this up is because much is being written about the exceptional warming that has been taking place in the last year and continuing this spring. Can the water vapor from the submarine Hunga Tonga–Hunga Haʻapai eruption last year be playing a role? Was any of the cirrus seen during the eclipse related to the eruption? Or more generally, is there a change in planetary albedo?