Smithsonian had an interesting article this week on a long-term source of proxy climate data that was collected by Japanese priests monitoring the ice conditions on Lake Suwa. As the lake froze each year, the priests recorded the time of development and the orientation of a ridge of ice that built up as the lake froze. In the days before the Industrial Revolution, the lake froze almost every year. Now, the lake freezes later and in some years it does not freeze at all, including five of the last ten. The data are called proxy because they don’t provide a direct instrumental record of the temperature and precipitation, but show variations in temperature by integrating the effects of the cooler or warmer seasons over time as the lake ice develops.
This is similar to lake freeze records that I kept when I was the Wisconsin State Climatologist in Madison, WI, a city surrounded by lakes. You can read the details of this proxy data collection at https://www.smithsonianmag.com/smart-news/japanese-priests-collected-almost-seven-centuries-climate-data-180958929/?utm_source=facebook.com&no-ist.
