The oldest records of lake ice

[ArcticMelt]

In 1442, Shinto priests in Japan began keeping records of the freeze dates of a nearby lake. Together they create the oldest inland water ice records in human history and mark the first inklings of climate change, says a new report published today out of York University and the University of Wisconsin. In recent years, says Magnuson, both waters have also exhibited more extreme ice dates corresponding with increased warming. For Lake Suwa, that means more years without full ice cover even occurring. Before the Industrial Revolution, Lake Suwa froze over 99 per cent of the time. More recently, it does so only half the time.

The records from Lake Suwa in the Japanese Alps, says Sharma, were collected by Shinto priests observing a legend about a male god who crossed the frozen lake to visit a female god at her shrine.

For example, the study found that, from 1443 to 1683, Lake Suwa's annual freeze date was moving almost imperceptibly to later in the year -- at a rate of 0.19 days per decade. From the start of the Industrial Revolution, however, that trend in a later freeze date grew 24 times faster, pushing the lake's "ice on" date back 4.6 days per decade.

Extreme weather events have also become more common. In the first 250 years, the Shinto priests recorded, there were only three years when the lake did not freeze. Between 1955 and 2004, there 12 years when the lake didn’t freeze. Between 2005 and 2014, there were five.

https://www.sciencedaily.com/releases/2016/04/160426110653.htm

http://www.zmescience.com/ecology/climate/climate-change-japanese-monks/

http://www.nature.com/articles/srep25061

https://nsidc.org/data/docs/noaa/g01377_lake_river_ice/

http://www.city.suwa.lg.jp/scm/dat/special/omiwatari/index.htm#3

Winter seasons without ice on Lake Suwa after 1443:

1546-1547, 1555-1556, 1671-1672, 1701-1702, 1724-1725, 1734-1735, 1737-1738, 1739-1740, 1759-1760, 1770-1771, 1793-1794, 1800-1801, 1804-1805, 1842-1843, 1844-1845, 1853-1854, 1865-1866, 1866-1867, 1867-1868, 1868-1869, 1879-1880, 1889-1890, 1915-1916, 1932-1933, 1948-1949, 1971-1972, 1978-1979, 1986-1987, 1988-1989, 1991-1992, 1992-1993, 1993-1994, 1994-1995, 1999-2000, 2001-2002, 2004-2005, 2006-2007, 2008-2009, 2009-2010, 2010-2011, 2013-2014, 2014-2015, 2015-2016.

News about the freezing lake in the current winter yet.

Percentage winters without ice in different centuries:

15th century - no winter without ice among the observed 57 years - <1%
16th century - two winters without ice - 2%
17th century - оnly one winter without ice - 1%
18th century - 8 winters without ice - 8%
19th century - 11 winters without ice - 11%
20th century - 12 winters without ice - 12%
21th century - 9 winters without ice among the observed оnly 16 years - 56% (!!!)

The rate of climate change in the 21st century is amazing.

[DrTskoul]

Thanks for the information Arctic Melt!!

[Tor Bejnar]

Do you know about Lake E?

Analysis of lake ice dynamics and morphology on Lake El’gygytgyn, NE Siberia, using synthetic aperture radar (SAR) and Landsat (Nolan, et.al., 2002)

Section 1.2 - Prior Research: Lake El’gygytgyn’s Climate Record and the Significance of Lake Ice - indicates evidence of changing lake ice coverage over some 300,000 years. (Subsequent studies have, I'm sure, looked at the rest of the 3.6 million years recorded by sediment cores drilled in 2008 and '09).

(I'm nonetheless impressed by those Shinto priests maintaining data since 1442.)

[budmantis]

Thanks Arctic Melt for the information. Question on the breakup graph; That spike in the early 16th century sticks out like a sore thumb, it seems to be too large a variance to be taken seriously.

[ArcticMelt]

That spike in the early 16th century sticks out like a sore thumb, it seems to be too large a variance to be taken seriously.

Maybe this is a very rare case of a cold spring. In another study, other abnormal date (about 1600) is also believed to be accurate, but doubts about the records of 18-19 centuries.

http://www.nature.com/articles/srep25061

Quotes from the article to the attached picture:

(A, ice freeze). Black dots indicate ice dates. Solid black lines indicate the best fit line of mean ice dates, and solid blue lines bound the 95% confidence interval around the estimated means. For Suwa (A), black dots with white centers indicate years when the lake did not freeze and gray points indicate years where the ice dates were considered unreliable (please see Methods for details).
...

Ice-freeze dates for Suwa were first recorded in 1443. Ice freeze date, defined as the first date of complete cover, was decided by observers from the shoreline. The name of the family observing ice freeze is provided, although the unique name of the observer is not given but would have included at least 15 generations of observers16. The Shinto Shrine also reported the Omiwatari date of ice ridge formation . Fujiwhara14 wrote that of the various ice phenomena recorded by the Shinto Shrine, first complete ice cover was the most robust14,16. Unfortunately, there are missing data in the midyears of the time series (1505–1515) and more importantly, data from 1682–83 to 1922–23 are considered unreliable for analysis ice cover freeze dates14,16,43,56. In those middle years, various changes in the calendar confused the record, ice cover dates often were indicated as approximate or were not provided even though the lake did freeze over, the group making the observations varied, and Omiwatari date or even the Omiwartari ceremony often were substituted for the ice cover date. We eliminated all data from 1682–1923 from the analyses to reduce the uncertainty in dates of ice freeze14,16,43,56.

...
However, the ice-freeze date between 1443–1682 and 1924–2014, in addition to the presence or absence of lake freeze from 1443–2014 are considered to be very reliable14,16,43,56.

The most reliable for years without ice.

[ArcticMelt]

Picture number of years without ice from the same work:

Figure 2. Proportion of extreme warm events over time as indicated by ice dates. In Suwa (A, black), a year was extreme if the lake did not freeze.