Cherry Blossom & UHI

By Paul Homewood

 

This story comes around almost as regularly as the cherry blossom does!

 

 

 

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The cherry blossom season, Japan’s traditional sign of spring, has peaked at the earliest date since records began 1,200 years ago, research shows.

The 2021 season in the city of Kyoto peaked on 26 March, according to data collected by Osaka University.

Increasingly early flowerings in recent decades are likely to be as a result of climate change, scientists say.

The records from Kyoto go back to 812 AD in imperial court documents and diaries.

The city has experienced an unusually warm spring this year.

The previous record there was set in 1409, when the season reached its peak on 27 March.

Graphic of peak cherry blossom day in Kyoto from 812 to 2021

https://www.bbc.co.uk/news/world-asia-56574142

 

Apparently we are all supposed to be alarmed that cherry blossom arrived a day earlier this year than it did in 1409!

 

According to the BBC, “scientists” say that increasingly early flowerings in recent decades are likely to be as a result of climate change.

But real scientists know that urbanisation has made cities like Kyoto much warmer than they used to be. One Japanese study for instance found that urbanisation has added a “few degrees per century” to temperatures in large cities. UHI is also significant in slightly urbanised sites with much lower population density:

image.

https://www.deepdyve.com/lp/wiley/urban-warming-in-japanese-cities-and-its-relation-to-climate-change-mwdgTZUgxj

 

 

Not only is Kyoto a large city, it has massively expanded since pre-war, and from the point of view of buildings and infrastructure is now unrecognisable from those earlier days:

 

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https://en.wikipedia.org/wiki/Kyoto#Demographics

 

Cherry blossoms now bloom about one week earlier than in the 19thC, which equates to between one and two degrees Celsius.

 

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 https://rmets.onlinelibrary.wiley.com/doi/epdf/10.1002/joc.1594 

 

However, the author of the study referred to by the BBC, Yasuyuki Aono, found in an earlier study in 2007, that UHI accounted for 1.1C of the warming at Kyoto since 1940:

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Although he calculates that March temperatures have risen by 2.2C since 1826, after allowing for urbanisation, most of this actually occurred pre-1940. Aono does point out, by the way, that the 1820s marked one of the much colder periods, so some warming since is to  be expected.

image

 

 

When UHI is allowed for, it appears there is very little difference in cherry blooming times now and prior to the Little Ice Age:

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 https://rmets.onlinelibrary.wiley.com/doi/epdf/10.1002/joc.1594 

 

 

One again we find that the BBC has not told the whole story.

via NOT A LOT OF PEOPLE KNOW THAT

https://ift.tt/3ey5IFv

April 26, 2021 at 05:51AM

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