世界の年平均気温の偏差の経年変化 meaning


I was reading the global warming article on the Japanese wikipedia and got
stuck on this phrase

> 世界の年平均気温の偏差の経年変化

I looked up the last two words individually, which lead me to an
interpretation of: 'world change [i.e. increase] of average temperature
deviation over the years'. Is this correct?

I think, from what I've understood in my previous reading, temperature
deviation is the difference from a baseline average temperature [pre-1950's
from memory]. But as this is the first time I've encountered 偏差 and 経年変化, I'm
worried I might be jumping the gun.

Any help would be appreciated. Thanks :-)

Edit: I found out later the baseline temperature is the 1981-2010 average, not
that of 1891-1950, as I originally presumed. The caption in the article
doesn't explicitly identify this average, which led to a lot of confusion on
my part. It would have been helpful if the Japanese article didn't leave this
information out.




> [①世界]の[②年平均気温]の[③偏差]の[④経年変化]

Just reverse the order and you can get the basic literal translation:

> [④annual change] of [③the deviation] of [②the annual average temperature] of
> [①the world]

Technical phrases can usually be translated rather literally. I don't think
"world change" is a good translation although it may mean something.

偏差 roughly means "some difference from some representative value (mean,
median, mode, etc) of the population". It's often a shorter synonym for 標準偏差
([standard deviation](https://en.wikipedia.org/wiki/Standard_deviation)), but
it can be a simple arithmetic difference from some average value. If you are
seeing [this](http://www.data.jma.go.jp/cpdinfo/temp/an_wld.html), the
"difference" is simple arithmetic difference, and the baseline "representative
value" is "世界の年平均気温の1981〜2010年平均", the mean of the world temperature in
1981-2010.

経年変化 is just ~~"annual change"~~ "change over the years".




> [①世界]の[②年平均気温]の[③偏差]の[④経年変化]

Just reverse the order and you can get the basic literal translation:

> [④annual change] of [③the deviation] of [②the annual average temperature] of
> [①the world]

Technical phrases can usually be translated rather literally. I don't think
"world change" is a good translation although it may mean something.

偏差 roughly means "some difference from some representative value (mean,
median, mode, etc) of the population". It's often a shorter synonym for 標準偏差
([standard deviation](https://en.wikipedia.org/wiki/Standard_deviation)), but
it can be a simple arithmetic difference from some average value. If you are
seeing [this](http://www.data.jma.go.jp/cpdinfo/temp/an_wld.html), the
"difference" is simple arithmetic difference, and the baseline "representative
value" is "世界の年平均気温の1981〜2010年平均", the mean of the world temperature in
1981-2010.

経年変化 is just ~~"annual change"~~ "change over the years".

