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Sunshine Increasing Across All Seasons In England

April 6, 2015

By Paul Homewood

 

I want to take a closer look at the trend in sunshine hours, this time on a seasonal basis. I am using the Met Office data for England only, as this is where one would expect the effect of industrial pollution to be greatest. It is also apparent that this is the part of the UK where there has been a significant increase in sunshine in recent decades.

For instance, let us compare England & Scotland.

 

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http://www.metoffice.gov.uk/climate/uk/summaries/actualmonthly

 

To analyse trends, I have compared decadal totals since 1930, when records began.

 

 

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http://www.metoffice.gov.uk/climate/uk/summaries/datasets

 

Across all seasons, sunshine hours have been consistently greater since 1990, than in earlier decades, particularly in the 1960’s. The least change seems to have occurred in winter months, and the greatest in spring.

 

We can also look at how sunshine hours correlate with mean temperatures. Perhaps counter intuitively, even in winter there is a positive correlation, albeit a weaker one, between sunshine and temperature. (Perhaps, we should think back to those cold, dank foggy days!)

Unsurprisingly, the strongest correlation is in summer, where a doubling of sunshine hours appears to equate to an increase in mean temperature of nearly 3C. Sunshine hours also seem to have a bigger effect on temperatures in spring, as opposed to autumn. Again, this should not be surprising, as the sun is higher in the sky in April/May than it is in October/November.

 

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http://www.metoffice.gov.uk/climate/uk/summaries/datasets

 

 

We therefore have clear evidence that there has been a significant increase in sunshine hours in the last two or three decades, and a clear correlation between that increase and higher temperatures.

Whatever the cause of the extra sunshine, it seems we have an explanation for at least part of the warming since in England during this period.

10 Comments
  1. Bloke down the pub permalink
    April 7, 2015 10:30 am

    From observing the output from my solar panels, I’ve noticed a significant increase while the sun is shining on a showery day as compared to a ‘clear’ day. While the overall production on clear days will be higher, the peaks attained during the gaps between showers are about 25% above the norm. Is the air in spring likely to be clearer and therefore more responsive to sunshine induced temperature rise?

    • April 7, 2015 10:53 am

      Possible answer -Likely showery days are associated with a westerly airflow and low pressure systems. Continuously sunny days more likely in anticyclones / continental airflows. Ever tried taking landscape pics in anticyclonic weather?
      (assumes you are in UK)

    • fjughuh permalink
      August 11, 2015 11:44 pm

      solar output increased on showery days due to reflection with the clouds. by the way, your comment appears to note that the april showers saying works. it rains any time of the year in the uk, showers are actually most common in autumn. spring is the driest season!

  2. A C Osborn permalink
    April 7, 2015 12:48 pm

    I don’t think sunshine “hours” will be linked very strongly with clearer air, but the power of the sun watts/m squared should be.
    Sunshine hours should be allied to Cloud cover and I don’t think it will just be the UK that shows the same thing.

  3. john cooknell permalink
    April 7, 2015 7:36 pm

    Paul,

    I support your view, but my view is increasing sunshine will remain unstudied, in the Climate Science field, unless you can link this to the current consensus of all weather trends are caused by increasing CO2.

    Also the sunshine hours figures you are using come from the Met Office, and they have been adjusted and homogenised from the raw data.

    The main reason for the adjustments to the raw data is that instrumentation for measuring sunshine hours has changed significantly during the timeframe of the record. Older measurements were taken by scorching a paper roll.

    Reading University are looking at these things.

    http://centaur.reading.ac.uk/18649/

  4. marchesarosa permalink
    April 9, 2015 10:55 am

    By a happy coincidence, the TV show Quizeum, which I saw for the first time last night, featured a sunshine hours measurement device from the Greenwich Maritime museum – a very large solid glass sphere/lens which concentrates the suns rays. When the intensity exceeds a pre-determined threshold, the heat burns a line on a piece of tape. The length of the line corresponds to the hours of sunshine. How clever! http://en.wikipedia.org/wiki/Campbell–Stokes_recorder

  5. fjughuh permalink
    August 11, 2015 11:48 pm

    you do release that your sunshine totals eg summer 5800 hours should be 580

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