1981-2010 Philip Eden Cet Averages

[Thundery wintry showers]

Philip Eden has created a set of provisional 1981-2010 averages for his alternative continuation of the CET (July-December values subject to revision as 2010 is not yet finished):

http://www.climate-uk.com/provisional.htm

Some of his 1971-2000 average values differ from the Hadley versions by one or two tenths of a degree, which was somewhat unexpected- clearly those occasional 0.3-0.4C differences do not iron out fully over a 30-year period. The annual average is much the same though.

But the most significant part is that 1981-2010 represents a similar rise relative to 1971-2000 as 1971-2000 did to 1961-90. The only month that has failed to warm is December, which is back down to 4.8C which is close to the average for the twentieth century. June has finally responded to the warming trend after seeing no warming trend at all between 1659 and 2000.

Central England appears to be warming at a rate of 0.25C per decade, as compared with an average global warming of about 0.15C/decade and an average Northern Hemisphere of about 0.2C/decade.

[TonyH]

Always wondered if there was something in that AGW stuff:rolleyes:(why wont smilies work for me!?)

Edited July 13, 2010 by Tonyh

[Gavin P]

With the PDO going cold and the AMO going cold in ten years I wonder if the 81-10 average could be the highest for the next few decades? Will 91-20 actually show a small drop?

[J10]

I have looked at this and done average for each 10 years, and there is a clear upwards pattern. However strangely winters have not risen as much as Summers, and December s now on average are cooler than 30 years ago.

[summer blizzard]

I have looked at this and done average for each 10 years, and there is a clear upwards pattern. However strangely winters have not risen as much as Summers, and December s now on average are cooler than 30 years ago.

Winter is also the only season which saw a blip in that the 1981-1990 average actually dropped, though it has risen since.

[Methuselah]

Good God, man...Is Philip Eden now a part of the conspiracy, too?

[summer blizzard]

Philip Eden has created a set of provisional 1981-2010 averages for his alternative continuation of the CET (July-December values subject to revision as 2010 is not yet finished):

http://www.climate-uk.com/provisional.htm

Some of his 1971-2000 average values differ from the Hadley versions by one or two tenths of a degree, which was somewhat unexpected- clearly those occasional 0.3-0.4C differences do not iron out fully over a 30-year period. The annual average is much the same though.

But the most significant part is that 1981-2010 represents a similar rise relative to 1971-2000 as 1971-2000 did to 1961-90. The only month that has failed to warm is December, which is back down to 4.8C which is close to the average for the twentieth century. June has finally responded to the warming trend after seeing no warming trend at all between 1659 and 2000.

Central England appears to be warming at a rate of 0.25C per decade, as compared with an average global warming of about 0.15C/decade and an average Northern Hemisphere of about 0.2C/decade.

The rise sounds about right really, given that higher lattitudes will warm more relative to average.

In regards to the actual rise, while December is the main suprise (the modern Ocober), the inter decadel average is also interesting, given that if you take July and December 2006 out of the equation, we have not seen a July, August or December more than 0.4C above average since 2004.

Edited July 14, 2010 by summer blizzard

[Optimus Prime]

The very warm Decembers of the 80s are keeping the December average up.

2000-2009 4.7c

1990-1999 4.5c

1980-1989 5.2c

Once we've lost the last cold decade of the 80s we'll be into the really warm series with the 1991-2020 is going to be a shock.

[Gavin P]

The very warm Decembers of the 80s are keeping the December average up.

2000-2009 4.7c

1990-1999 4.5c

1980-1989 5.2c

Once we've lost the last cold decade of the 80s we'll be into the really warm series with the 1991-2020 is going to be a shock.

Unless this decade is as cold as the 80's? :lol:

[Weather-history]

, given that if you take July and December 2006 out of the equation, we have not seen a July, August or December more than 0.4C above average since 2004.

Even more notable is when was the last time we had a December that was at least 2.0C above the average?

December 1988?

Every other month has recorded at least 1 month that was above either the 1961-90 or the 1971-2000 average int he last 20 years.

June 2003: 16.1 (2.0 above 1971-2000 average)

November 1994: 10.1 (3.6 above the 1961-90 average)

[Don]

Unless this decade is as cold as the 80's? :lol:

That would be nice, but I feel that the heat will return by the middle of the decade. Just hope we get a few more cold Winters before then!

[Paul T]

More evidence of the warming climate we seem to be inheriting.

I think people are clutching at straws (i.e Dec) the fact is its bloody warmer than it was 50 years ago.

However, i believe that the temps experienced in the 90's-00's are the 'general' peak...and thats the controversy i guess...

Edited July 15, 2010 by Paul T

[Optimus Prime]

I think people are clutching at straws (i.e Dec) the fact is its bloody warmer than it was 50 years ago.

Err you're wrong actually the 1950-1959 decadel average for December was 5.0c. We're bloody colder not warmer.

I think people are clutching at straws (i.e Dec) the fact is its bloody warmer than it was 50 years ago.

Err you're wrong actually the 1950-1959 decadel average for December was 5.0c. We're bloody colder not warmer.

[johnholmes]

Err you're wrong actually the 1950-1959 decadel average for December was 5.0c. We're bloody colder not warmer.

Err you're wrong actually the 1950-1959 decadel average for December was 5.0c. We're bloody colder not warmer.

you seem to have replied twice!

[Weather-history]

I think people are clutching at straws (i.e Dec) the fact is its bloody warmer than it was 50 years ago.

Well as OP has shown that is not exactly true but what I'm trying to work out is why December bucking the trend.

It is notable that whilst the January and February of the last 20 years have been above average with ease that the December hasn't

Take the 1971-2000 December CET average of 5.1 and note how many of the winter months were above that threshold since and including 1990.

December: 7

January: 10

February: 11

Now December should statistically have the most because it should be easier for December to surpass 5.1 than January or February because it is on average a warmer month than the other two months.

Also there have been only 2 Decembers of 6.0 or above since 1990. There have been 4 Januarys and 5 Februarys.

Why is December bucking the trend when there is a general warming curve?

[chionomaniac]

Philip Eden has created a set of provisional 1981-2010 averages for his alternative continuation of the CET (July-December values subject to revision as 2010 is not yet finished):

http://www.climate-uk.com/provisional.htm

Some of his 1971-2000 average values differ from the Hadley versions by one or two tenths of a degree, which was somewhat unexpected- clearly those occasional 0.3-0.4C differences do not iron out fully over a 30-year period. The annual average is much the same though.

But the most significant part is that 1981-2010 represents a similar rise relative to 1971-2000 as 1971-2000 did to 1961-90. The only month that has failed to warm is December, which is back down to 4.8C which is close to the average for the twentieth century. June has finally responded to the warming trend after seeing no warming trend at all between 1659 and 2000.

Central England appears to be warming at a rate of 0.25C per decade, as compared with an average global warming of about 0.15C/decade and an average Northern Hemisphere of about 0.2C/decade.

When comparing the changes between these two consecutive 30 year averages isn't it the same as comparing the 70's data to the 00's data, as in effect the data for 1981-2000 is the same between the two 30 year sets and just cancels each other out?

In short, what I am trying to say is that in fact one is just comparing the decade 1971-80 to that of 2001-10.

Edited July 16, 2010 by chionomaniac

[Thundery wintry showers]

Just seen your edit- you are almost right, we are comparing 1971-1980 with 2001-2010 but dividing the resulting trend by 3 because we are talking comparisons involving one decade out of 3 (as the two in the middle stay the same). Thus a 0.27C warming implies that 2001-2010 was approximately 0.81C (!!) warmer than 1971-1980.

I think the lack of warming in December is down to an increase in the frequency of cold synoptics, while in January and February, the underlying warming trend has been assisted by an increase in the frequency of warm synoptics. I think it's a statistical quirk and that we will probably see a warming of December at some point in the next two or three decades- after all June didn't "jump on board" the warming trend until around 2003.

Also, in the period 1977-87 the reverse was emphatically true with a run of Decembers dominated by warm synoptics and Januarys & Februarys dominated by cold ones, and so the 1961-1990 and 1971-2000 averages had a much larger gap between December and January/February than was true over the whole record since 1659. So in essence we have moved from an era of Decembers dominated by warm synoptics to a run of Decembers dominated by cold ones.

Edited July 16, 2010 by Thundery wintry showers

[chionomaniac]

Just seen your edit- you are almost right, we are comparing 1971-1980 with 2001-2010 but dividing the resulting trend by 3 because we are talking comparisons involving one decade out of 3 (as the two in the middle stay the same). Thus a 0.27C warming implies that 2001-2010 was approximately 0.81C (!!) warmer than 1971-1980.

I think the lack of warming in December is down to an increase in the frequency of cold synoptics, while in January and February, the underlying warming trend has been assisted by an increase in the frequency of warm synoptics. I think it's a statistical quirk and that we will probably see a warming of December at some point in the next two or three decades- after all June didn't "jump on board" the warming trend until around 2003.

Also, in the period 1977-87 the reverse was emphatically true with a run of Decembers dominated by warm synoptics and Januarys & Februarys dominated by cold ones, and so the 1961-1990 and 1971-2000 averages had a much larger gap between December and January/February than was true over the whole record since 1659. So in essence we have moved from an era of Decembers dominated by warm synoptics to a run of Decembers dominated by cold ones.

I am no mathematician TWS! When looking at the decades separately what was the difference?

[Thundery wintry showers]

JACKONE's Excel file gives the figures: 1971-1980 9.53C, 2001-2010 10.35C, difference 0.82C.

2001-2010 was 0.3C warmer than 1991-2000, and 1991-2000 was 0.34C warmer than 1981-1990- so since around 1988 we've been warming at more than 0.3C/decade.

[chionomaniac]

JACKONE's Excel file gives the figures: 1971-1980 9.53C, 2001-2010 10.35C, difference 0.82C.

2001-2010 was 0.3C warmer than 1991-2000, and 1991-2000 was 0.34C warmer than 1981-1990- so since around 1988 we've been warming at more than 0.3C/decade.

Thanks TWS. So when put like that when measuring in thirty year comparisons when twenty of the years are the same can lead to an underestimation of the warming (certainly by me) unless you have a good grasp of the statistical mathematics behind the figures.

[Thundery wintry showers]

I think it serves as a way of approximating the mean decadal trend, i.e. if the temperature is 0.82C warmer three decades later than it was before, then the mean decadal trend is +0.27C.

It isn't perfect because it assumes that the trend is linear- the apparent underestimation arises because the warming has accelerated recently, the warming from one decade to the next was 0.18, 0.34 and 0.3 respectively, yielding the cumulative total of 0.82C and mean of 0.27C.

[Thundery wintry showers]

Looking more closely there are clear-cut synoptic reasons why Decembers haven't warmed since 1990 but Januarys and Februarys have.

Northerly outbreaks in particular have been a lot more frequent during the Decembers of the past two decades than in the Januarys or Februarys. About half of the last 20 Decembers have seen some kind of northerly outbreak between Christmas and New Year, while 2005 had an easterly outbreak. In 1991/92, 1992/93, 1995/96, 1996/97, 1999/00, 2000/01, 2001/02 and 2005/06, December produced much colder synoptics than the January and February that followed.

In addition a large proportion of "inversion under a warm anticyclone" spells have also occurred during Decembers, most starkly so in 2006 and 2007.

In contrast there has been a remarkable lack of cold synoptics during the Januarys, though with 2010 strongly bucking that trend. Between 2000 and 2009, significant northerly outbreaks occurred only in the Januarys of 2003, 2004 and 2007. Other than arguably the third week in 2001 (that easterly was quite a slack half-hearted affair), we have not been able to sustain a potent easterly for more than 36 hours in January since 1997.