I am not very up-to-date with this literature, I have to say. Here a
few random references from searches in various combinations of
"diurnal temperature range" (DTR), "nightly temperatures", "climate
change" and may be some others:
http://www.ipcc.ch/publications_and_data/ar4/wg1/en/ch10s10-es-2-temperature-extremes.html
-- from Intergovernmental Panel on Climate Change (however, another
part of their report,
http://www.ipcc.ch/publications_and_data/ar4/wg1/en/ch3s3-es.html,
states that the daily maxima have been growing about as fast as daily
minima)
http://onlinelibrary.wiley.com/doi/10.1029/2004GL019998/abstract --
Geophysical Res Letters
http://wattsupwiththat.com/2009/06/27/new-paper-global-dimming-and-brightening-a-review/
-- observed decrease in the DTR is due to urban effects (the heat
stays in the cities in warm stones, and extra heat continues to be
produced by humans at night; see also
http://www.nature.com/nclimate/journal/v3/n1/full/nclimate1656.html)
From the graphs that I visually remember (in my environmental stats
class some 10 years back), the increase, on your scale, was of the
order 7+1, as the night temperatures were pulling up, and day
temperatures stayed nearly flat; and I explained the physics of that,
as I understood it, in my earlier email.
-- Stas Kolenikov, PhD, PStat (ASA, SSC)
-- Senior Survey Statistician, Abt SRBI
-- Opinions stated in this email are mine only, and do not reflect the
position of my employer
-- http://stas.kolenikov.name
On Sat, Sep 28, 2013 at 8:51 AM, John Bibby
<[log in to unmask]> wrote:
> Thanks Stas, that's interesting. So it is the cooler bits (nights) that are
> getting warmer, not the hotter bits. That seems to be REDUCING variability
> which is generally regarded as a good thing (but might not be in this case).
>
> Is there any data indicating how much of the average increase is night-time
> increase and how much is daytime? e.g. if the average is 4 degrees, this
> could be 5 at night and 3 during the day, or it could be 6+2 or 7+1 or even
> 8+0 (if these averages work the way I feel they should, which they may not).
>
> Thanks for your information.
>
> JOHN
>
>
> On 28 September 2013 14:35, Stas Kolenikov <[log in to unmask]> wrote:
>>
>> So far the primary mechanism of the warming was that the nights were
>> getting warmer -- the heat cannot escape the greenhoused atmosphere of
>> the Earth. The daily high temperatures have not moved as much as the
>> nightly temperatures have: this is just the amount of solar energy
>> that reaches Earth, and it has not changed that much. The seasons are
>> here to stay, but given that heat imbalances increase, there will be
>> more extremes as a manifestation of that loss of balance.
>>
>> -- Stas Kolenikov, PhD, PStat (ASA, SSC)
>> -- Senior Survey Statistician, Abt SRBI
>> -- Opinions stated in this email are mine only, and do not reflect the
>> position of my employer
>> -- http://stas.kolenikov.name
>>
>>
>>
>> On Sat, Sep 28, 2013 at 7:16 AM, John Bibby
>> <[log in to unmask]> wrote:
>> > So global warming is going up by 3.7 degrees (today's Guardian p.17;
>> > "extra
>> > global warming likely between 2081 and 2100").
>> >
>> > I don't want to doubt that, but how should it be interpreted?
>> >
>> > As an average presumably, but what sort of average?
>> >
>> > No, I don't mean mean, mode or median as per that Stats 100 course we
>> > once
>> > studied - I mean how are we to interpret that average? lt's an average
>> > over
>> > time and space presumably. (I leave aside the question of variability,
>> > which
>> > is generally far more interesting and/or dangerous than the average.
>> > After
>> > all, we can plan for well-predicted averages, as these are. But
>> > unpredicted
>> > tail-values are far more difficult, esp. if we do not know where and
>> > when
>> > they will fall.)
>> >
>> > So let's focus on me in York. If the temperature goes up by 3.7 degrees,
>> > that could be 3.7% every day and night for the whole day and night i.e
>> > the
>> > profile stays exactly the same; it just lifts up by 3.7 degrees.
>> > (Unlikely,
>> > but ok maybe as a first-step thought-experiment.)
>> >
>> > Far more likely however (I guess) is a switch between the seasons i.e.
>> > we
>> > might get more 'summery' days and fewer 'wintery' days.
>> >
>> > So what I'd like to know is (a) typical temperatures for 'summer' and
>> > 'winter', and (b) how much of a shift would be needed to reach the
>> > required
>> > temperature rise. A back-of-my-brain calculation led me to think that
>> > if
>> > 'summer' means 30 degrees, and 'winter' means 10 degrees, and if at
>> > present
>> > the ratio is 1 to 1, then an increase of 3.7 degrees corresponds to a
>> > ratio
>> > of roughly 1.6 to 1 i.e. more summer, less winter. Put that way, it
>> > does
>> > not sound so scary.
>> >
>> > However, my data may be flawed. Or my thinking may be flawed. Or my
>> > politics
>> > may be flawed. Or (probably) all three.
>> >
>> > Can anyone please put me on the straight-and-narrow so I c an sing from
>> > the
>> > same hymn-sheet as the rather incompehensible green-buffs whom I heard
>> > on
>> > the radio yesterday.
>> >
>> > Thanks to anybody who has read this far. (I never did understand or
>> > believe in hymns - but I do like to sing-along!)
>> >
>> > JOHN BIBBY
>> >
>> >
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>> >
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>> >
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