Saturday, May 19, 2012

4444.txt

cc: Phil Jones <P.JonesatXYZxyz.ac.uk>
date: Mon, 14 Sep 2009 16:44:32 +0100
from: Adrian Simmons <Adrian.SimmonsatXYZxyzwf.int>
subject: Re: humidity paper
to: Brian Hoskins <b.j.hoskinsatXYZxyzding.ac.uk>

Brian

I'm not sure I could argue that with confidence (or anything else much
about convection with any confidence) but it seems you've thought about
it, so I would hesitate to argue with you unless I can find good grounds.

Adrian


Brian Hoskins wrote:
> Adrian
> The humidity above the boundary layer affects the towers that entrain,
> but you could argue that the few towers that get from near surface to
> the upper troposphere, and probably set the temperature there may have
> little entrainment and therefore be sensitive mainly to the near surface
> humidity.
> Do you buy that??!!
> Best wishes
> Brian
>
> Adrian Simmons wrote:
>
>> Brian
>>
>> I'm glad you liked it. I should really have been spending more time on
>> GEMS/MACC than writing this up, but the main result was too interesting
>> to ignore. We did our best to convince first ourselves and then the
>> reviewers that there was a reasonable case that what we presented is
>> sound, and it was pleasing when Kate Willett produced the HadCRUH
>> extension that showed a similar drop in RH over land than ERA, and when
>> I noticed that variations averaged separately over land and sea were
>> similar. It all looks to hang together, but ...
>>
>> I have to get back to the day job for now, but will keep an eye on how
>> things unfold, and look a bit more at what happens higher up in a few
>> weeks time, I hope. Upper-air water vapour over the ocean is much better
>> in ERA-Interim than ERA-40, but not as good as it might be - not
>> correlating as well with qsat(SST) as the SSMI retrievals do - and
>> shifting radiosonde humidity biases make things tricky over land, so I'm
>> not sure quite how much progress can be made with current reanalysis
>> products.
>>
>> All the best
>>
>> Adrian
>>
>>
>> Brian Hoskins wrote:
>>
>>
>>> Phil
>>> The deep convective regions in the tropics would be very sensitive to
>>> the low level moisture supply and therefore to boundary layer humidity.
>>> Brian
>>>
>>> .JonesatXYZxyz.ac.uk wrote:
>>>
>>>
>>>> Brian,
>>>> The paper has now been accepted. I think I asked Tim Osborn to give
>>>> you
>>>> a copy as I was somewhere else when you were there for UEA degree. I'm
>>>> glad you found it interesting and impressive.
>>>> What you say sounds possible. It depends how much of the change in the
>>>> atmos column is related to changes at the surface? I need to think
>>>> about this. I'm supposed to be involved in a break out group here at an
>>>> IPCC meeting in Geneva, so it will be later in th week.
>>>> I guess a question for Adrian is whether ERA-INTERIM's tropopause
>>>> height
>>>> is reasonable, and whether any changes have occurred?
>>>>
>>>> Cheers
>>>> Phil
>>>>
>>>>
>>>>
>>>>
>>>>> Dear Adrian & Phil
>>>>>
>>>>> Phil left me your paper when I was visiting UEA. Impressive and
>>>>> interesting!
>>>>>
>>>>> If the tropical near surface specific humidity over tropical land has
>>>>> not gone up (Fig 5) presumably that could explain why the expected
>>>>> amplification of the warming in the tropics with height has not really
>>>>> been detected.
>>>>>
>>>>> Best wishes
>>>>> Brian
>>>>>
>>>>>
>>>>>
>>>>
>>>>
>>>>
>>>
>>
>>
>>
>
>

--
--------------------------------------------------
Adrian Simmons
European Centre for Medium-Range Weather Forecasts
Shinfield Park, Reading, RG2 9AX, UK
Phone: +44 118 949 9700
Fax: +44 118 986 9450
--------------------------------------------------

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