I am fortunate to put forward some ideas answering partially your query:
"In fact, if the water uncovered is relatively warm, it could result in a
greater loss of heat into space than would otherwise be the case.Can the clever
people (or the people with clever computers) estimate the significance of this
effect?"
This effect is very significant one, I am not the one who says how much loss of
heat it into space results, but there is definitely a very significant loss of
steam into aerospace below when the Arctic Ocean water is uncovered.
Therefore, it is no coincidence that the 2007 record Arctic Ocean summer-time
sea ice melting was followed by all-time record snowfall percipitation in the
Northern Hemisphere. By February 2008 the snowcover had stretched across the
Northern Hemisphere to the largest ever seen northern hemisphere terrestrial
snow cover stretching over China to the vicinity of Vietnamese borders. Huge
temperature fluctuations destroyed 60% of subtropical trees in China when the
Arctic air headed towards Vietnamese border before turning east and dumping its
cold into the vastness of Northern Pacific Ocean.
>From the thickness and spread of snow we could perhaps estimate the energy the
>ocean thus released knowing the evaporated volume Norht of Himalayas that mop
>up effectively most of he southern humidity. In 2008 the Finnish Lapland has
>again seen record snowfalls as the Barents Sea is quite warmed.
The loss of Arctic sea ice cover leads to massive autumn and winter time
percipitations until the Arctic Ocean becomes ice covered. The record summer
time melts and sea water warmings will be accompanied equally record
winter-time snowfalls on the periphery of the Arctic Ocean. While the
terrestrial snow cover is an excellent reflector of sun shine, it rests on
increasingly warmer soils. Previously the snow cover was supported by the
permafrost ground under it, no the ground under snow is increasingly clogged by
warm autumn time rainfall, not frosted and full of microbial activities. When
the insulating snow cover falls over the soil, the heat of the warmer ground
remains under and when warm spells come in the spring the snow cover disappears
melting record early like in Yakutia in 2008 when snow departed in record short
time. The microbial activity on warm ground under snow and frosted surface also
generate heat that stays trapped under the snow and there is major soil warming
as a result of thickened insulating snow blanket and microbial activities.
As a result the loss of sea ice leads into heat and steam pulses that pile up
first lots of rain wettening the grounds and then deposits snowfall on the top.
By the spring all that massive snow blanket released and deposited quickly
melts back into ocean. When the massive melt water pulse from Siberia returns
to the sea, this brings back with it an additional heat pulse melting the sea
ice earlier where the riparian discharges are disposed to the Arctic Ocean.
This situation has been worsening and remain rather useless as in case of
Yakutia the snow blanket despite of its increased thickeness and spread was
lost a month earlier than before. So, when the snowless spring started month
earlier the overall feedbacks were all but entirely negative, helping for
earlier sea ice melt as the warm water and then the warmed air masses started
pouring from the land onto the Arctic Ocean record early, a month earlier to
2007.
The Arctic Ocean only lost tiny bit of the melt water pulse when some of the
southernmost rainfall fell to Chinese rivers that then took the water back to
east rather to the Pacific Ocean rather than the north like the Russian rivers
do.
So, I would look into heat transported into system by the rain as perhaps the
best indicator as it may be cumulatively rather easily measurable due to energy
required for its evaporation and deposition. I hope this comment on this newly
amplified winter snow pulse would be of some use to your query.
Rgs,
Albert Kallio> Date: Mon, 29 Dec 2008 17:49:02 +0000> From:
[email protected]> To: [email protected]> Subject: [geo] Re: arctic
engineering needs and sea-ice science> CC: [email protected]; [email protected];
[email protected]; [email protected];
[email protected]> > > There's an effect which I've not seen discussed
here, but without> doubt it's important.> Ocean NOT covered by sea ice will
radiate heat into space far more> effectively than will the white ice it
replaces.> Ocean ice loss is potentially less significant than has been
assumed.> In fact, if the water uncovered is relatively warm, it could result>
in a greater loss of heat into space than would otherwise be the case.> > Can
the clever people (or the people with clever computers) estimate> the
significance of this effect?> > A> > 2008/12/29 Mike MacCracken
<[email protected]>:> > I would respond with two hopefully clarifying
comments:> >> > 1. While there is a lot of focus on when the ice will be gone
in summer,> > this will have little effect on the weather as the surface
temperature and> > water availability are similar for no ice and melting ice.
Indeed, more> > solar is absorbed, but that does not significantly raise ocean
temperatures.> > What really matters is what happens in the fall into winter,
because as long> > as there is no ice or thin ice, there will be a lot of heat
transport to the> > atmosphere and so the near surface air cannot cool to –40 C
and so create> > cold, dense air masses that spread out from the Arctic and
influence weather> > around the midlatitudes. With all the extra heat going up
into the> > atmosphere (the solar heat absorbed during the time with lower
albedo), the> > atmospheric circulation will be altered—causing, as Jennifer
notes, the> > "large-scale influence on winter weather patterns over much of
the northern> > hemisphere." So, while the retreat of summer sea ice is an easy
metric, what> > really affects the weather is the delayed formation of thick
ice that can> > insulate the atmosphere from the heat contained in the ocean.>
>> > 2. On the characteristics of low clouds, I thought the intent was to
raise> > the albedo when the Sun was out, not to raise the IR emissivity.
During the> > polar summer one wants the clouds with a high albedo (once the
surface> > starts to melt and its albedo comes down to below that of low
clouds). Then,> > during the polar night, one would want to decrease the cloud
emissivity so> > the surface can more rapidly radiate to space (the clouds tend
to retard the> > cooling process that allows ice to form, as Jennifer notes).>
>> > Mike MacCracken> >> >> > On 12/29/08 11:26 AM, "Andy Revkin"
<[email protected]> wrote:> >> > hi all,> >> >> > I consulted with a few
sea-ice wizards on the exchanges here related to> > Arctic trends, and Jennifer
Francis at Rutgers weighed in with the following> > thoughts. Note the
importance of the boundary layer changes as well. There> > are many important
factors besides albedo and ocean solar absorption.> >> > Winter cloudiness etc
important factor. But also note the importance of not> > over-interpreting
short-term wiggles as trends. Much more on Dot Earth and> > in my earlier
coverage of the sea-ice question. This post (shortcut) is a> > good starting
point: http://tinyurl.com/dotIceTrends> >> > Here's jennifer's comment (I sent
her that sea-ice graph that was making the> > rounds here)>> >> >> >> > Hi Andy
--> >> > The first figure you attached with the extrapolation from the 2007
summer> > ice loss is very unrealistic, in my opinion. Both the observed record
and> > model simulations of ice extent exhibit a great deal of interannual> >
variability, and most sea ice researchers would expect this behavior to> >
continue superimposed on a continuing downward trend. Some years the decline> >
will be dramatic, as it was in 2007, and some years there will likely be a> >
recovery, as random atmospheric patterns act on the ice cover. What's> >
different now as opposed to 2 decades ago is that the ice is now so thin> >
that any unusual forcing -- be it a persistent wind pattern, cloud cover,> >
heat transfer from lower latitudes -- will have a much bigger effect on the> >
ice, as thin ice is more easily moved by wind and/or melted by increased> >
heating. The small ice cover of recent years allows more solar energy to be> >
absorbed by the open surface during summer, but exactly how that extra heat> >
affects> > the system over the following months is still being worked out. Some
recent> > research suggests that during falls after low-ice summers the lower>
> atmosphere warms, the atmospheric boundary layer gets deeper, and low clouds>
> increase, all of which tend to retard regrowth of sea ice in the fall and> >
early winter. It also appears there's a large-scale influence on winter> >
weather patterns over much of the northern hemisphere. The reason I'm> >
telling you all this is that it appears there is no obvious mechanism for> >
the ice to rebound significantly unless there is a multi-year period of> >
colder-than-normal temperatures, but this is not likely as greenhouse gases> >
continue to increase at rates even faster than the most pessimistic IPCC> >
scenario.> >> > Regarding water temperatures, the main effect is through the
added> > absorption of solar energy in summer, which accelerates the melt
during late> > summer. Warmer winter temperatures in the Atlantic sector also
appear to be> > responsible for most of the retreat of the ice edge during
winter in that> > region, but not on the Pacific side.> >> > Maybe this is more
info that you needed and much of it you already know, but> > it's not a simple
explanation. Regarding the shipping text you sent, it> > looks like a bunch of
hooey to me. 51 ships in the area will not have a> > perceptible effect on the
clouds. The "good" low clouds they're talking> > about are already almost 100%
emissive of infrared energy, and adding ship> > smoke to them is not going to
matter.> >> > Hope this helps -- Happy New Year!!> > Jennifer> >> >
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~> >
Jennifer Francis, Ph.D.> > Institute of Marine and Coastal Sciences, Rutgers
University> > Co-Director of the Rutgers Climate and Environmental Change
Initiative> > 74 Magruder Rd, Highlands NJ 07732 USA -- Tel: (732) 708-1217,
Fax: (732)> > 872-1586> > [email protected] |
http://marine.rutgers.edu/~francis/> >> > At 9:14 AM -0700 12/29/08,
[email protected] wrote:> >> > Re Arctic ice, the issue is not just albedo, but
also thermai> > inertia. The effective heat capacity of the exposed ocean is> >
hugely greater than the ice.> >> > Tom.> > ++++++++++++++> >> >> >> > >> >> >
_________________________________________________________________
Live Search presents Big Snap II - win John Lewis vouchers
http://clk.atdmt.com/UKM/go/117442309/direct/01/
--~--~---------~--~----~------------~-------~--~----~
You received this message because you are subscribed to the Google Groups
"geoengineering" group.
To post to this group, send email to [email protected]
To unsubscribe from this group, send email to
[email protected]
For more options, visit this group at
http://groups.google.com/group/geoengineering?hl=en
-~----------~----~----~----~------~----~------~--~---
