Hi Lost In Kate Winslet
Sorry if I misjudged what you were trying to point out, it was last thing Friday and I was rushing to get away. (I have seen the increase in mass used as an argument that Greenland is getting cooler and that glaciers are growing again – I apologise if I misinterpreted what you were trying to say.
I’ll apologise in advance if I’m about to do it again, as I have to rush this too.)
‘A point of correction, the IPCC doesn't undertake any research. It is a literature review which summarises the current scientific publications on climate change.’
I hold my wrist out for a slap; I do know this but was clumsily trying to make the point that regional studies do feed into the IPCC process (as well as aid national planning) and sometimes are produced with an eye to both. There is some co-ordination going on between the different bodies.
‘What I'm interested in is the effect of increased water vapour on regional climate models as it will affect changes in temperature.’
But water vapour is included in all climate models, but as a feedback and not a forcing. (The air’s capacity to hold vapour (absolute humidity) is limited but increases as the air warms, roughly doubling for each temperature increase of 10°C. CO2 increase = Forcing. Water Vapour + temperature increase = Feedback.)
‘The move towards regional models is much more sensible as there is no such thing as a global climate.’
Your central point I think. I’d say we need both. There ARE regional models, an example would be the American South West drought scenario I referred to in the first post; this has been extensively modelled on a regional basis as an aid to water management policies. (It’s also possible to embed a high-resolution regional model in a larger global one.)
http://www.washingtonpost.com/wp-dyn/content/article/20...AR2007040501180.htmlThere are many other regional models, for Europe ‘Stardex’ amongst others.
However, for want of a better description, there is a global climate
system that is too complex (e.g. Hadley Cells, Polar Cells etc drive atmospheric circulation; there are global wind systems such as jet streams; changes in the major ocean pressure oscillations can have world wide effects - the El Nino Southern Oscillation if the best known example – others inc. the North Pacific Decadal Oscillation and the Oscillations in the N. Atlantic and Indian Oceans. - and a whole host of other phenomena) to separate out into autonomous regional areas. There’s also a global system of ocean currents that transport warm/cold water, world wide tele-connections and anti-phase phenomena that have to be considered etc.
It’s a big interconnected climate system, even if we can’t say there is just one global climate.
PossiblyPossibly.Regions don’t have self-contained atmospheric circulation patterns; but regional climate models can be driven from their edges by input from a global climate model.
‘Can we draw conclusions then as to patterns of regional climate behaviour?’
Possibly - an example from the WG2 summary. ‘Australia and New Zealand: As a result of reduced precipitation and increased evaporation, water security problems are projected to intensify by 2030 in southern and eastern Australia and, in New Zealand, in Northland and some eastern regions.’
That projection would take into account the role of WV as a feedback as well as looking at changes in precipitation patterns.
‘The statement I'm making remains valid that Greenland Ice Sheet gained mass during that period due to local precipitation levels being greater than the melt rates.’ (LIKW)
I’ll maintain that this situation may have changed recently, it does now seem to be losing more than it’s gaining; more evidence that this is the case…
A study [by Johannessen et al 2005] over 11 years noted the growth in mass on the plateau’s ice sheet but also found “The result is a mixed picture, with a net increase of 6.4 centimetres per year in the interior area above 1500 metres elevation. Below that altitude, the elevation-change rate is minus 2.0 cm per year; broadly matching reported thinning in the ice-sheet margins.” The team ascribes the increased snowfall above 1500m to the regional atmospheric circulation known as the North Atlantic Oscillation.
http://www.spaceref.com/news/viewpr.html?pid=18231A 2006 study by researchers at the University of Wales showed the two [Greenland] glaciers Kangerdlugssaq and Helheim have doubled their speed and are dumping twice as much ice into the sea as they did five years ago.
A more recently published study [06] by NASA over 10 years (1992-2002) found “The survey documents for the first time extensive thinning of the West Antarctic ice shelves and an increase in snowfall in the interior of Greenland, as well as thinning at the edges.”
http://www.jpl.nasa.gov/news/news.cfm?release=2006-023Another on changes to Greenland Ice Sheet found Greenland’s southern glaciers [06] are now dumping twice as much ice yearly into the Atlantic as they did in 1996.
http://www.esa.int/esaEO/SEMH59MVGJE_index_2.htmlThe difficult areas to measure are the sides (edges) of the ice sheet down to sea level, but from what I’ve read this is where melting has accelerated. [Think of an ice cube or iceberg, they melt from the outside in.]
So a picture of change and some complexity has emerged for Greenland in the few past years.
