Live from the Conference, day 2 – land cover and GCM's

I just watched a presentation Elsi Sertel from a university in Turkey showing how easy it is to introduce true land cover data into a climate model. Her study area was around the Black Sea near Istanbul, and used LANDSAT imagery along with a pixel by pixel truthing technique to determine the type of land cover, sea, forest, urban, etc and apply it to use in a GCM.

Her premise was that current GCM’s use land surface info that isn’t fully representative, out of date, and in some cases just plain wrong.

Her study showed a technique that allowed for a significant amount of automation to the process, to allow improved and current land surface types to be easily integrated into the grid cells of a GCM. Unfortunately, some GCM gridding schemes are too coarse to handle such data.

From what I’ve seen in this conference so far, and I’ve seen presentations now from Europe, Turkey, China, Australia and the USA, it is becoming more clear that land use is a major driver of climate change, and perhaps dwarfs even GHG effects. That’s just a hunch. One study from Australia showed the effects of removing a woody type bush over a large area over the past century, and the results on rainfall and temperature were profound.

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August 28, 2007 10:56 am

One question comes to mind is: How do they KNOW that the removal of the specific plant caused weather changes? I don’t see how you could translate correlation to causation from that.

August 28, 2007 11:09 am

That’s a good and valid question. From what I gathered from the presentation, this particular woody shrub was the dominant vegetation for thousands of sq km in eastern Australia. It looked a lot like Eucalyptus, but was another that I didn’t get the name of. It’s existence predated colonization and was its own ecosystem, much like the grassland prairies of the USA.
However this woody shrub has been systematically removed for urbanization, pastureland and other uses and was tracked well enough since the 1800’s that they felt comfortable drawing a causation from it since the temp and precip changes were downwind (prevailing winds for the region) of the broad area where it was removed.

August 28, 2007 11:16 am

Were the changes gradual, in line with the schedule of the shrub removal over time?

August 28, 2007 11:22 am

Was this woody shrub the plant shown in the Australian “rabbit fence” pictures that had a persistent hanging cloud bank a few hundred meters from the fence-line?

August 29, 2007 8:40 am

I’m almost certain you will find this is the Rabbit Proof Fence that transects Western Australia, and on it’s southern end there is hundreds of kilometers where there is native vegetation on the eastern side and mainly wheat cropping land on the other.
The prevailing winds come from the west, and the cumulus clouds begin within a hundred metres or so to the east of the fence.
Photos from air are quite remarkable, as you can see the clear sky over the cropping land and the clouds over the native vegetation extending to the horizon.

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