Friday, February 17, 2006

Last two millennias' climate

[Edit: I thought this was 9:00am: (video from NCAR) C. Ammann: last two millennia climate, but it was actually (Day before) 2:30pm: (video from NCAR) C. Ammann: Effect of solar and volcanic forcing on climate in the last millennia at the CCSM Paleo Climate Working Group meeting]]


Two important changes to the CCSM are needed. Solar forcing needs an upgrade. Please concentrate on UV-ozone model. The UV is damned important and especially on the multiple millenium models and uberimportant to get it fixed for regional impact (next gen) simulations.

The second element that is important: volcanic forcing. They think they might be overestimating the impact (!) right now. When looking at the climate for the last 2k years, the volcanoes seem to have major impacts in the models but it doesn't seem to be working out like that irl. Krakatoa popped its cork in the 1880s and it had really no impact. 1641 and 1808 were contrasting to this and were the same level, yet impacted. 1351 (~) had another big impact. 1258 was 4x times larger and there was a .8 degree change, but that was far less than they expected from the models. They think it has something to do with the aerosols. They think that different particle sizes make the differences. Pinatubo had some particle measurement and still had massive error bars. They have some data from hawaii from 50 years of optical perturbations. El Chichon had some good measurements without the error bars. Interesting! Very Interesting! They have some data based on the moon!!! (O.o) This is based on the aerosols and eclipses. They have a model that predicts the color and brightness of the moon when in eclipse. Their model works fscking good for the last 50 years. Pinotubo has to be much smaller than anticipated because of this. Interestingly, they get from ice cores that Pinotubo that was about 20-30 MTs of material. Interesting. They want to ssee if they can fix the data and model of the past eruptions to make it better.

FWIW, tidbit: he made the offhand comment that the Pacific warmed up during the Little Ice Age(!?). I was typing when I heard that and might have heard something that was a mistake in the model.

The attackers are circling. One is asking why bother with 2k year run? Medieval Warm Period is damned important to study and the ocean drift is fscking important. Longer runs give more solid prep results for global warming studies.


1 comment:

LeoPetr said...

Conventionally, there are two letters 'n' in "millennium".:)