The report is one of the series which Prez Shrub commissioned to "study" climate change. At the time, some of us thought that process was a way of pushing the climate change off until the next administration, which is what has happened. When the report (SAP 3.4) was first available for public comment, I threw in a bit of a rant about section 4, which is now part of the record. I've since done a bit more reading, some of which has confirmed my basic comments.
I thought they missed several important aspects of the problem, such as what is happening with Arctic sea-ice. I also thought that their fixation on the experiment which Sandström performed about 1908 is a bit off base, since Sandström used a model which is not very representative of the actual situation in the oceans. His large tank model was rather deep, when compared with the depth/distance ratios which exist in the Atlantic and Pacific. Also, Sandström's tank had no wind or tidal forces, nor are there any salt gradients. The SAP authors' conclusion; "Thus, if we want to understand the AMOC in a thermodynamical way, we need to determine how heat reaches the deep ocean" misses the fact that the ocean does circulate waters now and the question is what will be the changes in this process. They do not mention the fact that the Arctic and the Nordic Seas are directly connected, nor do they show any sinking of waters into the Arctic, which was found in studies decades ago. They only discuss sinking in the Nordic Seas, primarily the Greenland Sea, along with the Labrador Sea, when there are estimates that 2 Sv of deep water is formed in the Arctic as brine sinks below the sea-ice over the shelf areas to the north of Russia. Their cartoons of currents, such as Figures 4.1 and 4.4, do not include flows thru the Fram Strait. Then too, the RAPID program operates an array of current measurement instruments strung across the Atlantic at about 26N, which then is used to assess the net flow by differencing slow southward flows over large distances, a likely source of error. Thus, the discussion of the AMOC and the RAPID program leaves out the essential question of WHERE does the THC sinking occur and how might this change producing impacts on both weather and climate!! So, I think there's quite a bit left out of this report and the conclusions understate the seriousness of the situation. Perhaps as a result of my rant, the final report did add a graphic comparing recent sea-ice minimums with OGCMs, which was taken from Stroeve et al. 2007. E. Swanson ---------- Alastair wrote: > A new report about Abrupt Climate Change has just been released: > http://www.climatescience.gov/default.php > > I thought people here might like to discuss it. From my POV it says > notheing new, and rather than explain what caused D_O cycles they see > to covered all bases and are hoping for the best that such a change > won't happen again. --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups Global Change ("globalchange") newsgroup. Global Change is a public, moderated venue for discussion of science, technology, economics and policy dimensions of global environmental change. Posts will be admitted to the list if and only if any moderator finds the submission to be constructive and/or interesting, on topic, and not gratuitously rude. 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/globalchange -~----------~----~----~----~------~----~------~--~---
