cc: Dáithí Stone , Phil Jones , Peter Stott , Toru Nozawa , Alexey Karpechko , Michael Wehner date: Fri, 30 May 2008 16:40:37 +0100 from: Gabi Hegerl subject: Re: Revised polar attribution paper to: Nathan Gillett Hi all, nature geoscience seems like a good choice to me, and the paper reads very well. Similar to Alexey I am a bit ambiguous about showing results with SAM subtracted only, given it makes it a little bit harder to interpret. On the other hand, this is not an issue if discussed that results are not sensitive to subtracting the SAM, but that this addresses the concern if SAM related trends are wellr epresented in the models Also, the SAM subtracted pattern is very impressive and could be emphasized a bit more. I am also wondering why Arctic results are so jiggly with detection completely lost for a number of cases with lots of EOFs - do we have any idea why this is happening? writing suggestions: Abstract could mention that temperature trends over Antarctica have been reported as mixed, raising the question if Antarctica is not warming as predicted which would have huge importance on longterm sea level rise prospects. or so (is this too speculative?) p. 2 middle, should this explicitly mention that West Antarctica is still not covered due to hostile conditions? p. 3 first para: 5-yr average spatial means to avoid two means in short sequence? bottom 2nd line same page, exclusion of these data?? p 4 discussion of simulations: the anthro could be easily (kind of) be extended with scenarios, right, its the natural that give us trouble after 1999? p 5 top, add? 'residual observed trends show warming everywhere except..pole. THis makes them more similar to the model residual trends than the raw trends (see supplementary figure 1).' I am wondering if there is any way to quantify this, for example, by plotting your sectorial mean data model and obs raw and subtracted as a line plot, or by plotting zonal means with the peninsula separated as an extra point? This would also possibly strengthen the case... on p 6, bottom paragraph, I would also add at the end of the ANtarctica discussion that ...available and that circulation changes, which were largely antrhopgenic (citeyourpaper) have reduced warming rates over parts of Antarctica in models and observations in the past' does ch10 say something about futur, I think consistent warming is expected in future? (the time intensive approach would be to get the data for the future anthro runs and plot a bit into the future as well which might make this paper hotter for nature but I admit it does sound like work....) Gabi Nathan Gillett wrote: > Hi all, > Please find attached a revised version of the polar attribution paper, > and supplementary info. In response to your earlier comments and > suggestions, I've made the following changes: > > - I now subsample the monthly model data at observed locations, rather > than doing the sampling on 5-yr means. > - I mask the model data with its land mask, before applying the > analysis, so that I'm comparing observed land temperatures with > simulated land temperatures (except in the case of cells in which the > model has no land, but observations exist, in which case I take the > mean over the whole cell). > - I've applied the D&A analysis to the SAM-residual temperature > changes (see supplementary info). > - I haven't applied the analysis to data to the present, because the > data doesn't seem to be available yet. > > Subsampling the monthly model data makes the attribution analysis > slightly less robust to variations in truncation, but we can still > detect ANT. Applying the analysis to the SAM residual makes it easier > to detect ANT in the Antarctic. > > I'm inclined to submit this to Nature Geosciences, partly since it's > new and makes a change from GRL, and partly since I won't have to > reformat it to submit there... Let me know if you disagree. Comments > welcome - it would be good to get this resubmitted soon. > > Cheers, > > Nathan > > > -- Dr Gabriele Hegerl School of GeoSciences The University of Edinburgh Grant Institute, The King's Buildings West Mains Road EDINBURGH EH9 3JW Phone: +44 (0) 131 6519092, FAX: +44 (0) 131 668 3184 Email: Gabi.Hegerl@ed.ac.uk The University of Edinburgh is a charitable body, registered in Scotland, with registration number SC005336.