date: Thu Apr 24 15:02:43 2008 from: Tim Osborn subject: Re: Abnormal normals! to: Ian Harris Hi Harry, smoothing out the peaks might account for it, but (for pre) it seems too large a reduction. Can you calculate the mean of each of the normals files, since presumably the mean should be unaltered by such smoothing. Cheers Tim At 12:09 24/04/2008, you wrote: Hi Tim, Sit down.. it's the 'scaling' business again! I've examined the rd0 and pre normals at half degree and two-half degree binary, and half-degree ascii (the clim files we publish). Here are the results and my interpretations: FILE MIN MAX UNITS glo25.rd0.6190 0 303 days*10 glo25.pre.6190 0 391 ??? glo.rd0.norm 0 310 days*10 glo.pre.norm 0 1244 mm clim.6190.lan.wet.grid 0 3090 days*100 clim.6190.lan.pre.grid 0 12430 mm*10 As you can see, there is a big difference between the precip normals over all three versions! The best interpretation I can place on the 2.5-deg binary normals ('???') is that the much larger area is 'softening' the impact of individual high-recording stations.. what do you think? We can see from the rd0_gts_tdm.pro program that they are treated as days*10 (rd0) and mm (pre), assuming natural units are in play: rd0norm(nland)=(rd0norm(nland)/10)>0.49 prenorm(nland)=prenorm(nland)>5.0 I wonder if the squashing of variability in the 2.5 degree grid is causing the low variability you're seeing in the output? I will try running with half-degree synthetics to give us a comparison. Cheers Harry Ian "Harry" Harris Climatic Research Unit School of Environmental Sciences University of East Anglia Norwich NR4 7TJ United Kingdom