tag:blogger.com,1999:blog-7729093380675162051.post3435899324702520122..comments2024-03-28T13:56:47.604+11:00Comments on moyhu: NCEP/NCAR matched to GISS, NOAANick Stokeshttp://www.blogger.com/profile/06377413236983002873noreply@blogger.comBlogger6125tag:blogger.com,1999:blog-7729093380675162051.post-41091504917870352932015-06-19T18:13:15.863+10:002015-06-19T18:13:15.863+10:00Oops - memory lapse. NCEP is 2.5x2.5. Not so easy....Oops - memory lapse. NCEP is 2.5x2.5. Not so easy.Nick Stokeshttps://www.blogger.com/profile/06377413236983002873noreply@blogger.comtag:blogger.com,1999:blog-7729093380675162051.post-50769289004837761032015-06-19T16:23:43.731+10:002015-06-19T16:23:43.731+10:00Fortunately, GISS posts 2x2 grids of temperature a...Fortunately, GISS posts 2x2 grids of temperature anomaliess, and NCEP also posts 2x2 grids. I'll see if I can post difference maps (with global averages).Nick Stokeshttps://www.blogger.com/profile/06377413236983002873noreply@blogger.comtag:blogger.com,1999:blog-7729093380675162051.post-49587906251644091002015-06-18T22:26:14.203+10:002015-06-18T22:26:14.203+10:00Olof, Anonymous, you might be right about the caus...Olof, Anonymous, you might be right about the causes of discrepancy. When I check NCEP cfsv2 anomaly, it is to have an estimate of futur GISS data. Usually, you can have an estimate. But sometimes it doesn't work so I tried to understand why. Anomalies in polar regions (that you can see on NCEP month-to-date) seems to be associated with low giss global anomaly. So my question would be : can you use NCEP cfsv2 data to estimate Gistemp ? I would say it is possible to have an estimate if you make a correction, depending on anomalies in polar regions.KCnoreply@blogger.comtag:blogger.com,1999:blog-7729093380675162051.post-30420809411015368682015-06-18T21:19:57.375+10:002015-06-18T21:19:57.375+10:00I observed the difference over Antarctica too. The...I observed the difference over Antarctica too. The difference may be due the use of the sig995 level instead of 2m surface temperatures so missing inversions in the Antarctic winter?! See<br />http://www.moyhu.blogspot.com.au/2014/11/a-new-surface-temperature-index.htmlAnonymousnoreply@blogger.comtag:blogger.com,1999:blog-7729093380675162051.post-24145471055250411252015-06-18T20:59:52.383+10:002015-06-18T20:59:52.383+10:00Ok, different base periods explain some of the dis...Ok, different base periods explain some of the discrepancy. An other source of error could be that reanalyses calculate 2 m air temperatures, but the global observational datasets use 71% SST, and that is not always the same..<br />And then we have the polar regions that are poorly covered:<br />I encountered "strange" values when I ran NCEP/NCAR 2m for the Antarctic area 70S-90S at KNMI Climate Explorer. The May anomaly was +1.42 (1981-2010 base). That is not what the Gistemp map tells, the zonal anomaly for 70S-90 S is more like -1.7 for May (1981-2010 base).Olofnoreply@blogger.comtag:blogger.com,1999:blog-7729093380675162051.post-83069920374206249862015-06-18T16:33:05.389+10:002015-06-18T16:33:05.389+10:00I also compared NCEP and GISS temperatures and I t...I also compared NCEP and GISS temperatures and I think now there can be no doubt : each time you have cold anomalies in polar regions, the anomaly is lower for GISS that NCEP cfsv2. The opposite is true : look at may and september 2014 : these two months were warmer for GISS that for NCEP. Both months were quite hot in polar regions. July 2014 is quite extraordinary with low anomaly for GISS : it was cold in the Arctic an Antarctica. GISS is covering those regions and any discrepancy shows that something is going on there.KCnoreply@blogger.com