tag:blogger.com,1999:blog-7729093380675162051.post1814212153927746503..comments2024-03-28T13:56:47.604+11:00Comments on moyhu: Record warm periodsNick Stokeshttp://www.blogger.com/profile/06377413236983002873noreply@blogger.comBlogger41125tag:blogger.com,1999:blog-7729093380675162051.post-80495333814461956272015-08-14T08:30:14.611+10:002015-08-14T08:30:14.611+10:00Hi JCH,
I don't know that I have too much to ...Hi JCH,<br /><br />I don't know that I have too much to add to this. We know that AMO has gone negative before without the AMOC shutting down, so my guess is that AMOC is part of the dynamics of the AMO, but the AMOC dynamics do not encapsulate the AMO dynamics.<br /><br />I'd also be cautious against over-interpreting short-period changes in a system that could have components as long as 60-years in duration.Carrickhttps://www.blogger.com/profile/03476050886656768837noreply@blogger.comtag:blogger.com,1999:blog-7729093380675162051.post-45641438735856867112015-08-13T06:43:56.349+10:002015-08-13T06:43:56.349+10:00We see differences for June 2015 between using UAH...We see differences for June 2015 between using UAH/MERRA vs Kriging which is interesting as well. <br /><br />A big difference between our record and HadCRUTv4 is the treatment of 2010. The warming that occurred in 2010 was most extreme in areas without as good observations. In contrast, in 1998 the warming was most extreme where we had good observations. The effect was essentially that once you account for Arctic warming the ranks change substantially (as I'm sure you know).<br /><br />http://www-users.york.ac.uk/~kdc3/papers/coverage2013/ERA-I_2010_Minus_1998.png<br /><br />Anonymoushttps://www.blogger.com/profile/09100917268285610408noreply@blogger.comtag:blogger.com,1999:blog-7729093380675162051.post-464774614115682342015-08-13T01:45:41.708+10:002015-08-13T01:45:41.708+10:00Here's a comparison of rankings for HadCrut vs...Here's a comparison of rankings for HadCrut vs C&W Kriging (1961-1990 baesline).<br /><br />2007.04 0.832 2007.042 0.862<br />1998.12 0.763 2010.208 0.801<br />2015.46 0.728 2010.292 0.794<br />2002.12 0.705 2002.208 0.765<br />2002.21 0.699 2010.125 0.736<br />2006.96 0.698 2015.208 0.721<br />2015.38 0.696 2013.875 0.719<br />2015.04 0.688 2014.792 0.709<br />2015.21 0.681 2014.625 0.709<br />2010.29 0.679 2014.708 0.707<br /><br />I would say this is interesting, but probably a better measure would be trends.Carrickhttps://www.blogger.com/profile/03476050886656768837noreply@blogger.comtag:blogger.com,1999:blog-7729093380675162051.post-29963015303136413412015-08-12T20:17:40.252+10:002015-08-12T20:17:40.252+10:00BTW, all the C&W datasets were updated by the ...BTW, all the C&W datasets were updated by the evening August 10. I forgot that Cowtan is a wizard with data, working faster than expected.... :-)Olofnoreply@blogger.comtag:blogger.com,1999:blog-7729093380675162051.post-6920200749610021652015-08-12T13:42:11.634+10:002015-08-12T13:42:11.634+10:00Olaf, thanks! That's a good point.Olaf, thanks! That's a good point. <br />Carrickhttps://www.blogger.com/profile/03476050886656768837noreply@blogger.comtag:blogger.com,1999:blog-7729093380675162051.post-74491536297932229622015-08-11T03:23:15.752+10:002015-08-11T03:23:15.752+10:00Carrick - I've been thinking about your AMO co...Carrick - I've been thinking about your AMO comment, and I just cannot see it. I do not think the AMO can get significantly less positive than it is right now... unless the AMOC virtually stops. And nobody is predicting that. It has slown down; there is a persistent blue blob in the North Atlantic that is surrounded by walls of yellow and red SST; it's self limiting as long as the AMOC is up and going. JCHnoreply@blogger.comtag:blogger.com,1999:blog-7729093380675162051.post-84082592597204266742015-08-10T19:52:57.466+10:002015-08-10T19:52:57.466+10:00Carrick, if there is a seasonal change with changi...Carrick, if there is a seasonal change with changing base periods, the rank of warmest monthly anomaly may change. No 4 has changed, I believe. No major issue though, changes are likely within error...<br />These days, with all new dataset versions, are most frustrating. Everything, databases, spreadsheets, calculations, have to be updated.<br />It must be a major revision of almost everything for Cowtan, he is not paid for it, and have to do it in his spare time, so I think we have to wait a while for C&W updatesOlofnoreply@blogger.comtag:blogger.com,1999:blog-7729093380675162051.post-48032905325187302142015-08-10T04:40:36.151+10:002015-08-10T04:40:36.151+10:00Just to follow up--the only difference here should...Just to follow up--the only difference here should be the baseline (which doesn't matter for ranking). I used the shorter kriging series because I could compare the effects of kriging to their UAH and MERRA interpolation methods.Carrickhttps://www.blogger.com/profile/03476050886656768837noreply@blogger.comtag:blogger.com,1999:blog-7729093380675162051.post-5745801116163908932015-08-07T16:59:56.579+10:002015-08-07T16:59:56.579+10:00OK, that's the short one, with base 1981-2010,...OK, that's the short one, with base 1981-2010, for comparison with hybrid data... <br />Looks like the top three rank are the same as in the "operative" 61-90 base version.Olofnoreply@blogger.comtag:blogger.com,1999:blog-7729093380675162051.post-86638272781951148352015-08-07T10:25:12.801+10:002015-08-07T10:25:12.801+10:00I'm using this file:
http://www-users.york.ac...I'm using this file:<br /><br />http://www-users.york.ac.uk/~kdc3/papers/coverage2013/had4_short_krig_v2_0_0.txt<br /><br />Jan 2007 is 0.531 and Mar 2010 is 0.485<br /><br /><br />Carrickhttps://www.blogger.com/profile/03476050886656768837noreply@blogger.comtag:blogger.com,1999:blog-7729093380675162051.post-28043764285700526802015-08-07T08:02:01.077+10:002015-08-07T08:02:01.077+10:00Sorry, I did not see your anwer below.....Sorry, I did not see your anwer below.....Olofnoreply@blogger.comtag:blogger.com,1999:blog-7729093380675162051.post-22167694751677609922015-08-07T07:59:09.036+10:002015-08-07T07:59:09.036+10:00Looks like you got the new Hadcrut 4.4 data, but C...Looks like you got the new Hadcrut 4.4 data, but Cowtan has not yet laid his hand on it.<br />BTW, Your C&W numbers must be wrong, No 1 is Jan 2007 (0.863) and No 2 March 2010 (0.805) Olofnoreply@blogger.comtag:blogger.com,1999:blog-7729093380675162051.post-22453274196213869892015-08-07T07:34:41.089+10:002015-08-07T07:34:41.089+10:00This is the file I used:
http://www.metoffice.gov...This is the file I used:<br /><br />http://www.metoffice.gov.uk/hadobs/hadcrut4/data/current/time_series/HadCRUT.4.4.0.0.monthly_ns_avg.txt<br /><br />If there is a newer one, it hasn't made it's way to <a href="http://www.metoffice.gov.uk/hadobs/hadcrut4/data/current/download.html" rel="nofollow">their website</a> yet.Carrickhttps://www.blogger.com/profile/03476050886656768837noreply@blogger.comtag:blogger.com,1999:blog-7729093380675162051.post-31299644164273335842015-08-07T07:31:07.057+10:002015-08-07T07:31:07.057+10:00Olof---I downloaded it this morning. If there'...Olof---I downloaded it this morning. If there's something after version 4.4.0, somebody else will have do it.Carrickhttps://www.blogger.com/profile/03476050886656768837noreply@blogger.comtag:blogger.com,1999:blog-7729093380675162051.post-30089726512993316602015-08-07T06:23:06.764+10:002015-08-07T06:23:06.764+10:00Sorry Carrick, you have to redo the numbers. There...Sorry Carrick, you have to redo the numbers. There is a new version Hadcrut 4.4 out now. No adjustments per se, but a lot of new stations and data in CRUTEM. They seem to have warmed the past, 1885-1950, but there are small warming changes in recent years too..<br />http://www.metoffice.gov.uk/hadobs/crutem4/data/update_diagnostics/global_n+s.gif<br /><br />There is also a new record (like all other gridded datasets) for Hadcrut June ( 0.728), but it would have been so without the "adjustment" also.Olofnoreply@blogger.comtag:blogger.com,1999:blog-7729093380675162051.post-89473559752358630932015-08-07T02:14:28.766+10:002015-08-07T02:14:28.766+10:00JCH---managed to break the subthread sorry.
The l...JCH---managed to break the subthread sorry.<br /><br />The left column above is HadCRUT sorted by warmest temperature. The right column is HadCRUT + Kriging from Cowtan and Way's website, also sorted by warmest temperature.Carrickhttps://www.blogger.com/profile/03476050886656768837noreply@blogger.comtag:blogger.com,1999:blog-7729093380675162051.post-44894331289399278972015-08-07T02:10:02.506+10:002015-08-07T02:10:02.506+10:00JCH: Carrick - I do not think there is a time when...JCH: <i>Carrick - I do not think there is a time when ENSO is not effecting the GMSAT. ENSO is a big.</i><br /><br />This is a truism, but I think it's missing part of the point:<br /><br />The way I see it, there is a high correlation between the temperature in the region of the Pacific dominated by the ENSO and the ±30°. latitude band. So for periods of 2-5 years, the fluctuations in this band are driven almost entirely by what happens in the ENSO region.<br /><br />This statement is still true, whether you add or subtract a constant from a particular ENSO temperature index. The correlation coefficient between two series that are oscillating in the frequency band 1/5 - 1/2 years^-1 is trivially unaffected by the addition of an offset to one of the series.<br /><br />If the offset is generated by other longer period oscillations (without a redefinition of the series similar to what WHT is doing), these offsets won't get fully subtracted when you detrend the ENSO average. (I'd have to investigate MEI a bit further to see what happens there, but my speculation is that you'll get contamination in the MEI index from AMO generated fluctuations).<br /><br />Anyway, in my opinion, that's the problem with using fixed thresholds: It is sensitive to an over all bias in the mean value generated by longer period fluctuations. An temperature acceleration based metric would likely be more robust, if also quite a bit more obtuse for laypeople to interpret.<br /><br />What I would say is actually important is that we are seeing an upward trend of the ENSO index, and that's forcing an upwards trend in temperature. Given that we are likely to see a strong ENSO this year, I expect to see more new records set as we go along, especially in series like HadCRUT which effectively over-weight the regions most affected by ENSO.<br /><br />But the important thing is not to mistake short-period trends (which likely will continue to have both signs as we move forward) for longer period trends. <br /><br /><i>If the adjustments are correct, then adjustments did not set records, the climate system did that.</i><br /><br />The first question should be whether the records are meaningful. If they are monthly records and they amount to just a few hundredths of a °C, I would say not so much (the bias in the measurement is probably larger than this, and as I've pointed out above, by selecting a single month without smoothing to annual first, you're aliasing in high frequency noise).<br /><br />The fact that the (generally recognized as inferior) global mean temperature series from HadCRUT is showing large records is actually evidence (to me) of the importance of making adjustments of the Cowtan & Way variety. If you compare "unadjusted" HadCRUT to the adjusted records (using e.g., kriging), the recent two records from HadCRUT disappear once you account for the "missing" surface area of the Earth:<br /><br />2007.04 0.832 2007.042 0.531<br />1998.12 0.763 2010.292 0.485<br />2015.46 0.728 2010.208 0.454<br />2002.12 0.705 2014.708 0.437<br />2002.21 0.699 2002.208 0.431<br />2006.96 0.698 2014.375 0.425<br />2015.38 0.696 2014.792 0.413<br />2015.04 0.688 2013.875 0.412<br />2015.21 0.681 2010.875 0.412<br />2010.29 0.679 2006.958 0.401<br /><br />Adjustments are important, because they allow a more accurate determination. But one of the point of the adjustments is that series that don't make the adjustments are typically going to be less reliable than those that do.Carrickhttps://www.blogger.com/profile/03476050886656768837noreply@blogger.comtag:blogger.com,1999:blog-7729093380675162051.post-49100602216941495802015-08-07T00:15:14.812+10:002015-08-07T00:15:14.812+10:00Carrick - I do not think there is a time when ENSO...Carrick - I do not think there is a time when ENSO is not effecting the GMSAT. ENSO is a big.<br /><br />If the adjustments are correct, then adjustments did not set records, the climate system did that. JCHnoreply@blogger.comtag:blogger.com,1999:blog-7729093380675162051.post-14208872123864320662015-08-07T00:01:04.338+10:002015-08-07T00:01:04.338+10:00ehak, three new records have been created in the ...ehak, three new records have been created in the last twelve months by adopting the probably more accurate ERSSTv4 series. Most reasonable people would agree that corresponds to “recent”.<br />Carrickhttps://www.blogger.com/profile/03476050886656768837noreply@blogger.comtag:blogger.com,1999:blog-7729093380675162051.post-49709081377020768682015-08-06T23:49:39.600+10:002015-08-06T23:49:39.600+10:00JCH: As for ENSO, these records were reached not i...JCH: <i>As for ENSO, these records were reached not in El Nino conditions, but in ENSO neutral conditions. </i><br /><br />The ENSO indices are simple averages over different sectors of the Pacific ocean, and ENSO positive, negative and neutral are frankly arbitrary thresholds. This is an attempt to collapse a complex phenomenon into simple metrics that are easy to interpret, but the price is you lose a lot of science by doing this.<br /><br />I just don’t think you can look whether the ENSO matrix has passed some magical threshold to decide whether or not the ENSO is affecting the currently observed temperatures. <br /><br />Carrickhttps://www.blogger.com/profile/03476050886656768837noreply@blogger.comtag:blogger.com,1999:blog-7729093380675162051.post-30286043608687067282015-08-06T23:30:37.069+10:002015-08-06T23:30:37.069+10:00This comment has been removed by the author.Carrickhttps://www.blogger.com/profile/03476050886656768837noreply@blogger.comtag:blogger.com,1999:blog-7729093380675162051.post-67144848860762461812015-08-06T21:46:41.778+10:002015-08-06T21:46:41.778+10:00As for ENSO, these records were reached not in El ...As for ENSO, these records were reached not in El Nino conditions, but in ENSO neutral conditions. <br /><br />What did they say at Pearl Harbor? Are those blips birds? Better ask upstairs. No, don't worry. Those blips are our B-17s. Boom boom boom!<br />JCHnoreply@blogger.comtag:blogger.com,1999:blog-7729093380675162051.post-16231135504500839112015-08-06T18:51:44.966+10:002015-08-06T18:51:44.966+10:00"Mind you, I'm not objecting to adjustmen..."Mind you, I'm not objecting to adjustments, but since recent temperature records were created from these new adjustments, it would be perhaps disingenuous to suggest that these adjustments aren't important."<br /><br />What does this disingenuousness boil down to? February 2015, December 2014 and October 2014 got records with ERSTT4 in Gistemp. "Recent temperature records created from these adjustments". But of course, "recent" is a very moving goalpost.<br /><br />Truly impressed Carrick.ehaknoreply@blogger.comtag:blogger.com,1999:blog-7729093380675162051.post-40414981163080205392015-08-06T15:21:57.884+10:002015-08-06T15:21:57.884+10:00Olaf—I wasn’t t discussing JMA (which I never look...Olaf—I wasn’t t discussing JMA (which I never look at) nor HadCRUT. Nor am I disputing that we are currently in a warm period for Earth’s climate over the last say 6000 years at lest.<br /><br />Second, I absolutely recognize the need to make adjustments to data, when those adjustments improve the accuracy of the measure.<br /><br />Third, I’m not sure what you’re suggesting by “The high temperature trends of the recent century in the "adjusted" datasets is not a novelty…”. Nobody is disputing the reality of the trends.<br /><br />Now I will admit I am significantly a curmudgeon when it comes to comparing unsmoothed monthly records against each other. By picking a particular month of a 12-month series (without smoothing), you are under sampling the data series, which by aliasing, means (when the records are small) that you are basically just looking at noise.<br /><br />I do think the trends are meaningful, but of course, you have to wait a longer period to decide whether the recent records are part of a trend, or just some random ENSO created blip (odds are on “blip” in my opinion).<br /><br />The only point I was discussing was Nick’s comment that he didn’t use adjustments (technically he’s right that he doesn’t use adjustments for LAND temperatures, but that’s just 1/4 of the area of the Earth). Nor is it actually true that the effect of the adjustments are uninteresting.<br /><br />To answer your question, I was looking at GISTEMP with ERSSTv4 and compared it with GISTEMP ERSSTv3 and HRSSTv2. As far as I know, they don’t quote the global mean temperature series for all three of these SST series, which of course complicates things.<br /><br />They do have on-line tools you can use to pull 2*x2* gridded data for each of these cases. I wrote a scraper to pull these down, and then area averaged them. For the rare cases where there were missing grid points, effectively I averaged over the latitude containing that (those) missing point (points) and infilled. This is more accurate than what HadCRUT does (which is effectively replace the missing points with the global mean, a very poor assumption).<br /><br />Anyway, here’s some of the new records (by my current tally there is just one new GISTEMP record in 2015):<br /><br />Jan: no change (2007/0.965°C)<br />Feb: 2015/0.876°C (was 1998/0.861°C)<br />Mar: 2010/0.195°C (was 2002/0.885°C)<br />Apr: no change (2010/0.864°C)<br />May: no change (2014/0.858°C)<br />Jun: no change (1998/0.789°C)<br />Jul: 2009/0.759°C (was 2011/0.712°C)<br />Aug: no change (2014/0.787°C)<br />Sep: no change (2014/0.906°C)<br />Oct: 2014/0.832°C (2005/0.770°C)<br />Nov: no change (2013/0.806°C)<br />Dec: 2014/0.793 (2006/0.754°C)<br /><br />That means 5/12 months saw a new record in a different year, and for 4/12 months the newer record occurred in a more recent year than the previous one (this shouldn’t be a shock given that using ERSSTv4 gives a significant increase in total trend in global mean temperature:<br /><br /><a href="http://data.giss.nasa.gov/gistemp/updates_v3/ersst4vs3b/v4-v3b.gif”>Figure.</a>Carrickhttps://www.blogger.com/profile/03476050886656768837noreply@blogger.comtag:blogger.com,1999:blog-7729093380675162051.post-35665393986999731362015-08-05T09:44:38.184+10:002015-08-05T09:44:38.184+10:00Carrick, which records were created by ERSST v4 ad...Carrick, which records were created by ERSST v4 adjustments?<br />JMA got new records in March, May and June 2015 without adjustments.<br />HADCRUT4 got new records in March, May, and likely also in June without adjustments.<br />The 12-month running mean records have been broken month by month during 2015, in all global datasets, new and old.<br />The high temperature trends of the recent century in the "adjusted" datasets is not a novelty, it was already there in Cowtan&Way, BEST and TempLS MeshOlofnoreply@blogger.com