Saturday, December 3, 2016

NCEP/NCAR November up 0.06°C - warmest since April.

The Moyhu NCEP/NCAR index rose from 0.419°C in October to 0.48°C. Not huge, but it makes it the warmest (just) since April, an ENSO peak month. The change mirrors a rise to November of 0.04°C in UAH V5.6.

The month started with a big peak, then a dip, then a smaller peak, still current. The big feature was a cold band across Siberia, extending into N Pacific. But it was balanced by warmth in Arctic, Antarctic and N America.

Sea ice at both poles was unusually low, with even some days of melting in the Arctic. Arctic is still record low, but will probably become more normal. Antarctic is very low indeed, and seems to be getting more so, heading into peak melting season. Here is the recent part of the radial plot, where black is 2016, and colors are other recent years:







10 comments:

  1. Nick, I see by your post time of 5:28 am you're being the early bird again. I tend to be an early bird, while my wife and daughter are night owls.

    My tracking of the GFS/CFSV2 output provided by UM CCI shows a preliminary GMT anomaly estimate of +0.42C for November, up from +0.38C in October, referenced to 1981-2010. As of this writing, WxBELL has not published their final map for November, but their preliminary month-to-date through 00Z Nov 30 showed +0.429C, which is up from +0.376 in October, referenced to 1981-2010. Both of these results are very close to what you found and are slightly lower than for November 2015 (and thus not the highest November global temperature in the satellite era record).

    I agree it appears the Arctic ice extent seems to be trying to make a recovery more in line with typical extents for recent years and the Antarctic seems to be dropping even lower compared to recent years. It will be interesting to watch both over the next several months. I'm a novice at watching ice extents, so I don't have much of a clue as to causes, although I suspect the higher than normal ocean surface temperatures in the Arctic are a big player. Another possible player is cloud cover. In the Arctic night above normal cloud cover would help to prevent cooling at the surface and thus delay ice formation, especially in combination with higher than normal ocean surface temperatures. In the Antarctic, if cloud cover were below normal, it might help accelerate melting ahead of the summer minimum ice extent, despite the lower than normal ocean surface temperatures now seen along the edge of the ice extent. I have not seen any cloud cover anomaly information for either pole, so I'm not sure if that is really a factor in either case.

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    1. Bryan,
      Yes, I do get up early, especially now when the sun is early here. And about 3rd of month, I look for NCEP/NCAR which shows up about midnight our time.

      We had a few months of pretty divergent results among indices - so far, this month seems fairly consistent. Surprising, in a way, with the big features in Siberia and Arctic.

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    2. Nick, yes that huge contrast between very low temperature anomalies in Siberia versus very high anomalies over the Arctic Ocean was impressive. The preliminary GFS based UM CCI Arctic zone (60N-90N) daily temperature anomaly referenced to 1979-2000 peaked at +7.30C on November 19, which was slightly higher than the previous 2016 peak of +7.10C on January 3. The corresponding Northern Hemisphere anomalies were +.070C and +1.35C respectively, and assuming that the Arctic zone is about 14% of the NH surface area, I calculate -0.37C and +0.41C respectively for the remainder of the NH (0N-60N) on these two days.

      Here's the null school GFS view of temperatures and wind around the Arctic on November 19 for grins:
      Null School Arctic Orthographic View 2016-11-19

      Wish they had a way to overly actual GFS input station temperature data as colored bubbles on the map to see how well the GFS represents the actual measurements. It would be a great diagnostic tool.

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    3. WUWT is predicting GISS at .95 ℃. Even given 2016's phenomenal numbers, .95 remains a big number. Prior to the 2015 El Niño, only one month in the entire GISS record exceeded .95 ℃: January 2007 at .96 ℃. That month land was the warmest in the record and oceans 4th warmest... L&O warmest.

      So suggestions around the internet that temperatures have collapsed back to the pause levels are nuts.

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  2. Some noodling on the impact of low Southern Hemisphere sea ice. Recently, per the Mohyu data page, Antarctic sea ice has been running 2,500,000 square kilometers under last year. That is roughly 0.5% of the earth's surface. From a Tamino blog, the albedo difference between sea ice and ocean after accounting for clouds is 0.2. On the December solstice, the sun will provide roughly 50% higher insolation at 70S vs the global average. So up to 0.15% additional solar energy could be absorbed at the earth's surface due to low S Hemisphere sea ice this year vs last year. Of course the impact will weaken somewhat off the solstice and disappear during the long polar night. Still the impact will be similar in magnitude to going from the peak to valley in a solar cycle.

    Chubbs

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  3. NOAA PDO for November 2016 is out at .53, way up from October's -.76. I have never found anything that even begins to explain how the index is calculated, but it appears the presence or absence of upwelling along the west coasts of the US and Canada is determinant as lack of upwelling appears to have outweighed the emergence of the blue blob in the North Pacific. It will be interesting to see if JIASO follows with an uptick. Their index has yet to go negative in 2016,

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  4. Era-interim, the flagship of EU climate research, reports the warmest November on record, up by 0.04 C from Oct.
    https://climate.copernicus.eu/resources/data-analysis/average-surface-air-temperature-analysis/monthly-maps/november-2016

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    1. Olof, thanks for the link. I just downloaded the Copernicus monthly ERAI GSTA estimates since 1979 and will be comparing them with CFSR/CFSV2 GSTA estimates posted by UM CCI. UM CCI also has posted ERAI monthly GSTA estimates through 2015 and I did a quick comparison with the Copernicus ERAI data for 2015 and oddly found the UM CCI values to be 0.05C lower on average for the year when referenced to the same 1981-2010 baseline. I'm not sure why there is a discrepancy, although possibly the ERAI estimates have been adjusted upward since UM CCI retrieved them probably in early 2016 (they currently do not have any monthly 2016 ERAI estimates posted) or possibly they were obtained from a different source?

      The UM CCI just today provided final daily CFSV2 GSTA estimates for October 10 through November 30. From the final daily CFSV2 estimates I calculated semi-final monthly averages for October and November and got +0.379C and +0.438C respectively (referenced to 1981-2010), which correspond to 14.889C and 13.838C for GST. The semi-final November 2016 GST estimate ties the CFSR estimate for November 2005 and is slight lower than the CFSV2 November 2015 estimate of 13.87C. UM CCI have not yet posted final monthly CFSV2 estimates since July 2016.

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    2. Bryan, there is an SST and ocean SAT discontinuity in the publicly available Era-interim datasets. To correct those data 0.1 C should be added from 2002 and on, which makes about +0.07 C globally, and raise trends that run over the discontinuity.
      This issue has been fixed in the Era-interim version that is posted at the Copernicus site. I think this explains the version discrepancy that you have found..

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    3. Olof, thanks. That's it. Before I saw your reply, I just finished graphing the UM CCI versus Copernicus ERAI GSTA data since 2001 and I noticed right away the discrepancy started in 2002, with a close match for 2001. Hopefully UM CCI will update their data soon to the newer version to avoid confusion.

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