Saturday 30 August 2014

Ocean temperature spike

World Ocean Temps Spike to +1.26 Positive Anomaly as Antarctic Polar Amplification Ramps Up

29 August, 2014
Prospects for a moderate to strong El Nino are fading even as the eventual emergence of El Nino this year grows increasingly in doubt. But despite the failure of a weather system which tends to both spike global sea surface temperatures and atmospheric temperature values, the world’s oceans are screaming with heat, today entering hottest yet daily values for 2014 of 1.26 degrees above the already hotter than normal 1979-2000 average.
The monster Kelvin Wave that so many forecasters believed would set off a moderate-to-powerful El Nino this year by as soon as this summer was crushed by a failure of atmospheric feedbacks. Strong westerly winds did not emerge and powerful high pressure systems both north and south of the Equator kept fueling the easterly trades, which tended to over-ride west wind systems when they did emerge. One of these high pressure zones was the doggedly persistent blocking high sitting off the US West Coast and contributing to the worst drought conditions in a century for California.
The Kelvin Wave was strong enough, however, to set off conditions in which May and June of 2014 were the hottest in the global record and in which ocean surface temperatures during July were also the hottest in the 135 year global record.
During that time, June saw global daily ocean temperature anomalies spike to as high as +1.25 C above the already hotter than normal 1979 to 2000 average in the GFS measure. Today, despite equatorial Pacific Ocean temperatures backing off from June highs, global sea surface temperatures spiked to an extraordinary +1.26 positive anomaly, beating out a time when a very energetic Kelvin wave was dumping a high level of heat into the Equatorial Pacific surface zone.

Sea Surface Temperature Anomaly global August 29, 2014

(Global Sea Surface Temperature Anomaly as of August 29th of 2014. Image source:University of Maine.)

These are extraordinary high sea surface temperatures. And they are likely a continuation of a trend, now four months running, in which the global ocean surface was at or near record highs.
Globally, the hottest areas continued to include a very warm zone off the US West Coast, a zone of +3 to +4 C positive anomaly values in the Bering Sea and behind the arch of the Aleutian Islands between Alaska and Russia, and a zone of much warmer than normal waters from Maine to Greenland to Iceland and Svalbard.
Austral Polar Amplification Heats Up
Even as global ocean surface temperatures shot to record or near record high daily values, Antarctica was undergoing its own major warm-up.
Human greenhouse gasses, more efficient at trapping heat during the long polar night that is winter, and at record warming values in the range of 481 CO2e appeared to be doing their work. For yesterday, temperature anomalies for all of Antarctica spiked to above +3 degree Celsius positive anomaly. Though not as high as the +5 C and greater anomalies observed for the Arctic during the winter of extreme polar vortex disruption that was 2013-2014, the Antarctic heat spike is still quite high. This is especially true for a region that has seen an expanding pulse of cooling fresh water from glacial melt together with strong down-welling and atmosphere to waters heat transfer in the Southern Ocean.

Antarctic Polar Amplification
(Antarctic heat anomaly of +2.94 C above the already warmer than normal 1979 to 2000 average on August 29, 2014. Image source: University of Maine.)

As of today, Antarctic heat anomalies were still in the very well above average range at +2.94 C. Most of the excess heat centered over the now destabilized and seaward spreading glaciers of West Antarctica which experienced extraordinary temperatures in the range of 15 to 20 degrees Celsius above average.
This much warmer than normal pool of air spilled above average warmth in all directions. And were it not for the expanding fresh water wedge, salt water downwelling, and strong winds driving a powerful atmosphere to ocean heat transfer in the Southern Ocean, the overall Antarctic temperature anomaly values would be even higher.
Overall, global surface temperatures were at +0.71 C above the 1979 to 2000 average in the global GFS measure today. And with August remaining far warmer than average for most the month, it appears likely that we will have another record or near record warm month. It is almost certain that ocean values with be at record levels and atmospheric values are not too far behind. All this potential for new record heat despite El Nino failing to form and increasingly in doubt.
New Kelvin Wave Not So Strong As the Last
To this point it is worth noting that a new warm Kelvin Wave is now propagating across the Pacific. The current wave is not anywhere near as strong as the event which occurred during winter and spring of 2014. Despite the failure of that Kelvin Wave and the weaker stake of the current wave, NOAA is still predicting a 65% percent chance of El Nino before the end of 2014. This is a lower potential than the 75 to 80 percent prediction from earlier this year and even if El Nino does emerge, consensus models now show a rather feeble iteration peaking at around +0.6 C for mid ocean temperature anomalies.

Kelvin Wave August 21
(Most recent Kelvin Wave as detected by NOAA. Image source: NOAA’s Climate Prediction Center)

Regardless, even if El Nino doesn’t form it appears that 2014 is well on its way to being one of the hotter years in the global record, continuing a long trend of inexorable surface warming.


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