Bob Tisdale on Climate Change and Global Warming Blog
By Bob Tisdale
Thursday, June 10, 2010
La Niña Is Not The Opposite Of El Niño – The Videos
http://i46.tinypic.com/2zqznnn.jpg
Figure 1 – Sample Animation – Not Used In Video
Recently, I began animating maps that represent 12-month averages of “noisy” datasets with good results. The weather noise and seasonal variations are gone, for the most part. The 12-month-averaged TLT anomaly maps present a much “smoother” animation, as shown in the .gif sample, Figure 2.
http://i48.tinypic.com/2gt6slz.jpg
Figure 2 – Sample Of Animation Used In Video
In the video, I liken the effect to smoothing the data in a time-series graph with a 12-month filter, Figure 3.
http://i48.tinypic.com/160wk1w.jpg
Figure 3 – Smoothed Time-Series Graph
VIDEO DESCRIPTION
The following 2-part video series provides detailed descriptions, time-series graphs, and animations of the processes that take place during El Niño and La Niña events. It uses TLT, SST, Total Cloud Amount, Sea Level, and Downward Shortwave Radiation anomalies to help illustrate the significant differences between the 1997/98 El Niño and the 1998/99/00/01 La Niña.
The videos also help illustrate why the effects of ENSO cannot be removed from the global surface temperature record by simply subtracting scaled and lagged NINO3.4 SST anomalies (or another ENSO index) from global temperature anomalies. There are significant residuals that contribute to global temperature anomaly trends, and these residuals are not accounted for with the simple methods used in climate studies such as Thompson et al (2009). Link (with paywall) to Thompson et al (2009):
http://journals.ametsoc.org/doi/abs/10.1175/2009JCLI3089.1
I’ve also included animations that compare global SST anomalies with the other datasets. A sample frame that compares SST and TLT anomalies is shown in Figure 4. To indicate the timing of the maps as they proceed from El Niño to La Niña, many of the animations also include time-series graphs that fill in as time progresses.
http://i49.tinypic.com/2yl22bk.jpg
Figure 4 – Sample Frame From Animation Of Two Datasets
THE VIDEOS
Please view the animations full screen and, if possible, in high definition.
Part 1
YouTube Link
http://www.youtube.com/watch?v=Et3wjKKCy5o
####################
Part 2
YouTube Link
http://www.youtube.com/watch?v=A6bmb8hi6u0
SOURCES AND DATASETS
The maps were created using the map-making feature of the KNMI Climate Explorer, which was also used for the data in the time-series graphs.
http://climexp.knmi.nl/selectfield_obs.cgi?someone@somewhere
The primary SST and SST anomaly data used in the animations and graphs are NOAA/Reynolds Optimum Interpolation (OI.v2) SST.
http://www.emc.ncep.noaa.gov/research/cmb/sst_analysis/
For the comparison to tropical Pacific Ocean Heat Content, a longer-term SST dataset was required, and for that graph, I used Kaplan/Reynolds (OI.v2) NINO3.4 SST anomalies from the Monthly climate indices webpage of the KNMI Climate Explorer. Link to Kaplan overview:
http://www.cgd.ucar.edu/cas/guide/Data/kaplan_sst.html
The other datasets used in the videos are also available through the KNMI Climate Explorer and they include:
1. International Satellite Cloud Climatology Project (ISCCP) Total Cloud Amount data. Link:
http://isccp.giss.nasa.gov/projects/flux.html
2. CAMS-OPI [Climate Anomaly Monitoring System (“CAMS”) and OLR Precipitation Index (“OPI”)] precipitation data. Link:
http://www.cpc.noaa.gov/products/global_precip/html/wpage.cams_opi.html
3. RSS MSU Lower Troposphere Temperature (TLT) anomalies. Link:
http://www.remss.com/msu/msu_data_description.html
4. CLS (AVISO) Sea Level anomalies. Link:
http://www.aviso.oceanobs.com/en/news/ocean-indicators/mean-sea-level/
5. NCEP/DOE Reanalysis-2 Surface Downward Shortwave Radiation Flux (dswrfsfc) anomalies. Link:
http://www.cpc.ncep.noaa.gov/products/wesley/reanalysis2/kana/reanl2-1.htm
There is also an animation of the Equatorial Subsurface Temperature Cross-sections that are available through the ECMWF website:
The Trade Wind Index (5S-5N, 135W-180) Anomaly data is available through the NOAA CPC website. Scroll down to the second grouping for the anomaly data:
http://www.cpc.noaa.gov/data/indices/wpac850
FURTHER DISCUSSIONS
The first detailed posts on the multiyear aftereffects of El Nino events are:
Can El Nino Events Explain All of the Global Warming Since 1976? – Part 1
And:
Can El Nino Events Explain All of the Global Warming Since 1976? – Part 2
And:
Supplement To “Can El Nino Events Explain All Of The Warming Since 1976?”
And:
Supplement 2 To “Can El Nino Events Explain All Of The Warming Since 1976?”
The impacts of these El Nino events on the North Atlantic are discussed in:
There Are Also El Nino-Induced Step Changes In The North Atlantic
And:
Atlantic Meridional Overturning Circulation Data
The Lower Troposphere Temperature (TLT) anomaly responses are discussed in:
RSS MSU TLT Time-Latitude Plots… Show Climate Responses That Cannot Be Easily Illustrated With Time-Series Graphs Alone
And:
El Ninos Create Step Changes in TLT of the Northern Hemisphere Mid Latitudes
The misrepresentation of ENSO in climate studies are discussed in the following (The discussions are similar but there are differences in the presentation):
Climate Studies Misrepresent The Effects Of El Nino And La Nina Events
And:
The Relationship Between ENSO And Global Surface Temperature Is Not Linear
And:
Multiple Wrongs Don’t Make A Right, Especially When It Comes To Determining The Impacts Of ENSO
And:
Regression Analyses Do Not Capture The Multiyear Aftereffects Of Significant El Nino Events.”
Posts related to the effects of ENSO on Ocean Heat Content are here:
ENSO Dominates NODC Ocean Heat Content (0-700 Meters) Data
And:
North Atlantic Ocean Heat Content (0-700 Meters) Is Governed By Natural Variables
And:
North Pacific Ocean Heat Content Shift In The Late 1980s
Detailed technical discussions can be found here:
More Detail On The Multiyear Aftereffects Of ENSO – Part 1 – El Nino Events Warm The Oceans
And:
More Detail On The Multiyear Aftereffects Of ENSO – Part 2 – La Nina Events Recharge The Heat Released By El Nino Events AND…During Major Traditional ENSO Events, Warm Water Is Redistributed Via Ocean Currents.
And:
Posted by Bob Tisdale at 9:32 AM
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The article has raised many comments and questions that point to the complexity of the subject of climate change, global warming and global cooling. It is very clear that the debate is far from over. Water in the atmosphere is a dynamic variable in itself, which I believe is far more influential in causing changes than the other greenhouse gasses that has been the focus of the debate. The gathering of moisture by hurricanes and storms, the evaporation from the oceans, the moisture traps of forests as well as its vapor production, the hydrologic cycle acceleration, the infinite capacity of the atmosphere to hold water as in Venus, etc. are still to be understood in terms of their combined effect upon climate. And so it is still too early to lay down the verdict. Let the debates continue without having to label the sides as deniers and climate mafia. No side has yet proven correctness without doubt as would meet the standard of the scientific method to arrive at any conclusion. More learning and better understanding is still needed.
Bob Tisdale is truly masterful in graphic presentations of SST-related data that are clear and instructive. When dealing with anomalies, especially temporally-smoothed ones, however, care needs to excercised in associating apparent migrations of anomaly values with actual flows of mass or heat. In the case of the latter, a water mass showing a negative temporal anomaly can be warmer than an adjoining mass showing a positive one. The correspondence of statistical temperature anomalies to actual physical levels is not one that permits unambiguous inferences about physical flows to be made.
In studying currents, oceanographers use both salinty and ACTUAL temperature as a function of depth (STD) as a water-mass tracer. It’s been decades since I’ve worked with equatorial STD data, but I don’t recall ever seeing a profile where subsurface waters were actually warmer. Nor do equatorial waters overturn in either phase of ENSO. Thus I’m sceptical of any claim that the surface is ever warmed by heat transport from below. And the whole idea of WestPac waters “sloshing” back to the east during El Ninos is vague, at best. There are east-flowing equatorial countercurrents, but I doubt that they strengthen with increased countervailing winds. These objections aside, Bob’s presentation is, as usual, quite fascinating.
Mr. Tisdale
Maybe this is an interesting site for you:
http://indic.mercator-ocean.fr/html/produits/indic/index_en.html
sky: You wrote, “Thus I’m sceptical of any claim that the surface is ever warmed by heat transport from below.”
Please advise where in the post I wrote “the surface is ever warmed by heat transport from below.” I did not present subsurface equatorial Pacific anomalies in these video, even though they can and do show warmer anomalies rising to the surface:
You wrote, “And the whole idea of WestPac waters ‘sloshing’ back to the east during El Ninos is vague, at best. There are east-flowing equatorial countercurrents, but I doubt that they strengthen with increased countervailing winds.”
The equatorial countercurrent do strengthen. And I’m sure you could find papers that discussed it if you searched, but to save you some time, I had also prepared a post with videos on just that subject:
http://bobtisdale.blogspot.com/2009/02/equatorial-currents-before-during-and.html
Also refer to the descriptions of ENSO by Bill Kessler of NOAA in his FAQ webpage:
http://faculty.washington.edu/kessler/occasionally-asked-questions.html
I’m not the only person using the word slosh in discussions of ENSO.
Thanks Bob, your,” And East Pacific, Atlantic, & West Indian SST anomalies versus versus detrended and scaled NINO3.4 SST anomalies:
http://i50.tinypic.com/de21vs.jpg” seems to agree with that Ashkok et al reference that you gave me, http://www.jamstec.go.jp/frcgc/research/d1/iod/grl_ashok.pdf
There seem to be ‘mini’ El Nino pulses in the sea level anomaly video http://www.youtube.com/watch?v=ELDkYJWHNiU at :54 and 1:54.
I’m thinking of how many tens of thousands of sailors who languished in the tropic heat, stuck for days and weeks in the equatorial doldrums would have liked to have been be able to see (and predict) these large scale wind and current movements before they set out.
Keith Minto says: “There seem to be ‘mini’ El Nino pulses in the sea level anomaly video http://www.youtube.com/watch?v=ELDkYJWHNiU at :54 and 1:54.”
If the pulses you’re referring to are travelling from west to east, they’re called Kelvin Waves. Not every warm Kelvin Wave turns into an El Nino.
Ibrahim: Thanks for the Mercator link.
sky: To add to my reply above, you wrote, “It’s been decades since I’ve worked with equatorial STD data, but I don’t recall ever seeing a profile where subsurface waters were actually warmer. Nor do equatorial waters overturn in either phase of ENSO.”
In what part of the video did I write that “subsurface waters were actually warmer” than the surface waters above it? During ENSO-neutral and La Nina phases, the subsurface waters in the western tropical Pacific are warmer than the surface waters in the eastern tropical Pacific.
http://i48.tinypic.com/288v8yd.jpg
When the warmer water in the west travels to the east during an El Nino, it replaces the normally cooler water in the east, and temperatures in the central and eastern equatorial Pacific rise.
And in what part of the video did I write or infer that “equatorial waters overturn in either phase of ENSO”?
You wrote, “When dealing with anomalies, especially temporally-smoothed ones, however, care needs to excercised in associating apparent migrations of anomaly values with actual flows of mass or heat. In the case of the latter, a water mass showing a negative temporal anomaly can be warmer than an adjoining mass showing a positive one. The correspondence of statistical temperature anomalies to actual physical levels is not one that permits unambiguous inferences about physical flows to be made.”
The processes described in these videos are also visible in animations of SST anomalies and sea level anomalies that have not been smoothed using 12-month averages. For animations of weekly SST anomaly maps, refer to:
http://bobtisdale.blogspot.com/2010/01/animation-of-weekly-global-sst-anomaly.html
And:
http://bobtisdale.blogspot.com/2009/07/animations-of-weekly-sst-anomaly-maps.html
And for an animation of sea level anomalies produced by the JPL that are from daily maps, refer to:
And here’s one by Sebastian Krieger:
http://www.youtube.com/watch?v=VNefCmc3_1Y&NR=1
The maps of 12-month average anomalies were used primarily for the TLT data. I carried the smoothing over to the other datasets for continuity. The smoothing did clean up the weather noise in the other datasets, though.
More from ENSO “recent study” department –
http://www.livescience.com/environment/cool-medieval-pacific-ocean-100610.html
“Famines in Medieval Europe may have been the result of a cooler Pacific Ocean tens of thousands of miles away, a new study suggests….”
Bob Tisdale:
Early in Pt. I of your video you DO treat subsurface anomalies in a way that associates them intimately with water flows. The point of my comment was that migrating anomalies are not in one-to-one correspondence with flows. Land-based anomalies also migrate, though there can be no flow of land involved. In mathematical terms, the total time derivative displayed by changing anomalies does not distinguish between local changes and those induced by advection.
Reference to sloshing is appropriate in connection with minor flow produced by readjustment of sea-level. Yet, at 2:53 you seem to connect this flow, which is concentrated in the middle portion of the basin, with dramatic changes at opposite ends, which sloshing cannot produce. And at 4:03 you advise viewers “Keep in mind that most of the warm water that had spread across the surface of the Central and Eastern Tropical Pacific during the El Nino came from BELOW the surface.” Such physically unconvincing interptretations prompted my original comment.
Bob, your OHC / ENSO ‘zig-zag’ graph is a piece of the puzzle of why a pattern in stratospheric-volcano / lunisolar patterns does something [seemingly] temporally-inconsistent around ~1974-6. This gets me wondering what we’d know either side of ~1896-7 if we had OHC records for then.
I can suggest a future step: Breaking your analysis down seasonally [but still using ‘annual’ smoothing (with a reduced number of months)].
Rationale: NH annual smoothing is raking in some pretty serious seasonal nonlinearities due to continentality [skew/outliers leveraging misleading distortion]. [My instinct is that this will not be an issue for SH (which is naturally damped).]
As often: I read one of your articles & discover a missing piece of the puzzles I’m exploring [ e.g. http://www.sfu.ca/~plv/VolcanoStratosphereSLAM.htm ] somewhere in your notes —– and as always: appreciated.
Bob, where can I find the image displayed 4:15 – 4:21 in Part 2?
Also, can you provide links to your webpages which discuss this?
Regards,
Paul.
Paul Vaughan: You wrote, “Bob, your OHC / ENSO ‘zig-zag’ graph is a piece of the puzzle of why a pattern in stratospheric-volcano / lunisolar patterns does something [seemingly] temporally-inconsistent around ~1974-6.”
I assume you referring to this graph of NINO3.4 SST anomalies and tropical Pacific OHC since you qualified it with your later comment:
http://i46.tinypic.com/14u9ulx.jpg
I don’t see anything inconsistent with the rise in 1974 to 76. There was a La Nina at that time that lasted for 3 plus years. If the tropical Pacific OHC hadn’t risen, then I would have wondered why.
You asked, “Also, can you provide links to your webpages which discuss this?”
It was discussed in:
http://bobtisdale.blogspot.com/2010/02/la-nina-underappreciated-portion-of.html
And:
http://bobtisdale.blogspot.com/2009/11/more-detail-on-multiyear-aftereffects_26.html
And:
http://bobtisdale.blogspot.com/2009/11/global-temperatures-this-decade-will-be.html
And:
http://bobtisdale.blogspot.com/2009/10/why-are-ohc-observations-0-700m.html
And:
http://bobtisdale.blogspot.com/2009/09/enso-dominates-nodc-ocean-heat-content.html
I think that gets them all.
clarification: The [seeming] inconsistency involved “stratospheric-volcano / lunisolar patterns” …and your insights appear (at first glance at least) to remove the appearance of inconsistency.
Thanks for the links.