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Tuesday, December 8, 2009

More Detail On The Multiyear Aftereffects Of ENSO - Part 3 – East Indian & West Pacific Oceans Can Warm In Response To Both El Nino & La Nina Events

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INTRODUCTION

This is Part 3 of a multipart post. It addresses critical comments about my earlier posts that dealt with the multiyear aftereffects of major traditional El Nino events. Two specific major traditional El Nino events, those in 1986/87/88 and 1997/98, caused Sea Surface Temperatures (SST) of the East Indian and West Pacific Oceans to remain at elevated levels during the subsequent La Nina events. These SST residuals, what I have called step changes in earlier posts for the sake of simplicity, bias global SST upward during the La Nina events and give the impression of a gradual increase, one that is erroneously attributed to anthropogenic greenhouse gases.

Links to Parts 1 and 2:
More Detail On The Multiyear Aftereffects Of ENSO – Part 1 – El Nino Events Warm The Oceans

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.

Part 3 is a relatively short post in comparison to the first two in this series. It illustrates very simply that East Indian and West Pacific SST anomalies can rise during both phases of major traditional ENSO events. That is, it shows that the East Indian and West Pacific Oceans can warm in response to both an El Nino event and to the La Nina that follows it.

THE DIPOLE EFFECT

In Part 2 (More Detail On The Multiyear Aftereffects Of ENSO - Part 2 – La Nina Events Recharge The Heat Released By El Nino Events AND...) I discussed the processes that cause the East-West dipole effect between East Pacific SST anomalies and the SST anomalies of the East Indian and West Pacific Oceans. A .gif animation, Figure 1, shows the SST anomalies for the SST anomalies for November 1997 (the peak of the 1997/98 El Nino) and for November 1998 (the peak of the 1998/99 La Nina) and shows the resulting El Nino-La Nina seesaw relationship of SST anomalies between those two regions.
http://i48.tinypic.com/xc6s0l.gif
Figure 1

EAST INDIAN AND WEST PACIFIC SST ANOMALIES WARM FIRST IN RESPONSE TO THE EL NINO

Part 1 (More Detail On The Multiyear Aftereffects Of ENSO – Part 1 – El Nino Events Warm The Oceans) discussed how the changes in atmospheric circulation in response to the El Nino travel from west to east, with the Atlantic Ocean SST anomalies peaking 4 to 5 months after the El Nino and the Indian Ocean SST anomalies lagging by 5 to 7 months. These changes in atmospheric circulation continue east and raise SST anomalies of the East Indian and West Pacific Oceans. Refer to the 1986/87/88 and the 1997/98 El Nino events in Figure 2.
http://i46.tinypic.com/epks8.png
Figure 2

INVERTING NINO3.4 SST ANOMALIES ILLUSTRATES THE RELATIONSHIP BETWEEN LA NINA EVENTS AND EAST INDIAN AND WEST PACIFIC SST ANOMALIES

After the changes in atmospheric circulation begin to raise the SST anomalies of the East Indian and West Pacific Oceans, the warm water that was released from below the surface of the Pacific Warm Pool returns to the surface of the East Indian and West Pacific Ocean, raising the SST anomalies there to higher levels. The SST anomalies of the East Indian and West Pacific Oceans are then maintained by the La Nina. To illustrate this relationship, I’ve inverted NINO 3.4 SST anomalies and shifted them upwards by 0.2 deg C. Refer to Figure 3.
http://i48.tinypic.com/28bhgjk.png
Figure 3

CLOSING

Since both the El Nino and La Nina portions of major traditional El Nino events warm the SST anomalies of the East Indian and West Pacific Oceans, their SST anomalies appear to rise in steps. Ocean currents then blend these natural increases in SST anomalies for the East Indian and West Pacific Oceans with the other oceans, raising the SST anomalies globally. The resulting increases in global SST anomalies are mistakenly attributed to anthropogenic greenhouse gases.

SOURCE
SST Anomaly data and maps are available from the NOAA NOMADS webpage:
http://nomad3.ncep.noaa.gov/cgi-bin/pdisp_sst.sh?lite=

6 comments:

d said...

Currently UAH LT Trpcs is tracking 1997 at this time.

I look for global LT temps to top out in Jan or Feb based on previous annual cyclical patterns. Depending on Dec data for Trpcs and global, it's likely 2010 will exceed 2007 (global) in amplitude.

So, my UWAG is that if Dec exceeds Nov, then we well see a very warm 2010, at least in peak temps.

RSS and UAH are quite diverged for November however.

My question to you Bob is how does SOI fit into all this? Also is it likely this much heat being released will bring about a stronger La Nina?

It would seem OHC to be an important part of the recipe, yes?

Bob Tisdale said...

d: You asked, "My question to you Bob is how does SOI fit into all this?"

The SOI is the sea level pressure component of ENSO. At times, the variations in the SOI precede the SST portion (NINO3.4, CTI, etc.) by a few months, but not always, so it's value as a forecasting tool for an El Nino event is iffy.

You also asked, "Also is it likely this much heat being released will bring about a stronger La Nina?"

Yes. The tropical Pacific typically replaces the discharged heat with a strong, sometimes multiyear, La Nina.

You asked, "It would seem OHC to be an important part of the recipe, yes?"

El Nino events discharge heat, lowering tropical Pacific OHC. La Nina events recharge the heat, replacing the dischareged heat and raising tropical Pacific OHC. The ENSO events also redistribute warm water to the oceans adjacent to the tropical Pacific via ocean currents, raising their OHC, and change atmospheric circulation, which also cause OHC to vary.

d said...

Bob,
When you say La Nina "recharges the heat", does the bulk of the heat come from above (less clouds, more SW) or below (deep welling up) the surface?

It seems to to me if the bulk is coming from above due to decrease in cloudiness that would indicate OHC is increasing, but if from below OHC is decreasing.

How can we know which is dominant?

Bob Tisdale said...

d, you asked, “When you say La Nina ‘recharges the heat’, does the bulk of the heat come from above (less clouds, more SW) or below (deep welling up) the surface?”

I've read a paper recently that said the majority of the tropical Pacific OHC variability is in the upper 300 meters. I could search for it if you'd like the reference.

Therefore, the heat comes from above (less cloud cover and more downward shortwave radiation) just like you said. Refer to the recharge discussion that illustrates tropical Pacific OHC to 700 meters:
http://bobtisdale.blogspot.com/2009/11/more-detail-on-multiyear-aftereffects_26.html

d said...

Thanks,
There needs to be closure then as to why OHC is not agreeing with Hansen et al 2005 predictions.

It would seem logical to conclude understanding clouds is the most important metric to diagnose and predict both short and long term climate change if ENSO is driven more by SW more so than upwelling of heat from the oceans.

OTOH, it's still unclear to me that SST increases would mostly come from above (sun) rather than from stored heat that could be driven upward by convection from warm ocean currents seeking out cold. Maybe it is both and cannot be accurately measured in realtime.

In other words, SST is clearly ramped up substantially from 2008, but why and by what mechanism? Will 2010 result in a new "step" similar to 1998, then a new reset but at a lower threshold followed by a strong La Nina?

So many questions. 2010 and 2011 will be very interesting to watch. I'll read your recommended discussion.

Bob Tisdale said...

d: You asked, “SST is clearly ramped up substantially from 2008, but why and by what mechanism?”

It’s primarily a response to ENSO:
http://i48.tinypic.com/34obn6t.png

And the source of energy for the increase in NINO3.4 SST anomalies is the rise in Downward Shortwave Radiation…associated with the decrease in cloud amount…caused by the increase in trade wind strength…during the La Nina conditions of 2007/08 and 2008/09.

You asked, “Will 2010 result in a new ‘step’ similar to 1998…?”

I hope. And I hope we don’t have a major volcanic eruption to skew the data, but there are reports that Mayon is rumbling again.

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