Guest post by Bob Tisdale
In addition to the title discussion, this post will serve as the Mid-July 2012 Sea Surface Temperature Anomaly Update. It also includes a status update on my book about El Niño-Southern Oscillation (ENSO).
COMPARISON OF THE EVOLUTIONS OF EL NIÑO EVENTS
NINO3.4 sea surface temperature anomalies (a commonly used ENSO index) have been above the +0.5 deg C threshold of an El Niño for 4 weeks. While it’s far from an “official” El Niño, it appears that it’s likely to become one. Let’s see how the 2012/13 El Niño is evolving compared to past El Niño events. Figure 1 compares the weekly NINO3.4 sea surface temperature anomalies for each El Niño event since 1982, starting with the first week in January of those years. The 2012 data is in red, using a greater weighting. The first thing that stands out in the graph is how there really is nothing typical about the evolution of El Niño events. Five started from ENSO-neutral conditions; that is, with NINO3.4 sea surface temperature anomalies between -0.5 and +0.5 deg C. Five, including the current one, started from La Niña conditions, with the NINO3.4 sea surface temperatures cooler than -0.5 deg C. And there’s the outlier, the 1987/88 portion of the 2-year 1986/87/88 El Niño. Other than having the coolest NINO3.4 sea surface temperature anomalies at one point, there’s nothing remarkable about the evolution of the NINO3.4 sea surface temperature anomalies this year.
Figure 2 compares the evolution of the El Niño events that started from La Niña conditions. This year’s NINO3.4 sea surface temperature anomalies had been tracking along at the pace of the most recent El Niño, the one that occurred in 2009/10, until recently. Over the past two weeks, NINO3.4 sea surface temperature anomalies have been cooling.
NINO3.4 sea surface temperature anomalies appear as though they’re being suppressed by the cooler-than-normal waters being circulated southward from the North Pacific, which should be feedback from the back-to-back La Niña events. Refer to the sea surface temperature animation from Unisys, Animation 1, but keep in mind that positive temperature anomalies are light blue. Most people associate shades of blue with negative anomalies. (You may need to click on the animation to start it.)
It will be interesting to see how long the cooler waters from the North Pacific can suppress the central sea surface temperatures in the east-central equatorial Pacific.
Figure 3 shows the NINO1+2 sea surface temperature anomalies for the same El Niño events that were presented in Figure 2. The NINO1+2 region is in the eastern tropical Pacific, just south of the equator. The coordinates are 10S-0, 90W-80W. This year the NINO1+2 sea surface temperature anomalies warmed before the NINO3.4 region, but they also have been cooling.
But referring to the animation of NOAA subsurface temperature anomaly cross sections for the equatorial Pacific, Animation 2, there’s still a pocket of elevated anomalies at depth in the eastern equatorial Pacific, and there’s a long way to go before the peak of the ENSO season.
Weekly NINO3.4 sea surface temperature anomalies for the week centered on July 11, 2012 are approximately +0.55 deg C, having dropped from about +0.73 over the past few weeks.
And global sea surface temperature anomalies are continuing the upward march, rebounding from La Niña conditions and responding to the evolving El Niño.
STATUS OF MY UPCOMING BOOK ABOUT ENSO
After a good number of suggestions, the current working title of the book is Who Turned on the Heat? with the subtitle El Niño-Southern Oscillation, the Unsuspected Global Warming Culprit. I’ve added 4 chapters to Section 2 and 7 chapters to Section 4 since the last status update, and I’m currently working on Chapter 5.6. See the following Table of Contents as it exists at present. Please let me know if there are any topics you can think of that I’ve missed.
Section 1 – A Description of El Niño and La Niña Events Using Annotated Illustrations
1.1 Preliminary Discussion of the ENSO Annotated Illustrations
1.2 The ENSO Annotated Illustrations
1.3 Recap of Section 1
Section 2 – A Few Preliminary Discussions
2.1 Do the Words “Oscillation” and “Cycle” in the names “El Niño-Southern Oscillation” and “ENSO Cycle” Cause Misunderstandings?
2.2 The Types of Graphs Presented
2.3 Linear Trends
2.4 How El Niño and La Niña Events Present Themselves in the Sea Surface Temperature Record
2.5 Our Primary ENSO Index is NINO3.4 Sea Surface Temperature Anomalies
2.6 How ENSO Events Are Presented in the Text
2.7 On the Use of Anomalies
2.8 Converting Monthly Absolute Data to Anomalies
2.9 Using the Model Mean of the IPCC’s Climate Models
2.10 Why We’ll Be Using Satellite-Based Sea Surface Temperature Data
2.11 Data Smoothing and Detrending
2.12 The IPCC Says Only Climate Models Forced by Manmade Greenhouse Gases can Explain the Recent Warming
2.13 The Additional Mode of Natural Variability in the North Atlantic Sea Surface Temperatures—Introduction to the Atlantic Multidecadal Oscillation
2.14 The Two Primary Data Sources
2.15 Recap of Section 2
Section 3 – A More Detailed Discussion of ENSO Processes
3.1 A Quick Look at the Size of the Pacific Ocean
3.2 Pacific Trade Winds and Ocean Currents
3.3 Putting the Equatorial Pacific Cross Sections in Perspective
3.4 The ENSO-Neutral State of the Tropical Pacific
3.5 The Transition from ENSO-Neutral to El Niño
3.6 El Niño Phase
3.7 The Transition from El Niño to ENSO Neutral
3.8 La Niña Phase
3.9 The Transition from La Niña to ENSO-Neutral
3.10 The Recharge of Ocean Heat during the La Niña
3.11 Summary of Section 3
Section 4 – Additional ENSO Discussions
4.1 How El Niño Events Cause Surface Temperatures to Warm Outside of the Tropical Pacific
4.2 Central Pacific versus East Pacific El Niño Events
4.3 ENSO Indices
4.4 ENSO Indices Also Fail to Capture the Relative Strengths of ENSO Events
4.5 The Repeating Sequence of Primary and Secondary El Niño Events
4.6 A Look at How a Few More Tropical Pacific Variables Respond to ENSO
4.7 ENSO Events Run in Synch with the Annual Seasonal Cycle
4.8 Subsurface Temperature and Temperature Anomaly Variations in the Equatorial Pacific And an Introduction to Kelvin Waves
4.9 An Introduction to the Delayed Oscillator Mechanism
4.10 ENSO Versus the Pacific Decadal Oscillation (PDO)
4.11 There is a Multidecadal Component to ENSO
4.12 ENSO Monitoring
4.13 An Introduction to the Indian Ocean Dipole and How It’s Impacted by ENSO
4.14 Impacts of ENSO Events on Regional Temperature and Precipitation
4.15 Further Discussion on What Initiates an ENSO Event
4.16 Weak, Moderate and Strong ENSO Event Thresholds
4.17 ENSO – A Cycle or Series of Events?
4.18 ENSO Influence on Tropical Cyclones (Hurricanes)
Section 5 – The Long-Term Impacts of Major ENSO Events on Global Temperature Anomalies
5.1 No Surprise – East Pacific Sea Surface Temperature Anomalies Mimic ENSO, But Where’s The Anthropogenic Global Warming Signal?
5.2 But Global Sea Surface Temperature Anomalies Have Warmed During the Satellite Era
5.3 Where and Why Sea Surface Temperatures Can Warm in Response to Certain El Niño AND La Niña Events
5.4 The Obvious ENSO-Caused Upward Shifts in the Sea Surface Temperature Anomalies of the East Indian and West Pacific Oceans
5.5 The ENSO-Caused Upward Shifts Still Exist if We Add the South Atlantic and West Indian Sea Surface Temperature Data to the East Indian and West Pacific
5.6 The Additional Warming of the North Atlantic Sea Surface Temperatures is Caused by the Atlantic Multidecadal Oscillation AND Additional ENSO-Impacted Processes
5.7 The IPCC’s Climate Models do a Terrible Job of Simulating East Pacific, “North Atlantic Plus”, and South Atlantic-Indian-West Pacific Sea Surface Temperatures
5.8 The IPCC’s Climate Models Appear to Warm in Response to Absolute Surface Temperatures and Not Natural Processes
5.9 The Long-Term Impacts of Major ENSO Events on Lower Troposphere Temperature Anomalies
5.10 The Long-Term Impacts of Major ENSO Events on Global Land-Plus-Sea Surface Temperature Anomalies
5.11 A Look at the Impacts of ENSO and Other Natural Factors on Ocean Heat Content Data
5.12 Does Downward Longwave (Infrared) Radiation from Anthropogenic Greenhouse Gases do Anything More Than Increase Evaporation?
Section 6 –Common ENSO Myths
6.1 ENSO is an Oscillation and as Such Cannot Contribute to the Long-Term Trend
6.2 A New One: El Niño and La Niña Balance Out to Zero over the Long-Term
6.3 Similar to the Above, The Effects of La Niña Events Counteract those of El Niño Events
6.4 ENSO Only Adds Noise to the Instrument Temperature Record and We Can Remove its Effects through Linear Regression Analysis
6.5 The Frequency and Strength of El Niño and La Niña Events are Dictated by the Pacific Decadal Oscillation
Section 7 – Closing
I’m hoping to have it done within a month. But it may take longer if I continue to add to it.
The Reynolds Optimally Interpolated Sea Surface Temperature Data (OISST) are available through the NOAA National Operational Model Archive & Distribution System (NOMADS).