To help understand the context of the NASA GISS announcement, I’m reposting Bob Tisdales’s excellent analysis from 2009 which ran on WUWT on November 10th
Global Temperatures This Decade Will Be The Warmest On Record…
…And It Will Be Exploited By Those Who Fail To Understand The Reasons For The Rise
Guest post by Bob Tisdale
INITIAL NOTES
For some visitors to this blog, this post will be a merging and rehashing of a few of my earlier posts. But this post is different in a very important way. I have attempted to simplify the discussion of El Nino-caused step changes for those with less technical backgrounds.
The post does assume the reader knows of El Nino and La Nina events. If not, here are links to two NOAA El Nino Frequently Asked Question web pages:
http://www.aoml.noaa.gov/general/enso_faq/
http://faculty.washington.edu/kessler/occasionally-asked-questions.html
The following narrated video “Visualizing El Nino” from the NASA/Goddard Space Flight Center Scientific Visualization Studio provides an excellent overview of the 1997/98 E; Nino, one of the El Nino events that created the aftereffects illustrated in this post.
YouTube Link:
http://www.youtube.com/watch?v=DbNzw1CCKHo
I have provided links to the referenced studies and to the posts that provide more detailed explanations at the end of the following. They do not appear within the general discussion of this post.
Many of the illustrations in the following are .gif animations, with 5- to 10-second pauses between cells.
GLOBAL TEMPERATURES THIS DECADE WILL BE THE WARMEST ON RECORD
It became apparent a number of years ago that the current decade, the 2000s, would have the highest surface temperature since the start of the instrument temperature record. Prior to now, the record decade for Global Surface Temperature Anomalies, Global Lower Troposphere Temperature (TLT) Anomalies, and Global Sea Surface Temperature (SST) anomalies had been the 1990s. Table 1 shows the average 1990s and 2000s (to date) temperature anomalies furnished by different suppliers, and the difference between the two decades. And with the end of this decade drawing near, one should expect to hear of this new record time and time again. There are those who will exploit this in the next few months and in the years to come. Those parties will, of course, blame anthropogenic greenhouse gases for the rise.
http://i33.tinypic.com/2i7mj4i.png
Table 1
THOSE WHO TRUMPET THE ELEVATED TEMPERATURES WILL FAIL TO ACKNOWLEDGE THE NON-LINEAR RELATIONSHIP BETWEEN THE EL NINO-SOUTHERN OSCILLATION (ENSO) AND GLOBAL TEMPERATURES
There have been a number of recent research papers that have illustrated a linear relationship between El Nino-Southern Oscillation (ENSO) and global temperature. These papers contradict what is clearly visible in the instrument temperature record, and that is, that the relationship between ENSO and global temperature is non-linear. In a comparison of global temperatures and natural variables, the researchers scale one of the ENSO indices, and after adjusting for other natural variables such as solar irradiance and volcanic aerosols, the researchers claim the difference between those natural variables and global temperatures must be caused by the increase in anthropogenic greenhouse gases. A simplified example of these comparisons is shown in Figure 1; it compares global SST anomalies and scaled NINO3.4 SST anomalies, one of the ENSO indices. It also shows their linear trends. I’ve excluded volcanic aerosol and solar adjustments to simplify the illustration. Note how the Global SST anomaly trend is increasing while the NINO3.4 SST anomaly trend is decreasing. As noted earlier, there are those who would like you to believe that the difference in those trends is caused by anthropogenic greenhouse gases.
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Figure 1
MULTIYEAR AFTEREFFECTS OF ENSO ARE VISIBLE AS STEP CHANGES IN THE SST RECORDS
The first dataset to be discussed is the sea surface temperature (SST) anomalies of the East Indian and West Pacific Oceans. This dataset represents approximately 25% of the global ocean surface area between 60S and 65N. A sizeable area, as can be seen in Figure 2.
http://i34.tinypic.com/iwrz39.png
Figure 2
Figure 2 also shows the location of the NINO3.4 region of the equatorial Pacific. Its coordinates are 5S-5N, 170W-120W. Climate change researchers use this and other similar datasets when studying the magnitudes of El Nino and La Nina events and how often those events occur. Meteorologists also monitor NINO3.4 SST anomalies and other ENSO indexes to help them forecast the impacts of the current event on regional climate, hurricanes, etc. The SST anomalies of the NINO3.4 area of the Pacific correlate well with global temperature measurements. That is, when the SST anomalies of the NINO3.4 area rise during an El Nino event, global SST anomalies, and global TLT anomalies, and global surface temperature anomalies typically rise by lesser amounts. Researchers assume this relationship is constant, that it is linear, but as will be shown in the following, it is not linear. The global response to La Nina events is not the same as it is to El Nino events. This will be clearer as the discussion progresses.
Keep in mind that it is not only the SST anomalies of the NINO3.4 that rise and fall during El Nino and La Nina events. As can be seen in the video “Visualizing El Nino” above, the SST anomalies entire tropical Pacific are impacted.
Of the 9 official El Nino events since November 1981 (the start year of the SST dataset used to illustrate the effect), only two of these specific major traditional El Nino events occurred, one in 1986/87/88 and the other in 1997/98. See Figure 3, which is a .gif animation of the time-series graph of NINO3.4 SST anomalies. The other significant traditional El Nino in 1982/83 was counteracted by the volcanic eruption of El Chichon.
http://i37.tinypic.com/2la6640.gif
Figure 3
Links to the individual cells of Figure 3:
Link to Figure 3 Cell A:
http://i33.tinypic.com/9pw0no.png
Link to Figure 3 Cell B:
http://i36.tinypic.com/apigjq.png
Link to Figure 3 Cell C:
http://i35.tinypic.com/2yorexg.png
Something very curious happens in the East Indian and West Pacific area of the global oceans shown in Figure 2. The SST anomalies of the East Indian and West Pacific Oceans rise in steps in response to specific El Nino events. These particular El Nino events are major events that are traditional in nature, as opposed to El Nino Modoki (pseudo El Nino events), and they are also El Nino events that have not been impacted by explosive volcanic eruptions, such as El Chichon in 1982 and Mount Pinatubo in 1991.
Figure 4 is a .gif animation of two datasets presented in different ways. Cell A is a graph that compares the SST anomalies of the NINO3.4 region of the equatorial Pacific to the SST anomalies of the East Indian and West Pacific Oceans. The NINO3.4 SST anomalies have been scaled (multiplied by a factor of 0.2 in this case) so that the changes in them during the El Nino events of 1986/87/88 and 1997/98 are approximately the same magnitude as the responses in the East Indian and West Pacific Oceans. Note how the SST anomalies of the East Indian and West Pacific Oceans had little response to the 1982/83 El Nino. As discussed earlier, that El Nino was counteracted by the sunlight-blocking volcanic aerosols of the explosive eruption of El Chichon. Note also that there is a dip in the East Indian and West Pacific SST anomalies in 1991 and a rebound a few years later. That dip and rebound is caused by the eruption of Mount Pinatubo. In Cell B, linear trend lines have been added to the same datasets to show the relationship presented by researchers who assume the relationship between ENSO and global temperature is linear. The linear trends skew perspective and hide the actual cause of the rise in SST anomalies of the East Indian and West Pacific Oceans. In Cell C, I’ve included the average East Indian and West Pacific SST anomalies for the period before the 1986/76/88 El Nino, the period between the 1986/76/88 and 1997/98 El Nino events, and the period after the 1997/98 El Nino. These averages highlight the step changes that occurred in this portion of the global ocean. Again, these step changes are aftereffects of the 1986/87/88 and 1997/98 El Nino events.
http://i37.tinypic.com/smrt44.gif
Figure 4
Links to the individual cells of Figure 4:
Link to Figure 4 Cell A:
http://i33.tinypic.com/2cparf4.png
Link to Figure 4 Cell B:
http://i38.tinypic.com/dz5go.png
Link to Figure 4 Cell C:
http://i33.tinypic.com/14wu8pk.png
As you will note, the multiyear aftereffects aren’t true step changes. The SST anomalies for the East Indian and West Pacific Oceans don’t remain at the new higher temperatures indefinitely. They do, however, remain at higher levels (failing to respond fully to the La Nina) until the next series of lesser El Nino events drive the temperatures back up again, helping to maintain the higher levels. (The effects are easier to describe as step changes, which is why I refer to them that way.)
It is important to notice that the response of the East Indian and West Pacific Oceans to 1998/99/00 La Nina was not the same as the response to the El Nino that came before it. The SST anomalies for this area of the global oceans rose as would be expected in response to the El Nino, but it did not respond fully to the La Nina phase. Global SST response to La Nina events is not always the same as it is to El Nino events. And this difference between how Global SST responds to El Nino and La Nina events causes Global SST to rise.
These step changes in the East Indian and West Pacific Ocean SST anomalies are important for a number of reasons. First, the oceans represent approximately 70% of the surface area of the globe, and SST anomalies are included in the calculation of global surface temperature by GISS, Hadley Centre, and NCDC. Refer again to Table 1. In fact, the NCDC’s Optimum Interpolation SST dataset (OI.V2) used in Figure 4 has been included by the Goddard Institute for Space Studies (GISS) in their GISTEMP product since 1982. Second, these step changes are not reproduced by climate models. They also are not acknowledged by the scientific community–if they were, the papers listed at the end of this post would not illustrate a linear relationship between ENSO and global temperature. I have searched but have been unable to find any scientific paper that discusses these step changes. Third, the step changes bias the global SST anomalies upward and give the impression of a gradual increase in SST anomalies. This can be seen in a comparison graph of the SST anomalies of the East Indian and West Pacific Oceans, the SST anomalies of the “Rest of the World” (East Pacific, Atlantic, and West Indian Oceans), and the combination of the two, Figure 5. The period since 1996 is unique in the last 40+ years. There haven’t been any major volcanic eruptions to add noise to the data. This is why the data in Figure 5 starts in 1996.
http://i38.tinypic.com/2ezjk9s.png
Figure 5
Note how in Figure 5 the East Indian and West Pacific SST anomalies linger at the elevated levels while the SST anomalies for the “Rest of the World” are mimicking the variability of the NINO3.4 SST anomalies, shown in Figure 3. (That is, the SST anomalies for the “Rest of the World” are responding as researchers expect to both El Nino and La Nina events.) Over the next few years, ocean currents “mix” the elevated SST anomalies of the East Indian and West Pacific Oceans with the depressed SST anomalies of the “Rest of the World” oceans, dropping one and raising the other, until they intersect in 2003. This is more than 4 years after the end of the 1997/98 El Nino. Because the Global SST anomalies are a combination of the two, they are biased upward by the elevated East Indian-West Pacific SST anomalies and by the mixing with the waters of the “Rest of the World”. This gives the false impression of a gradual increase in global SST anomalies.
In other words, the effects of the major traditional El Nino events can linger for at least 4 years, causing gradual increases in global sea surface temperatures during that time. This gradual increase is incorrectly attributed to anthropogenic sources.
These effects are also discussed and illustrated in my video “The Lingering Effects of the 1997/98 El Nino”.
YouTube Link:
http://www.youtube.com/watch?v=4uv4Xc4D0Dk
MULTIYEAR AFTEREFFECTS OF ENSO ARE ALSO VISIBLE AS STEP CHANGES IN THE TLT RECORDS
Since 1979, two groups have analyzed the satellite-based Microwave Sounding Unit (MSU) radiometer data to determine atmospheric temperatures at different levels. These groups are Remote Sensing Systems (RSS) and the University of Alabama in Huntsville (UAH). We’ll be using the data from RSS in this discussion. One dataset, the Lower Troposphere Temperature (TLT) anomalies, correlate well with the global surface temperature anomalies determined from direct land and sea surface temperature observations.
Lower Troposphere Temperature (TLT) anomalies also show upward step changes in response to the significant traditional 1986/87/88 and 1997/98 El Nino events. And similar to the discussion of sea surface temperatures above, only a portion of the global TLT anomalies show clear signs of these upward steps. In this case, it’s the latitude band of 20N to 82.5N or the Mid-To-High Latitudes of the Northern Hemisphere. Refer to Figure 6 for the area of the globe included within these latitudes. It represents in the neighborhood of 33% of the global surface area.
http://i34.tinypic.com/id7h4k.png
Figure 6
The graph in Figure 7 compares the NINO3.4 SST anomalies to the Lower Troposphere Temperature (TLT) anomalies of the Mid-To-High Latitudes of the Northern Hemisphere. The scaled NINO3.4 SST anomalies are used again as a reference for the timing and magnitude of significant traditional El Nino events. As you can see, the TLT anomaly data for this area of the globe is noisy, but it is obvious that the TLT anomalies rose since 1979, a rise that is normally attributed to manmade greenhouse gases.
http://i35.tinypic.com/2coiln8.png
Figure 7
A common technique used to reduce data noise is to smooth it by calculating the average of a number of months before and after a given month, and to calculate this average for each month for the entire length of the dataset. (The same technique was used in Figure 5.) The TLT anomaly data in Figure 8 has been smoothed with a 13-month running average filter. Note how, when compare to Figure 7, there is much less noise in the smoothed data. Figure 8 is another .gif animation. It illustrates the TLT anomaly data for the Mid-To-High Latitudes of the Northern Hemisphere and the scaled NINO3.4 SST anomalies from different points of view. Cell A illustrates the data without any comments. Depending on your perspective, you can see a gradual rise in the TLT anomaly dataset that’s disrupted by ENSO events and volcanic eruptions or you can see three periods of relatively flat TLT anomalies that are punctuated by ENSO and volcanic eruptions with two major step increases caused by the 1986/87/88 and 1997/98 El Nino events. In Cell B, the impacts of the two major volcanic eruptions are noted. These are the 1982 eruption of EL Chichon and the Mount Pinatubo eruption in 1991. As with the SST data, the El Chichon eruption counteracted the impact of the 1982/83 El Nino. But the lesser El Nino in 1991/92 was no match for the Mount Pinatubo eruption, and TLT anomalies made a substantial drop. The TLT anomalies rebounded a few years later as the volcanic aerosols in the stratosphere dissipated. Cell C shows the positive linear trend of the TLT anomalies for the Mid-To-High Latitudes of the Northern Hemisphere and it shows the negative trend in the SST anomalies of the NINO3.4 region of the equatorial Pacific. The difference between the two, as discussed earlier, is attributed by researchers to anthropogenic greenhouse gases. However, the attribution is unfounded when the global data is broken down into smaller subsets. The heat released by significant El Nino events can and do cause step changes in the TLT anomalies of the Mid-To-High Latitudes of the Northern Hemisphere. This is clearly visible when the average temperatures before and after those significant El Nino events are displayed on the graph, Cell D.
http://i35.tinypic.com/j0f89k.gif
Figure 8
Links to the individual cells of Figure 8:
Link to Figure 8 Cell A:
http://i37.tinypic.com/30rraky.png
Link to Figure 8 Cell B:
http://i37.tinypic.com/2yjocr9.png
Link to Figure 8 Cell C:
http://i38.tinypic.com/2jcdc13.png
Link to Figure 8 Cell D:
http://i37.tinypic.com/2ue1jz8.png
It is primarily those two shifts in the Mid-To-High Latitude TLT Anomalies of the Northern Hemisphere that cause the upward trend in Global TLT Anomalies.
DO ANTHROPOGENIC GREENHOUSE GASES FUEL EL NINO EVENTS?
The source of heat for El Nino events is the Tropical Pacific, and there is no evidence that greenhouse gases have a significant effect on the Ocean Heat Content (OHC) anomalies of the Tropical Pacific. Refer to Figure 9. It is also a .gif animation. Cell A shows the comparison graph of Tropical Pacific OHC, scaled NINO3.4 SST anomalies, and scaled Sato Index of Stratospheric Aerosol Optical Thickness. The Sato Index data is presented to illustrate the timing of explosive volcanic eruptions. Like the other comparisons in this post, the NINO3.4 SST anomalies are used to illustrate the timing and magnitude of El Nino and La Nina events. The OHC dataset was created by the National Oceanographic Data Center (NODC). It presents OHC to depths of 700 meters. This OHC data was introduced with the Levitus et al (2009) paper “Global Ocean Heat Content 1955-2008 in light of recently revealed instrumentation problems”. Cell B highlights the two decade-long declines in Tropical Pacific OHC. Cell C calls attention to the upward surges (steps) in Tropical Pacific OHC that occurred during the multiyear La Nina events that followed the 1972/73 and 1997/98 El Nino events. And Cell D highlights a curious rise in Tropical Pacific OHC that occurred in the few years leading up to the 1997/98 El Nino. I have searched for but have not found any scientific paper that discusses this sudden surge that fueled the 1997/98 El Nino.
http://i36.tinypic.com/dpzu6h.gif
Figure 9
Links to the individual cells of Figure 9:
Link to Figure 9 Cell A:
http://i33.tinypic.com/2gwys1t.png
Link to Figure 9 Cell B:
http://i37.tinypic.com/kamom.png
Link to Figure 9 Cell C:
http://i35.tinypic.com/w075g6.png
Link to Figure 9 Cell D:
http://i34.tinypic.com/10e28ic.png
An additional note about Figure 9: Note how the OHC dips during the El Nino events and rebounds during the La Nina events. The El Nino discharges heat from the Tropical Pacific, and the La Nina recharges the heat. This is accomplished by variations in total cloud amount. If the La Nina is not being impacted by volcanic aerosols and if the La Nina lasts for more than one year, ocean heat content rises above its previous level, creating the upward step.
The changes in Tropical Cloud Amount Percentage mimic NINO3.4 SST anomalies. Refer to Figure 10. That is, when NINO3.4 SST anomalies rise, Tropical Pacific Cloud Amount increases, and when NINO3.4 SST anomalies drop during the La Nina phase, Tropical Pacific Cloud Amount decreases. Less cloud cover means more downward shortwave radiation (visible sunlight) is able to warm the Tropical Pacific. In Cell C of Figure 10, the sudden drop in Tropical Pacific Cloud Amount in 1995 is highlighted. As noted above, it appears this decline in cloud amount fueled the 1997/98 El Nino.
http://i37.tinypic.com/24wztqe.gif
Figure 10
Links to the individual cells of Figure 10:
Link to Figure 10 Cell A:
http://i35.tinypic.com/4rxele.jpg
Link to Figure 10 Cell B:
http://i36.tinypic.com/2z4d6hc.jpg
Link to Figure 10 Cell C:
http://i36.tinypic.com/34obno7.jpg
NATURAL VARIATIONS IN THE NORTH ATLANTIC SST ALSO CONTRIBUTED TO THE DIFFERENCE IN GLOBAL TEMPERATURE BETWEEN THE 1990s AND THE 2000s
The SST anomalies of the North Atlantic Ocean are also impacted by another natural variable, the Atlantic Multidecadal Oscillation or AMO. The AMO is a semi-periodic variation (50 to 80 years) in the SST anomalies of the North Atlantic that has its basis in Thermohaline Circulation (THC) or Atlantic Meridional Overturning Circulation (AMOC). These variations are visible in the reconstruction of North Atlantic SST from 1567 to 1990, Figure 11. This dataset was created by Gray et al (2004) “Atlantic Multidecadal Oscillation (AMO) Index Reconstruction”. (IGBP PAGES/World Data Center for Paleoclimatology Data Contribution Series #2004-062. NOAA/NGDC Paleoclimatology Program, Boulder CO, USA.)
http://i36.tinypic.com/wld5kl.jpg
Figure 11
For the period of the instrument temperature record, the AMO is presented as detrended North Atlantic SST anomalies. Refer to Figure 12, which is also a .gif animation. Cell A of Figure 12 illustrates the AMO data calculated by the NOAA Earth System Research Laboratory (ESRL) from January 1956 to March 2009. The data has been smoothed with a 37-month filter to remove the noise. Cell B notes that the AMO is a naturally occurring variation in the SST anomalies of the North Atlantic. And Cell C illustrates the average AMO SST values for the 1990s and the 2000s. The difference between these two averages represents the contribution of the AMO to the rise in North Atlantic SST Anomalies from the 1990s to the 2000s. Keep in mind that, while the North Atlantic covers only a surface area that is approximately 15% of the global oceans, the AMO is also known to also impact the surface temperatures of Europe and North America and the SST of the Eastern Tropical Pacific.
http://i38.tinypic.com/oj4bqg.gif
Figure 12
Links to the individual cells of Figure 12:
Link to Figure 12 Cell A:
http://i37.tinypic.com/mwqeqh.jpg
Link to Figure 12 Cell B:
http://i34.tinypic.com/kaqtjq.jpg
Link to Figure 12 Cell C:
http://i35.tinypic.com/2gtddn7.jpg
CLOSING
There is little doubt that the decade of the 2000s will have higher land surface, sea surface, and lower troposphere temperature anomalies than the 1990s. There will be those who will wrongly attribute the rise from decade to decade to anthropogenic greenhouse gases, when it is very apparent that the actual cause is the lingering effects of the 1997/98 El Nino event. Attempts will be made to contradict the obvious by those who fail to acknowledge or comprehend the multiyear aftereffects of significant traditional El Nino events. They will present numerous unfounded arguments. Here are a few that have been tried.
Argument 1: The short-term global warming of El Nino events are countered by the short-term global cooling of the La Nina events that follow them.
What The Instrument Temperature Record Shows: That’s true for only parts of the globe and for some El Nino events. It is not true, however, for the SST anomalies of the East Indian and West Pacific Oceans and for the TLT anomalies of the Mid-To-High Latitudes of the Northern Hemisphere. Refer to Figures 4 and 8. The effects of the 1986/87/88 and the 1997/98 El Nino lingered through the La Nina events that followed them in those datasets. This created the appearance of gradual rises in global SST and TLT anomalies.
Argument 2: Global warming caused by anthropogenic greenhouse gases is responsible for the increase in the number of major El Nino events since 1975. (This argument is normally made by someone referring to an ENSO Index that starts in 1950.)
What The Instrument Temperature Record Shows: There are multidecadal variations in the frequency and magnitude of ENSO events. This can be seen by smoothing the NINO3.4 SST anomalies from 1870 to 2009 with a 121-month filter. Refer to Figure 13. During epochs when the frequency and magnitude of El Nino events outweigh the frequency and magnitude of La Nina events, global temperatures rise. And during epochs when the frequency and magnitude of La Nina events outweigh the frequency and magnitude of El Nino events, global temperatures drop.
http://i43.tinypic.com/33agh3c.jpg
Figure 13
Argument 3: El Nino events don’t create heat.
What The Instrument Temperature Record Shows: During El Nino events, warm water that had been stored below the surface of the western tropical Pacific (in the Pacific Warm Pool) sloshes to the east and rises to the surface. Tropical Pacific SST anomalies increase in response. In this way, more heat than normal is released from the tropical Pacific to the atmosphere. But El Nino events not only release heat into the atmosphere, they also shift atmospheric circulation patterns (Hadley and Walker Circulation, surface winds, cloud cover). These shifts in the circulation patterns and cloud cover cause surface temperatures and OHC outside of the tropical Pacific to rise.
It is important to note that the vast majority of the warm water that sloshes east during the El Nino had been stored below the surface before the El Nino. While below the surface (to depths of 300 meters) it was not included in the instrument temperature record. But during the El Nino, that warm water has been relocated to the surface and is included in the surface temperature record. So, El Nino events relocate warm water from an area that was not included in the calculation of global temperature to the surface where it is included.
Argument 4: Climate models used by the IPCC reproduce these El Nino-induced step changes.
What The Climate Models Show: Most of the climate models (GCMs) used by the IPCC in AR4 for hindcasting 20th Century climate do not bother to model ENSO. Those that make the effort do not model it well. The frequency, magnitudes, linear trends, and multiyear aftereffects of those models do not match the surface temperature record. The step changes that exist in the instrument temperature record, which are the bases for the much of the rises in global temperatures, do not exist in the model outputs of the 20th century.
If and when GCMs can reproduce the past frequency and magnitude of ENSO events, if and when GCMs can reproduce the multiyear aftereffects of ENSO events, which are these El Nino-induced step changes (including the ones that also appear in the OHC records), then GCMs may have some predictive value. At present they cannot reproduce ENSO or its multiyear aftereffects. At present they have no value.
This failure of GCMs to properly account for the multiyear impacts of major El Nino events (and other natural variables such as the North Atlantic Oscillation) can be seen in a graph of the actual rise in global OHC versus the projected rise forecast by GISS, Figure 14. The GCM used by GISS based its projection on the rise in Ocean Heat Content during the 1990s, assuming the trend would continue at that pace. But during the 1990s, the vast majority of the rise in OHC was caused by the combined effects of ENSO and the North Atlantic Oscillation, and these are natural variables that the GISS GCM did not model. Since 2003, Global Ocean Heat Content has been relatively flat, while the GISS projection reaches to unrealized levels.
http://i37.tinypic.com/i6xtnl.png
Figure 14
LINKS TO MORE DETAILED DISCUSSIONS
The upward step changes in the SST anomalies of the East Indian and West Pacific Oceans were discussed in the following posts:
1.Can El Nino Events Explain All of the Global Warming Since 1976? – Part 1
2.Can El Nino Events Explain All of the Global Warming Since 1976? – Part 2
And I discussed the step changes in the Mid-To-High Latitudes of the Northern Hemisphere in the post RSS MSU TLT Time-Latitude Plots…Show Climate Responses That Cannot Be Easily Illustrated With Time-Series Graphs Alone.
The erroneous assumption that the relationship between ENSO and global temperatures is linear was discussed in the following posts:
1.Multiple Wrongs Don’t Make A Right, Especially When It Comes To Determining The Impacts Of ENSO
2.Regression Analyses Do Not Capture The Multiyear Aftereffects Of Significant El Nino Events
3.The Relationship Between ENSO And Global Surface Temperature Is Not Linear
This link discusses and illustrates that El Nino Events Are Not Getting Stronger.
The impacts of natural variables (ENSO and NAO) on Ocean Heat Content were discussed in the following posts:
1.ENSO Dominates NODC Ocean Heat Content (0-700 Meters) Data
2.North Atlantic Ocean Heat Content (0-700 Meters) Is Governed By Natural Variables
3.NODC Corrections to Ocean Heat Content (0-700m) Part 2
Refer also to La Nina Events Are Not The Opposite Of El Nino Events.
The curious drop in cloud amount in 1995 and its possible impact on the 1997/98 El Nino is discussed further in Did A Decrease In Total Cloud Amount Fuel The 1997/98 El Nino?
LINK TO LEVITUS ET AL (2009)
I referred to the Levitus et al (2009) paper “Global Ocean Heat Content 1955-2008 in light of recently revealed instrumentation problems”. Here’s a link to the paper:
ftp://ftp.nodc.noaa.gov/pub/data.nodc/woa/PUBLICATIONS/grlheat08.pdf
PAPERS THAT PORTRAY A LINEAR RELATIONSHIP BETWEEN ENSO AND GLOBAL TEMPERATURES
In a good portion of this post, I’ve illustrated that the relationship between ENSO and global temperatures is not linear. The following is a list of papers that portray a linear relationship even though the instrument temperature record indicates otherwise. There are likely more of them in existence, and there will likely be more of them in the future.
Lean and Rind (2008), How Natural and Anthropogenic Influences Alter Global and Regional Surface Temperatures: 1889 to 2006
http://pubs.giss.nasa.gov/docs/2008/2008_Lean_Rind.pdf
Lean and Rind (2009), How Will Earth’s Surface Temperature Change in Future Decades? http://pubs.giss.nasa.gov/docs/2009/2009_Lean_Rind.pdfSanter, B.D., Wigley, T.M.L., Doutriaux, C., Boyle, J.S., Hansen, J.E., Jones, P.D., Meehl, G.A., Roeckner, E., Sengupta, S., and Taylor K.E. (2001), Accounting for the effects of volcanoes and ENSO in comparisons of modeled and observed temperature trends
http://pubs.giss.nasa.gov/docs/2001/2001_Santer_etal.pdfThompson, D. W. J., J. J. Kennedy, J. M. Wallace, and P. D. Jones (2008), A large discontinuity in the mid-twentieth century in observed global-mean surface temperature
http://www.nature.com/nature/journal/v453/n7195/abs/nature06982.html
Thompson et al (2009), Identifying signatures of natural climate variability in time series of global-mean surface temperature: Methodology and Insights
http://ams.allenpress.com/perlserv/?request=get-abstract&doi=10.1175%2F2009JCLI3089.1
Preprint Version:http://www.atmos.colostate.edu/ao/ThompsonPapers/TWJK_JClimate2009_revised.pdf
Trenberth, K.E., J.M.Caron, D.P.Stepaniak, and S.Worley, (2002), Evolution of El Nino-Southern Oscillation and global atmospheric surface temperatures
http://www.cgd.ucar.edu/cas/papers/2000JD000298.pdfWigley, T. M. L. (2000), ENSO, volcanoes, and record-breaking temperatures
http://www.agu.org/pubs/crossref/2000/2000GL012159.shtml
SOURCES
OI.v2 SST data is available through the NOAA NOMADS website:
http://nomad3.ncep.noaa.gov/cgi-bin/pdisp_sst.sh?lite=
Sato Index data is available from GISS:http://data.giss.nasa.gov/modelforce/strataer/tau_line.txt
The AMO data is available through the NOAA ESRL website:
http://www.cdc.noaa.gov/data/correlation/amon.us.long.data
The RSS TLT data is available here:http://www.remss.com/data/msu/monthly_time_series/RSS_Monthly_MSU_AMSU_Channel_TLT_Anomalies_Land_and_Ocean_v03_2.txt
HADISST data (Used in Figure 13) NODC OHC data and ISCCP Total Cloud Amount data is available through the KNMI Climate Explorer website:
http://climexp.knmi.nl/selectfield_obs.cgi?someone@somewhere
The data for the North Atlantic SST Reconstruction is available through the NCDC’s World Data Center for Paleoclimatology:
ftp://ftp.ncdc.noaa.gov/pub/data/paleo/treering/reconstructions/amo-gray2004.txt
For those who want to verify the outputs of the GCMs used by the IPCC, refer to the KNMI Climate Explorer webpage here:
http://climexp.knmi.nl/selectfield_co2.cgi?someone@somewhere
Chris H: I’ve posted the one-page summary:
http://bobtisdale.blogspot.com/2010/01/does-instrument-temperature-record.html
Paul K2: Oops. Just noticed. My apologies for spelling your last name wrong in my prior reply.
Bob, you say this:
“But El Nino events not only release heat into the atmosphere, they also shift atmospheric circulation patterns (Hadley and Walker Circulation, surface winds, cloud cover).”
However you have previously called upon me to provide datasets in support of a similar contention put forward by me.
Have I misunderstood something ?
As a separate issue would you concede that in evaluating the oceanic effects on global climate one would need to take the net effect of ALL the widely diverging states of each ocean surface into consideration rather than just the present state of ENSO even if it is the dominant component ?
Do you attribute the observed changes in SSTs in the Tropical Pacific entirely to trade wind effects or would you accept involvement of the Thermohaline Circulation ?
I raise this last point because of a report which suggested that the ITCZ was at the equator during the LIA which suggests a larger scale and longer term oceanic oscillation not really catered for in your work so far – unless I have missed something.
I made a remark about this on a separate thread, so at the risk of sounding redundant, let me explain that the Stefan, 4th power law, does not pertain to this case. Since LW radiation goes out a narrow water vapor window the actual power law could be quite different. If, for instance the peak LWIR spectrum is far removed from this wind, the effect is the produce a much lower power than 4, but if, as is the case here, the peak is within the window, then the actual power is higher, and I’d estimate something like 4.6 power. However, it is important to realize that the Stefan constant does not apply either, and the actual proportionality constant depends on the details of the full spectrum vis-a-vis the water vapor window.
Look for it in the sidebar under “pages”
[Mac/Safari users can change the screen size by Cmd – [minus] until it appears. ~dbs]
IOW the likelihood of a record hot year in 2010 is 90%. But skeptical bettors on the well known event prediction website Intrade ( https://www.intrade.com , under Climate & Weather) are betting that the odds are only 25%. Where are the sincere Warmists who should be making bets against them at such odds?
Stephen Wilde: You quoted my statement in the post, “But El Nino events not only release heat into the atmosphere, they also shift atmospheric circulation patterns (Hadley and Walker Circulation, surface winds, cloud cover),” then wrote, “However you have previously called upon me to provide datasets in support of a similar contention put forward by me,” and asked, “Have I misunderstood something ?”
The changes in atmospheric circulation I mentioned in the post are documented in a multitude of papers. Simply perform a Google Scholar search of ENSO ”Walker circulation” or ENSO ”Hadley Circulation” or ENSO precipitation or ENSO “cloud cover”, etc. Web pages are dedicated to the ENSO-related data, and data such as precipitation, wind speed, etc., is available through the KNMI Climate Explorer.
On two earlier threads here at WUWT, you mentioned your research into the “latitudinal position of the air circulation systems”. These included:
http://wattsupwiththat.com/2010/01/11/ipcc-scientist-global-cooling-headed-our-way-for-the-next-30-years/
And:
http://wattsupwiththat.com/2010/01/06/this-wuwt-article-from-last-year-was-on-fox-news-tonight/
On them, I asked for the data on which you were basing your research, so that I could also study it. There was an admission on your part that you were “not aware of any other sources of data tracking the latitudinal position of the air circulation systems beyond seasonal variability.” This led to further questions, which you have not yet replied to.
You raised the subject. Is this the thread on which you wish to respond to the unanswered questions?
So on the one hand we should probably dismiss the warmists’ land-surface temperature claims because of tinkering and inadequate data, and on the other we should dismiss their sea-surface and lower-troposphere results because they misinterpret the cause.
Makes sense to me. I was just trying to figure out whether ‘the globe’ could be said to be warming, or not. Since the seas constitute a much larger portion of the Earth than the land, I guess the answer is a qualified ‘yes’, but not for the reasons the warmists give.
A more pertinent question might be, does it make sense to speak of a ‘global climate’ at all? Someone in another thread suggested using instead a total energy budget for the Earth, which if definable and measurable could at least be more solidly based than some rather speculative average of Earth’s multitude of climates over some arbitrary period of time.
I suggest ‘climate science’ begin a hundred-year program of intensive satellite and other measurements aimed at describing how the Earth’s energy budget changes over time, and until that time is up, refraining from any more pronouncements about ‘climate change’.
This is, admittedly, more or less equivalent to telling them, “Get thee to a nunnery!”
/Mr Lynn
Well,Bob. Point 3 is a good one. El Ninos don’t create heat. An explanation of how El Ninos redistribute heat follows,but that’s no rebuttal of the statement.
Which bits of the relationship between ENSO and global temperature are linear and which are non-linear?
Which features of the relationship between enhancing AGHGS and ocean /atmosphere coupling are linear and which are non-linear?
Bob Tisdale (18:46:28) :
You said:
Actually, I have shown that the PDO is an aftereffect of ENSO. Refer to:
My response: No you have NOT!
With respect Bob, simply pointing to two of your non-peer reviewed articles does not make what you say true. You must back up your claims with causal
logic which makes sense in the real world.
Let’s put it in its simplest terms.
The PDO swings between being positive and negative. The transition from one phase to another is a gradual process, however, on decadal time scales the PDO remains postive for about 30 years and then transitions to being negative for about 30 years (with the occassional foray).
If we are trying to establish a causal link between two quantities A and B, we normally try to show that A affects B (or vice versa). If A affects B then B will change in response to earlier changes in A, with some time lag.
Soon after the PDO becomes positive, the cumulative strength of the El Nino events begin to increase. They continue to increase while the PDO remains positive. Soon after the PDO changes to being negative, the cumulative strength of the El Nino events begin to decrease. They continue to decrease while the PDO remains negative. The same train of events occurs when you consider the relative frequency of El Nino to La Nina events.
If what you are saying were correct i.e. the PDO is a long-term cumulative response to changes in the properties of the ENSO (e.g. the cumulative strength of El Nino events or relative frequency of El Nino and La Nina events) then you should expect the following to happen:
As the cumulative strength of El Nino events increased over a roughly 30 year period you would expect the PDO to become more and more positive, so that by the end of any give postive phase of the PDO index, the PDO index would be very positive (i.e. very strong PDO conditions).
A similar pattern should be observed if the PDO were being driven by the frequency of El Nino to La Nina events.
The simple fact is that this is not the case. What you are claiming completely contradicts the observations. Unless you can explain how your theory (on the relationship between the PDO and the ENSO) overcomes these very basic contradictions then I am afraid that it cannot be taken seriously.
Bart (00:44:43)
The apsidal precession completes one rotation in the same time as the number of sidereal months exceeds the number of anomalistic months by exactly one, after about 3233 days (8.85 years).
I hope this is of some help.
Ninderthana: In response to my reply to you, “Actually, I have shown that the PDO is an aftereffect of ENSO. Refer to,” you replied, “No you have NOT!”, and continued with, “With respect Bob, simply pointing to two of your non-peer reviewed articles does not make what you say true. You must back up your claims with causal logic which makes sense in the real world.”
Had you bothered to read the two “non-peer reviewed articles” I linked you would have found two peer-reviewed papers that go to great detail to explain why the PDO is an aftereffect of ENSO. The first is Zhang et al (1997) who were the first to calculate the PDO and whose methods are still being employed by Nate Mantua in his calculation of the PDO. Note that Zhang et al refer to the PDO as the NP Index in the paper:
http://www.atmos.washington.edu/~david/zwb1997.pdf
The second paper is Newman et al (2003). In their abstract they write in their Conclusion, “The PDO is dependent upon ENSO on all timescales.” Can’t get any more basic than that.
http://www.cdc.noaa.gov/people/gilbert.p.compo/Newmanetal2003.pdf
And after my two posts were written yet another paper has been written that comes to the same conclusion, Shakun et al (2009). They write in their conclusion, “Deriving a Southern Hemisphere equivalent of the PDO index shows that the spatial signature of the PDO can be well explained by the leading mode of SST variability for the South Pacific. Thus, PDV appears to be a basin-wide phenomenon most likely driven from the tropics. Moreover, while it was already known PDV north of the equator could be adequately modeled as a reddened response to ENSO, our results indicate this is true to an even greater extent in the South Pacific.” Link:
http://www.leif.org/EOS/2009GL040313.pdf
Regards
Bart (00:44:43)
Can I aslo recommend the 20.295 year period that marks the relaignment of New moon with closest perigee (i.e. when the Moon is at 356, 000 km)?
In addition, there is the excellent article by Basil Copland and Anthony Watts at:
http://wattsupwiththat.com/2009/05/23/evidence-of-a-lunisolar-influence-on-decadal-and-bidecadal-oscillations-in-globally-averaged-temperature-trends/
Bob,
I have read the first two article in great detail. I would not comment if I had not done so. (Thank you for the third reference, I will look into it over the coming days). The first two articles are demonstrably wrong.
I see that I am going to have to publish a peer reviewed article to point out why they are wrong. I have the evidence to prove my case. They are simply getting the wrong answer because they are refusing to think out side the box. They refuse to countenance the possibility that the PDO and ENSO are BOTH being driven by a third underlying cause (i.e. the Lunar tides).
This is a classic example of the “experts” saying something must be true and everyone else agreeing that they must be correct because the (so-called)experts say so.
There are too few days to correct all these silly errors.
Nick: You wrote, “Well,Bob. Point 3 is a good one. El Ninos don’t create heat. An explanation of how El Ninos redistribute heat follows,but that’s no rebuttal of the statement.”
You are correct that it’s an explanation. My explanation actually agrees with the statement. It’s the La Nina that replaces the heat released and redistributed by the El Nino.
You asked, “Which bits of the relationship between ENSO and global temperature are linear and which are non-linear?”
The discussion of a linear relationship between the ENSO and global temperatures pertains to the methods employed by the authors of numerous climate studies who attempt to remove the impacts of ENSO by subtracting, basically, a scaled and lagged ENSO index such as the CTI or NINO3.4 SST anomalies from global temperatures. Refer to the seven papers listed under the heading of PAPERS THAT PORTRAY A LINEAR RELATIONSHIP BETWEEN ENSO AND GLOBAL TEMPERATURES. Since the East Indian and West Pacific Oceans, or approximately 25% of the global oceans between the latitudes of 60S to 65N, warm in response to El Nino events (due to changes in atmospheric circulation) and La Nina events (due to the East-West dipole that takes place in the Pacific during ENSO events), one would have to conclude that the methods used by those studies miss the additional natural heating that takes place during the La Nina. A similar shift takes place in the TLT anomalies of the mid-to-high latitudes of the Northern Hemisphere. Both of these points were discussed in the post. You must have missed them, Nick.
You asked, “Which features of the relationship between enhancing AGHGS and ocean /atmosphere coupling are linear and which are non-linear?”
Since I can find no evidence of an anthropogenic greenhouse gas influence on Ocean Heat Content, I cannot answer your question. Refer to:
http://bobtisdale.blogspot.com/2009/09/enso-dominates-nodc-ocean-heat-content.html
AND:
http://bobtisdale.blogspot.com/2009/10/north-atlantic-ocean-heat-content-0-700.html
AND:
http://bobtisdale.blogspot.com/2009/12/north-pacific-ocean-heat-content-shift.html
Regards
You were correct about the millenium because there wasn’t a year ZERO.
But there was a year 0. It was the one before 1 AD. Hence all decades run between years ending in 0. Like anyone with sense knows they should.
Given that the Gregorian calendar did not come into play until quite recently, all starting dates are entirely arbitrary. As are all “decades”, “centuries” and “millenia”. To somehow claim the arbitrary “third” millenium did not start until 2001 because of an arbitrary choice to not have a year 0 is ludicrous. I choose to have a year 0, and so should you.
In fact January 1 was not the start of the year in the year 1 for the Romans (whose calendar we use in much mutilated form). Nor for the Chinese, Indians, Persians or Mayans: the other large empires of the time. All new years are totally and utterly arbitrary.
Sorry for the rant, but this fretting about “true” starting dates is the sort of excessively precision based on faulty initial premises that we accuse the AGW warmistas of.
Ninderthana (18:51:42) :
Thanks. Now, I need to read what you have written and the link you provided more carefully to try to understand if there is a reason the dynamics associated with these frequencies would have a dominating effect on atmospheric CO2 variation. If you have any suggestions, I would be interested in hearing them. It may be of particular interest to compare the phases in my expansion and see if they correlate in any way to the relative timing of tidal forces exerted.
Another point of interest is that I can easily replace the linear and quadratic terms in my expansion by a couple of longer term sinusoids which approximate a constant, linear, and quadratic term over the 50 year timeline and get just a good a fit, e.g.,
P = 354.2692 + 6.6192*cos(0.1257*t-2.0400) + 36.7897*cos(0.0628*t+2.7652) + 0.6624*cos(0.2992*t-2.6377) + 0.3351*cos(0.7392*t+2.3971) + 0.2659*cos(1.7453*t-0.9227) + 2.8398*cos(6.2832*t-1.6918) + 0.7956*cos(12.5664*t+1.0635) + 0.1142*cos(18.8496*t+1.9700) + 0.0918*cos(25.1327*t-1.3635)
where I have arbitrarily chosen to replace the linear and quadratic terms with 100 year and a 50 year sinusoids, but you could easily choose just about any two very long period terms and do as well. So, it might be asked, are there any very long period tidal effects which could induce such variation?
Bob Tisdale (13:43:42)
I have never anywhere referred to ‘my research’. I have simply pointed to the observations of myself and others and have mentioned that there is no full data set of latitudinal shifts in the air circulation systems beyond normal seasonal variation over time.
The sources that you refer to in support of your contention serve adequately to support mine as well.
Indeed we are both saying much the same thing so I don’t understand your problem 🙂
Barry R. (13:45:02) :
Very interesting speculations.
I have often wondered if Pinatubo occurred just when an El Nino was due, thus delaying but not denying the inevitable. Consequently, when the El Nino finally overcame the forces repressing it, it was the 1998 whopper.
I often notice things like this, but the devil is in the details. I greatly appreciate the people who have the brains and the time to crunch the numbers. Thank you, Bob Tisdale.
It is when we have the numbers correct, (and not “adjusted” to promote specific political viewpoints,) that we can start making some headway, in terms of understanding the actual mechanics involved in the switch between warm El Nino’s and cold La Nina’s, and between warm and cold phases of the PDO.
Stephen Wilde: You replied, “I have never anywhere referred to ‘my research’.”
Excuse my choice of words, but I assumed you performed research to create your published material. Then my comment above should have read your, “material published over the past two years,” which is from your comment on this thread…
http://wattsupwiththat.com/2010/01/11/ipcc-scientist-global-cooling-headed-our-way-for-the-next-30-years/
… in which you wrote in response to the papers published by Mojib Latif, “He seems to have read my material published over the past two years…”
You wrote, “The sources that you refer to in support of your contention serve adequately to support mine as well.”
The subject and data in question were those on which you base your discussions of “latitudinal position of the air circulation systems is the best indication as to whether the troposphere is warming or cooling.” Please identify which of the sources I referred to identifies latitudinal position.
Ninderthana: You wrote, “They refuse to countenance the possibility that the PDO and ENSO are BOTH being driven by a third underlying cause (i.e. the Lunar tides).”
That is not being discussed; at least I’m not discussing it. You wrote, “Correct me if I am wrong, but I think that you have shown that when the PDO is postive, the frequency of El Nino events exceeds the frequency of La nina events, and so the World’s temperatures increase. Similarly, when the PDO is negative, the frequency of La Nina events exceed those of the El Nino events, leading to decreasing World temperatures.”
And I corrected you. I do not present the relationship between the PDO and ENSO that way. I’ve presented the opposite. If the PDO is a lagged response to ENSO, then when the frequency and magnitude of ENSO makes El Nino events dominant, the PDO is positive, and when the frequency and magnitude ENSO makes La Nina dominant, the PDO is negative.
You wrote in another reply, “Unless you can explain how your theory (on the relationship between the PDO and the ENSO) overcomes these very basic contradictions then I am afraid that it cannot be taken seriously.”
Whatever you’re referring to is not MY theory. Coupled ocean-atmospheric processes originating in the tropics create the PDO pattern. The PDO pattern (warm in east versus cool in central and west for positive PDO and vice versa for negative PDO), which is all the PDO data illustrates, is a lagged response to ENSO events. This is discussed in Miller et al (2005) “Decadal-Scale Climate and Ecosystem Interactions in the North Pacific Ocean”:
http://www.springerlink.com/content/h60764x7742250k0/
Miller at al suggest how Newman et al (Linked above) can improve their model. They write:
“Recent studies with a simple first-order Markov model with forcing specified by the tropical SST index, damping rate specified by SST persistence (with re-emergence) and white noise forcing (simulating midlatitude weather) reveals that the BULK of the PDO index is explicable by atmospheric forcing from tropical teleconnections (Newman et al., 2003).”
[So Newman et al don’t explain all of the variability, just the BULK.]
“The forcing with tropical origins (Graham et al., 1994; Giese and Carton, 1999; Schwing et al., 2002b; Yasunaka and Hanawa, 2003; Deser et al., 2003b) clearly drives the canonical SST pattern portion of the PDO.”
[There are a number of other papers that agree the pattern originates in the tropics, where ENSO dominates. So it’s not only the three I’ve linked earlier.]
“However, THE SIMPLE MODEL RESULT IS SOMEWHAT DEFICIENT IN DECADAL TIMESCALE ENERGY. This suggests that the KOE SST pattern portion of the PDO is not simply driven by (OR AT LEAST IS NOT IN PHASE WITH) this tropical forcing.” [My emphasis].
[So Miller et al is saying that Newman is incomplete, something that Newman et al had noted in their paper. Miller et al then go on to suggest how to improve Newman et al.]
“ADDING A LAGGED KOE RESPONSE PATTERN, MIMICKING THE GYRE-SCALE SPIN-UP DELAY, may improve the fit of the Newman et al. (2003) simple model. Alternatively, midlatitude ocean-atmosphere, or oceanatmosphere- ecosystem, feedbacks may be important.” [My emphasis].
Miller et al doesn’t disagree with Newman et al. They agree with Newman that Newman’s model is incomplete and offer a way to improve it. And adding a lagged response for the KOE region would put it out of phase with the NINO regions and with the Northeast North Pacific, which then creates the PDO pattern.
In other words, you have to account for coupled ocean-atmosphere processes in your evaluation of ENSO and PDO. At the end of an El Nino event, trade winds and Pacific equatorial currents strengthen and return warm surface waters to the western tropical Pacific, where they are swept northward to the KOE by ocean currents. At the end of an El Nino event, a Rossby wave (located about 10N) returns subsurface waters to the western tropical Pacific, where they are swept northward to the KOE by ocean currents. Another contributor to the warming of the KOE after an El Nino is the change in atmospheric circulation that has been working its way eastward, eventually reaching the Northwest Pacific. Trenberth et al (2002) illustrate these lags in the individual ocean basins in their Figure 7:
http://www.cgd.ucar.edu/cas/papers/2000JD000298.pdf
At the end of an El Nino event, as the changes in atmospheric circulation travel from west to east, they don’t stop at the Indian Ocean; they continue east and contribute to the warming of the northwest Pacific. The end result is the lagged warming of the KOE, which gives the negative PDO pattern its warm appearance in the central and western North Pacific. At the same time, the La Nina is causing the cooling of the eastern North Pacific.
Caleb: You wrote, “I have often wondered if Pinatubo occurred just when an El Nino was due, thus delaying but not denying the inevitable. Consequently, when the El Nino finally overcame the forces repressing it, it was the 1998 whopper.”
There was a moderate El Nino in 1991/92 and lesser El Nino conditions (not a full-fledged El Nino) in 1993. Refer to Figure 3 above. Both of these were counteracted by the eruption of Mount Pinatubo. But they didn’t have a large volume of warm water to back them. Neither did the 1994/95 El Nino. This lack of warm water can be seen in the tropical Pacific OHC data, Figure 9. The 1995/96 La Nina created the warm water that fueled the 1997/98 El Nino. The additional warm water production during the 1995/96 La Nina was caused by unusually strong trade winds, which reduced cloud cover, which allowed more downward shortwave radiation to warm the tropical Pacific.
Were the unusually strong trade winds in 1995/96 an aftereffect of Mount Pinatubo? Dunno, but it seems like a long time for that to happen.
Regards
Caleb: I forgot the link the explanation of the curious 1995/96 upsurge in tropical Pacific OHC. It was explained in McPhaden (1999) “Genesis and Evolution of the 1997-98 El Nino.” It is the result of “stronger than normal trade winds associated with a weak La Nina in 1995–96.”
http://www.pmel.noaa.gov/pubs/outstand/mcph2029/text.shtml
Bob Tisdale (13:43:42)
This article makes a start on the issue and confirms a basic interaction between ENSO/PDO and the speed and position of the jets.
http://www3.interscience.wiley.com/journal/121537407/abstract?CRETRY=1&SRETRY=0
I disagree with their finding that the observed latitudinal changes are statistically insignificant. They do after all accept a statistically significant speeding up of the jets and a spacially consistent trend. Given a longer study period I consider it likely that the latitudinal changes would have become statistically significant. Ideally one needs to observe a couple of full PDO cycles.
The sources you referred to may not focus on latitudinal positioning but they do focus on size and intensity of the air circulation systems concerned and I take the view that it is but a small step to suggest that along with such changes comes a change in the width of the equatorial air masses and a shift in the mean latitudinal positions
It is quite true that I do not have definitive proof but there is no definitive disproof either and my suggestions fit a lot of puzzling observations.
They do say this with which I concur:
“The jet stream data support the connection between the jet and the Pacific-North American atmospheric teleconnection pattern and between the jet and the oscillation of sea surface temperature anomalies in the northern Pacific Ocean known as the Pacific Decadal Oscillation.”
There is data available to indicate that during the LIA the ITCZ was nearer the equator and ships logs of the time show more equatorward storm tracks.
Furthermore there is much discussion in the media and elsewhere that the jets were more towards the poles during the recent warming spell.
There is enough to persuade me and I respect your right to retain doubts.
I am content to rely on future research and real world events to support or rebut my proposals.
“Mooloo (19:53:35) :
You were correct about the millenium because there wasn’t a year ZERO.
But there was a year 0. It was the one before 1 AD. Hence all decades run between years ending in 0. Like anyone with sense knows they should.”
So in what year did Julius Cesar die according to the Mooloo calender?
And do you think we should rewrite all the history books about old Europe?
And no, if I have a ruler with zero in the middle (looking like the abscissa), I would say the point x = -0.5 is in the FIRST inch to the left.