Digital Diatribes

A presentation of data on climate and other stuff

Archive for the ‘Oceans’ Category

The Best of Digital Diatribes (In one man’s opinion…)

Posted by The Diatribe Guy on July 15, 2010

Over the course of my time here, there seem to be a handful of posts that I keep referring to. These posts are referred to because of other studies that arise, or questions that come up.

I don’t consider my blog to, for the most part, have provided a plethora of new information to the discussion on climate, climate change, or the science behind the data. Most of my posts on the subject are more of a curiosity. “Hey, here’s a bunch of data. Here’s a bunch of trends at different lengths. Here’s how those trends are changing.” Most people with an understanding of Excel and statistics could do something similar. I guess maybe others aren’t as interested to just look through a bunch of numbers to see if any interesting things jump out, so to the extent I’ve been able to add something, that’s great.

There have been times, though, where I do an analysis and put together a post that I’m particularly proud of. I believe it actually does add to the debate.

Interestingly, those more complex posts with an actual interesting conclusion seem to get less attention than a simple trend line chart. I continue to be astonished by the debates that can ensue over a simple line chart.

But nevertheless, since there are a few posts that (a) I really like, (b) refer to quite a bit – and every time I do I have to dig through and remember where it is, and (c) I think actually add a new insight to the debate, I thought I’d highlight these posts again, while putting them all into one post.

So, with that introduction, here they are:
(1) Sunspot study that derives a correlation between sunspots and temperature

(2) A best fit of sine waves to HadCrut data that clearly shows cycles within the temperature data

(3) A look at the AMO data, demonstrating where we are in the current cycle, and where we’re headed

(4) A look at a few ocean cycles, but the focus here is the PDO analysis

(5) A demonstration of the fallacy of a singular trend-line fit in the recent temperature data, and how most of the increase in temps has come from a single step

Posted in Climate Change, Cycles, Data, Earth, Global Warming, Information, Oceans, Science, Temperature Analysis | 10 Comments »

Uh Oh… Does the plummetting ENSO Index portend a cold winter?

Posted by The Diatribe Guy on July 10, 2010

We’ve had a wetter than average summer, but the temperatures here have been glorious. Out East, they have been scorching temps as of late, and a lot of people are making a lot of hay about that (I’ve never really understood that expression).

Global temperatures have been warmer. It is what it is. No use pretending otherwise.

But this wasn’t completely unexpected. In fact, as a resident skeptic, I personally suggested prior to last winter that we’d have mild one. It isn’t rocket science. The ENSO index was into persistent El Nino territory and that was that. My prediction turned out to be right. Oh, sure, as always in Wisconsin, we had our extremely cold days, but all in all it was warmer, we had more days than normal get into temps that melted snow, and we had an early spring. And thanks, at least in part, to an ENSO index that stayed above the 0.5 mark from the 2009 May/June reading to the 2010 April/May reading we have continued to see warm temps.

So, imagine my surprise when I just randomly clicked on the index to see a May/June reading of -0.412.

Now, without any other context, this isn’t an extraordinarily low number. But there is a bit of context here that makes this a fairly fascinating number.

First, the index tracks on a two-month average basis. Thus, going from an April/May value of 0.539 to a May/June value of -0.412 (a drop of 0.951) must imply a very dramatic cooling in June. It’s one thing to see that kind of number when the previous one was -0.2, it’s quite another to see it after an El Nino-esque reading in the prior period.

So, I was curious to see how this compared to previous drops in the index.

I was both surprised, and not surprised, to see that this drop is the largest single month-to-month negative change in the index since the beginning of the readings in 1950.

Ouch.

I am not entirely sure what this means, and I suppose we need to see what happens over the next couple months. But I don’t like the timing. The impact of La Nina will have a few month lag, which puts us squarely in line for a harsh winter.

If you’re curious about the other laregest drops and what happened after those drops:

2nd place: -0.915 May/June 1998. This was a drop from an extremely high index reading to a still high reading. (From 1.982 tp 1.067) Within 3 months we saw La Nina, and it persisted 19 months, if you include one reading just above -0.5.
3rd place: -0.825 Apr/May 1954. This was a shift from a shallow La Nina value (-0.598) to a deep La Nina reading (-1.423). Including the initial value, this started a La Nina that persisted for 34 months.
4th place: -0.799 Oct/Nov 1950. This was a move from a negative reading (-0.381) to La Nina (-1.180). Something seems odd here. Deep La Nina readings are in place from the first month of 1950, then we had a jump, and then this drop. La Nina persisted another 5 months.
5th place: -0.775 May/June 1988. This was a move from barely positive (0.090) to La Nina negative (-0.685). This started a La Nina that persisted for 12 months.

Not to be a pessimist, but if you’re in my area, enjoy the next 2-3 months while you can.

Posted in Cycles, Data, Earth, El Nino, ENSO, La Nina, Oceans | Tagged: , , , , , | 10 Comments »

Curve-Fitting the ENSO Index Suggests We Have the Highest El Nino Event since 1998

Posted by The Diatribe Guy on January 28, 2010

ENSO 200912

ENSO Index and Fitted Curves @ 12/31/2009

I’ve continued to work, as I have the time to, on pulling the Oceanic Oscillation data, developing a fitting spreadsheet for each index, to get some idea of what the underlying cyclical nature of the oscillations may be.

I decided to post the above chart on ENSO, since I (a) completed it, (b) we’re currently in the midst of an El Nino, and (c) most amateur climatologists know about it and occasionally like to take a look at it.

The source for the data can be found on the right side of this page. The largest hurdle in the curve-fitting is that good(?) data only goes back to 1950. Even this may be a little questionable, and from what I’ve read, any proxied data prior to that is even less reliable. But, we’ll run with the data we have with the caveat that is always there about analysis only being as good as the accuracy of the data and all that.

I’ve been very interested in trying to understand the tendency of these oscillations to cycle (or not cycle, as the case may be). The ENSO index, in particular, can have the appearance of a random variation with no particular pattern.

At this point, I need to explain what I did here, and then I need to explain what I am saying and what I am not saying regarding the conclusions.

PROCESS

1) I have simultaneouosly fitted a long-period wave and a short-period wave to the ENSO data
2) The following elements have been fitted:

For the long period wave:

  1.  Best fit sine wave with a period of at least 30 years
  2. A scale factor to determine amplitude of the wave
  3. A phase increment amount to determine the length of the wave
  4. A starting point on the wave cycle to be fitted at the beginning of the data
  5. A vertical shift, to account for bias in the zero-anomaly base assumption
  6. A slope of linear trend

For the short wave:

  1. Best fit sine wave with a period less than 30 years
  2. A scale factor for amplitude
  3. A phase increment amount to determine cycle length
  4. A start point on the wave at the beginning of the data

There is no shift or trend determined on the short wave determination, since this will follow the path of the long wave.

Through a simultaneous and recursive process, all these elements are simultaneously solved to produce the minimum value of squared differences from the point on the short wave to actual ENSO index readings.   The ultimate solution is not necessarily incorporating the best-fitted long wave taken in isolation.   I initially ran the long-wave fit first, and then separately ran the best fit short wave along that curve.   Moving to running everything simultaneously helped the overall fit and actually reduced the length of the long-wave.    The difference is not huge, but since it is the best fit and the results appear reasonable, I went with that.

RESULTS

The results of this analysis show a 50.5 year ENSO cycle that underlies the shorter-term variations.   I have shown this before, and it is an interesting consideration in evaluating the relative magnitude of certain ENSO events, not so much as it relates to the zero value, but as it relates to the long-term wave.   The current long-term wave is on a decline, and may, in fact, be bottoming out in another four or five years.

The starting point is just past the halfway mark of the cycle, so we see a lower-index period at the beginning of the chart.  The amplitude of the wave is about 0.32 at its peak.   So, from top to bottom (with no linear trend) there is a difference of 0.64 in the magnitude contributed to ENSO events from one period to another, depending on where the long-term cycle is at.

There seems to be, in addition to the cycle, a linear trend in the data for which the long-term cycle moves along, at least since 1950.   It may be that there is a third cycle that is substantially longer that is being mistaken for a linear trend.   This may matter in the long run, but for a 60-year time period the linear approximation should suffice.   However, it may well be that we need a number of additional years of data to better fit this and judge whether or not there is a linear trend, or some other cycle at work.  For now, though, I go with the best fit, and for that the rate of change is 0.7 degrees Celsius per century.

This long wave is being fit simultaneously with a short wave placed on its path.   The period of this short wave is 4.93 years.  Its scale is 0.49.   So, at the top of this wave, plus the top of the long wave, we are adding 0.81 degrees to the ENSO index.   The first wave starts at about the 220 degree mark of a cycle.

Key Assumptions (What I’m doing versus what I’m suggesting)

There are a couple key assumptions here.  The primary assumption is the selection of a sine wave for fitting.  I am not saying this is the best assumption.  All I am saying is, given this assumption, there is a best fit.   As I look at the data, it actually doesn’t do too bad a job in aligning with peaks and valleys.  However, it is far from perfect.   There are other ways to manipulate this, if desired.  One can select a skewing assumption so that the wave peaks earlier or later in the cycle than at 90/270 degrees.   Or, once can assume that there is a factor that compresses or expands length over time (or both in some oscillating pattern over years).   Another thing to look at is to see if the length of sunspot cycles impacts the difference in timing of ENSO peaks/valleys, as I’ve seen suggested.

All these are potential refinements that could improve results.   However, all that said, I still think there are some interesting results here.   The most significant El Nino events do seem to correspond well with peaks in both waves.

The other assumption is that there are two cycles to consider.  A third assumption that can be questioned is the validity of a linear trend in the data.

DEVIATIONS

One may think that the waves represent the anticipated direction of the ENSO index.  That is actually not what the waves imply.  The red wave pattern marks the “starting point” for the current index.  From there, deviations may go up or down.    This may be the most confusing aspect on how to read the chart.   It’s not so much about predicting El Nino or La Nina, it’s about showing how the ultimate magnitude is affected.

Examples:

June 1955 ENSO index = -2.270; Wave value = -0.76.  Negative deviation = -1.51

September 1973 ENSO index = -1.71; Wave value = +0.20.  Negative deviation = -1.91.

One could argue that the 1973 event was substantially more profound than the 1955 event, even though the actual ENSO index reading was lower in 1955.

Likewise:

The most profound El Nino event, in terms of a deviation from the underlying wave, actually occurred in 1983 – not 1998.  The March 1983 reading = 3.11, and the wave value = 0.77, for a differential of 2.34.    The maximum deviation during the “Super El Nino” was actually August 1997 – a difference of 2.03.

In fact, we actually have a fairly significant event occurring right now.   The December 2009 deviation from the wave is +1.54, which is the largest difference since April of 1998!

Posted in Cycles, Earth, El Nino, ENSO, Oceans, Pacific Ocean, Science | Tagged: , , | 4 Comments »

Eastern Pacific Oscillation and Random Stuff – Believe it or not, a New Post…

Posted by The Diatribe Guy on December 1, 2009

Ah, it’s been a while, hasn’t it? My friend Jeff at The Air Vent asked me if I’m giving up. I understand the appearance of this, given my lackluster performance (or more accurately, zero performance) as of late.

Before I present a chart of the EPO Index, which most of us probably don’t care all that much about anyway (if we’ve even heard of it), I have a few random observations:

1) To Docattheautopsy: Ha! I told you! (Check out comment #6 here: https://digitaldiatribes.wordpress.com/2009/09/30/el-nino-is-back-with-the-fury-of-a-woman-scorned/#comments). Good thing, too, because I get enough spam. Anyway, as complex as climate is, it is actually kind of amazing that so much of the simplicity can be missed among the complexity. I know it doesn’t always hold, but there are some rules of thumb that stand up pretty well. La Nina in spring/summer ==> cold Wisconsing Winter. El Nino in Spring/Summer ==> mild Wisconsin winter. It’s not really rocket science. So, each of the last two years gave us frigid temps and lots of snow, and so far this year we have above average temperatures in November. It’s supposed to cool off soon, but nothing unusual. I admit I was nervous in October – it was a very cold and wet October, but November has been beautiful.

2) Climategate: I love it. I don’t “love it” in the sense that it should have ever happened. That part ticks me off, because it’s simply a blight on the scientific process and public trust, and a validation of the more underhanded aspects of the whole thing – it’s about money, politics, control and power. That’s a major shame. But I do “love” the fact that this has been exposed. It may well be true that much of their analysis doesn’t change, and they may actually believe their conclusions. But what is lost in making that simple argument of dismissal about the relevance of the situation is that there are other scientists who have reached different conclusions who were essentially shut of of the public debate, and in doing this it led to a global, incessant mantra that brainwashed policymakers and citizens alike. It’s not whether or not their studies are meritorious, it’s about the fact that the full debate and scientific process was not implemented, and the full range of views were shut out of attaining credibility through reprehensible methods of collusion and intimidation. And really, it just shows the overall poor character of the participants in these exchanges, which also leads to a lack of trust.

3) Where are the temperature charts? Well, I’ll get back to them. I really wanted to spend time on the Oscillation Data, so I’m continuing down that path at the moment. The trends don’t change so much from month to month, and I am in no way avoiding it due to recent uptick in temperatures. I don’t do that, even if Phil Jones and Michael Mann may suggest implementing a trick to disguise the uptick, if they were skeptics.

And so, with that, let me explain the following chart: The Eastern Pacific Oscillation Data are available since 1950 (link to the right) and is just another one of the Oceanic Oscillations. It’s not one we hear about much, and may well not be highly important in the climate discussion. That’s OK. By plowing through the different indices, I hope to isolate the ones that do have an apparent oscillation pattern, because it seems to me that this is an indication that the Oscillation is a driver of temperature, rather than the other way around. The interesting thing about most of the oscillation patterns is that they tend to cycle on a longer time period. Even ENSO, with its shorter term spikes (not on particularly predictable intervals, it seems) has a longer term cycle. The EPO index suggests something else – an 8.9 year cycle.

Caveat: there are no December values in the data set. I have adjusted this by using the average of the November and January values. I have sent an e-mail to NOAA seeking an explanation for this. If I receive a response, I’ll either comment about it or update the post.

EPO_200910_raw

EPO Data as of 200910

It’s hard to say how much impact this metric has on global temperatures, and I probably won’t know until I can do a full correlation analysis of all the oscillations, solar index, and CO2, at minimum. But it may have some impact. There is almost no linear trend whatever on this, and the index seems well-centered around a zero anomaly.

There also does seem to be a very shallow 40-year cycle, if I expand the analysis out to look at that, but nothing worth more than a note. The driving cycle is the shorter-term one.

Hope all is well with everyone. If I find I cannot get to data analysis, I will try to do better at posting some fluff just to let you know I’m still here ;).

Posted in Cycles, Data, Earth, EPO, Oceans, Pacific Ocean, Science | Tagged: , , , | 6 Comments »

El Nino is back with the Fury of a Woman Scorned!

Posted by The Diatribe Guy on September 30, 2009

OK, not really. But the headline is kind of catchy, no?

El Nino is, in fact, back. And to hear some of the early prognostications about it, we would all melt like the Wicked Witch of the West mighty soon. And this was going to prove once and for all that global warming was real, because – we heard – the recent cooler temperatures were a byproduct of recent La Ninas. (Please forgive my laziness in not including the squiggly lines over my n).

I admit to not quite understanding that argument. The skeptics among us have pointed out that the increase in global temperatures that took place a decade ago were driven by a Super El Nino. And at the time, we heard that global warming was causing more severe El Ninos. But then the severity decreased and we had La Nina, and we were told that such statements were never really made. Or, at least, not by serious scientists. Which, if true, would mean that they should have agreed that the increase in warming at that time was exacerbated by the big and mean El Ninos. (Which, as an aside, brought very enjoyable winters in the Midwest. Why do people want to send us really cold weather all the time?) But other than some footnoted statements on page 23 of the reference section in a boring document, few people have been told the story about how El Nino affects should be viewed independently from overall warming.

That is, they didn’t know this until La Nina affects brought us some cooler temperatures. Then, suddenly, we heard about some “unusually cold” La Ninas, and how this affected global temperatures, and skeptics were being disingenuous by not properly considering that. And to the extent that such a criticism is true, they are right. But there is a strange thing that happens when ideology is part of the equation: you fail to heed your own criticism when the reverse occurs.

And so we have now seen three consecutive measures above 0.5 in the ENSO index. This is hardly unusual, but it does qualify – to my understanding – as a true El Nino. And before that, the La Nina waned, so we had a relatively neutral index for a couple months leading up to El Nino. So it’s been 5 consecutive measurements now since the La Nina has ceased. I remember when it became evident that an El Nino was on the way. This was going to prove skeptics wrong! Why? I have no idea. If El Nino had an anomaly of 1.00, 2.00, or 5,432.00 it would not prove anything other than when there is a natural warming of the Ocean, it warms our global temps. Wow… there’s a revelation. The fact that this has nothing to do with Carbon emissions is beside the point when it fits the argument.

Even stranger, skeptics tend to accept the cyclic variations as the legitimate explanation for warming. We don’t dispute warming periods. So, the skeptic will nod and agree that an elevated ENSO index will probably lead to warmer global temperatures. But then, we kindly point out, don’t blame carbon. Or people. And don’t get all in a tizzy when a La Nina comes around and we see cooler temperatures. What the hell do you expect? Sorry it doesn’t fit the model.

Having said all that, I certainly don’t expect any records to be broken in this recent El Nino. Sorry, experts. I base this simply on data analysis, admittedly knowing very little about all the climatolological influences that could prove me wrong. But what does the data indicate? Looks like it’s time for a chart:

ENSO_200908_raw

ENSO Data as of 200908

The first observation from the data is that we’ve had four consecutive positive anomalies, and three consecutive positive anomalies greater than 0.5. Note here that a single data point is actually a two-month running average, which helps smooth out month-to-month fluctuations. The latest reading is 0.978, which is the largest of the four positive anomalies. Prior to this period, there were 9 consecutive negative anomalies, with a stretch of 7 months less than -0.50. This was on the heels of only a two month set of barely positive anomalies after a stretch of 12 consecutive negative anomalies that included an eith-month stretch less than -0.5.

So, it is pretty clear that after some real solid La Nina-esque reality, we’ve now flipped to El Nino. What is not clear is the ultimate magnitude and persistence of our new friend, Mr. Nino. But we can talk likelihoods. And for that, we observe the path of the best-fit sine wave.

The red curve below has been fitted in accordance with the other Ocean Oscillations I have observed. Take a sine wave and manipulate it in a few ways in order to ascertain the minimum least-squares deviation from the curve. You see, while El Nino exhibits noticeable short-term variation, it seems to do so about a longer-term cyclical pattern. Thus, a large deviation in one direction at point A on the curve will not produce the same magnitude El Nino at point B on the curve.

The specifics of the best-fit curve are as follows: The 1950 starting point in the data looks to be at 268 degrees in the full 360 degree cycle. The length of the best-fit curve appears to be 102 years for a full cycle. This is an imperfect estimate, since we don’t even have 102 years of data. It is also a longer fit than what was made last year when I did a similar exercise. But the calculation is what it is.

You can see from the chart that the magnitude of ENSO events can have quite a range: -2 to +3 in the data provided. The scale factor applied to the wave is +1.24 in order to achieve the best fit. However, it looks as if the anomalies in the index may be significantly overstated, at least near the beginning of the curve. The best fit line requires an upward shift of all values of the curve of +0.98. This means that the early part of the curve should have appeared “colder” than it did. The interesting thing to me is that, despite the apparent rise in the average ENSO index levels, the best-fit curve actually has a negative linear slope element to it that is pretty significant: -0.00316, or -3.792 degrees Celsius per Century. This actually means that those high El Nino anomalies are centered around a curve that, without that negative trend line, would have been significantly higher – possibly as much as a degree and a half.

So, where are we now? We are 122 degrees into the cycle, which means we have a ways to go into the negative yet, if this best-fit curve is correct. While it appears to the eye that we’re past the 180-degree point, this is not so because of the negative linear slope the curve lies along. No, if this is right, we will not reach the minimum depth of the ENSO curve until around 2050. The curve itself has a staggering implication of coldness – what was a depth of around -0.4 degrees in the 1950s would be -4.0 degrees in 2050. Should we proceed along these lines, we can continue to expect positive and negative significant deviations from the curve, as we see today. But the positive deviations will produce fewer, shorter and less severe El Ninos while the negative deviations produce more, greater and more persistent La Ninas.

OK, here’s the good news: unlike climate modelers, I don’t proclaim this analysis to be infallible. First of all, we’re fitting the best curve to data that is quite variable in its short-term fluctuations. Second of all, the best-fit curve tells us that the cycle period is a longer period than the data period for which we are evaluating. I already know that this supposed cycle period has fluctuated quite a bit from analysis a year ago.

If I had to rank my certainty on the subject, I would bet confidently that (1) there is a long-term ENSO cycle of somewhat indeterminate period, probably somewhere between 60 and 100 years, (2) that we are entering the negative phase of the cycle and we can expect less severe El Ninos and more severe La Ninas.

I am far less certain about the linear trend of the cycle, and the extent of any such trend, as I am about the shift of the curve. These elements are probably much better measured as more data arises over time.

However, in any case, I think it looks very unlikely that we will see any record-breaking El Ninos for quite some time, in either persistence or in magnitude. We may, however, see some major La Ninas surface over the next few decades.

And that won’t be our fault, either.

Posted in Cycles, Data, Earth, El Nino, ENSO, La Nina, Oceans, Science | Tagged: , , , , | 13 Comments »

A Gander at the Caribbean Oscillation Index

Posted by The Diatribe Guy on September 29, 2009

We hear a lot about the ENSO index, the PDO Index, and the AMO Index.

I’ve also taken a look at the Arctic and Antarctic Oscillation Indices.

But there are more. Quite a few more, actually. While I have not done a comprehensive study on these, myself, one would assume that the reason we hear about the PDO, AMO, and ENSO is because these have quite evidently shown correlation to weather patterms that affect a lot of people. And it may well be the case that these are the main drivers that matter, and all the other ones have only negligible contributory effects.

Nevertheless, some time ago I decided I wanted to take a closer look at these. Readers here will notice that I’ve been focusing on Ocean Index posts recently. Based on the wide discussion that has broken out on these posts (yes, that’s sarcasm) it doesn’t appear that this is the main point of interest to a lot of people. That’s OK. Hopefully it’s interesting at some level. But it’s an important aspect of a full study on global temperature. And I still have the goal of doing a full analysis at some point combining the impacts of all these measures, along with solar cycles and CO2 levels.

As the next step in this journey, I have compiled the data from the Caribbean index. It is found as part of this data set (under the CAR column). The permanent link to this is on the right of this page.

I wasn’t sure what to expect on this index. As you recall, the polar regions didn’t demonstrate any shorter-term cyclicality to speak of, while the majors that everyone speaks of did show clear cyclicality.

The results of the raw data plot with the best-fit sine curve are shown here:

Caribbean_oscillation_200908_raw

Caribbean Oscillation Data as of 200908

It certainly looks as if there’s some cyclical thing occurring here, based on a best-fit analysis. It’s not quite as predominant as the AMO and PDO, but it’s there. There do seem to be short-term spikes with some months of persistence, similar to ENSO.

The best-fit line has the following parameters: A phase reduction of 0.61 degrees per month implies a full cycle of 49.15 years. There is a vertical shift downward of -0.053 needed, with a linear trend of 0.000187 – which is a rate of 0.224 degrees Celsius per Century.

Thus, the index, on average, has been understated enough to be noticeable and has exhibited an upward trend over time. This longer-term upward trend is more noticeable in the charts below as we collapse the data into longer-term rolling averages. Caution is needed to make sure we understand the autocorrelation, but even considering that there is an upward trend in the Caribbean surface temps exhibited.

Similar to ENSO, however, there look to be shorter-term spikes that may play more immediately into the local temperature/weather patterns. Since October 1989, we’ve seen the following stretches of positive/negative anomalies (keep in mind that the best-fit implies that there should be a shift from these figures):

198910 – 199108: 23 consecutive positive anomalies
199109 – 199410: 31 of the 38 months – negative anomalies
199411 – 199601: 15 consecutive positive anomalies
199602 – 199703: 5 consecutive negative / 4 consecutive positive / 3 negative / 1 positive / 1 negative
199404 – 199910: 31 consecutive positive anomalies
199911 – 200007: 9 consecutive negative anomalies
200008 – 2007121: 89 consecutive positive anomalies

Since then, it’s been back and forth.

Caribbean_oscillation_200908_12

Caribbean Oscillation Data as of 200908 - 12 month Smoothing

Caribbean_oscillation_200908_60

Caribbean Oscillation Data as of 200908 - 5 Year Smoothing

Caribbean_oscillation_200908_120

Caribbean Oscillation Data as of 200908 - 10 Year Smoothing

Posted in Caribbean, Cycles, Earth, Oceans, Science | Tagged: , , , | 2 Comments »

September 2009 Update on the AMO

Posted by The Diatribe Guy on September 23, 2009

I’ve looked at the AMO data set to see what it’s been up to lately, and after a brief plunge into negative territory, it’s come back to a level in accordance with the current sine wave path of the cycle. If you recall, there was a period of 77 consecutive months of positive AMO anomalies, with January 2009 finally breaking that string of positives. We then had 5 consecutive negative anomalies. Historically, such a deviation is not necessarily unexpected, as can be easily enough seen from chart observation. However, it was not an expectation for a persistent state, and we’ve now seen the last three anomalies come in at 0.175, 0.282, and most recently 0.205.

While these are positive anomalies, viewing them relative to the red wave line on the chart shows us that they are right around what would normally be expected.

When looking at certain Oceanic oscillations, the cycle is very clear, and the strength of a given anomaly should be placed in the context of the overall wave path. Deviations from the wave are a stronger indication of the unusualness of an anomaly than the actual value of it.

As I’ve noted in my previous write-ups, we’re nearing the peak of the wave. We should expect many more positive AMO anomalies. In fact, we should expect more positive AMO anomalies for the next 20 years (well, sort of – I’ll explain why this is probably shortened artificially in a bit). Since the wave is at its peak, we will soon see continually cooler anomalies for the next 34 years or so. However, the next few years will still be positive, but dropping.

Here’s the chart:

amoraw200908

Atlantic Multidecadal Oscillation Data as of 200908

Maybe it’s just me, but this is one of my favorite charts. Admittedly, the change in it is nearly imperceptible on a month-by-month or quarter-by-quarter basis. But one reason I present it occasionally is because I think it really tells a good story.

The story begins with the cyclicality, which is very evident. This, combined with ENSO and PDO (and I’ll keep looking at other indices) show a clear cyclicality in Ocean Temperatures. In my humble opinion, this should raise a red flag with regard to temperature correlations to anyone who even remotely wishes to get to the truth of what drives global temperatures. Making this cyclicality more clear is the fact that the Arctic and Antarctic Oscillations do not show this behavior at all. Click on the link related to the Arctic to read more about the PDO and ENSO cycles as well.

The next story is, where are we in the cycle? As I’ve alluded to, we are at the peak of the cycle. That means that the anomaly has, on average, risen continually for over the last 30 years. The most rapid point of acceleration of the wave occurs in the early-mid 1990s. Since then, it’s been increasing at a decreasing rate. In a couple years, it will start decreasing at an increasing rate for the next decade and a half.

The AMO is about a quarter-phase out of sync with the PDO (Again, see link above – click on the word “Arctic”). Thus, the PDO has been decreasing over the last number of years. As we’ve seen in the Temperature Charts we’ve been flat for about 12 years now, and we’ve actually seen decreasing temperatures over the last handful of years. This seems to correspond will with an AMO that is only slightly increasing and a PDO that is cooling off more rapidly. Read the rest of this entry »

Posted in Atlantic Multidecadal Oscillation (AMO), Atlantic Multidecadal Oscillation (AMO) Index, Cycles, Data, Earth, Global Warming, Oceans, Science | Tagged: , , , | Leave a Comment »

Antarctic Oscillation

Posted by The Diatribe Guy on September 21, 2009

I thought I’d start taking a look at the different Oceanic Oscillations to see if there’s anything at all I can glean from the data.

The first set of data is the AAO Index data which goes back to 1979 here. This could be a mistake, but I pulled in data from this source for the pre-1979 numbers. The reason I say it could be a mistake is because the latter source’s numbers do not match all that well to the former’s. This puts the pre-1979 data in question as it relates to the newer data. And, as the chart results came into view, I think we see that splicing this data probably does more harm than good. With that said, I have kept it in for this view of the data, but may choose to eliminate it in future reviews.

We’ll start here with the raw data, and a fitted line that I will explain:

antarctic_oscillation_200908_raw

Antarctic Oscillation Data as of 200908

The current anomaly value is -0.686, which is the fourth consecutive negative anomaly. Previously, there were 11 consecutive positive anomalies.

The line on the chart isn’t actually a linear fit, though it is very close. It is actually a best-fit sine wave. However, there are no short-term waves evident in the data, so the best-fit wave is a long-term wave that completes a 360-degree phase over 12,000 years. Obviously, trying to make a strong case for a 12,000 year cycle is a bit silly based on 60 years of data. Nevertheless, it’s interesting to consider that the earth’s precession of the poles moves along this approximate time period. It’s also worth noting that this same approach on the Arctic Oscillation yielded a sine wave of 9500 years. I make no assertions as to the accuracy of this, I just find it a point of interesting congruence.

So, with a 12,000 year fitted wave, the 60 years essentially has a linear fit associated with it. In the chart, it is clearly an upward trend. However, observe the differene between the pre-1979 and post-1979 areas of the chart.

Two things are apparent: (1) the volatility in the anomaly values is much higher prior to 1979, and (2) the upward trend occurs in the pre-1979 data.

Putting numbers to these observations:
1) The Standard Deviation of observations for the data prior to 1979 is 1.749. The standard deviation for 1979 – current is 0.988. The average positive anomaly prior to 1979 is 0.960. The average positive anomaly 1979-current = 0.746. The average negative anomaly pre-1979 is -1.778. The average negative anomaly for 1979-current is -0.830.

2) The slope from 1948 – 1978 represents warming of 5.26 degrees Celsius per Century. The slope from 1979 – current represents 0.68 degrees warming per Century.

It seems pretty clear that the data prior to 1979 is a different animal than post-1979. Read the rest of this entry »

Posted in Antarctic Oscillation (AAO), Antarctica, Data, Earth, Global Warming, Oceans, Science, Temperature Analysis | Tagged: , , | 1 Comment »

The NOAA and Claims of the Highest August Ocean Temperature

Posted by The Diatribe Guy on September 17, 2009

I was going to write a post on this whole thing, but before I did, I decided to scan some of the otehr blogs. It would appear that I have little to add to this, so I am gooing to link to them instead.

Here’s the basic summary: NOAA announced that we’ve just seen the highest Ocean Surface temperatures in, like, ever! Here’s the link at Watts giving us that story.

Jeff at The Air Vent also provided us with a skeptical take on the announcement. His post has since been updated, to now refer to ICECAP’s Joe D’Aleo, who summarizes the now-discovered issue:

Icecap Note: to enable them to make the case the oceans are warming, NOAA chose to remove satellite input into their global ocean estimation and not make any attempt to operationally use Argo data in the process. This resulted in a jump of 0.2C or more and “a new ocean warmth record” in July. ARGO tells us this is another example of NOAA’s inexplicable decision to corrupt data to support political agendas.

Bob Tisdale now has a guest post on Watts Up With That, showing the incongruence in NOAA’s assessment versus others.

This is so blatant, it’s almost amazing.

Whatever one’s thoughts on climate change, nobody should stand for such shoddy science, changes in methodology, and exaggerated statements of “fact.”

It does nobody any good.

Posted in Climate Change, Current Events, Global Warming, NOAA, Oceans, Science | Tagged: , , , | Leave a Comment »

AMO Update – June 2009

Posted by The Diatribe Guy on June 9, 2009

The Antlantic Multidecadal Oscillation data has been released and the May index value is -0.014. That is the fifth consecutive negative value, and it’s the first time we’ve seen 5 consecutive negative months since the period ending October 1994. Previous to this negative stretch, there had been 77 consecutive positive months.

Similar to my look at the ENSO index, I have updated my best-fit sine wave against the AMO data. The chart is presented here:

amo200906

Best-fit wave pattern against AMO data.

One nice thing about the AMO data as compared to the ENSO data is that it goes back to the mid 1800s. I cannot speak to the robustness of the index value, particularly for the older periods. I can only assume that it’s as good a measure as we have to work with.

A couple things can be noticed about this graph, especially in relation to the ENSO chart in the post referenced above. First of all, we are right now at the peak of the AMO wave. It last reached a trough in 1979, and has been increasing for the last 30 years. Since we are now at the peak, we will be descending down that wave now for the next 30 years, if the cycle is as presented. It should, however, remain in the warmer mode for the next 15 years of so, even though overall it is in a decline. Compare this to ENSO, where we just crossed the zero line.

It appears, then, that the ENSO (and PDO, as well) is offset almost exactly 90 degrees from the AMO. If true, this helps explain the contribution to warming over the last 30 years, and the stagnation of the last few years. 30 years ago, the AMO wave was at its trough, and the ENSO wave had crossed the zero line, moving upward. The next 15 years showed a situation in which all three waves were increasing. AMO from its trough up to the zero line, and ENSO/PDO from zero to its peak. Then, AMO increased while ENSO/PDO decreased, but both were above the zero line, so temperatures remained elevated, but the increase in temperature slowed and/or stagnated. Is it just coincidence? I suppose it could be. I consider that doubtful, however, because of the identification of waves in the HadCrut data that I presented.

Well, today, we are in the opposite siutuation as we were 30 years ago. The AMO is at a peak, and the ENSO/PDO index is at zero. It would seem, then, that we will experience significant cooling, along the same order as the warming of the 1980-2000 period over the next 20 years or so. Then, the period of time after that will likely be a stagnation of colder weather for 10-15 years, before we see the next warming cycle occur.

I’m sort of repeating what I did in this post. But it bears repeating. It seems fairly obvious to me, and it’s almost implausible to believe that such a relatively straighforward analysis that shows the Ocean cycles and how it affects the temperature cycles is not considered noteworthy when projecting forward temperature changes.

The other thing to note regarding the AMO chart above is that we seem to prematurely be getting some negative index values. I wouldn’t read much into that. Looking back at the chart, there are numerous times where negative readings – even consecutive ones – occur during the warmer side of the wave. In fact, the negative readings we see probably do indicate that we are in the warm wave yet, because the magnitude isn’t great, despite some persistence.

I may just be a layman and a data guy, but between this kind of analysis, a quiet sun and the analysis I’ve done as temperature relates to that, and the simple observation that we haven’t warmed in 12+ years, I can’t help but feel somewhat perturbed at the continuing warnings of global warming, and outright amazed at the audacity of predictions of multi-degree temperature increases by the end of the Century.

At this point, I would give odds on cooling until 2030 or so, regardless of what the fancy climate models say. It’s the only reasonable conclusion by looking at strict data. I suppose maybe the models say something that can’t be foound in the data. We’ll see.

Posted in Atlantic Multidecadal Oscillation (AMO), Atlantic Multidecadal Oscillation (AMO) Index, Climate Change, Cycles, Earth, Global Warming, Oceans, Science | Tagged: , , , , | 2 Comments »