Pielke Sr: Climate Includes Extreme Events

A Forecast Extreme New Zealand Weather Cold and Snow Event

By Dr. Roger Pielke Sr.

While it is common to state that weather is not climatology, the reality is that climatalogy is composed of a collection of weather events over some time period. 30-year average temperatures and precipitation, for example, are two examples.  NCDC has recently released its new climatological averages; e.g. see

Anthony Arguez, Russell S. Vose, 2011: The Definition of the Standard WMO Climate Normal: The Key to Deriving Alternative Climate Normals Bulletin of the American Meteorological Society Volume 92, Issue 6 (June 2011) pp. 699-704. doi: 10.1175/2010BAMS2955.1

It is also important to recognize, however, that extreme weather events are themselves part of climatology. It is such occurrences that often cause the most significant societal events.  It is also useful to identify thes extreme events as there are often claims that extreme events, such as drought and heat waves, will become more common (e.g. see), or less common such as snowstorms (e.g. see).

The extreme snow event in New Zealand that is forecast this weekend is noteworthy in the context of climatology since, according to the IPCC-type predictions, such events should be becoming less common.  The forecasts for this event are quite serious. The news agency TVNZ just released the article

Much of NZ braced for a polar blast

The text reads

Snow to sea level and blizzard conditions are set to hit New Zealand’s deep south, with snowfalls also spreading north.

MetService is warning of a polar outbreak in the deep south overnight tonight and tomorrow morning.

An extremely cold southerly outbreak is expected to bring snow to sea level over the south of the South Island early Sunday morning, the forecaster says.

A heavy snowfall warning has been issued for Fiordland south of Te Anau, Southland and the south and east of Otago including Dunedin.

Snow is forecast to spread to many other parts of the South Island and the lower North Island later on Sunday, it says.

Significant accumulations are likely in Fiordland south of Te Anau, Southland and the south and east of Otago.

The snow is expected to continue on Monday and into Tuesday.

The heavy snow is likely to cause major disruptions to traffic and make driving conditions very difficult, MetService warns.

Strong southerlies, gale-force on exposed coasts, with the cold temperatures will make the wind feel bitterly cold and create blizzard like conditions in some places, it says.

Farmers are being advised that stock may need shelter.

Road workers at the ready

Roading contractors are preparing to work around the clock this weekend clearing snow and laying grit.

The Transport Agency says it’s inevitable restrictions and some closures will be needed during the polar blast predicted.

Spokesman Andy Knackstedt says the number one concern is ensuring people’s safety.

He says people need to plan ahead, check the latest information, and think carefully about whether the journey is necessary or not.

This quite likely will be an historic extreme event for New Zealand, and is not in the direction of expected extreme events forecast such as presented in the news article in Cosmos by Oliver Chan titled

No snow, more drought, climate report warns

that I posted on yesterday in

Interesting Quote On Climate Model Prediction Skill By Steven Sherwood Of The University of New South Wales

source of the two images ECMWF

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Latitude

While it is common to state that weather is not climatology, the reality is that climatalogy is composed of a collection of weather events over some time period. 30-year average temperatures and precipitation, for example, are two examples.
=====================================================================
serious question…..
How did we get stuck on this 30 year thing?
Other than it being convenient………it has no real relation to anything

I live here in snowey Ottawa, Canada, where we are always ready for the worst that winter can, and does, throw at us. However, my sympathies to the people of New Zealand, who are probably simply not ready for this sort of thing. Please dont travel unless it is necessary. Stay safe and warm at home.

http://dictionary.reference.com/browse/Generation
Generation: The term of years, roughly 30 among human beings, accepted as the average period between the birth of parents and the birth of their offspring.

Dr. Pielke,
Like Latitude, I question the 30 year convention. With the global impact of climate modes like the PDO, it seems that 60 years should be the minimum. Is there any literature on the issue that could be used to confront the IPCC authors on the issue? — thanx

noaaprogrammer

Latitude asks:
“How did we get stuck on this 30 year thing?”
Somewhere in the distant past in one of my probabiliity & statistics course, I remember something to the effect that to compute an average, at least 31 data values are needed in order to meet some criteria which I have forgotten. Can someone speak to this?

Warren

This quite likely will be an historic extreme event for New Zealand,
It’s historic in that if it will reach as far north as predicted areas that haven’t seen snow fall for many years will get a covering. But it isn’t all that extreme.
It’s winter, we’ve had heavy dumps of snow before, sometimes as late as October in the South Island. Hunker down, keep warm, make sure the stock are moved off the mountains and be prepared to accept loss of livestock.
Situation normal, nothing to see here 🙂

Olen

They say it is better to be safe than sorry when admitting their models could be off the mark. In other words the old warning from the warming crowd, can we take the risk that we are wrong.
When a group of people are consistently wrong in their work while supporting a political agenda at what point is the risk they are warning against ridiculous?

Warren
Alexander K

As a Kiwi, this weather report does not sound all that unusual – weather happens. Historically, NZ experiences it’s most severe lamb losses due to Summer snow and rain storms.

Roger Knights

While it is common to state that weather is not climatology, the reality is that climatalogy is composed of a collection of weather events over some time period.

“Climatology” above is the wrong word; it should have been “climate.”

I have always thought we should use as long a period of data as is possible, so presumably, for the US, it could extend to 1900 or so. At the very least, we should endeavour to get it as long as 60-80 yrs to cover a full AMO cycle — PDO cycles apparently being shorter.
In fact, given the computer resources we have today, why shouldn’t the length vary with the station/location? If it has sufficient data for 30 yrs, let’s use 30 yrs by all means, but if it has data for 90 yrs, let’s use 90. So the weather guys

Above comment is in response to Latitude’s question on August 13, 2011 at 9:03 am.

Anything is possible

Latitude says:
August 13, 2011 at 9:03 am
serious question…..
How did we get stuck on this 30 year thing?
Other than it being convenient………it has no real relation to anything
______________________________________________________
I asked the same thing on another thread a few weeks ago. The silence was deafening.
As far as I can tell, 30 years has no particular scientific significance whatsoever – it was merely a compromise figure that the WMO got everybody to agree to back in the day.

Curiousgeorge

@ noaaprogrammer says:
August 13, 2011 at 9:13 am
Latitude asks:
“How did we get stuck on this 30 year thing?”
Somewhere in the distant past in one of my probabiliity & statistics course, I remember something to the effect that to compute an average, at least 31 data values are needed in order to meet some criteria which I have forgotten. Can someone speak to this?

It varies, but there is a minimum recommended data set in order to fit a frequency distribution. The fewer data points available, the less accurate the fit (mean, median, mode, etc. ). Typically it is at least 50 points, and 500 or more is desirable. For a brief description of common distributions and fitting thereof: http://www.statsoft.com/textbook/distribution-fitting/?button=1 . There are many more than just the Normal distribution, and basing predictions on the wrong one can result in huge errors.

Rhys Jaggar

I think there’s little doubt that with 30 year flips in oceanic modulations that the 30 years has some usefulness, once you have several 60 year cycles of data available.
That 30 year average will be what you might expect within a warm/cold PDO for example. But it won’t necessarily be relevant to the other mode.
As an example, when as a young man I started reading about alpine snow patterns, all that was written was, in fact, for cold PDO. My experience for 20 years was that the ‘traditional’ patterns simply didn’t happen. Now that the pattern has flipped back, we are seeing ‘traditional’ patterns more often again. Earlier start to winter, less snowy springs.
The 30 year average has some relevance, but you need the start and finish dates right to know what it actually means. I suggest people look at the following 3 30 year periods for their own region and see what they find:
1. Cold PDO or AMO cycle.
2. 2nd half cold/1st half warm PDO/AMO cycle.
3. Warm PDO/AMO cycle.
That will indicate the susceptibility to decadal change, how much difference there is between the two modes and how sudden the change is.
A long way still to go before either the data records are long enough or human understanding great enough for ‘averages’ to have much meaning I’m afraid.

Richard Patton

I agree that 60 years should be the minimum if you have the data. I noticed years ago in data for PDX before I had heard of the of the PDO or AMO that there was a 60 year cycle, 30 years of warming, 30 years of cooling. If we use only a 30 yr cycle someone will always ‘find’ that the climate is warming or it is cooling and run around in circles saying either “an Ice Age is coming! The Government needs to interviene NOW before we all die!” or “the world is over heating! The Government needs to interviene NOW before we all die!” I’ve lived long enough to see both.

What is it happening in the southern seas?, the south pacific has been agitated the last weeks, with waves bigger than normal along the coasts of south america.

My short-form understanding of climate change (the proportions of which are “natural” and “man-made” to be put to one side for the moment) is that the added heat in the system, if actually present, can be thought of as energy available to drive weather. In a nutshell, while the climate trends generally upwards in terms of temperature, the weather becomes more extreme, either in the cold or hot directions; the “spread” gets wider and the customary norms lessen. “Seasonal” weather becomes less expected, and historical norms (or at least of the last eye-blink of a century!) are exceeded.
Of course, it’s a mug’s game to base single weather events to predict climate, but if there is more energy in the system, one might expect wilder oscillations in weather events and unseasonable spells.

HankH

noaaprogrammer says:
August 13, 2011 at 9:13 am
Latitude asks:
“How did we get stuck on this 30 year thing?”
Somewhere in the distant past in one of my probabiliity & statistics course, I remember something to the effect that to compute an average, at least 31 data values are needed in order to meet some criteria which I have forgotten. Can someone speak to this?

As I recall, in a standard distribution the standard deviation increases with sample size then starts to level off at around 45 samples at which point it becomes stable. The World Meteorological Organization (WMO) settled on achieving 2/3 of reaching a stable standard deviation because 45 years was too long to wait and 66% accuracy in such a chaotic system was seen as good enough to differentiate a trend and eliminate most year to year variation in averaging the data.

Latitude

………we use 30 years because of satellites
more than that, and you would have to use some “trick” to blend the data
30 years is just convenient…and has no real relation to anything

Nuke

Latitude says:
August 13, 2011 at 9:03 am
serious question…..
How did we get stuck on this 30 year thing?
Other than it being convenient………it has no real relation to anything

Because that’s was once the time frame best suited for showing the most warming?

Jantar

I’ve been watching this weather develop over the past couple of days. It’s nothing that we haven’t seen before, the only unusual part is that we had something similar only a couple of weeks ago.

Fred Allen

Alchemy, as an interested weather observer, I think I can respond to your note in a small way. The AGW proponents have again been barking up the wrong tree by saying increasing temperatures result in more energy in the system, whereas in my experience, weather is driven in large extent by temperature differentials. In other words, if temperatures go up or down across the board, then not much will occur. If temperatures rise or fall markedly in one area compared to another area, then that causes extreme weather. As an example, storms and tornadoes at a cold front could be exacerbated either by warmer (than normal, whatever that is) air ahead of the front, or colder (than normal) air behind the front. Same applies for cyclones/hurricanes. It’s the method the atmosphere has of moving energy from one area to another to try and achieve equilibrium.

Latitude says:
August 13, 2011 at 9:03 am
> serious question…
> How did we get stuck on this 30 year thing?
I don’t know. I recall my “Climate of the US” (or whatever) book from the early 1960s which had 30 year averages, so the’ve been around for a while. The Coop program started in 1890, it may be that in the 1920s someone wanted weather averages and someone else said “Hey, we have this 30 year record.” Or maybe someone in the 1950s wanted weather averages and someone else said “Hey we have this 60 year record, but you only gave us enough money to average the last 30 years’ data. Hope that’s okay!”

The old paper weather record books were pages with 10 years of records with a month per page, with the days of the month from left to right, so they would fill out the decade long book then along the bottom of the page was a couple rows for the 10 year average for each date, The furthest right column was the averages for the month for each of the ten years, and the lower right block was the two average sums from each month that should match the totals for each day averages for the decade.
When questions arose about how it compared to the past, they just got out the last three decade long books and the current partially filled out book of records, laid them out together side by side on the desk and turned the pages simultaneously, it is easier to get an average from three sets of data than just two, and there was no more room for more books to be open at the same time, on a 3 X6 foot table. Simples.

rpielke

africangenesis – you have asked a very good question. The answer quite simply is that it is arbitrary. It reflects the assumption that there is a “stable” climate if one averages over this time period. However, this assumption does not fit the climate system even if the human intervention were small.

John F. Hultquist

Thirty years! Thirty years?
Once more with feeling: 30 years of reports with the end year ending with a zero: This was chosen as “normal” in the mid-1930s at a meeting in Poland – before computers. The idea was that a child under 10 or so probably did not pay much attention to climate but would be familiar with her or his local weather. Thirty years was believed to be long enough that the results would be fairly stable (noted by the comments above about statistics and N=30) and sufficiently recent that a person hearing the day’s temperature was above (or below) “normal” could relate to the notion within the reality of her or his own experience.
There are practical reasons why 300 years could not be used and without computers and digital reporting a yearly update would be cumbersome.
As a baseball announcer once said, you can look this stuff up.
This document
http://www.wmo.int/pages/prog/wcp/wcdmp/documents/WCDMPNo61.pdf
has this comment:
“The concept of the 30-year climatological standard normal dates from 1935, when the Warsaw conference of the International Meteorological Committee recommended that the period 1901-1930 be used as a world-wide standard for the calculation of normals. In 1956, WMO recommended the use of the most recent available period of 30 years, ending in the most
recent year ending with the digit 0 (which at that time meant 1921-1950).”

rpielke

Warren and Alexander K
Thank you for the feedback.
We will see, of course, if this is a record extreme event. The latest news reports seem to indicate it is on track to rank quite high in New Zealand cold and snow events; e.g. see as just one example
http://www.hawkesbaytoday.co.nz/local/news/polar-snow-storm-moving-towards-hawkes-bay/3962987/

Mark.R

Hope this snow does not hit Christchurch as hard as they say.
There are people still living in homes with little heating.
Homes with cracks in there walls and still trying to get on with lives after the earthquakes.
Christchurch has been hit hard over the last year and we dont need this.

Purakanui

Nothing unusual just north of Dunedin so far. We were snowed in for a couple of days a fortnight ago, which was unusual but not at all extraordinary. So far there is quite a bit of overnight snow on the ranges but nothing below about 500 metres.
I recall an event similar to this in the 1980s coming as late as 1 October; it closed the hill country roads and I couldn’t get out for the opening day of the fishing season.

paulsnz

I looked at the isobar map and saw a large High that would WEDGE out the southern blast as it has, We have mild temps and lots of rain.. My super computer brain doe’s it again.

I live in Dunedin. There are snow showers here just now but this ‘event’ is more or less normal for this time of the year. We get snow down to sea level once or twice a year – had one about 2 weeks ago and I was snowed in for three days. Nothing unusual here – move along.
Douglas

Rab

I am a farmer in the central South Island of New Zealand. Farmers have to live with weather. While we are on the same latitude as the south of France we do get snow in winter. About every 5 years we get snow to sea level over most of the island. This storm looks no different to many and looks as though it will be a less than 5 yr event.
What has chahged is the forecasting and reporting and peoples expectations.. As forecasters switch to computers they forecast further ahead and start beliveing their models. Thankfully, one of the more repsected independent forecasters is doubting what his computer is telling him and backing off the hype.
TVNZ, while govt owned, is in a competitive market and sensationalist headlines win market share.
Modern 4WD vehicles are far more capable of handling these conditions that cars of 50 yrs ago but we seem much more ready to close things down as we, as a people (not as farmers), forget that nature is changeable and not always benign and do not think of taking the simple precautions we would have taken just a few years ago.

The question of whether to include extreme events in climatology should depend on the nature of the extreme event in question. If it belongs to a time series that shows statistical variability that makes sense. On the other hand, events that are unique should not be averaged out of existence. Among these unique events I count the super El Nino of 1998. By superficial analysis it seems to be just an unusually strong El Nino. El Ninos belong to the ENSO system of alternating warm (El Nino) and cool (La Nina) events involving a physical oscillation of ocean water from shore to shore. It can be demonstrated that the 1998 super El Nino is not part of it and was interpolated in a time slot that should have belonged to a La Nina. It brought much more warm water across the ocean than a regular El Nino does and this warm water was responsible for the very warm first decade of this century. Its probable cause was a storm surge near the beginning of the equatorial countercurrent that carries El Ninos across the ocean. The presence of this extra warm water near the west coast of the Americas raised global temperature by a third of a degree by 2002. I should point out here that this how all El Nino peak temperatures are created, and they do have a global influence. The warm water also suppressed a La Nina that should have appeared around 2004 and thereby created a six year warm period, the twenty-first century high. ENSO oscillations that were effectively interrupted by the super El Nino resumed with the 2008 La Nina. But the current mean temperature of the new oscillations is very nearly the same as the twenty-first century high which means that the warming brought by the super El Nino amounts to an permanent step change in climate. Taking this observation into account it is clear that temperatures from 2002 on must not be averaged in with temperatures before 1998. And the four year period from 1998 when the super El Nino arrives until 2002 is a transition period that must not be averaged in with any temperature curve. I can think of other situations where this has happened. An example is the early twentieth century warming. The step warming initiated by the super El Nino was the second warming of the twentieth century and accounts for about half the warming of the century. The first half took place from 1910 to 1940, and was terminated by a severe cooling at the start of World War II. Available temperature charts show World War II period as a heat wave that is purely fictitious. Temperature dropped severely in the winter of 1939/40 and the Finnish Winter War was fought at minus 40 Celsius. It stayed cold for the rest of the war as Hitler found out when attacking Russia. Later in the West the GIs had to fight their way from the Battle of the Bulge to the German border in the coldest winter West Europeans could remember. I assume this nonsense about the heat wave during the war is due to poor or lacking records due to the war. After the cold spell during WWII the temperature stabilized and from the fifties to the nineties there was not much movement, maybe a little cooling, maybe a little warming from the great Pacific climate change until the super El Nino arrived. Which leaves us with a definite climate and temperature break point in 1940. Clearly there are two climatological periods involved, one from 1910 to 1940 and the other from 1950 to 1998, that should not be part of a single, averaged temperature curve. Missing from this description of climatology is that “late twentieth century warming” which does not exist. For explanation of this and other facts about the climate read “What Warming?” available on Amazon.

tango

well done boys this weather event will get us more grants

Their government are away that things will get colder over coming decades, they just dont want to do anything about it because the models show after that the warming will return

rbateman

Reality is when you begin to realize that the warming period ain’t coming back for a long time. Large-scale Instability rules in times of extremes, and it’s root cause is cold getting loose from the Poles. It was the extended period of warming which put the pressure and the check on the Polar Air masses, keeping them hemmed in.
Remember the blast of cold air that ran up the Andes last S. Hem Winter?
It’s for whom the Poles Toll, and it’s for you & for me.
The N. Hem. turn will come.

Brian H

Alchemy says:
August 13, 2011 at 10:11 am
My short-form understanding of climate change (the proportions of which are “natural” and “man-made” to be put to one side for the moment) is that the added heat in the system, if actually present, can be thought of as energy available to drive weather.

And that’s the problem. Your understanding, while matching the claims of the alarmists, is false. It is FLUX which matters: the flow between contrasting areas or zones. And ‘global warming’ preferentially adds energy (heat) to the coldest areas — the high latitudes, such as the poles.
This makes the temperature more homogeneous , resulting in LOWER FLUX, and quieter, more benign weather.
Cooling of the high latitudes results in STRONGER FLUX, which is extreme weather and storminess.

Brian H

Reading those weather reports for us NA residents is momentarily disorienting; the thought of blizzards approaching from the south is very upside down!
😉

“:It’s the method the atmosphere has of moving energy from one area to another to try and achieve equilibrium.” Thanks, Fred Allen. As a sailor, I have a fairly direct appreciation of tightly clustered isobars as they can lead to the spilling of beverages.
Brian H: Interesting point. Your contention is that global warming, disproportionately higher in the polar regions, makes for less rather than more severe weather as it is the differential between climate zones that powers that more severe weather?
My understanding is that it is evaporation and condensation that power weather systems, and that this process is accelerated by heat, whether particularly differential or not. Due to the polar highs, for instance, and other surface-related features, much of Canada’s Arctic is actually quite dry, and in some places qualifies as a desert, if a cold one with frozen sand!. The reported melting of the permafrost is releasing frozen water onto the land, where it presumably evaporates, making the high, dry Arctic more humid and therefore at greater potential for weather making.
I would find it interesting if torrential summer downpours became a feature of the Arctic regions in the years to come. That would indeed be an example of fluxion.

Cadae

It’s started snowing heavily here in Wellington, NZ. I’ve been in Wellington just over 20 years and this is the most snow I’ve seen.

dp

My view of climate is quite simple: Climate is the framework within which weather happens, and defines the extreme limits of what weather is likely capable of. Climate is regional, not global. Regional climates can interact in influence adjacent climates. Climate continually changes. Weather extremes vary as climate varies. Trends in weather extremes are an indication of climate change. Sporadic weather extremes only reflect what extremes a climate state allows. Climate change is common, frequent, and normal. Climate can, does, and will change in quick steps. It can also move slowly.
To date, all major climate changes have been cyclic but not centered.

Purakanui

Just an update from north of Dunedin, NZ. Snow has been falling all afternoon and our little coastal village is now cut off as short blizzards roll in one after another. No great snow depth but bitterly cold with gale force winds. Two such events in a fortnight is unusual (maybe things are getting cooler?) but neither is really unusual of itself.
Home distilling is legal in NZ and so we have sufficient supplies to see us all through this storm. I think I see neighbours coming. :o)

We’ve never* had snow in Auckland – that’s never as in never in recorded history and recorded history here goes back about 170 years – but apparently this storm is likely to be the best chance in our lifetime to see some. Sadly, it appears the weather system developed “a little too far to the west” so the chances of snow are only small. This is only the second time I can ever remember our chances of snow being described as “small” rather than “non-existent”, the other time was late last month.
*Whenever snow in Auckland is mentioned someone will bring up a possible dusting in the 1930s. However, the none of the local newspapers at the time saw fit to record this for posterity, I think it might have at least made page four or five?

As I write, it is snowing heavily in Wellington in the lower North Island. Something exceptionally rare, and last I saw was I think about 1993.
Back then, Wellington ground to a complete halt, simply because the infrastructure (and the traffic) was not used to such conditions.
Coming originally from a relatively cool environment in Northern England where snow was a regular occurance, it is quite funny to see how inexperiened drivers loose control in even the smallest depths of snow
Let’s see what unfolds from this smattering (that has actually just stopped pro tem)

Mike Jowsey

rbateman says:
August 13, 2011 at 9:17 pm
Reality is when you begin to realize that the warming period ain’t coming back for a long time. Large-scale Instability rules in times of extremes, and it’s root cause is cold getting loose from the Poles. It was the extended period of warming which put the pressure and the check on the Polar Air masses, keeping them hemmed in.
Remember the blast of cold air that ran up the Andes last S. Hem Winter?
It’s for whom the Poles Toll, and it’s for you & for me.

This Google Earth screenshot shows the reality of what you are talking about. This latest weather event hitting NZ is straight from the Antarctic. Brrrr!
[IMG]http://i55.tinypic.com/2i22y9.jpg[/IMG]

Mike Jowsey

oops – my bad tagging…. try this?
http://i55.tinypic.com/2i22y9.jpg

paulsnz

Brrr… My SuperComputer malfunctioned after being distracted by Al Gore.

Anything is possible says:
August 13, 2011 at 9:42 am
“serious question…..
How did we get stuck on this 30 year thing?”
I asked the same thing on another thread a few weeks ago. The silence was deafening.
____________________________________________
Mr AnythingisPossible, surely you dont mean this thread last month:
http://wattsupwiththat.com/2011/07/07/noaas-new-normals-a-step-change-of-0-5-degrees-f/
If you scroll down you will find quite a noisy discussion speculating on the backstory to the WMC/IMO decisions quoted by John F. Hultquist above.

Paul Deacon

Just past 7:00 p.m. here in Christchurch, NZ. No snow yet. It has been warm and sunny most of the day, with the wind building and dying away repeatedly. A short and light shower of hail/snow/sleet at mid-day was all so far. It looked like the bad weather was passing us by to our east (out to sea). This may be what has hit Wellington (according to Cadae above). One boffin at our met service blogged about a temperature inversion in Timaru today (temperatures rose while those around fell). Timaru is on the east coast of the South Island, south of Christchurch.