According to the best-sited stations, the diurnal temperature range in the lower 48 states has no century-scale trend.

It seems that a number of folks have missed one of the more important conclusions from our first paper on the surfacestations project. Co-author Dr. John Nielsen-Gammon has some things to say about it the finding that is the title.

For layman readers that don’t know what diurnal variation is, it is the daily variation of temperature due to the variation of incoming solar radiation from rotation of the earth on its axis.

It looks like this:

Source: http://apollo.lsc.vsc.edu/classes/met130/notes/chapter3/daily_trend4.html

Fall, S., A. Watts, J. Nielsen-Gammon, E. Jones, D. Niyogi, J. Christy, and R.A. Pielke Sr., 2011: Analysis of the impacts of station exposure on the U.S. Historical Climatology Network temperatures and temperature trends. J. Geophys. Res., in press. Copyright (2011) American Geophysical Union.

Fall et al. 2011: What We Learned About the Climate

By Dr. John Nielsen-Gammon

Our paper has a lot of info and analysis about temperatures and temperature trends and their correspondence to siting class.  Perhaps the most important question, “Is the mean temperature trend different from previous estimates?” is answered in the negative, albeit with an asterisk associated with the limited scope of the study.  While negative results are useful, they’re also boring.  So in this post I’ll talk about something we did learn about the climate that’s new and different, and why I think it matters.

This new finding is stated succinctly in the abstract as: “According to the best-sited stations, the diurnal temperature range in the lower 48 states has no century-scale trend.”

The diurnal temperature range is simply the difference between the daily maximum temperature and daily minimum temperature, “diurnal” being a more impressive way of saying “daily”.  It’s conventionally abbreviated DTR.

The change in global DTR trends roughly coincides with the change in phase of the Pacific Decadal Oscillation, for example, so it’s hard to tell whether the DTR trends were natural or forced.

That’s where Fall et al. 2011 comes in.  The figure below shows the change in DTR anomalies over time over the United States, as estimated using data from each of the four classes of station siting.  The data goes all the way back to 1895, making this (as far as we know) the longest evaluation of regional DTR trends done anywhere.

Diurnal Temperature Range since 1895

Dotted lines represent average values and are plotted 1.5 C apart from each other

All four classes of stations show the decline from the 1950s through the 1970s.  But if you take a broader view, you see that the black line, representing the estimate from the best-sited stations, has a long-term positive (!) trend using unadjusted data or time-of-observation adjusted data, and has no trend at all for fully adjusted data (top set of curves).  The lower-quality siting classes all show a negative long-term trend, and the worse the siting, the larger the trend.

These results suggest that the DTR in the United States has not decreased due to global warming, and that analyses to the contrary were at least partly contaminated by station siting problems.  Indeed, DTR tended to increase when temperatures were fairly stable and tended to decrease when temperatures rose.  Maybe DTR really isn’t a robust signal of global warming, and maybe the discrepancy between models and observations is primarily a problem with the observations rather than the models!

I’ve used the words “suggest” and “maybe” here.  That’s because I regard our results as tentative.  The zero trend estimate is based on only 80 stations, which might be only marginally adequate.  The systematic change in trend with station siting quality makes me more confident, but the fact that the closest poorly-sited stations have a weak but positive DTR trend suggests that DTR may be strongly site-specific and makes me less confident.  Maybe the best-sited stations have actually improved their siting over time, and maybe the adjustments haven’t fully corrected for this.  Because of all this, I think these results need to be confirmed through other means or in other parts of the world before I will wholeheartedly believe that the real DTR has not been decreasing.

Nonetheless, all the ongoing work to understand the consequences of a faster rise in minimum than maximum temperatures for ecosystems and human health might, just might, be misguided.

Read the full post here

Advertisements

  Subscribe  
newest oldest most voted
Notify of
Rhys Jaggar

Can I applaud you and your colleagues for your labour of love in trying firstly to identify the best sited, maintained and monitored weather stations and secondly to carry out analyses to show that by determining which set of weather stations you use in your analyses, you may determine what conclusions you are going to draw.
I hope that the next 50 years sees the standards you have set rolled out globally in order that any scientific conclusions drawn about our climatic patterns are based on the best standards of data capture, comparison and standardisation.

D. Holliday

Is 80 stations better than 1 tree?

John Marshall

I do not believe that temperature, due to your discovered difficulties of measurement, and the fudging which seems to continue despite the arguments against such questionable practice, is a good indicator of human effect on climate. Despite this, Anthony, your painstaking research on the siting of the surface stations has opened many peoples eyes to the many problems of data gathering. Well Done!

Batheswithwhales

If the trend is that the worse the siting – the more negative the trend, I guess this must be because sitings such as next to buildings would provide shade, change the wind conditions, etc.
But could it also have to do with the age of the stations – that the worst sited tend to be older, with aging instrumentation? Or even different instrumentation, different huts, etc?
And if the best sited stations are the newest – could it be that these to a larger extent are located in areas more exposed to urbanization, thus being more affected by UHI?

BarryW

I’m surprised at the usage you’ve made of the surface station data. The siting data is only a snapshot of the history of the sites. What is now a 1 may have been a 5 or a 5 a 1 historically due to either changes in the site location or site relocation. Your analysis seems to imply a static situation which I don’t think is supportable. Consider Washington National airport. When built in the 1940’s Washington was a sleepy southern town that shut down in the summer. Now the airport is surrounded by concrete and asphalt and is basically in the middle of an urban area. I think there is too much uncertainty in the historical siting to make the inferences you’re making.

TerryS

Re: BarryW
Try reading the post before commenting:

Maybe the best-sited stations have actually improved their siting over time

Leron

I wonder could the 3 hour lag between maximum solar radiation and maximum temperature be because the humidity is generally lower in the afternoon than it is in the morning?

Dave

You forgot to adjust the most recent temperatures up and the adjust temperatures further in the past down!
This is a key scientific principle when measuring global warming. Don’t you understand science?

Andrew Dodds

In response to the ‘why lag?’ comment – as long as incoming radiation exceeds outgoing radiation (as per the second graph), temperature will rise.

richard verney

What interests me in the best sited stations is:
1. What is the trend for maximum daytime temperatures (both annually and month by month).
2. What is the trend for minimum night time temperatures (both annually and month by month).
3. How does this correspond with their counterparts in the entire station series.
Any feedback on this would be interesting.

Steve Keohane

TerryS says: May 19, 2011 at 5:15 am
Re: BarryW
Try reading the post before commenting:
“Maybe the best-sited stations have actually improved their siting over time”

Yes, airports are obviously the best placement:
http://chiefio.wordpress.com/2009/12/08/ncdc-ghcn-airports-by-year-by-latitude/

Shevva

Can someone remind me again why the tax-funded IPCC, ‘Climate Scientists’ or GISS cannot or did not do such a study. The Dutch had to get a private firm invovled before anyone took notice, in NZ it was said that actually their temp series wasn’t really a temp series and then over in the US you have to have individuals give up their free time to do such studies. I will not even comment on the MET/CRU here in blighty.
I guess when people are just simply handing you money hand over fist it’s too much bother to actually do an in-depth study before you have politico’s declaring that they will cut CO2 emissions by 80% in 20/30 years and all the economic hardships this puts on the poorest in our society.

Sam Glasser

Dear Shevva:
“……hardships on the poorest” and everyone else, too – please don’t forget!

BarryW

TerryS says:
May 19, 2011 at 5:15 am
Re: BarryW
Try reading the post before commenting:
Maybe the best-sited stations have actually improved their siting over time

So what? I read the post and stand by my comment. Using present conditions to extrapolate that the sites have the same conditions in the past is wrong. Especially when the location is not the same historically. Assuming that the site location has remained static you might assume that the microsite state is constant but only during that timeframe taking the data back to 1900 assuming that the CRN value is constant is making a big leap in my opinion especially if the site location has changed. Showing the data for the static siting timeframe would have more validity.

B.O.B.

I spent four summers planting trees in Northern Ontario (Canada) – a completely forested area the size of France (maybe bigger). We lived and laboured outdoors 24/7 so we were very much in touch with the elements. We worked in huge clear-cuts, which were surrounded by the remaining forest. Late afternoon was the time I looked forward to with dread. It was almost always the hottest time of the day. The wind would die down, the sun would still blaze (albeit at a higher angle of incidence), and we toiled in the latent heat that accumulated throughout the day. Not a very scientific explanation, I realize, but the lag in temp. between noon and 3 – 5 P.M makes sense to me.

John Silver

“Why lag?”
Heat inertia in the heated ground?

Geoff Sherrington

Yes, heat inertia in ground. Once did an experiment related to radon release mechanisms near a uranium mine, by using long stem thermometers set at different depths near Darwin Australia. There is a pronounced lag after the surface warms, before it warms at 20 cm depth (IIRC, the deepest we went) and then a later lag as it cools, of about the same duration. Unfortunately, I think the data were lost in a corporate takeover.

RHS

One question/observation regarding high temp of the day has a correlation in the low temp of the day. The lowest temp of a day is typically 30 – 45 minutes after sunrise, sometimes an hour. My basic understanding of this has to do with atmospheric heating and the change in wind direction. This causes the cooler air to blow from where the sun has not risen yet, blowing from cooler air masses to warmer air masses I wonder if there is a correlation in that at some point after noon, perhaps there is sufficient heating to cause the winds to blow from warmer air masses to cooler air masses until 5 pm’ish.
Anyway, just my $.02 worth…

mkelly

We not only have a lag during the day but a lag for each season. The hottest days of summer are not around 21 June nor are the coldest days around 21 December.
It takes time to heat/cool a large mass of humid air. (daily) It takes time to heat/cool a large mass of water. (seasonal)

JFD

Using DTR as a single analog for global warming is fraught with potential problems. There are other influences that must be accounted for before reaching any conclusions. For example:
1. There could be global warming (or cooling) and the DTR remain constant if the driving force(s) affected both night and daytime temperatures equally.
2. The daytime temperature could go up (or down) or the nighttime temperature could go up (or down).
3. Natural cycles such as ENSO affect humidity which plays a role in heat transfer.
4. Natural cycles affect winds which play a role in heat transfer.
5. Shielding may affect daytime temperatures more than nighttime temperatures.
6. From a harm to earth perspective, increasing daytime temperatures are more critical than increasing nighttime temperatures. DTR does not capture this aspect.
While one always tries to make answers as simple as possible, DTR seems too simple to me to fully explain changes in the temperature of the atmosphere. Less I sound too critical, earlier I expressed appreciation to the whole team who did the work and published the paper on the impact of measurement stations on climate change. I repeat my thanks.
REPLY: No worries. I think you may not have read the entire post on his website. The IPCC made significant use of DTR as a metric for AGW, and John N-G talked about the history of that in context. Here’s his full essay. Also this recent guest post on Pielke Sr. ‘s website
Guest Post “European Diurnal Temperature Range (DTR) Is Increasing, Not Decreasing by Francis Massen is instructive, and also talks about the IPCC using it. – Anthony

son of mulder

BarryW has a reasonable point so what sort of result would the following give?
Take the current best 80 and the current worst 80. I’d suggest that the best 80 had tended to get better not worse on average over time and the worst 80 now would have tended to get worse on average over time. Reasonable?
Then plot the 2 sets of data and see how they differ. That would give an insight into how improvements and degradation affect the trends if at all.

Jack Simmons

Who would have thought something as simple as measuring and tracking temperatures would prove to be quite challenging?
Just defining the standards across a network of weather stations is a major task.
Lots of work and sort of boring after a while. No wonder a lot of guys would prefer to do all this temperature tracking stuff from a computer.

Bill Illis

For the diurnal charts at the beginning of the post, just noting that the temperature change is exaggerated by quite a bit in these charts compared to a real-world station. There is far less change in the actual energy levels/temperature at the surface over a 24 hour period (between Max and Min), than should be expected.
http://img140.imageshack.us/img140/4109/tablemountainall.png
For the large differences in diurnal patterns that is found in Fall et al., there has to be quite large energy changes in terms of Watts/m2.

Andrew Dodds says: May 19, 2011 at 5:41 am
“In response to the ‘why lag?’ comment – as long as incoming radiation exceeds outgoing radiation (as per the second graph), temperature will rise.”
True only if heat lost from evaporation and conduction remains constant. But if e.g. the wind started to blow and there was significant loss from evaporation and conduction, then even at midday the temperature could drop.
And as I’m being pedantic, there is heat flow from the ground/sea … etc.

wayne

@ Dr. John Nielsen-Gammon
John, I see a question on you graph asking “Why the lag?”. Is that really a question?
To me that is because the insolation rate is still greater than the total upwelling surface energy rate lost to space, up until about 3 PM to 4PM. That point in the afternoon is when the insolation equals the outgoing.
These hourly breakdowns show that very affect. In these that lag was set be me (probably 1½ hours too late) to 5 PM as a rough guess:
http://i56.tinypic.com/avc5g.jpg : KT97
http://i53.tinypic.com/ir6lie.jpg : TFK09
Look at the point where the “Mean Surface Temperature” reverse and start to drop in the afternoon and then look notice the relation of incoming and outgoing energy fluxes. No adjustments for and thermal inertia were included in these figures, just a rough cosine weighted breakdown.
BTW: Thanks for giving the DTR some real scrutiny. Much deeper analysis on this needs to be performed for any re-siting where changes in the ground cover can affect this (IMHO) along with changes in the proximity to UHI sources and even where the site is located in relation to the seasonal prevailed winds. I have always felt they all affect the diurnal range and not necessarily in the same direction.

REPLY:
Not his graph, I added it. Note the source link below it – Anthony

LKMiller

@B.O.B.
I also worked in northern Ontario (Timmins Region and points north, west, and south) in the early 1980’s. While I agree that the later afternoons were the warmest, I looked forward to them for the simple reason that the 500 quadrillion things that bite (blackflies and mosquitoes, mostly) don’t like it hot and dry.
Give me heat instead of clouds of insects flying up your nose, into ears and mouth, hair, and climbing under clothing to suck your blood.

John F. Hultquist

Leron says:
May 19, 2011 at 5:28 am
“I wonder could the 3 hour lag . . .”

For an explanation; see:
http://www.physics.isu.edu/weather/kmdbbd/notesc3.pdf
Do a “find” for “Diurnal Cycles”

cal

There is no mystery regarding the lag in temperature with respect to peak insolation. Andrew Dodds points out correctly that – “as long as incoming radiation exceeds outgoing radiation (as per the second graph), temperature will rise”.
This is important when discussing the active sun hypothesis and the silly argument from climate ” scientists” that the temperature does not correlate with insolation. As Anthony has tried to explain before we should not expect it to correlate. An active sun means an increase in the energy released. The change in insolation at the top of the atmosphere is known to be small but its impact may be amplified by things like reduced cloud seeding (Svenmark). The extra energy reaching the surface causes an increase in temperature which results in an increase in outgoing radiation just the same as in the diurnal case. The overall temperature (I will not call it average temperature because it it not really the average which controls the energy balance) will increase until the outgoing radiation equals the incoming radiation. Because the sea is by far the most dominant source of radiation to space (either directly or after evaporation and other forms of atmospheric heating ) and since it takes such a long time to warm up, temperatures will continue to rise for years after the peak insolation. Indeed temperatures will continue to rise for most of the time that the sun remains above average output.
This is certainly not proof that the sun is the cause of any warming we have seen but it does make a nonsense of the claim that is cannot be the cause of the warming because the temperatures did not decline when the sun’s output declined.

KAP

But should we expect to see a century-scale trend? It’s clear that the primary cause of the 1880-1940 temp increase was due to solar effects rather than greenhouse, which should increase (not decrease) DTR. So the expected decrease in DTR should not be apparent until the LLGG forcing predominates, which didn’t happen until roughly 1970 or so. Therefore the expected DTR decrease should not be expected on the century scale (at least not yet), but only on shorter timescales.
Since the poorly-sited stations would seem to have an instrument-change bias that infects DTR, it would be quite useful to have a 30-year running average for DTR from the best-sited stations, or at least a data source for the same.

Veronica

I am struggling with this data and need to look at it when I am less tired. Some sort of units on the y axis would be helpful. I don’t think I can see any meaningful trend in any of the data sets… Like everything else in climate science it seems to be a highly derivative measurable that can be affected by many variables, and very little to do with the point people are trying to make about humans adversely affecting their own habitat. I’m not sure how meaningful diurnal differences are, just like I am not sure how a single point CO2 measurement in Hawaii means anything, or adjusted, averaged data from badly sited, uncalibrated and under-maintained surface stations in changing degrees of urbanisation mean anything. Let’s stick to what we can see, rather than what we can derive. Sea levels, volume of polar ice… I dunno. I studied bacteria, they are easier to keep tabs on than planets.

wayne

Sorry Anthony, my eyes seem to have been malfunctioning (or my brain). Gee, the answer is right below! ☺

David Y

OT, but interesting if valid data re: atmospheric heating in advance of earthquakes: http://www.technologyreview.com/blog/arxiv/26773/
The more we learn, the more we realize there is to learn.

Rhoda Ramirez

KAP, unless I’m reading the study incorrectly, there shouldn’t be a century long trend, just one from around the 50’s when all that awful manmade CO2 (sarc) began polluting the atmosphere. And yes, if AGW were in effect we should see the DTR decreasing – remember, we’re talking about the difference between the high and low temperatures. AGW predicts decreasing DTRs since CO2 is supposed to prevent the warming IR from escaping into the atmosphere.

theBuckWheat

I recently noticed that the NWS has a daily Climate Summary page on their web site for each station and that has a section devoted to heating and cooling degree-days.
for example, see: http://www.crh.noaa.gov/product.php?site=lsx&product=CLI&issuedby=cou
I would be interested to see if the annual heating or cooling D/D numbers correlated with the DTR trends noted in this paper.

SteveSadlov

So, therefore, when you take UHI and local albedo mods out of it, night time lows have not moved up at all. That’s huge.

DonB

Water in a tea kettle doesn’t boil instantly nor does it cool instantly once the fire is removed.

Owen

@SteveSadlov
Indeed, the entire thesis of CO2 caused global warming hinges on a decrease in DTR due to higher temperature night-time lows. A result which shows no trend at all is a rather significant counter result. As Einstein said (paraphrased since I never get quotes right) It only takes one counterexample to prove the whole thing wrong.

DAV

The graphs (at least the top one) of diurnal temperature at the cited page ask “Why the lag [in temperature between noon and 3-5PM]?” and the site has a big green ANSWER button that basically says it’s because the temperature is greatest at 3-5PM. I guess students couldn’t figure that out for themselves. Very educational.

wermet

Bill Illis says: May 19, 2011 at 7:40 am
For the diurnal charts at the beginning of the post, just noting that the temperature change is exaggerated by quite a bit in these charts compared to a real-world station. There is far less change in the actual energy levels/temperature at the surface over a 24 hour period (between Max and Min), than should be expected.
I don’t know where Bill Illis lives, but the charts shown in Fall’s paper do seem to match with the places that I have lived. For example, using the historical data from weather.com (the easiest place I could located DTR data on short notice) here are the ranges of DTR data for the places that I have lived:
Patuxent River, MD — 20-25F (11.1-13.9C)
Dahlgren, VA — 16-19F (8.9-10.6C)
Blackburg, VA — 20-27F (11.1-15C)
Columbia, SC — 22-27F (12.2-15C)
Ridgecrest, CA — 29-37F (16.1-20.6C) [Yes, these are the real daily temp. ranges seen in the middle of the Mojave Desert.]

kramer

The diurnal temperature range is simply the difference between the daily maximum temperature and daily minimum temperature, “diurnal” being a more impressive way of saying “daily”.
Ok, I’m lost here. If there is warming going on in the temperature record, then both the daily max and daily min temp could be (and I would think would be) higher by the warming offset, right? So I don’t think you’d see any warming using this method. What comes to mind is the Mauna Loa CO2 graphs that show a sinusoidal wave with an offset that is increasing steadily over time. Each successive year there is a higher Co2 level in the sine wave but there is also a higher ‘lower’ CO2 level in the sine wave but the delta between the high and low for each year is virtually the same.
What am I missing here???

Owen

@Kramer
Not really. While there would be a slow tendency for the next day to be warmer due to less heat lost the night before, the real effect of CO2 is supposedly its ability to prevent radiation of the warm surface to space. During the day there is some of that effect, but the heating of the sunlight coming in far overpowers the CO2 effect (the higher temps cause more energy to escape than cooler ones). At night there is no energy coming in so if there were no blocking of outgoing IR, the low heat capacity of air would tend to equilibralize (is that even a word?) with space rapidly making it quite cold. The greenhouse effect is our friend in that regard. But if the AGW theory is to be true, then the rising CO2 would cause the night time atmosphere to hold on to even more heat than it did previously thus rising minimum temperatures as compared to the daily maximum. Just as adding insulation to your house doesn’t do a thing for the maximum temperature your heater can put out (though it does affect the maximum differential to outside air, but that is a much more complicated problem with no analog to climate – space is always COLD), it does affect how long it takes for your house to reach thermal equilibrium with the outside air (ie how rapidly your house cools off), CO2 is this mechanism in the atmosphere according to AGW theory. My personal opinion is that while the broad brush strokes of the theory are correct, the amount of effect they accredit CO2 with is off by an order of magnitude.
This would also indicate that if there were no detectable change in the difference between the max and min, the rise in temperature is not likely caused by CO2, but by some other driver (the sun/ocean equilibrium anyone?)

jorgekafkazar

kramer says: ““The diurnal temperature range is simply the difference between the daily maximum temperature and daily minimum temperature, “diurnal” being a more impressive way of saying “daily”. ”
Ok, I’m lost here. If there is warming going on in the temperature record, then both the daily max and daily min temp could be (and I would think would be) higher by the warming offset, right? So I don’t think you’d see any warming using this method. What comes to mind is the Mauna Loa CO2 graphs that show a sinusoidal wave with an offset that is increasing steadily over time. Each successive year there is a higher Co2 level in the sine wave but there is also a higher ‘lower’ CO2 level in the sine wave but the delta between the high and low for each year is virtually the same. What am I missing here???”
For one thing, the alleged effect of added greenhouse gases differs between night and day.

Mike McMillan

When we look at the hockey stick chart, we see the frightening fraction of a degree rise that will lead to a tipping point and runaway greenhouse effect that will turn us into Venus and boil away the rising seas and melt lead, etc.
It’s been pointed out that much of the drama is a result of the chart’s vertical scale. Perhaps someone more proficient at graphing from raw data than me might plot the world annual average temperature, not the anomaly, on a chart, along with the average high temp and the average low temp, three curves together. Plotting that way would force a reasonable scale that would put things in perspective.
I suspect the rise over the past century would be barely noticeable.

rbateman

Climate has 4 states: Warm, Cool, Wet & Dry.
A warm dry year has higher diurnals than a warm wet year, that is the highs are higher and the lows are lower therefore the range of day-night temps is greater.
Fixating on Warm vs Cool is misleading.

Orson

Most of the literature I’ve read has conceded that the DTR decline is likely consistent with increasing CO2 or AGW. Mostly the latter.
These results subtly undermine this little leg for the rise of AGW during the 20th century to stand on. Or at least we can hope that similar efforts elsewhere to find the best sited Temp stations will either confirm or deny this little toppling.
But if so many well-maintained stations cannot find an undeniable AGW signal, then maybe AGW isn’t very strong. Maybe the Enhanced Greenhouse Hypothesis is wrong.

Greg Cavanagh

Before I put pink bats in my roof, I did extensive temperature readings throughout the house, under the house, and outside. I live at 26deg 38sec Southern Latitude.
Summer (Feb) peaked between 1pm and 2pm reliably every day.
(March) peaked 1pm to 2pm, some times between 12pm and 2pm.
(April) spreak slightly further, typicaly 1pm to 2pm with variuous days starting a peak at 12pm and some days lagging the peak to 3pm.
(May) Peaks were generaly 12pm to 3pm every day.
(July) (one reading only) Peaked 1pm to 4pm.
These peaks were simply flatlined temperature readings, I read all measurements by eye to an accuracy of 0.5C.

sky

All the features of the diurnal cycle are readily explained in terms of a linear system with capacitance, i.e., a low-pass filter. If the capacitance is increased, then the system output is REDUCED BILATERALLY in the transition range of frequencies between the pass-band and the stop-band, while the phase delay of peak output is INCREASED. Proponents of AGW misanalyze the effect of increased system capacitance in their attribution of increasing diurnal lows to increasing CO2 and fail to provide any evidence of any change in phase delay. What we observe in the urban dominated 20th century temperature records is mostly the effect of winter heating and other urban effects, rather than a sign of increased atmospheric capacitance.

“Maybe DTR really isn’t a robust signal of global warming, and maybe the discrepancy between models and observations is primarily a problem with the observations rather than the models!”
John, perhaps you could talk about the relationship between cloudiness and DTR under a presumption of global warming. Assuming the best observations show both an increase in mean temp and no secular trend in DTR that would point toward changes in cloudiness.. or have I got that wrong