By Steve Goddard
Arctic Ice (red line above) has dropped just below my June forecast (dashed line.) Over the last two weeks, strong southerly winds reminiscent of 2007 have compacted and melted significant amounts of ice. The modified NSIDC image below shows ice loss over the last week, in red.
The break in the weather can be easily seen in the DMI temperature graph, as a sharp upwards spike two weeks ago.
The NCEP forecast calls for colder and calmer weather during the next two weeks, so ice loss should drop off quickly.
The DMI 30% concentration graph has already flattened, and is running even with 2009.
The modified NSIDC image below shows ice gain over 2007 in green, and loss in red.
PIOMAS continues to overestimate (red) ice loss by a substantial margin. Green shows areas where they underestimated ice loss.
It continues to look like my June forecast will be close to correct, though as we have seen – this contest is a crap shoot. It all depends on the wind.
Julienne Strove from NSIDC asked last week what it would take to be convinced of man’s influence. I will respond with a question of my own. What does it take to prove that changes in the wind are driven by changes in CO2?
Extra bonus : Does anyone see a familiar pattern (below) in Greenland temperatures? What year did satellites monitoring the Arctic come on line?
Enquiring minds want to know.
WOW..Didn’t know that there was THAT much involved when the Sun melts a little surface ice on a puddle…
Anthony Watts says:
September 1, 2010 at 2:59 pm
No need to wait for Phil. I’ll do it.
=====
Steven, you really need to stop.
Thank you Anthony.
Anthony
That is exactly what I was saying.
At 0C, you have water in all three phases in the Arctic, and a small change in temperature can shift the balance rapidly – causing significant changes in ice extent.
That was my point, which bob disagreed with.
OMG, Steven stop talking. You said,
The triple point of water at zero C is at a pressure of a pressure of 611.2 Pa. This pressure is quite low and a pretty good vacuum, normal sea level barometric pressure is 101,300 Pa for comparison.
It is unlikely you find sea ice behaving as if it was in vacuum.
Steven, seriously this is not fun for me. It is getting sad beyond belief.
jeez
So you are suggesting that that we don’t find ice, meltwater and water vapour at the same place in the Arctic at the same time?
That is the definition of the triple point. The world does not exist in a test tube.
If you have been watching the DMI temperature graph and ice extent data, it is abundantly clear that a small change in temperature is correlated with a large change in rate of ice loss. One degree makes a huge difference.
That is because the ice straddles the triple near the margins of the summer.
Steve you have created a rhetorical black hole. There is no escape from this one.
There are only four paths available to you.
You can change the subject.
You can be dignified and admit you were completely wrong about triple points and phases.
You can disappear into the hole.
You can continue to embarrass yourself with nonsensical defenses. That appears to be your current course of action. By your usage all temperatures are triple points of all substances at all pressures. I can hold ice in my hand on a hot summer day, while drinking water in a sauna.
Um, so water clearly isn’t at the triple point in the Arctic, but if the relative humidity above the water is 100% (partial pressure = 611 Pa) and the ice/water/air are all at 0 C, isn’t the behavior essentially the same as if it was?
Anyway, can we get back to talking about how the rest of the season is going to turn out?
-Scott
jeez
Please discuss science rather than launching ad homs.
Liquid water, ice, and water vapour coexist quite nicely in the Arctic summer. That is exactly the definition of a triple point.
There have been no ad homs.
Your defenses are nonsensical. They show complete ignorance of the subject. You arguments are demonstrably false. They show you refuse to understand things which are explained to you. I do not ever attack you, your credentials, your race, your lifestyle, your education. Those would be ad homs. I attack your ideas and behavior on this blog, which is less than exemplary.
Read this statement again. It may help you comprehend what a triple point is:
When you have a glass containing water and ice, it is unlikely that it is simultaneously boiling.
Obviously ice is not stable above 0C. Liquid water is not stable below 0C. The triple point has to be at 0C, just as the phase diagrams show. You are looking at simple problem under a high power microscope and confusing yourself.
I see there is confusion here about the triple point and at zero (0.0 to 0.4c etc) centrigrade of course solid ice melts and changes state to liquid water. We have a mixture of both forms at zero because it is a slow progress, but thanks to the latent heat flux on the planet this liquid water at this temperature can evaporate. Hence, some molcules can gain enough energy to form water vapor and all 3 different states occur at the same time because both are slow transitions.
The phase diagrams don’t take latent heat flux via shortwave radiation into account and of course it should be obvious by now that water vapour forms in the atmosphere due to latent heat flux, despite being much lower than the boling point of water at 100c. The planet doesn’t behave exactly like the phase diagram or we would have no water vapour in our atmosphere because it is too cold.
Imagine you are sitting in a park in Phoenix, holding a glass of water with ice in it.
The temperature outside is 45 degrees C. But the temperature at the ice/water boundary is 0C. That is the only temperature which ice and (fresh) water can coexist. Thus, the triple point of water has to be at 0C.
Eventually the ice will melt, and the temperature of the water will rise – above the triple point.
This is just too sad. I can’t do it anymore. Steven you can’t use one-half of a scientific definition.
at 611.2 Pa
at 611.2 Pa
at 611.2 Pa
That is near vacuum. At that temperature and pressure, water is freezing, melting, boiling, and condensing all at the same time. That is the triple point. Not the heat of vaporization or the heat of fusion, which you are so keen to focus on.
Near vacuum behavior is not occurring in the Arctic except perhaps in somebody’s laboratory. It is irrelevant to any discussions of Arctic ice behavior. The triple point of water is irrelevant to any discussion of Sea Ice behavior because none of this is occurring in near vacuum conditions.
Steven, this is your last thread on WUWT. You are going out on the most embarrassing note I could imagine. I could not have conceived of a script where you could behave worse.
jeez says:
September 1, 2010 at 3:47 pm
But it is boiling (and sublimating) if the partial pressure above the liquid/solid is below the vapor pressure at that temperature (someone said 611 Pa earlier). Boiling points are subject to both temperature and (partial) pressure, and you’ve neglected the pressure.
Regarding the last sentence in:
jeez says:
September 1, 2010 at 3:38 pm
That’s not a valid comparison because it’s not at equilibrium…the ice you would be holding would be a different temperature than you, the summer day, the sauna, etc.
—
The Arctic is not at the triple point of pure water. But it’s a mixed system, and could potentially be at/near the triple point of the mixed system. If the ice/water are at 0 C (and yes, I know, dissolved salts lower the freezing point, this is an example) and the relative humidity is 100%, then the system is at equilibrium with water vapor, liquid water, and ice all present in equilibrium. Now, Steven did not make this clear in his original comment (and arguably not in the comments since). I don’t see why this argument can’t be cleared up with that simple clarification (that this is a mixed system and all can be present in equilibrium). That way we can get back to serious discussion of the topic at hand.
-Scott
Phase diagrams represent pure equilibrium conditions, which never exist in nature. It is impossible to completely insulate any system from outside fluxes of heat, because there are no perfect insulators. Thus, phase diagrams are theoretical.
They do however provide tremendously valuable information, if you understand their limitations.
Scott,
For all practical purposes, the Arctic at 0C is at the triple point. Liquid water, ice and water vapour all coexist.
As I stated in my last post, it is impossible to create a perfect triple point equilibrium condition, so we scientists deal with the real world instead.
jeez
You are really overstepping here and behaving incredibly badly.
REPLY: No he’s not, you are. And since you won’t take the hints, I’m closing the thread with this image:
Note the pressure of the triple point at “T”. It is not an ambient earthly surface pressure.
The single combination of pressure and temperature at which liquid water, solid ice, and water vapour can coexist in a stable equilibrium occurs at exactly 273.16 K (0.01 °C) and a partial vapour pressure of 611.73 pascals (ca. 6.1173 millibars, 0.0060373057 atm)
– Anthony
Update: I should have added sources, here they are.
Image: http://www.sv.vt.edu/classes/MSE2094_NoteBook/96ClassProj/examples/triplpt.html
Last paragraph: http://en.wikipedia.org/wiki/Triple_point
No Steven,
I tried to tell you to stop but you continue digging your hole. I gave a simplified example to help explain your error. You don’t see a lot of boiling sea water in the Arctic which would indicate triple point conditions, but you continue to embarrass yourself.
If you wished to say that Sea Ice behavior can be unpredictable because Sea Ice exists close to the temperature of the heat of fusion, that would make some sense. By bringing in water vapor and triple points you clearly demonstrate that you either have no idea what your are talking about or are willing to deceive. I will give you the benefit of the doubt and believe simply that for some reason you refuse to understand that you have no idea what your are talking about.
But it is clear that what your are saying about triple points is utter nonsense. This is not an ad hom. This is fact.