Short to Medium Term Arctic Sea Ice Conditions Discussion

[wanderer]

Who is still thinking, that we will see another record this year and why?

[jdallen]

Who is still thinking, that we will see another record this year and why?

I'm still thinking we will beat 2012, but no "melt out".  I'm still comfortable with my 3.25m figure. My primary basis is the dis articulated stat of the pack.  My secondary is, peripheral extent - Kara, Beaufort, Baffin, Hudson - exceed the "shortfall" between 2012 & 2013 losses to date.

July and to a lesser degree August weather will be the wild cards.

[Juan C. García]

Who is still thinking, that we will see another record this year and why?

The ice is weak and I am concern about possibilities like other strong cyclon. After all, July and August have strong melts and we are now on "the unexpected at the Arctic". That is, the weakness that we have now it hasn't been seen in several milleniums.
Other than the unexpected, I have to agree that the melt has been less than anticipated.

[Nightvid Cole]

Who is still thinking, that we will see another record this year and why?

Me, for the same reason as before (reply #560).

I am expecting 5 - 8+ cm/day bottom melt over large areas of the CAB by month's end.

[werther]

Today there’s a low just under 1000Hpa being drawn in the NE Svalbard ice weakness area (r03c04 MODIS).
The steering comes from the strong anomalous jet stream branch delivering energy and moisture from the N Atlantic. It fills the tile with clouds. But in the centre, about 350 km from the Pole, there’s a cloudless feature.
It is possible to compare the visible floes with yesterday. At the centre, not much movement. Forty km to the SE, 9 km in a day. There’s good punching, but not yet a knock-out blow… I wonder what it will look like  when the low has passed to Siberia.

BTW, have a look at Frantsa Yosefa… you’ll get an idea of the flow power as clouds ripple to the SE at the leeside of the islands.

After this, a high pressure zone will establish for some days. To the end of the 10-day period, a Beaufort High is settled. To its SW side, a Laptev Low features a strong wind field right over the weakness zone toward the Pole.

All together, a promising week …

[deep octopus]

UNI Bremen/AMSR2 picked up a substantial fading of ice in Hudson, Kara, Baffin, and Chukchi over July 1st. Kara had been a laggard for weeks, but in the span of about two weeks, has all but disappeared (or rather appeared if we're talking the sea itself, as it were.) That high is really doing work to it.

Will also be interesting to see how well the forecasts for a high swathing the basin hold up. Aside from some tweaks, the overall story seems to suggest a fateful Beaufort High taking position over the next week--a "promising week", as Werther has already stated. Still, I'm going to try freeing myself of racking my brain over any more exact numeric predictions, and therefore any confirmation bias. I'd rather contemplate the abstraction of the mysteries of the Arctic at this point in the season, because it's frankly too on-the-fence to say where we go from here.

[jdallen]

...Will also be interesting to see how well the forecasts for a high swathing the basin hold up. Aside from some tweaks, the overall story seems to suggest a fateful Beaufort High taking position over the next week--a "promising week", as Werther has already stated....

It the weather certainly does not seem to be following the prescribed path required to maintain extent and prevent a fall below 2007/2012...  several "IFs" not being adhered too.  IF it remains cloudy. IF it remains cool. IF it remains calm....

[jdallen]

I've just done my morning perusal of CT, IJIS, Bremen, etc.  looking at extent graphs, does anyone else see a trend change which suggests 2013 catching up to 2007/2012 around the third week of July?

[Neven]

The weather forecast looks like a high decrease rate is in the cards. Whether that will be enough to catch up with the top 3 years, remains to be seen. But I think 2013 will creep closer. The Beaufort is going to get torched, and there's a lot of melt potential there.

[ChrisReynolds]

Sea Level Pressure (NCEP/NCAR) for June, 2004 to 2013.
http://dosbat.blogspot.co.uk/2013/07/june-status-part-2a-atmosphere-slp.html

Amongst the post 2007 years, 2013 clearly stands out as very odd indeed.

[ChrisReynolds]

Very nice cloud clearance in MODIS R04C04 for yesterday.
http://rapidfire.sci.gsfc.nasa.gov/imagery/subsets/?subset=Arctic_r04c04.2013182.terra

The 250m resolution has been kept. 

I love 20Mb broadband. 

[jdallen]

Very nice cloud clearance in MODIS R04C04 for yesterday.

The 250m resolution has been kept. 

I love 20Mb broadband. 

An in that image, we see directly how the fracturing events this year now come fully into play. It seems fairly obvious to me that all the "interstitial" small flows and nilas are melting out promptly, rapidly increasing sea exposure.  The affect on a disrupted pack will be greater than the same area if compact; more heat which would otherwise just go into seawater in larger exposures instead can act directly on disconnected floes. It will be interesting to see if this affects the melt the way I think it will.

[Tor Bejnar]

DMI Daily Arctic mean temperatures north of 80N remains stubbornly close to 0 C, and has remained below the long-term average for about 50 days, now.  Having read here and on Neven’s ASIB from people who know endlessly more about thermodynamics than what I know, I wonder if the Central Arctic’s open water - due to the persistent Arctic cyclone (PAC13 - that has since died) – is keeping the temperature where it is.

Maybe:  the Central Arctic’s open water has been pumping heat into the atmosphere.  As this “heat” is the temperature of icy seawater, it dominates the high-Arctic near-surface temperature. (This heat would be heading to the stratosphere where it is truly cold.)  The historical average was created by a Central Arctic having a solid (often snow covered) ice sheet that would transmit heat between ocean and air much more slowly, allowing the air temperature to rise a degree or so above 0 C from warm southerly winds.

Conversely (I accept that my understanding might be backwards or even upside-down!):  maybe the bits and pieces of open Central Arctic water are absorbing heat like crazy from the air, preventing the near-surface temperature from going above 0 C.

What does somebody who knows the physics say?

[ChrisReynolds]

Tor,

Check out my reference to Arctic sea level pressure in June 2013 above. I think the weather is the main reason the Arctic has been cool, low pressure -> cloud -> less direct sunlight. Also more fractured ice mush will peg local temperatures down to zero more effectively than open ice-free water surrounding more compact ice.

JD Allen,

Heat flux from a warm to a cold body depends on the temperature difference between them. Consider two cases.

Large region of open water with a compact ice mass and defined ice edge, with dominant high pressure. In this case the water can warm up to substantially above zero (say 5 degC) so when it is blown into contact with the ice mass (high pressure causes convergent Ekman pumping towards the high pressure centre), it rapidly transfers that heat to the ice. The ice melts.

Large region of broken up ice and water, with dominant low pressure. In this case the water's temperature is pegged to degC. The energy that goes into the water will result in lateral melt, but there's a far greater surface area for that to work on. And as the water is kept at freezing heat flux from water to ice isn't as rapid. Furthermore the dominant low pressure causes divergent Ekman transport making sure that the ice/water mush doesn't get the chance to form as easily and pumping cold water from under the ice out into any polnyas that form.

I had interpreted the persistent low concentration ice in 2012 in the East Siberian sea as a result of MYI presence. I still think this was a factor, but I am wondering if the sort of smashed ice we saw then and see now between Laptev and the Pole is actually less prone to melt than a neater ice edge.

[Neven]

That would be another nice counterintuitive phenomenon, Chris. 

[wanderer]

NSIDC Update: http://nsidc.org/arcticseaicenews/

[Paul Beckwith]

Who is still thinking, that we will see another record this year and why?

  I stick with my predictions of a complete ice slaughter.  A few massive cyclones should help clear out the Arctic basin.

[roman_01]

This is maybe most important NSIDC update ever They usually choose words very carefully, but today:
"An Arctic pre-conditioned for rapid summer ice loss?"
"According to Andrew Shepherd at the University of Leeds, preliminary results from the European Space Agency CryoSat satellite suggest that the ice pack was 8% thinner in March 2013 compared to March 2012."
...
"High-resolution passive microwave concentration data from the Japan Aerospace Exploration Agency AMSR2 sensor, produced by the University of Bremen, indicate a highly unusual region of broken-up ice near the North Pole. Development of this low concentration ice may have been assisted by the cyclonic atmospheric pattern noted earlier."

 "MODIS data do confirm that the ice is highly fractured with numerous small floes. Such small floes are more easily melted from the sides and the bottom by ocean waters that are exposed to the 24-hour sunlight. It remains to be seen how many of these small floes will ultimately melt completely"

Wow...

[jdallen]

JD Allen,

Heat flux from a warm to a cold body depends on the temperature difference between them. Consider two cases.

Large region of open water with a compact ice mass and defined ice edge, with dominant high pressure. In this case the water can warm up to substantially above zero (say 5 degC) so when it is blown into contact with the ice mass (high pressure causes convergent Ekman pumping towards the high pressure centre), it rapidly transfers that heat to the ice. The ice melts.

...

I had interpreted the persistent low concentration ice in 2012 in the East Siberian sea as a result of MYI presence. I still think this was a factor, but I am wondering if the sort of smashed ice we saw then and see now between Laptev and the Pole is actually less prone to melt than a neater ice edge.

I'll mull that, but I'm not sure I agree with the conclusion.  The difference seems primarily dependent on weather, rather than the mechanical state, as you describe. I would think ekman pumping more probable with a broken sheet. I'm also not convinced wind would transport warmed surface water in volume sufficient to counteract the more favorable albedo of a "solid" pack. I can be convinced, however.

[ktonine]

For most of the year arctic clouds are a positive feedback.

Determining when clouds are a negative feedback isn't simple.  There are multiple cloud types varying in albedo, base height temperature, condensation nuclei radius, etc; there are variations in solar angle by latitude; and differences in the surface beneath the clouds.  All of these can effect the shortwave/longwave radiation budget.

Most years the CAB surface is insulated from the ocean by a moderate layer of ice.  This allows the SSTs to rise above the upper layer ocean temp of -2.4 C.  The UNI Bremen N80 graphs show this as the temps are constrained by the melting point of snow and ice at the surface (freshwater) at approximately 0C.

This year we've seen widespread portions of the CAB have lower sea ice concentration.  To me, this means that more of the ocean - at -2.4C - is exposed to the atmosphere.  Rather than constraining the SSTs to 0 C, we're constraining it to a temperature closer to that of the ocean at -2.4C.

With air temps constrained below the melting point of snow, we should expect to see little if any surface melt, but increased bottom melt.

In other words, I don't believe the UNI Bremen N80 temp graph is telling us that 2013 is colder than previous years - it's telling us a different story - one that we haven't heard before.  And I can't reconcile UNI Bremen with this:

[jdallen]

This year we've seen widespread portions of the CAB have lower sea ice concentration.  To me, this means that more of the ocean - at -2.4C - is exposed to the atmosphere.  Rather than constraining the SSTs to 0 C, we're constraining it to a temperature closer to that of the ocean at -2.4C.

Makes sense when you consider by removing ice, you put two convective systems in direct contact, one of which, the water, is a much greater sink than the ice. Implies a substantial portion of the increased heat capture is becoming part of the arctic ocean's energy budget. If true, this could show up later as a delay to the re-freeze, regardless of extent, and might imply thinner ice at the start of the next season.

[Artful Dodger]

This allows the SSTs to rise above the upper layer ocean temp of -2.4 C

Hi ktonine, welcome.

Where do you get the value -2.4 C for the sea surface temperature?

At 32 psu salinity and 1 atmosphere, the freeze/melt point of sea water is about -1.8 C

Sea Ice and the Climate System

I do see this page lists -2.4 C as the freezing point, but at 1100 dbar pressure!

Key Physical Variables in the Ocean: Temperature, Salinity, and Density

Interesting working theory, however! That the ration of snow/ice cover to open water clamps the SST to a blended temperature between that of the melting point of fresh water and salt water.

I don't think it quite works, but interesting theory! 

Again, welcome to the 'forum!

[wili]

If you haven't yet, please do check out the recent imagery that ATeam and Chris R have presented for us here http://neven1.typepad.com/blog/2013/06/asi-2013-update-3-the-arctic-goes-pop/comments/page/2/#comments

and above.

If find these to be really striking and disturbing images. Does anyone else?

[ktonine]

Lodger - not sure where/why -2.4C stuck in my head ... old age and a faulty memory
I should have reread my Wadhams
-1.8C is actually a little better ... I thought the disparity should be about half the difference and -1.8C brings that closer to what we see. 

[Apocalypse4Real]

Another short term impact on the Beaufort is the amount of discharge from the MacKenzie River and the Canadian flooding. It is spewing brown fresh water into the Beaufort - water that has been heated by the anomalously hi temps in Canada and Alaska.

[Jim Hunt]

Hi Wili,

Check out the recent imagery that ATeam and Chris R have presented for us.

I find these to be really striking and disturbing images. Does anyone else?

Having presented the striking red images a bit further up that thread I'd certainly describe them as "extremely interesting". I'm also interested to know why you describe them as "disturbing". Chris has recently substantially increased his "prediction" for the ultimate state of Arctic Sea Ice this summer, for example.

I haven't made a prediction yet. It seems to me that the current state of play is unprecedented, in the satellite era at least. If pressed I'll go for somewhere between Chris and Paul!

[wanderer]

For most of the year arctic clouds are a positive feedback.

Determining when clouds are a negative feedback isn't simple.  There are multiple cloud types varying in albedo, base height temperature, condensation nuclei radius, etc; there are variations in solar angle by latitude; and differences in the surface beneath the clouds.  All of these can effect the shortwave/longwave radiation budget.

Most years the CAB surface is insulated from the ocean by a moderate layer of ice.  This allows the SSTs to rise above the upper layer ocean temp of -2.4 C.  The UNI Bremen N80 graphs show this as the temps are constrained by the melting point of snow and ice at the surface (freshwater) at approximately 0C.

This year we've seen widespread portions of the CAB have lower sea ice concentration.  To me, this means that more of the ocean - at -2.4C - is exposed to the atmosphere.  Rather than constraining the SSTs to 0 C, we're constraining it to a temperature closer to that of the ocean at -2.4C.

With air temps constrained below the melting point of snow, we should expect to see little if any surface melt, but increased bottom melt.

In other words, I don't believe the UNI Bremen N80 temp graph is telling us that 2013 is colder than previous years - it's telling us a different story - one that we haven't heard before.  And I can't reconcile UNI Bremen with this:

I was wondering the same thing - why should 2013 be that much colder there than any other year on record? If 2013 really beats 2012 we will talk about this a lot!

[Frivolousz21]

I posted this on Americanwx








SSTs are still behind last year obviously in the Kara, Baffin, and Beaufort.  Persistent weather is allowing for the water in the Fram to warm up above the ice preserving threshold.  Mostly because of the ice that was there melting out and the pattern slowing the amount of ice entering.  It hasn't come to a halt but it's not being shuttled out by any means.  The SOO is blow torching like last year pretty hard now.  The Barent's is on fire so to speak. 




The models around mid afternoon tomorrow.  Turn the winds from the Northern Fram past Svalbard to the Islands you see along 80N parallel to the Svalbard. Winds are progged from end of day 1 to at least day 5 on the Euro and threw day 8 on the GFS attm to be an inflow into the Atlantic side of the ice sheet around the forming HP.  You can see on the models above the 850s will be above zero upwards of 5C.  Obviously the other two factors are the surface winds coming off the SSTs that are now 2-3C within  50-100 miles of the ice with a longer fetch originating deeper into the warmer 5-10C sst's that will wrap up around the Eastern Svalbard.

 

There is also strong potential for quite a bit of sunny skies and that 475-500W/M2 potential heating to be not obstructed.

 

I will keep a very close eye on this to see if this happens and is a real test on the Nansen Basin ice.

[werther]

Interesting week, eh?
And ECMWF forecasts a churning low spawned by a Siberian jetstream branch 8-10 July, crossing from the NSib islands to the CAA. A Nemesis 'petite forme' ?
Fits right with your graphs, Friv, as that low level low pulls in a lot of warmth over Chukchi/Beaufort.

[werther]

Now that I’m on line…

Just some reflections of last nights’ lurking over MODIS.

I have the impression that a lot of regions are thinning out ‘in situ’. There isn’t much visible indication large scale compression or movement. Most of the Kara Sea ice is rapidly nearing the ‘vanishing line’. That area can be discarded. Though on its own thinning regime, the ESAS is also going down. A lot of ‘holes’ out there, up to 1-2 km wide. The Amundsen Gulf, as other waters in the CAB, is breaking up in situ.

There’s lots of melt puddles now on the floes in the splintered part of the CAB. Soon they’ll evolve in sight of the NP webcams.

I’ve been working through the NCEP/NCAR Reanalysis for June. According to that, SLT’s were about ‘normal’ to the climo over the larger part of the Arctic Basin. Just a million km2 next to the CAB and some Laptev area that’s been 1 dC colder. DMI is expressing some other physical reality (?), and tells only something above 80 dN (about 4 Mkm2, the Basin is 9 Mkm2).

Then, the pressure and winds.
Vorticity, zonal winds, even meridional winds out of the N Atlantic, they are all anomalous on the ‘bad’ side. It looks like a lot of energy is coming in even though it doesn’t express itself in temperature.

[Jim Hunt]

Not forgetting this bit of information from the NSIDC update:

NASA Operation IceBridge data collected during March and April indicated thick ice along the Greenland coast (5 meters, or 16 feet or more), but thin ice north of Alaska in the Beaufort and Chukchi seas, ranging from 1 to 1.5 meters (3 to 5 feet) in most areas and as low as 0.5 meters (approximately 2 feet) in others.

[johnm33]

On frivolousz21 post above I see the first signs of the Mackenzie anomaly this year and as A4r pointed out this water is brown on the sats, but probably blacker close up, and is only going to get hotter.

[Neven]

I have the impression that a lot of regions are thinning out ‘in situ’.

This IMO is definitely one of the new properties of the ice pack, something I was struck by last year looking at the Northwest Passage. It was closed for a long time, but then it opened up rapidly without the large-scale transport that I had gotten used to in previous years.

[Frivolousz21]

Here is the most recent scan of the region I was talking about in the post above.  It's decently clear.  With the HP forming we should get much more clear images this upcoming week.


The models basically say no temps below freezing at the surface.  Possible 3-5C surface temps flowing off the SST's maybe even slightly warmer on the big sunny days.


This is going to seriously rev up bottom melt.

[werther]

That's the one I've been comparing to '12 yesterday. It's worse now, Friv. And the latest passing Low/jetstream branch brought melt ponds on a large part of the floes. Even on this scale you see the blue hue indicating where it is worst.

[Frivolousz21]

This is really exciting.  Man has never witnessed an event as unique as this.  New record or not.  It's pretty unprecedented for the Nansen Basin to see a direct melting of this scale. 

To me this is like it being May 10th where I live near St. Louis, Mo and have the models 3-4 days out show an epic blizzard with 20 inches expected after a long April of record cold.


It's never happened in modern history. 

So with this I have to err on the side of caution.  But I am definitely thinking we will see the Atlantic edge actually melt out vs just being mostly compressed this year.

How far poleward is the question?

[Neven]

This is really exciting.  Man has never witnessed an event as unique as this.  New record or not. 

My thoughts/feelings exactly! If 2013 edges past 2007/2011 after such a bad start to the melting season, it will be just as spectacular as last year.

[werther]

BTW about this r03c04 tile... for days (weeks?) we are fooled on the ice quality in the zone directly N of Frantsa Yosefa. I think we see thick fog over there. As I posted yesterday, you see the moisture rippling away at the leeside of the islands.
Where does it come from? Tantalising to think an extra dosis being picked up in the SW flow over the splinter zone.
When it's fog, allow me to propose ASMR2 and CT present this as 90+ % concentration by means of their "Al Gore-rhythm...."

[jdallen]

This is going to seriously rev up bottom melt.

Thumbnail estimate suggests as much as 10cm/day, if surface water temps approach 0C.  That should clear out all the interstitial slush, which could be an indicator.

[Jim Hunt]

A tantalising glimpse of ice at the Pole, courtesy of NASA WorldView bands 3/6/7

[wili]

JH, I guess I find it disturbing for the same reasons I and others find it interesting and fascinating--as far as I can tell, the nature of the ice is different than anytime before, and it is behaving differently than it ever has.

Regardless of what the final official numbers show, it is clear to me that, as frivolous pointed out, we are seeing a fundamentally different Arctic behaving in fundamentally different ways in a fundamentally different climactic earth.

And we have no really clear idea about how these fundamental changes will effect the rest of the globe, but the best estimations are that it will not be mostly for the better for most of us.

Perhaps the 'interesting' factor outweighs the 'disturbing' factor for you, which I can understand. But do you really find these novel developments entirely comforting?

[OldLeatherneck]

This is really exciting.  Man has never witnessed an event as unique as this.  New record or not.  It's pretty unprecedented for the Nansen Basin to see a direct melting of this scale. 

........................................................................It's never happened in modern history. 

This year, as in the past few, we are witnessing the earth's largest science experiment.  Unlike working in a laboratory  or other controllable test environment, we did not write this test plan.  Humankind's only contribution to this experiment has been to keep adding CO2 to the mix of variables.  The remaining variables are all un-controlled and the behaviors of each of them (positive and negative), as well as interactions between them, are not all fully understood.  Hence the difficulty in predicting the outcome and the differing opinions of competent, knowledgeable and ethical experts in a variety of disciplines and fields of expertise.

But not to worry, we're going to keep repeating this experiment on an annual basis for the next few decades.  To spice things up, we'll add a little more CO2 and CH4 each year!!

I wonder which lessons we learned this year will be applicable next year, or do we have to start the learning process anew, each and every year.

[Vergent]

The Eastern half of the CAB turns to Swiss cheese in the next week. TOPAZ4 V2 has been tracking well with MODIS images.

http://myocean.met.no/ARC-MFC/

[Frivolousz21]

The 00z GFS and Euro both crush the Arctic.  Exp the Pacific side and demolish the Russian side.

[iceman]

Vergent, thanks for that image.  Comparing to the HYCOM animation http://www7320.nrlssc.navy.mil/hycomARC/navo/arcticictn_nowcast_anim30d.gif , the latter forecasts a similar thinning toward the open water in the Laptev (near the 80th parallel).  However, HYCOM has consistently not forecast much thinning toward Frantsa Yosefa as TOPAZ4 V2 now projects.  A week from now we'll see which model is more accurate in this respect.


Edit: the HYCOM concentration map would make a more direct comparison with  TOPAZ4:

[wanderer]

Area down from 7.51155 million sq. km to 7.31803 million sq. km

[Vergent]

A week from now we'll see which model is more accurate in this respect.

HYCOM is way off in that area in the here and now, it is calling this area 80-90%. no need to wait a week.

http://rapidfire.sci.gsfc.nasa.gov/imagery/subsets/?subset=Arctic_r03c04.2013185.terra.250m

Hycom is off by +20% in this area at least.

Vergent

[helorime]

I was  looking at NSDIC data from there “Charctic” site
http://nsidc.org/arcticseaicenews/charctic-interactive-sea-ice-graph/
This time last year the ice was melting in a roughly linear fashion.  I decided to compare the last 2 weeks changes from this year compared to last year.


2012 June 19 : 10.417 million km squared
2013 June 19: 11.452 million km squared

difference =  1.035 million km squared up from 2012

Two weeks later
2012 July 3  9.141 million km squared
2013 July 3: 9.901 million km squared

difference =  0.760 million km squared up from 2012

That’s a decrease of 0.275 million km squared in the difference


At this rate in about 5 or 6  more weeks 2013 would equal 2012.  That would be mid-August.  This all assumes constant rates of course, and constancy is not the nature of arctic melting these days.

[Dromicosuchus]

I've just done my morning perusal of CT, IJIS, Bremen, etc.  looking at extent graphs, does anyone else see a trend change which suggests 2013 catching up to 2007/2012 around the third week of July?

It has been an impressive drop (and interesting that it's not mirrored in the Area charts; I would guess, although I haven't actually checked this, that that might be due to melt pond draining occurring at the same time as edge retreat, masking the increase in the rate at which the area is drawing back), but I'm not inclined to think that it's anything important unless it carries on after the melt in Hudson Bay is done.  We shall see soon enough, though.

[jdallen]

Fascinating shot of the Amundsen Gulf from yesterday:

http://lance-modis.eosdis.nasa.gov/imagery/subsets/?subset=Arctic_r05c02.2013184.terra

I'll draw your attention to the "seam" in the center.  I don't think its a ridge.  I'm also fascinated by the color gradient, and wondering what it indicates.  It would *appear* that the browner ice in the gulf proper is very weak.  If it disintegrates promptly as predicted, those conditions may be indicative of what may happen elsewhere in the pack.

For example, in the mid-right of this image, is an area of similar appearance, and probably 90%+ extent:

http://lance-modis.eosdis.nasa.gov/imagery/subsets/?subset=Arctic_r05c04.2013184.terra

So my conclusion is... we may not be at the same extent levels as 2012/2011/2007, but the quality of that extent is far more tenuous, and will be melting out catastrophically over the rest of the melt season.  The next two weeks should be enough to prove or disprove my conclusion.