Deepwater Oil Spill - windows can be short, and a digression

The windows that allow significant work on the oil spill in the Gulf are likely to become rarer and more valuable opportunities as the hurricane season, forecast to be stronger than average, moves towards its mid-point. While the starting signals for a hurricane don’t begin by looking that ominous, and those initial signals don’t always grow into a significant threat, as Bonnie just demonstrated, the last thing that can be afforded in this disaster is complacency. And so, as plans are laid out for a methodical approach to sealing the Deepwater well, so we see two more possible threats appear on the horizon.


At the moment the casing is being run for the relief well, there is some curiosity on where all the supposedly spilled oil went (some of which might be explained by the ramp up in flow as the BOP eroded so that in the earlier stages of the disaster there might have been significantly less oil escaping into the Gulf than the flow levels seen at the time of the capping), but there is not a lot of new information. And so, with your indulgence, a little digression.

One of the reasons that I write is to help explain why things are being done the way that they are, and how technical processes now being used to produce fossil fuels came to happen. Early in my experience of doing this I discovered that you can really help ease a descriptive explanation by using the right illustration. As a result my classroom type lectures are now made up with many more illustrations than they are with word-intensive Power Point slides. Yet, to be honest, that knowledge came, in part, from the memories of my childhood, and my still fond recollections of reading historical fiction where, if I was lucky, the story would be illustrated with four or five illustrations of the action. (And it was the presence of those illustrations that often drove the selection of the books that I borrowed from the local library).

Many of these early stories were illustrated by N.C. Wyeth and it was his teacher, Howard Pyle, who noted that “Pictures are highly important for children, well worth a thousand words, especially if they don’t understand 800 of them. First graders know 6,000 words, adults 30,000 or more.” This remains true with older audiences where the technologies being discussed are a little arcane, where the artisans of this new era use words that are not in the common lexicon.

And so, having the chance at the end of the family vacation, today we dropped by the Brandywine River Museum, where for the second time in the last month we spent almost from opening to closing time, wandering around the galleries. (The other was the Peabody Essex in Salem, a more conventional museum and thus a totally different experience).

The Wyeths are a legend in American art, with the major focus being on Andrew and Jamie, and indeed the tour we lucked into joining and given by Andrew’s grand-daughter Victoria focused very much on those two with wonderful, and unique insights. (We went out to the Kuerner Farm that Andrew painted, and also up to the House and Studio that N.C. built; both of which were well worthwhile, and seeing the “backset” with some of the props held a fascination that could have used a lot more time than we had available).

Having stayed across the street in the Brandywine River Hotel, and eaten dinners at the two immediately local restaurants, we have had a really enjoyable break, and one that I would really recommend.

The art of illustration has, to a large extent, been lost over the last half-century even though there are with programs such as Poser, Bryce and Vue; tools that folks such as I (who needs two rulers, a computer and a drawing table to create a straight line) can use to make our less mechanical ideas visual. (I use Strata for my mine models.)

It is no less critical now than it was in Howard Pyle and N.C.’s days that folk understand what the words are trying to say. Witness that Kent Wells uses illustrations and animations to help explain the complexities of the processes being planned at the Gulf.

Our family argue about ranking the members of the Wyeth family and their work, but the legacy of illustration that Howard Pyle and his students grew, and which N.C. Wyeth came to be a master of, brought his work and the pleasure of viewing it to more folk than I suspect have been influenced by his later family. Wyeth and the critics of his time downplayed the role of the illustrator, but it is an honorable and indeed vital need that we, who communicate information, have and make use of.

Sadly I don’t think that nearly enough technical teams across the board of technical application take the trouble to phrase their talks with illustrations, so that those outside of the “select few” that are masters of the technical terms can follow the discussion. And yet I should admit, on the other side there are also those who can present, with a suitably generated illustration a promise of a technical future that is not really born out by the technical details of the technology that is being sold.

But illustration can be a great help to imagination, and so I take my hat off to the masters who made it so, and if you’re in the neighborhood . . . . .

Deepwater Oil Spill - the hundredth day

Admiral Allen held a press conference in the Gulf region (rather than recent ones held in Washington), in which he noted that the news of the rapid disappearance of the oil already emitted by the Deepwater well is raising questions as to how long to retain the different parts of the fleet assembled to deal with it. Well pressure continues to slowly build, and there are no signs that the well integrity has been breached. The problem of the skimmer fleet, and the distributed lengths of boom are non-trivial. Should a hurricane appear then the oil-contaminated boom segments can become polluting sources themselves if they are carried inland. And so they must be collected, cleaned and stored, if there is no longer a need. (Or if they are too contaminated they may need to be disposed of as hazardous waste).

The Admiral also discussed the continuing developments with both the top static kill, (waiting on the cementing of the relief well) and the progress of the relief well itself. The packer sealing the well has been released and recovered, and the well is now being cleaned, before operations restart.

They removed the subsea containment device—which they call a packer—that was put in to protect the well while they evacuated the site before of the severe weather.

After that (was) done, they will run another drill string clear to the bottom of the relief well, and then they're going to flush the entire wellbore out to make sure there's no particles or anything—sediment from the formation. When that is done, they will be ready then to put the casing pipe in. The casing pipe is the last structural member that will go into the relief well and cement that in place.

Once that is done, that will be the cue to start the static or the top kill we've talked about, which will happen next week. Following that—then we'll be in a position, once the cement dries, to go ahead and drill into the annulus and begin the bottom kill sequence of events as I've briefed before.

Note that once the RW is cased and cemented then it is not necessary to have the cement harden before doing the static kill, though it will be necessary for the relief well operation to complete.

In the latter case, since the cemented casing will act as a springboard to allow the drill to advance the last one hundred feet to meet the 7-inch casing of the original well, accuracy in positioning is still critical to success. The RW is planned to run alongside the original well, slowly chewing through the original cement annulus and finding out whether that is the source of the oil, or whether its integrity is still sound. (And with lots of opinions there is yet little real data on which to give a definitive answer.)

In regard to the static kill, he answered a question on the chances of success by noting

One of the things that, as you know, has been a subject of a lot of controversy or discussion, I would say—maybe not controversy, but discussion, spirited discussion among the science team, BP engineers, and so forth—is why the pressure was so low when we capped the well itself, down in the 6,000 range.

The competing theories from that are we have depletion in the reservoir that caused the pressure to be lower or there could potentially be a leak down there.

One of the things we're going to find out when we start to put the mud in for the static kill—if there's a precipitous drop in pressure, we'll know we have a well integrity issue at that point. If there is not, and we fill that well with mud right away, and it holds pressure, I think we'll know a lot more about the condition of the well.

One of the big concerns with injecting fluid into the well lies with the strength of the rocks in the bottom of the existing well. There is some concern that if the mud injected into the well is too heavy, then it can raise the pressure in the bottom of the hole to the point that the surrounding rock fractures. At this point the build-up of pressure in the well is relieved, as the fluid can now flow into the crack generated (and there is the precipitate drop in pressure that the Admiral refers to). That (because the rest of the well is lined with a cement and steel jacket or casing) is most likely to occur in the lowest section of the well, where it was not lined with both steel and cement, but rather a full-well-length steel tube (the production casing) was cemented into place, with cement only at the bottom of the well. Further the oil bearing rock tends to be weaker than the rest.

It is thus down around the zone of the producing rock that this fracture and leakage – the loss in well integrity – is likely to occur. And it is that zone that will be penetrated by the relief well. Thus if there are problems that arise during the static kill from the top of the well, then they will likely be remediated by the following arrival of the relief well in the critical region.

Now I think there may be another complexity (and in reality there are many in this process) and that relates to the possible injection of cement at the end of the static kill as a way of sealing the well. My concern is that while the static kill will displace oil and gas in the well by pushing them back into the formation, from which they earlier escaped, that is not true with the mud. The oil and gas, having flowed out of the rock with the differential pressure having the well pressure lower, can flow back, when the well pressure is higher. Mud on the other hand, bear in mind, is designed in part to line the well and provide an impermeable liner to the well during drilling. Thus to inject cement with the intent of driving some of the mud that the cement displaces into the formation may require higher pressures that with the oil and gas. This may, in turn, bring the well pressure above that at which the formation fractures. It is for reasons such as this that I expect the process to be carried out somewhat slowly, and in stages, rather than as a sudden “magical” flourish to end the crisis.

Deepwater Oil Spill - Clearing the Relief Well to restart

The work in the Gulf that is moving toward a more permanent solution to the leaking well beyond the current cap on the well is moving forward at a slow and cautionary pace. In his briefing at 2 pm this afternoon, Admiral Allen noted that the riser has now been connected between the Development Driller III and the BOP on the relief well. When that pipe is put into place it is full of seawater, and for a variety of reasons it is best that this is replaced with drilling mud of the required density before proceeding any further. (You may remember that it was the reverse of this process that led, in part, to the Deepwater Horizon disaster). Once this process was completed, then the pressure holding the packer in the well so that it sealed against the walls of the well, has been released. This allows flow down the drill pipe in the well, and then back up through the gap between the drill pipe and the steel and concrete casing of the well that is known as the liner. This gap that the mud will flow through is known as the annulus, and mud will be pumped down the pipe and up the annulus in a process known as circulation, which, because the mud will leave the drill pipe at the bottom of the well is known as “bottoms up.” According to Mr Wells in his later brief once everyone is sure that the well is in good condition, they will pull the packer. This will likely occur tomorrow, and once that is out of the way and the well recleaned, the final length of casing for the relief well will be run down to the bottom of the well and cemented in place.

Normally this is a job for which Halliburton would be subcontracted (as they would have been for the earlier cementing of the casings higher in the well bore. However, in the brief Admiral Allen became a little coy in regard to who would actually be doing the work.

You know I don’t know off ha(n)d but we can find that out and get it to you. You know a lot of these things are done by subcontractors and there are a lot of them that are out there. And they aggregate together to do what their specialty is and we will get that and pass it to you. I just don’t know off hand.

The casing should be in place and cemented by the weekend, at which time the preparations for the static kill will move into performance, with Mr. Wells anticipating that the process could even start late on Sunday night.

Going back to the animation that was used the first time that the top kill was tried, the flow will, this time, include a vessel holding the mud, as well as a vessel with the high pressure mud pumps needed to inject the mud into the well through the choke and kill lines. Here is the initial animation from BP:


I expect that this operation will follow much along the same lines, only the relative locations of the choke and kill lines may be relatively displaced by the changes in circuitry that happened during the oil collection phase of the effort.

There is increasingly less concern over the likelihood of there being an additional leak of oil from this well, into the Gulf, though that does not preclude other accidents from happening elsewhere. As Admiral Allen noted:

the Coast Guard received a report that the uninspected towing vessel, Pere Ana C pushing the barge Captain Beauford collided with an oil and natural gas rig in the northern part of Barataria Bay south of Lafitte.

The structure itself is called C117 and that is a state owned well. We have about 6,000 feet of boom around the facility right now, there’s an over flight in progress with Admiral Paul Zukunft and Governor Jindal right now and they are assessing the issues on scene, and will be available to report updates on that later today and out of the JIC and so forth.

Subsequently the well was reported to be spouting a mixture of fluids into the air from the unplugged well. Fortunately there are enough resources in the area to deal with the developing problem.

With the time since oil was flowing into the Gulf getting longer, the amount of oil that can be collected from the Deepwater Horizon well is significantly reduced, and so some of the fleet could more easily be made available if needed. The dispersal of the oil does seem to be justifying the decisions of both BP and the various agencies to rely on the dispersant at the beginning of the spill. The longer term effects of the process will not, however, be available for some time.

And in the meanwhile, BP, having agreed to pony up the $20 billion for compensation payments, is making a business charge of $32 billion for the spill, so that, it appears that it will not have to pay taxes on those funds, which will thus cost the taxpayer somewhere around $10 billion. It is, after all, a business cost. But there are also going to be questions raised about how long the funds should pay for damage, if the oil is dissipating, the sands are clearing and the fishing is returning. Obviously, for example, the sand islands being raised along the coast will not be installed in time to be of much benefit for the current problem, given the speed with which the oil is dispersing so does the $0.36 billion being spent on that project reflect the best use of funds? These issues are likely to remain very contentious as we move into the election cycle.

Deepwater Oil Spill - Restarting Progress

BP does not seem to have gone back to the daily briefings, let alone the twice-a-day ones that were being issued just a couple of weeks ago. Admiral Allen has given permission for the top and bottom kill (through the relief well) activities to continue. The Admiral also noted that the riser for the RW has been reattached, and the reconnection, removal of the plugging packer, and cleaning of the well is in process. It is estimated that the intersection with the original well will now occur on the 7th August, with the final set of casing being run into the hole this week, and then, after cement injection, the well will WOC (wait on cement) while the cement hardens, and is then checked. In the meanwhile the undersea valve system is being modified to carry out the static kill that I discussed earlier. (And the leak monitoring has transferred to the BOA ROV 2, which is now showing four leaks.)

Once the flow channel to the well is restored, and the casing set and cemented in the relief well, then the Q4000 will carry mud from the HOS Centerline, driven by pumps on the Blue Dolphin into the riser, and down to the BOP to carry out the static kill. The Admiral currently expects that this will begin on August 2nd. He did note that the plan is still to inject cement into the top of the well, after the mud has killed any pressure differential between the bottom of the well and the reservoir, and thus also stabilized the well.


As the more immediate and visible problems reduce, with this path toward the final sealing of the well, and with future flows from it into the Gulf becoming less likely, the oil on the surface, and that migrating towards the shore is getting less. This will allow the Admiral to redeploy assets. For example it now appears that the risk of oil East of the Mississipi is declining, and that commercial fishing there may reopen before the end of the week, given that

"We're 90 days into this, and I think the data speaks for itself," said Randy Pausina, assistant secretary for fisheries at the Department of Wildlife and Fisheries. "There's been no indication that any seafood is even remotely close to being at any level of concern. Find me the concern and prove it to me."

Sport fishing has already been restarted.

We are now in the most intense driving season of the year, and this is evident, with traffic noticeably heavier on the roads in New England in recent days. SeaCoast Sunday noted in their paper edition on Sunday that occupancy rates in the York area of Southern Maine are over 90% during the week and at 100% on weekends. It is therefore not surprising that gas prices are on the rise, being on average 25 cents higher than this time last year.

We have been fortunate that the weather in the Gulf has not generated that much damage to the rigs and platforms yet this year, and those that were affected by Bonnie are now back in business. But the season is still young, and may yet remind us of our vulnerable dependence on oil.

Deepwater Oil Spill - After the storm

The “Bonnie” storm has passed, and the different vessels are not only returned to the site, but are already making progress in returning to operations. As Admiral Allen noted on Sunday

DDIII is now running the riser pipe down. They have 67 joints to complete, they've done 39 of those as of about 10:30 Central Daylight time this morning, need about five more hours to do that. They are planning to latch on to the well around midnight tonight. Development Driller II which was – had drill – was involved in drilling the backup well is returning to site and will start running their riser today.

Q4000 is inspecting the yellow pad, that is the control device that's placed subsea to operate the hydraulics. They replaced the valve on that and they plan to install it later on today and then they will begin preparations for the static kill operations.

He also noted that the pressure in the well has now risen to just over 6,900 psi, while the temperature at the BOP remains at 40 deg – suggesting no flow and that well integrity is apparent. The storm has, however, dispersed and moved the oil, and they are resurveying to find where the threats now lie.

He then gave the current anticipated time line for the kill of the well.

.

The time line is roughly over the next week. We'll return the Development Driller III, run the riser pipe, latch in, pull that undersea containment device, which they call a packer.

They're going to need to circulate conditioning fluids through that pipe line to make sure it's ready what they call conditioning a hole and then some time in the next week they'll be in a position to be able to run that (nine and seven-eighths inch) liner which is the critical path right now to moving – to move ahead.

Once that liner is laid, they're going to put cement in and around it. And at that point the two vessels that were supporting the liner operation, one call the Blue Dolphin, the other is called the Center Line will redeploy and hook up with the Q4000.

This is sometime – this will be sometime during the week of 1 August. And they will set up for that to be able to inject the static kill and during that week of August subject to the (inaudible) I'm sorry the containment pipe being installed and cemented in then we will go to the static kill with the Q4000.

Kent Wells has also now released the animation showing how the different kill methods will take place, and interestingly also showed the section at the bottom of the well that shows the different layers of oil bearing rock in the reservoir.

The animation follows along the process in much the way that I described in an earlier post on the bottom kill, which is now scheduled in two parts. As the Admiral noted, the first part is to case the relief well. Once that is in place, and the cement run, then the top kill will start.

Because the well is shut-in, the plan is that the flow to the surface will be reversed. the flow lines are now passing oil and gas to the surface, the circuits will be reversed to return them to their original condition, and then mud will be fed into the well. Because this can be done a little at a time, it will be, and the pressures will be monitored to ensure that, as the well fills with mud, that there are no integrity problems.

Once the well is full of mud, they may try pumping cement into the well from the top (this is shown in the animation), though, because of concerns over flow control, I would suspect that they will not put the cement in until they connect through the relief well, and they will then do a two stage (annulus and then inside the casing) final kill.

And I should note that, contrary to my concern, the leaks that are being shown again now by the HOV ROV1 are no worse than they were before the storm, so perhaps that is not going to be much of a problem going forward.

Pre-mechanized longwall mining

In the last post on this subject, I wrote about how miners were able to remove almost all the coal from a section, either by leaving small remnant pillars or building packs to hold the roof in place, while that coal was removed. By retreating the face back towards the shafts the overlying roof rock was then allowed to collapse into the void left by the coal removal. However, as this process began to evolve the miners noticed a couple of significant things that helped in the understanding of how the roof was responding, and helped to make longwall a safer and more effective method of mining. The first was that at the roof broke behind them, so the rocks would bulk up (they gain about 60% volume as they break and pile). Within a distance of about 2 seam heights, as the roof was converging, without underlying support, it would then meet the broken pile of rock, and thus get some support from this. As a result any support that the miner installed would not need to carry the full weight of the overlying roof to the surface, but only that of a few feet, which needed much less strength.

Thus by about 1870, and possibly in the Lancashire coalfield in the UK, they had modified the process further, and were only supporting the roof around the actual mining operation. How could they get away with this?

There was one other fact that helped make it possible. In some of the earliest tech talks I mentioned that the weight of the overlying ground can be simplified to being around 144 lb./sq ft for every foot of depth – based on the simplifying assumption that a cubic foot of rock weighs 144 lb. Thus converting this to a pressure in lbs/sq inch. (of which there 144 sq ins to a sq ft) this means simplistically that for every foot of depth one goes into the ground, the pressure increases by 1 psi.

Now when you make a hole in the ground, that load, or equivalent rock pressure, has to move somewhere. And it moves just a little so that the weight of the ground over the hole is carried by the rock on either side. However, what happens if this additional load is too high for the rock and it fails?


Well if the rock were just a thin column it would collapse, but if it were thicker, then the weight would just move further into the coal. Now if we came along and moved the coal that had failed, then the hole would just continue to get bigger. But if we leave the coal in place, then the broken coal acts to confine the coal further into the solid. And this confinement gets higher, as the failing pressure continues to move into the wall. And what happens is that this confinement builds up the strength of the coal, so that at some distance into the wall (or face) the coal strength reaches a point that it can carry the weight of the ground above the working area.(For a simple analogy think of a deck of cards, which individually cannot bear weight, but when held together by a rubber band, or a carton, can support quite a bit of weight). (And for those who prefer a more scientific description – the lateral confinement moves the failure from two-dimensions into three, with the minimum principal stress building as one moves into the solid material, and raising the overall failure stress behind it).

This works not only for the coal in pillars, or ahead of the working face of the longwall, but also for the rock that has fallen into the waste and is confined by the rock around each piece allows it to regain some strength, and so collectively the broken rock behind the working face (called the goaf or waste) will continue to compress as the full load comes on it, but will carry the weight of the ground from about twice the seam height, all the way to the surface, and with the other end of the "bridge" as it were resting on the confined coal ahead of the working face.(While the width of this bridge varies with depth, coal and rock strength etc, for an initial estimate you can imagine it as being around 500 ft).

Simplified side view of the coal as the miners removed the coal along the face, moving to the left. They put up wooden supports (three wooden props and a top bar) and let the roof behind the working face that these protected, collapse.

Thus the miner, working at the face, needed only to support only the rock that is up about twice the seam height he was working (in those days women did not do the actual mining). And this could be done with relatively small tree limbs, called props. However, because the rock could break into pieces, the prop support would be distributed, by having a plank, or half split timber, as a bar on top of the prop. Putting one prop at each end thus gave a sort of "goal post" support. Thus, along the face, there would be, at about 4-5 ft intervals, these prop supports holding the roof up.(The coal is made slightly blue in the pictures to give a better contrast - sorry!)

View looking down on the working area from the top of the fallen rock pile. I have erased a small section of the coal to show the position of the cutter bar of the coal-cutter as it is either dragged, or self propels itself along a cable stretched down the working face.

In the initial working of the longwall panel, the coal was undercut by a team of holers, who each cut a slot at the bottom of the seam, to a depth of about 3-ft, and collectively undercut the face over the course of a shift. As the faces grew longer there was a search for a machine that would make that undercut without the intensive manpower. One such tried to mechanize the simple swinging action of the pick.

Early coal cutting machine used at Garth Colliery in Wales in 1863. (National Museum Wales )

The development of the machine, the coal-cutter, dates from around 1876 when a compressed air machine was developed by Francis Lechner, in which picks mounted on a chain, did the cutting of the coal. (The more modern versions of this look like a chain saw on its side). It took a number of years for the machine to evolve into something that was widely accepted, and by that time the company had been taken over by Joseph Jeffrey (a banker) and became Jeffrey Manufacturing Company. (By the time my dad worked for them they had become British Jeffrey Diamond, and they later became part of the Dresser Group). They had spread to Europe by 1905.

And electrically driven machines were developed, which have not changed that much in the intervening years.

Early Coal Cutter (Iron Miners )

With these machines pulled along the face, undercutting the coal, to give a cut depth that was more typically 7-ft deep, the next step was to break down the overlying coal. Sprags (small wooden wedges) were slipped into the slot at intervals, as the cutter passed up the face – usually run by three men. At the same time holes were being drilled along the face, about 6 ft apart, with a stick of dynamite placed in each one.

After the face had been undercut the coal was blasted down between shifts (7.5 hours) then the collier shift would come in and each man would have about 10 yards of face to load the coal from, and to re-support. To get the coal from the face, a rubber conveyor belt was run along the back end of the supports that were in place before the blast, and the coal would normally not break that far from the face. As the miner shoveled he would also put in a new set of timbers, overlapping the old, and supporting the new working area. Typically this would take another seven hours, with an ideal seam height being about 4.5 ft. Above that the coal volume to move was much greater, and below that it got a bit awkward. For example, below 2 ft thick you lie on your back, with a prop under your shoulder and shovel over your head - how would I know? Yes, there was a reason to go to college).

View of the face, after the coal has been loaded out. The rubber coal conveyor between the last two rows of props must now be broken into strips, and moved forward a row, ready for the next cycle. Then the back props and bars are removed. (Saving the front two props and chopping out the back one).

In the third shift, the men would come in and break down and move over the conveyor belt, and then remove the last row of wooden supports, bringing the roof down, beyond the new line of supports.(Smart folk would use a come-along and a chain to pull down the props, young idiots (guess who) would go in with an axe to chop them first). For this was the state of the industry when I went to work in it in 1961. There have been many changes since.

Colorado temperatures using TOBS

Back in March I first looked at the temperature data for Colorado, comparing the GIS station data with that generated with the homogenized data from the USHCN. (Incidentally their process is described on that site, explaining in part how they were able to generate data from sites that did not have full sets of information. The immediate concern that I have with that, for the purposes of the present discussion, was that as I went through the data tables for the sites in Coloradolooking at the data corrected only for time of observation (TOBS) I was struck by how few stations were providing data in the early years. Averaging has some problems, that I will likely discuss in a future post, but when there are less than half the stations reporting, then using them to estimate the values for the unknowns becomes a little more questionable.

OK, so let me go back and insert the TOBS data in the spreadsheet of the form that I used for the original post: I note, while doing so that there are 24 stations in the USHCN group, while there is only one for the GISS network. Yet of those 24 only 6 have temperatures given for 1895, when the series starts (and for which there were a full set of values for the homogenized data I had originally used – for that set the only value missing was an 1896 value for Telluride – ah, well.) There was also only one GISS station at Grand Junction.


Running the averaged values and comparing the difference between that station and the USHCN TOBS values gives an average temperature difference of 6.15 deg. While that is still high, it is less that the 6.65 deg warmer that the homogenized data suggest. As to how it played out over the years:


And there has been a clear increase in the recorded GISS temp, relative to the USHCN over the decades. The correlation has a lower correlation than there was with the homogenized data, but that data plot (in the original post) showed that the difference was getting less over the years not greater.

Now as for the average state temperature itself, and this is a bit of a surprise, since the first time I ran this, there was a clear increase in temperature over the years. Using the TOBS data (but including the GISS value) that is no longer the case.


There is that curious blip upwards after 1984, but looking at the overall not any remarkable changes. In regard to the change in the Standard Deviation with time, the shortage of data points in the earlier years skews this value beyond where it might completely valid, though the decline in recent years might be more credible.


Moving on to the effect of population, Colorado has a smaller population in larger cities, and without the homogenization to remove the effect of UHI there is a correlation to the log relationship that I have noted before (and which has previously been suggested by others).


The correlation coefficient is slightly lower, in fact, with the TOBS data, which isn’t supposed to be the way that it correlates, since the homogenization was supposed to remove those effects.

Looking at the effects of Latitude, there was no correlation with the homogenized data, and that also holds true with the TOBS data. (This, from the other states reviewed is relatively inconsistent).


Because, to a great extent, the mountains get higher going toward the west, there is a correlation with longitude:


However, when checked, the correlation is better with elevation, explaining the apparent result.


And that correlation has held true for both sets of data.

Interestingly, since my first post, there has been some interest in Colorado climate, with there being a paper out by Noah Diffenbaugh of Stanford, which apparently claims that the increase in global temperatures will be emphasized in higher states such as Colorado.

Given that there has been a CO2 increase Dr. Alan Keen refuted that prediction based on an examination of the trends in temperature data, which included the USHCN homogenized values, though after they had been used to give a value for the “Colorado” grid – a value that I will get to in future posts, when I have some more state data completed. Dr Keen provided the following plot:


Well let’s press on and get some more data.