Golden Juarez

El Paso Texas and Ciudad Juarez Mexico False Color with Red Vegetation

El Paso Texas and Ciudad Juarez Mexico False Color with Red Vegetation

Original Image

You can click on this image to get an enormous 3200 x 3200 version.

This is a false color image. The Red is vegetation, while the city is grey and the dirt is brown. The river dividing El Paso, Texas from Ciudad Juarez, Mexico, is that thin line through the middle of the image from upper left to lower right, more or less along the vegetation. I-10 runs near it for much of the distance.

So Why Mention This?

While driving down I-10 at about midnight I noticed something “different”. Ciudad Juarez was golden…

About 20 years ago, while driving past, I’d noticed that El Paso was brightly lit (with a lot of that garish bright Mercury Vapor lighting). Ciudad Juarez was quite dark. Clearly the poor Mexicans could not afford night lights.

Now, while driving past, Mexico has plenty of oil revenue for night lights. Ciudad Juarez is brightly lit in that golden yellow color of High Pressure Sodium from edge to edge.

So I have to wonder:

How much do “night lights” tell use about the “size” of this area, really? Yes, it IS an urban area. Yes, it ought to be flagged as “urban”. But does the change from “dark” to “light” really tell us that Ciudad Juarez has suddenly come to life as an urban center, and that in 1980 it was rural?


It’s been urban the whole time. What the night lights tell us is that it is urban now. But the status in the past would be incorrectly classed based on lighting. Notice those mountains on the left hand side? The cities have be smack up against them for a very long time. Growth has been along the river and freeway (and a little bit back from them toward the desert out back…) How many other places in the world today are urban, but as poor as Mexico was 20+ years ago? How many places today will be classed by ‘night lights’ as rural, that are in fact densely populated poor?

Look At The Middle Top – Airport

OK, so in the middle toward the top we have the airport. All around it is brown dirt. “Night Lights” would tend to class a lot of this area as rural. Yet the airport will be a very hot place (black asphalt / tarmac is like that in the desert sun of West Texas / Northern Mexico…) So ‘night lights’ from a little N.E. of the Airport will tell lies about the airport.

Furthermore, you have city on 2/3 of the triangle of airport land.

There is only one direction from which the wind can blow that does NOT blow the UHI of El Paso / Ciudad Juarez over the airport (and the wind most often blows from the city toward the airport…)

There is just no way you can get a valid “rural” temperature from anywhere inside El Paso / Ciudad Juarez nor at the airport.

The only way to get a valid representation of the area would be to set up a station out in the rural area modestly far from the cities. And we have poor / no records from those places against which to compare.

In Conclusion

In this case, Night Lights will indicate rampant growth of an area “changing” from rural to urban in Ciudad Juarez, when in fact all that has happened is that they have gotten enough ‘richer’ to install high efficiency lighting.

I would assert that in many cases the same will be true in the history of the USA as prosperity increased. When I was a kid, most towns had poor / little lighting. I distinctly remember 150 watt incandescent bulbs in ‘tin hat’ fixtures, widely spaced and not very bright. Today that same farm town has very brightly lit streets with very high efficiency lighting (much more light for much less power). The town has “grown” from 3339 to 4009 or so people during the last 50 years. Not exactly gigantic growth, and most of that from more people per house, very few new homes. The farm land around that farm town now glows with hundreds of low pressure sodium, mercury vapor, and High Intensity Metal Discharge lamps. Brightness has increased dramatically, while ‘growth’ has largely been elusive.

So I really do have to wonder: Just how valid IS night light brightness as an indication of ‘growth’ over a decades time scale? Does it not, much more completely, reflect a threshold of prosperity where street lighting becomes affordable? A measure of prosperity rather than physical size? And are not the technical changes much more important that the physical land use? We’ve changed from dim incandescents to very bright HID and Mercury Vapor. Those are now giving way in many places to High Pressure Sodium. (In between, we had the darkish egg yolk yellow Low Pressure Sodium. So won’t the ‘color spectrum’ sensitivity of the sensor be very important too?)

I don’t have the answers here, but it sure looks like there are a boat load of “issues” with using “night lights” as a proxy for urban vs rural temperature profiles.

One final note: Last time I looked, the Marine Air Station at Quantico Virginia was classed as “rural”. Military air bases often conduct night operations without lights (the folks need to be practiced for war time actions). So the airport at El Paso has gone from dark at night (in the old days when prop planes tended to fly Visual Flight Rules and mostly in the daytime) to the modern International Airport with 24 x 7 operations and wall to wall lighting. Yet it’s been a barren place with tarmac and concrete as those transitions happened. It seems to me that “night lights” will be spectacularly prone to failure at comparing places like El Paso airport to Quantico, and Ciudad Juarez to El Paso.

Finally, El Paso is looking more dim to me on this last drive through. Businesses are now ‘conserving’ by shutting off lights at night ( that used to be left on as ‘advertizing’ of sorts). The city looks to have dumped the older more garish lights for a more ‘mellow’ lighting. Does this mean that El Paso is shrinking?

No, I don’t think so James…

So why are we using a “proxy” for urban vs rural at all? There are only a few thousand stations currently in use in the GHCN. Is it really all that hard to hit Google Earth for a couple of hours and just LOOK at them and see what’s urban and what’s rural? Really?

Never use a proxy when the truth is knowable…

Still not convinced Ciudad Juarez is glowing Golden now?

Here’s a picture from NASA….

El Paso / Ciudad Juarez at Night

El Paso / Ciudad Juarez at Night

Original Image

The bright white diagonal line is Interstate 10, the freeway I just drove through. All that Juarez part WAS nearly black a couple of decades ago, but was full of houses and shops in daylight hours, with a lot of dirt, pavement, and adobe buildings. Urban, but unlit. Now it is highly lit. Though I’d question the value of it. The social decay that has moved Ciudad Juarez from the “over the border night life hot spot” to the “avoid it due to murder capital status” and killed the “night club” industry in the process has not been slowed by the lighting.


About E.M.Smith

A technical managerial sort interested in things from Stonehenge to computer science. My present "hot buttons' are the mythology of Climate Change and ancient metrology; but things change...
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15 Responses to Golden Juarez

  1. Nice thinking EM.
    Proxies are only useful when time or effort are limiting factors – we now need the real assessment of urban status. BTW did you see the EU figure of about +1 Degree C per +500,000 population.

    I have been pondering on the exact same rural/urban issue and was asking myself why not contact each of the ?8000? stations and ask the custodian what is their assessment. We need an organisation like Rotary International to help.

    Did you see E R Long’s paper? He shows a massive difference between rural and urban trends. By contrast, NOAH can see no difference between rural and urban temperatures using their methods of adjustment – hmmm!

  2. Gordon Oehler says:

    Good morning,

    If I am not mistaken, it is the low pressure sodium lamps that have the golden glow. The high pressure sodium lamps are whiter.

    The low pressure sodium lamps are more efficient. And from an astronomer’s view, better because the sodium spectral lines are more narrow and more easily filtered out.


  3. Pascvaks says:

    Thanks for the info. Haven’t been to, through, or over EP/CJ in years. Kind’a looks the same from this distance, except for the lights over the border at night. One day some genius is going to invent a better way to measure temps.

  4. E.M.Smith says:

    @Gordon Oehler: Both of the sodium types have a “yellow” color. The low pressure sodiums are a deep egg yolk yellow, while the high pressure sodiums are a light golden with hint of redish undertone and generally lighter color. It can be hard to decide what they are from a distance as the human eye automatically ‘color corrects’ (within rather broad bands) based on any ‘true white’ you have in the field of view. But if you have no true white to key off of, the ‘color’ you see can be way off.

    From the freeway, with little as my ‘white balance’, they looked sort of a ‘high pressure light yellowish’, but I’d not argue it if someone with on the ground info said they were low pressure sodiums. To decide by eye really takes a true white balance reference. (A light box with a white light in it in the corner of the field of view is enough…)

    The two sodium bulbs really have the SAME sodium lines in their spectrum. It’s mostly how much energy is ending up in the high energy bands vs the lower energy egg yolk yellow bands. It’s a lot easier to judge from close up than far away. First off, close up the low pressure sodiums will give incredibly crappy color rendition (so anything where you know the proper color will tell you that you are under LPS.) Secondly, you can get the fixture center of field of view and then ANY other light source as a peripheral view will ‘white balance’ and you clearly see the Egg Yolk vs “white gold” difference. The other problem is that from far away you are getting an average of ALL the public lights. So the random yard and business lights get added to the street lights, shifting the average color somewhat, and shifting the ‘white balance’ you see too.

    The NASA picture looks like the darker yellow of low pressure sodiums, but that just means that we have to know how their film white balance was set…

    So, in essence, it comes down to what you think is ‘golden’. Egg yolk yellow, or 14 carat …

    In Santa Clara / San Jose / Silicon Valley, we’re largely all low pressure sodiums so that Mount Hamilton Observatory can continue to work well… Though it was my impression that the high pressure sodiums were ‘almost as easy to filter’ for astronomy?

    At any rate, the point isn’t wether Ciudad Juarez is high or low pressure sodiums, it’s that they have loads of lights. Any lights.


    I’ve seen several analysis that included a degrees-per-population curve. It’s a lot more than the codes like GIStemp ‘adjust’ in any case. AND a lot better method.

    There are about 8000 TOTAL stations in the inventory, but many of those records are from times like the 1800’s and not NOW. For NOW, we only have about 1200 stations. ( I haven’t looked in about a year, thus the ‘about’). So to get the “Urban vs Rural” you mostly need to just look at 1200 stations NOW. For the historical, you get to do a bit of digging…

    But even worse: GHCN does NOT have any historical state. If a station is “urban” NOW, it was urban for all time. They only store one value.

    So to actually fix their UHI method you would need to have the Urban / Rural / Suburban field set for each year of the history of each station. Same thing for Airstation code. The Tempelhof Airport:

    was flagged as an airport in the 2009 GHCN data set. So that means that their temperature reports from the 1700’s are also “airport” as are the 1800’s… A couple of years ago it was ‘retired’. When GHCN gets around to recognizing that it’s a shopping mall now, the entire “airport” history of the Berlin Air Lift will evaporate as far as GHCN temperature class is concerned. It will have been a shopping mall forever…

    This, as they say, is just broken…


    I’ve been through it, on and off, for about 40 years now. It hit the mountains as a limit some long time ago. Economic advancement, and extension out of the area along the freeway over time. But not much “growth” in the central area. Economic advancement and renovation, yes. So a lot of lights added…

    Airport plugged up growth ‘out that way’ (so you have the dark triangle near the airport with the city creeping around the edges). In the top picture you can see the black runways rather well. It’s gonna be hot near all that pavement and desert… much more so than down near the river and vegetation back in 1850 …

  5. Larry Geiger says:

    What are you doing on vacation here in Florida mucking around in this stuff? Man, you are addicted :-)

    Turn off the laptop.
    Turn off the cell phone.
    Go find a place where Parrot Heads hang out and chill for a while. Listen to some tunes. Close your eyes and enjoy the warm breeze. This stuff will wait.

  6. E.M.Smith says:


    I’m only quasi on vacation. Right now, for example, I’m working. I have to figure out what the election returns and probably Fed actions will mean for making money…. I’m still trading for a living, so I’m still “working”.

    It’s just that this week or 3 I’ve decided to do it from a friends home in Orlando; and we’re going to watch the launch together.

    So it isn’t so much a “vacation” as a “pleasant alternative commute to work” ;-)

    Until the launch happens, I’m just ‘hanging’. He has a pool and a “drinks fridge” so some fair amount of time is AFK. But I still need to ‘check the charts’ and that means I’m at the keyboard. And as often as not this part is more interesting that the state of the MACD on GLD… And today I was checking out cameras at COSTCO (unimpressed, so will likely use friends camera).

    Right now I’ve got an enormous cat in my lap. I’d guess about 18 lbs? A Black Tiger Stripe American Shorthair by my estimation, but the biggest one I’ve ever seen. He’s decided he likes me… Earlier today, the ferret decided he liked me too, so we spent some “quality time” together as he explored my dirty laundry (that I was preparing to wash).

    Oh, and we’ve run out of beer. (He has 2 fridges…) So it’s not like things are all work and no play. I’ve had to swap over to sangria today… It’s raining now, so my biggest question is “Do I want to swim in the pool in the warm rain, or go get beer?” while waiting for the election returns to come in.

    Decisions, decisions….

  7. ROM says:

    There is a public lighting regulation which I believe applies to all of Australia that sets limits on the amount of light allowed to be reflected upwards.
    So all our public street lighting and government controlled and lighted areas have very substantial overhead reflectors or cut-offs above the horizontal incorporated into their structures.
    Which of course reduces the satellite pixel count from the street and public lighting in any sizable habitation by quite a large amount.

    I don’t know the background to this regulation but I think it relates to the efficiency of public lighting and the reduction of energy and in many case glare from street and public lighting that may interfere with operations such as aviation.
    Also as the public authorities such as local government councils have to pay for their street and public lighting costs, it is in their interest to reduce the light losses and raise the efficiency of the public lighting system where ever possible.

    Secondly there is a whole range of public lighting of widely varying intensity and concentration across many countries and across countries with some outlying and remote centres, sometimes with quite significant populations, that rely on diesel powered generators, even here in Australia, which turn off nearly all their street and public lighting by around 10 pm to save on fuel.

  8. David says:

    Re E.M.Smith

    “I’m only quasi on vacation. Right now, for example, I’m working. I have to figure out what the election returns and probably Fed actions will mean for making money…. I’m still trading for a living, so I’m still “working”.

    My WUWT comment was …?Wow, in Calif not only did we affirm the “green” agenda, we also apparently passed legislation which allows an increase in spending with a simple majority.

    The saying, “as Calif goes, so goes the country” may enable our failure to be a warning for the rest of the country. OTOH, Obama may send so much stimulus here that it makes the green agenda appear, on the surface, to be a success. I hope not, but fear this.

    I know you live in Calif and share this concern.

  9. Interesting thought….what will all cities look if the Green Madness succeeds?

  10. BTW: A few weeks ago I told here, if I remember well, after my experience with South American economies of the 1980’s that the best time for devaluation was right after an election, when everybody is distracted with the results. It seems that, as a new economy, yours is gonna do the same :-)

  11. E.M.Smith says:

    @ROM. Interesting, so we have time, geographic, and POLITICAL dimensions to how much “lighting” correctly reflects “urban” character.

    @David: The Republican House assures he can’t keep California afloat without a large number of republican states agreeing. Like that’s gonna happen.

    So while it pains me to have “Major Nuisance” (Mayor Newsom) as our vice-governor, and Governor Moonbeam being retreaded (that’s what we called Jerry Brown ‘back in the day’…) the simple fact is that with them presiding over the collapse of the state, the place the blame belongs will be pretty clear.

    At least we can serve as an example of what what not to do…


    Just back from a road trip (posting “soon”) so have not had time to evaluate the Fed actions yet, but yeah, this is a key “leverage” point…

  12. LarryOldtimer says:

    EM, best pack and get your goods out of CA and move. Avoid the rush. I was a highway engineer with CalTrans when “moonbeam” Brown was governor the last time. He is the one who killed the CA goose that layed the golden eggs last time he was governor.

    With him as governor, and Mary Nichols as head of CARB, and CA going to solve the problem of global warming all by itself, CA will go quickly.

    CA’s death throes will be interesting to behold, but only those who like morbidity will enjoy watching them.

  13. Pascvaks says:

    Careful when you go back home. Understand that someone’s been moving the border fence a little North each day and I-10 will soon be closed.

  14. David says:

    “Calif will fall quickly” Republicans will not allow a national bail out.


    I am cautious, these people are extremely adept at creative ways to move money and will take steps, not yet contemplated, to make calif look successful on the surface; you know, the green economy had created this many jobs, bla bla bla. Indeed, ther success in 2012 now has greater dependence on how calif does, calif may be a “tipping point” in the political arena.

  15. E.M.Smith says:


    Yup. I lived a few blocks away from “Governor Moonbeam” then. We had a couple of decades of phantom overpasses in San Jose when they had the interchange built, but not the roads…

    And “Moonbeam” sold the 85 right of way. After he was ousted, we got to buy it back (including the homes that had been built) and destroy several miles of new houses, thanks to him…

    You can still see iconic pictures of those overpasses way up in the air with no freeway on either side, from time to time.

    Unfortunately, I have a spouse and family who are not inclined to see the future. Spouse is a teacher, so the idea that Brown would not cut spending on teachers was being pushed by the teachers union.

    Though, oddly, I’ve gotten a text message while on the road to perhaps look into employment opportunities out here…


    They already have a border crossing / immigration station ON I-10 to the east of El Paso… I was thinking I’d take the airplane home and leave a car out here so I can just fly back over Mexico, er, NEW Mexico, next time ;-)


    They will try to spin it, but California is “toast”. We’re variously 14 Billion to 40 Billion in the hole (depending on who’s lies you believe) and do not have a budget. BY LAW 1/2 the state expenditures must go to Education. Basic wealth creation has fled the state ( I periodically drive the Sillycon Valley areas where I got contracts for years looking for signs of life…)

    What we have left is not much and not pretty. Large established things making tons of money so they don’t have to leave the state (yet) but will eventually hit a wall. ( EBAY, Google) and some with increasing “sourcing” from overseas (Apple). Your iWhatzit is largely an Asian device…

    Their is Hollyweird, that increasingly shoots in other locals.

    Some farming (being hosed and broken at the best possible rate). but still growing many specialty vegetables (that increasingly come from Mexico…)

    And a whole lot of support and “service” industry…

    But I’ll expect to see some (more) of the financial center banking move to Phoenix (credit card processing moved some years back, and then some moved on again from there) from Los Angeles. I’ll expect to see farming move. Mexican lettuce is fine…

    Wine will stay (larger price premium…) and fruit will take a while to convert to pasturing and hay.

    As the bite gets bad, retail will suffer. As prices rise a lot, more folks will go skiing out of state. Etc.

    But it won’t be fast. Large economies move slowly, in all directions. So it will take 1/2 decade or so to get really ugly. (it’s only “ugly” now…)

    Yes, they will try to paint it in pretty colors.

    No, it won’t work.

    The only way to “fix it” is with $25 Billion +/- $5 Billion of “new money”. (ALL Ponzie schemes can only be extended by bringing in ‘new money’…).

    The Dimocrats will try to do that, but fail. The Republican House will block it (if they have 1/2 a brain…) then the Obamanation will try to do it administratively (that will be harder to block).

    They may even find a way for The Fed as part of the new $600 Billion “QE2” to funnel some money to California. (My “best guess” at a working “back door funding” would be for The Fed to buy up $20 B of California Bonds – newly issued – as part of QE2 during the lame duck session. If something like that doesn’t happen, it will be very hard to do the bailing directly and next year…)

    Yea, it’s a ‘possible’ that they will find a way. But very unlikely once the new House is sworn in…

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