This is interesting, and of course it goes hand-in-hand with what I have been saying for years.
Scott Sistek, of KOMO News/Weather reports:
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For several years the thermometer at SeaTac airport has been reporting temperatures 1-3 degrees above surrounding areas.
Instead, it seems the thermometer at Sea-Tac is finally back on track, reporting temperatures more realistic with respect to other nearby thermometers. It’s been a long suspicion among some local meteorologists that the thermometer at the airport been running a bit warm over the past few years, frequently reporting temperatures 1-3 degrees warmer than surrounding sites. (Both UW professor Cliff Mass and I have done blogs on this apparent warming in the past.)
Here is just one example from July 16 last year when Sea-Tac reported a high of 88 degrees but everyone else around the Sound was closer to 83-86. (KSEA is Sea-Tac, the numbers on the far right are the preliminary highs for the day. This link will help decode the other cities listed here.)
UW research meteorologist Mark Albright has been tracking this anomaly for the past couple of years and has been among the most vocal in this apparent discrepancy. As just one example, he found for those first two weeks last July that the Sea-Tac gauge ran an average 2.3 degrees warmer than four other neighborhood thermometers placed within a couple miles of the airport.
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Apparently, they fixed the ASOS thermometer, and the problem went away.
Read the whole story here: http://www.komonews.com/weather/blogs/scott/Did-Seattles-climate-cool-15-degrees-in-a-blink-of-an-eye-254419491.html
h/t to reader Steve Z.
And as I’ve documented before, such errors remain in the climate record. Like the malfunctioning airport sensor in Honolulu, where the skewed temperature set new high temperature records. See this interview with a NOAA/NWS meteorologist on the issue:
But, even after knowing they were caused by a malfunction, the NOAA/NWS leaves the bogus high temperature records intact. Only government could screw up data this badly.
Here is where the sensor is:
The SeaTac ASOS, according to NCDC HOMR, is located below.
SeaTac is part of the GHCN network used for climate. But was it surrounded on three sides by heat holding asphalt in 1948 when the weather records began there?
Doubtful.
First Sea-Tac Airport Terminal, ca. 1946
I wonder what this revelation will do to this study, which used Sea-Tac and other GHCN stations as the basis for the claim?
New study finds “nighttime heat waves” increasing in Pacific Northwest
UPDATE: more on why these sorts of failures tend to be mostly hot failures:
@Non Nomen at 2:02 am
That ASOS failure makes me shiver: … So, it seems to me that if one instrument shows false readings, safety of air traffic might be severely endangered.
I positively know of other automatted wx-reporting-systems, that all relevant instruments have a second circuit with a second set of instruments, thus providing mutual quality control if one instrument should fail. If ASOS does not have that feature, it ought to be retracted immediately from use for aviation purposes.
There is an old saying:
The man who has one clock always knows the time.
The man with two clocks seldom knows the time.
I agree, Non. If it is possible for a ASOS to “go crazy” and be off more than 5 degrees, then some additional redundancy is needed.
From the lesson of the two clocks, you really need three stations, maintained on non-synchronized maintenance schedules.
Argument against: There have been no accidents as a result of a bad temp sensor.
Counter argument: Do we know about the close calls?
55% of the RTO [rejected take-off] accidents happened after V1.
A temperature reading too warm will cause the real V2 [min take-off on loss of one engine] and V1 to be estimated too low which won’t be discovered until after the calculated V1. Since pilots are trained to proceed with takeoff after V1, a bad temp sensor will not cause a problem by itself, just a longer take-off roll. But in the event of engine loss, it has reduced the margin of safety.
Considering what is at risk,
a) a billion dollars per hour of air frames leaving the ground,
b) thousands of passengers per hour leaving the ground,
c) trillions of dollars of global economy dependent upon dodgy data collection,
a little redundancy in major airport temperature recording doesn’t seem an unreasonable expenditure.
[Ref. 1] https://www.faa.gov/other_visit/aviation_industry/airline_operators/training/media/takeoff_safety.pdf
@ur momisugly Stephen Rasey
You made my day. Your sound explanations will give others a clue of what this is all about. BTW:
A system where implausible data are collected will call for help and shut down itself partially. Then the good old human workforce comes back into action and a) fixes it and b) in the meantime uses the emergency instruments that are stored in such a station(or ought to, at least) or vice versa. That’s the procedure I learned from a sytem called AMDA. And even if the system is running well, there is still some quality management behind the scene, where data are checked for inconsistencies etc. If this QC is ok, the data will go out. ASOS seems to be different and NOAA/FAA doesn’t seem to care.
Many accidents in aviation happen because errors sum up: wrong altimeter setting in the a/c, wrong ground data, sudden bad visibility under vfr, loss of communication, pilot’s error etc etc. and here comes trouble. If only one source of errors can be eliminated -and, in this case at ridiculously low cost- it is well worth it.
Therefore I heartily agree with your conclusion
“a little redundancy in major airport temperature recording doesn’t seem an unreasonable expenditure.”
Safety First!
Stephen Rasey says:
April 15, 2014 at 11:51 am
Stephen: I don’t understand this. If a temperature reading is higher than it should be, air density, therefore lift, will be greater at any speed than what is calculated from the false temperature, am I correct? It seems to me that any RTO decision reached by the book will be slightly more conservative than absolutely necessary, so I don’t understand how a false high reading diminishes safety.
It has something to do with the power-settings of the engine as well. Piston engines, turbocharged and jet engines require sometimes delicate settings to operate properly during take-off and landing(lean/rich/mixture, certain rpm settings etc.).
Air speed(true/indicated) may deviate, the rate of climb calculated wrong.
Not just take-off but landing roll distances as well may be different than expected from the tables.
This, and much more, are all factors a good and professionally acting pilot has to take into his equations and preparations. So it is definitely a matter of SAFETY.
There are old pilots and there are bold pilots. But there are no old, bold pilots.
But don’t worry: what goes up must come down.
@Alan Watt:
You are right. It is an Airport thermometer reading lower than actual that would cause a longer than expected take-off roll and a potentially more dangerous takeoff under loss of one engine.
A thermometer reading too high would be a problem near freezing conditions, but I expect the deicers to be used on other criteria.
My mistake. Thanks for questioning it.
David A says:
April 15, 2014 at 1:33 am
“With the trillion dollar harm already done by these Blackbeard rule the world CAGW nut jobs, we do not have time anymore for the long run.”
You seem to think that facts or the truth would make any difference, irrespective of how quickly we make those idiots in power aware of them. In the US, at least, we have a minimum of three more years of idiots running things, with at best, morons or imbeciles waiting in the wings to take over.
Note:
Though the terms idiot, imbecile and moron were previously scientific terms used to describe IQ’s of 0-70 they have long been abandoned. The term mental retardation has also gone by the wayside as too derogatory. “On October 5, 2010, President Barack Obama signed Senate Bill 2781, known as “Rosa’s Law”, which changed references in many Federal statutes that referred to “mental retardation” to refer instead to “intellectual disability”.”[11] (Wikipedia) It would appear that those in Washington, DC were offended, perhaps due to their personal ‘intellectual disabilities’.
Michael Moon
Eggs fry at 55 C in 20 minutes according to the experiment of The Science Guy. Peak solar insolation at noon approaches 1,000 W/m^2 equivalent to about 90 C of exposed asphalt surface.
Cover the egg to prevent convective cooling by air. Watch this video. That egg looks yummy!
@Dale Rainwater. Strangelove
YOU eat it! I’ll pass. I prefer mine over easy. 😉
“SeaTac is part of the GHCN network used for climate”
WHY? Why on Earth include a site surrounded by a major airport with jets?! According to NOAA, “The Global Historical Climatology Network (GHCN) is an integrated database of climate summaries from land surface stations across the globe that have been subjected to a common suite of quality assurance reviews.” One wonders exactly what that “common suite of quality assurance reviews” includes.
Even if the thermometer in question were absolutely accurate, its readings should never be included in the GHCN.