This is not the first time this has happened. And excessively warm temperatures at airport stations seems to be a growth industry around here. In a previous blog I talked about the problem at Yakima--which has been fixed. Ellensburg is running too warm as well.
But this blog will be about Seattle-Tacoma Airport, whose official NWS/FAA temperature sensor is located between two of the runways.
Why should you care about this? Because the official records will be wrong and all kinds of records could be broken because of the bad sensor. And since Sea Tac is the most cited temperatures around here, you will think it is a warmer than it really is. You might even buy an air conditioner.
Let me show you why several of us are worried. First, here is a comparison between Sea-Tac's high temperatures and those of a very close station (SEAT6, located 10 blocks away) for days Sea-Tac got to 90F or more this month (see below). So far this month, Sea Tac got to 90F five times, while SEAT6 did not do it once. On average, SeaTac is 3-5 F warmer than SEAT6 and other neighborhood stations.
There is another way to show the Sea Tac warming--a longer term comparison to another station. Let's compare Sea Tac against Boeing Field. You would expect Boeing Field to be warmer, since it is in the middle of a more urbanized area, within the Seattle Urban Heat Island, and at lower elevation.
Let's first do the comparison for July 1-25, 2014, after the sensor was replaced follwoing the last warm period. Boeing Field was warmer than SeaTac on most days for the highs and nearly all the time for the lows.
This year? Very different. SeaTac generally has higher maximum temps than Boeing Field and the lows are similar...something has changed.
I could provide more evidence...but there appears to be a problem, with Sea Tac being too warm...probably a bad temperature sensor.
Have you noticed that when there are sensor problems, the result are temperatures being too warm? Often that is due to a broken fan, which is supposed to bring fresh air into the sensor unit. If the fan slows or is broken, the enclosure heats up.
Now, an error of several degrees can result in Sea-Tac breaking daily records, or monthly records, or record number of days about 90F, etc. Then the media will headline the records and talk about global warming being the cause.
Don't think this scenario is plausible? It happens all the time--let me give you an example.
Earlier this year, the Yakima airport temperature sensor failed and provided temperatures roughly 3F too warm...which is a lot. The national media noticed. An AP story by Seth Bornstein and Nicky Forster headlines about 30 years of global warming and cites the Yakima warm anomaly as proof of anthropogenic global warming. But it really was only a bad temperature sensor.
Anthropogenic global warming IS warming the planet, but the effects are muted here in the Pacific Northwest.
How much have we warmed ? Let's take a look at the mean daily temperature for July for the NOAA/NWS climate division encompassing the Puget Sound lowlands (see below). Around 62.5F before 1980 and warming to around 64 F the last decade (smoothing out the annual ups and downs)-- so about 1.5F over the past 90 years--and a lot of the change occurred between 1975 and 1985. So July's are warming around here.
Some of this probably was the result of human-caused global warming, but not all. Of particular interest is the major warming during the late 1970s, when circulation patterns were shifting as the Pacific Decadal Oscillation (PDO) moved into its warm mode (the PDO is a mode of natural variability). Human caused global warming is occurring, but it does not explain periods like this week, when we are 10-15F above normal.
I called a colleague at the Seattle NWS office and he said they will check out the SeaTac temperature sensor.
from Cliff Mass Weather and Climate Blog https://ift.tt/2JXpB7A
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