“Differences in the average daily temperature minima (nighttime) of San Antonio relative to New Braunfels for the summer months from 1946 to 1990 (dark line). The warming trend due to the UHI in San Antonio is shown by the red line, which represents a least-squares fit to the data.”
“The UHI effect itself may be an important contributor to the investigation of global warming. Most temperature measurements are made at weather stations located at airports, which are intense heat islands because of their long runways, terminals, large parking lots, and buildings. A question thus arises about the significance of these measurements influenced by the UHI in relation to global warming.”
Looks like they are making an argument against the global warming nonsense by showing most of the measurements are simply showing the UHI, though they stop short of specifically saying the doom merchants are pedaling false information.
But they do show what I have been harping on forever, which is airport weather stations are critical safety factors for aviation, both general and commercial. it is critical to know the actual air temperature, pressure, dewpoint and wind speed and direction for planes to safely take off and land. And for that purpose they are correctly sited and maintained and monitored. In fact you can obtain the near real time values (updated every 30-60 minutes) from automated radio broadcasts and online, each of the ~67,000 airports worldwide.
https://metar-taf.com/
So these weather data at airports are fit for the purpose of aviation safety, but are not fit for the purpose of gauging climate change – due to UHI.
(to clarify just how important accurate temperature and pressure data is, all aircraft from the smallest to the largest have both charts in the POH [Pilot’s Operating Handbook] and often apps in their EFB [Electronic Flight Bag] which show both takeoff and landing distance required for a range of gross weight, temperature, altitude and pressure. A difference of +5 degrees can mean a plane needs more runway than is available to take off, or land, in the current conditions so it’s super important to know the actual air data on the actual runway)
Sorry for the rant, but I so often see well meaning folks learn about the UHI at airport stations and say we need to move them away from these heat islands. That is wrong headed, the airport weather stations are where they need to be for their intended purpose, which is aviation safety. They are not the right data to use or mix in with climate monitoring or assessing exercises.
For more insights into the UHI read https://www.drroyspencer.com/2021/02/urban-heat-island-effects-on-u-s-temperature-trends-1973-2020-ushcn-vs-hourly-weather-stations/
San Antonio Area city, 412 square miles (1,067 square km).
On summer days in San Antonio, each degree above 70 degrees Farenheit requires an additional 60 megawatts of power from San Antonio’s electric power utility.
Retail power (lights, heating / cooling) all goes to waste heat.
60,000,000,000 W / 1,067,000 SqM = 56,232 W/m^2 for each each degree of temp over 70.
56K W/m^2 or a few extra CO2 molecules? You decide. Then let’s talk about the cars, trucks and busses.
oops, you got the conversion from km² to m² wrong by 1,000. So the power per degree over 70F is 56.23 W/m²… there are 1,000,000 square meters in a square kilometer.
And in addition to your arithmetic error, not all of that 60 MW is dissipated as heat. Lights and electric motors only dissipate maybe 10-15% of their input power as heat – the rest produces light or mechanical work.
So that 56.23 W/m² input to the electric grid is really only 6 or 7 W/m² dissipated as heat.
Hang on, something about your official numbers does not pass the smell test…
San Antonio has 535,610 housing units.
https://www.point2homes.com/US/Neighborhood/TX/Bexar-County/San-Antonio-Demographics.html
Presumably normal electricity use is not tied to temperature, only air conditioning would be above 70F. Now a typical home air conditioner system would draw 3,500 watts when running, and properly sized ones would run for 30% of the time under light load (70F), and perhaps 50% of the time under heavy loads.(95F ) (as mine does here in South Florida)
So 535,610 x 3,500 is 1,875 MW when all air conditioners are on. But at 70F they’re on only 30% of the time so that is 563 MW when air temps are 70F. And at 95F they are on for 50% of the time making the power draw 938 MW,
So the difference between 95F and 70F is 25 degF, and the load increase is 938-563 which is 375 MW. So 375/25 is only 15 MW per degree over 70F.
I think those official numbers are exaggerated, because if we use the 60MW increase in power consumption for every degree above 70F, then at 95F that puts all the air conditioners are 80% of the maximum power draw, meaning they are on for 80% of the time, which is not plausible.
Granted my back of the envelope cross check has not included commercial and office space air conditioning, but that is perhaps only 10% more energy required than all the domiciles. So again the official numbers from San Antonio’s electricity provider does not pass the smell test.