I’ve mentioned problems with airports as climate stations in the past, mostly that they are pockets of UHI that have grown with the 20th century aviation boom. A good example is Chicago O’Hare airport. I’ll bet that many of you don’t know that the ICAO ID for O’Hare, is KORD, and FAA uses ORD which is what you see on airline luggage destination tags. “ORD” has nothing to do with the name O’Hare, which came after the airport was established. It has everything to do with the name “Orchard Field” which is what the airport started out as, which at the time was far more rural than it was now. You can read about its early history here.
Here’s that same view today from Google Earth:
Look at O’Hare today, a sprawling megaplex of concrete and terminals surrounded by urbanization:
The weather station location above is designated by the orange pushpin. Here’s a closeup view:
Note that there’s two electronics equipment buildings nearby with industrial sized a/c exhaust vents. While not USHCN, NCDC metadata lists O’Hare as a Class “A” station, which means it does in fact record climate. Data from O’Hare can be used to adjust other stations with missing nearby data.
The point I’m making with all the photos is that airports are far from static, especially since airline deregulation in the 1980′s. The are just as dynamic as the cities they serve. We measure climate at a great many airports worldwide. E.M. Smith reports that the majority of the GHCN record is from airports.
Even NOAA meteorologists admit that airports aren’t necessarily the best place to measure climate. In a series of stories I did…
How not to measure temperature, part 88 – Honolulu’s Official Temperature ±2
..about the failure of the aviation weather station at Honolulu causing unparalleled record highs, the NOAA Meteorologist there had this to say:
“ASOS…placed for aviation purposes…not necessarily for climate purposes.”
The key issue here is “aviation purpose, not climate purposes”. The primary mission is to serve the airport. Climate is a secondary or even tertiary consideration. And that’s exactly what happened in the story from the Baltimore Sun below. The observer used FAA guidelines rather than NOAA guidelines to measure snow for the climate record. NOAA doesn’t like the record because he didn’t follow their procedures, so they toss it out.
However, when a new high temp record is set in Honolulu due to faulty equipment, NOAA thinks THAT’s alright to keep in the records:
A nearby station shows the error:
Sat 20 Feb 2010
A contractor working for the Federal Aviation Administration at BWI Thurgood Marshall Airport, paid to measure the snow for the aviation industry’s needs, did not follow a separate protocol required by the National Weather Service and the National Climatic Data Center for valid climate data.
So while the contractor measured 28.8 inches of snow during that storm, the National Weather Service has thrown out the reading. Instead, climatologists will rank the storm as “only” 24.8 inches – a number that almost surely understates the “true” total.
Worse, for climatologists, it now appears the weather service’s rules for snow data had been ignored for years at BWI, throwing a cloud over the validity of snow totals as far back as 1998, when the FAA took the job over from the weather service.
Only BWI’s data are known to be affected, but the problem could be more widespread. That possibility has caught the attention of top officials at the FAA.
“We plan to meet with the National Weather Service next week to begin a discussion on making sure that we’re all on the same page in terms of measuring snow accumulations at our airports,” FAA spokesman Jim Peters said. “There will be a national discussion.”
In the meantime, the weather service’s Baltimore- Washington Forecast Office in Sterling, Va., is preparing to convene a committee of climatologists and other experts to review Baltimore’s snowfall records from the 2010 and 2003 storms, and perhaps back to 1998.
“I feel very strongly about historical records and getting the climate data correct,” said James E. Lee, the meteorologist-in-charge at Sterling. “Obviously, with the increased media attention and political attention to climate, it is really up to NOAA [the National Oceanic and Atmospheric Administration, of which the National Weather Service is an agency] to make sure … the climate record is a genuine one, and consistent to the best of our ability.”
The problem at BWI came to light Feb. 6, as snow accumulations reported at the airport passed 26 inches. They seemed poised to break the record set in February 2003 – the storm listed on Sterling’s Web site as Baltimore’s biggest.
But when reporters called asking about a new record, Lee said that because of measurement errors by an FAA contractor at BWI, the two-day storm total would be pegged at “only” 24.8 inches. He had discarded a 28.8-inch measurement from BWI because it was the sum of hourly measurements throughout the storm – a method invalid for climatological data.
Even at 24.8 inches, Lee said, the storm total beat the previous two-day record of 24.4 inches, set at BWI during two days of the four-day 2003 event. “I’m convinced that was the most amount of snow Baltimore has seen [from a two-day storm] in recorded history.”
But Lee had to use the most conservative reading from the airport – a “snow depth” measurement of the total on the ground when the storm ended, after hours of compaction.
The FAA requires its observers to take hourly snow measurements and wipe the boards clean after each hour, adding the totals as they go. That provides pilots with better real-time information about changing conditions. But it virtually eliminates compaction and so inflates accumulation. Climatologists require measurements every six hours, striking a balance between the hourly and snow depth readings. Some airports maintain separate snow boards for the different protocols. But not BWI.
Richard Carlson, vice president of Pacific Weather Inc., said his company has experienced weather observers at 20 U.S. airports, including eight at BWI. Pacific has held the contract there since 2008.
“We follow the FAA manual … and that is the guide book on how these meteorological observations are to be taken,” Carlson said. “We had heard about the six-hour measuring thing, but … if you have high winds at all, this really is not going to work.”
Read the full article at the Baltimore Sun
Read Frank Roylance’s blog on MarylandWeather.com