What instruments are (or were) in the white louvered boxes at Flight Service Stations? The boxes are (or were) about two and a half feet wide and three feet tall, were painted white, made of wood, had louvered sides, and sit (or sat) at a convenient height on four legs. IIRC there was a wet thermometer, a dry thermometer, and a rain gauge (I think). Anything else?
Resurrecting this thread because this post reminded me of it.
Here is a photo of one (in the foreground). Does anyone know all of the instruments it contains, and perhaps have a photo of the inside that shows the layout? My memory hasn’t improved in nearly three years.
thermometer, barometer and hygrometer are common instruments to be inside. it could contain any or all of these or more depending on purpose, usually a thermometer is always there.
it is called an instrument shelter, Stevenson or cotton region shelter.
If you haven’t received an answer in almost 3 years, I guess my 2 cents won’t hurt, even tho I’m not a meteorologist.
I think there are instruments to measure temperature, barometric pressure, and humidity as a minimum. Isn’t that kinda obvious?
And if there are any outside gadgets: rainfall, wind direction & speed.
There are similar devices in the oceans and large lakes that measure all those as well as wave height, wave direction, swell period, water temperature and a few more.
Well, yes, it’s kinda obvious. It’s not that I can’t figure it out; it’s that I’ve seen inside of them many times, but it’s been so long that I can’t remember all that was in them.
As I recall, there was a rain gauge inside of the shelter. I don’t remember how the rain was collected. It could have been collected on top, with a pipe leading to the receptacle. ISTR dad emptying them. Or my memory could be faulty on that point.
I’ve never seen one with an anemometer. Those were on top of the FSS building. I don’t remember seeing barometers inside. These were on consoles inside of the building.
All the ones I’ve seen were in deserts, at airports. Humidity is an important factor in calculating density altitude. But I don’t recall seeing hygrometers. Since they were in deserts, either they were there and I didn’t notice them or didn’t know what they were, or they were not considered necessary in a consistently dry environment, or humidity data was collected elsewhere. All I’ve seen have had both wet- and dry thermometers. Since all the ones I’ve seen have been for the same purpose, I assumed there is a standard layout. But it sounds as if they contain the instruments needed for the application.
Thank you for that. Now I have terms to search on.
it could contain a hygrometer or the humidity calculated from the wet and dry bulb thermometer measurements.
a less accurate but frequently used rain gauge is a tipping bucket rain gauge. the sensor is exposed and the readout would be sheltered.
airports like automated weather collection systems because of the amount of data collected and the time it takes for manual collection. the criteria for collecting weather data for aeronautical purposes and meteorological purposes are different; good enough for flying is what is needed for airports.
Dad retired from the FAA in the early-'90s. It was shortly before that that local FSSs were being closed down and consolidated into regional ‘superstations’. In the '70s and '80s, the Flight Service Specialist (spelled out, since I’m using FSS for Flight Service Station) would go out to the Stevenson shelter and collect the data there. I remember that Daggett Airport also had a spotlight near the Stevenson shelter. This was used at night to determine cloud height. (I only saw it used once – the Mojave Desert being clear much of the time – so I don’t know how it worked. I assume that it was at a fixed elevation and the height was calculated trigonometrically.)
FWIW, the meteorological data in the SA reports were ‘Can Vera Make Tom Dance Without Any Toes?’. That is, Ceiling, Visibility, pressure (Millibars), Temperature, Dewpoint, Wind speed and direction, Altimeter, Trash (remarks).
in the USA the FAA (air transportation regulation) has a criteria for data collection, NOAA (weather bureau) does use that data even though it is not all to their criteria.
airports that can afford it have automated instruments as part of the Automated Surface Observing System so people don’t have to go out and collect data from the instrument shelters.
Aren’t all rain gauges supposed to be enclosed to prevent losses from evaporation and wind action? Or does that not apply to the tipping bucket gauges?
precipitation gauges for accurate measurement are cylinders out in the open. in warm weather when expecting only liquid rain there is a funnel on top.
a tipping bucket is fed by a funnel. rapid high volume rain can give a low measurement because of splash and unmeasured spillage.
I think I was mistaking the need for barriers like the one seen in the photo here for the need to enclose the rain gauge (which apparently doesn’t exist.)
ETA: The text below the picture refers to an ‘attachment’ that is not the vertical barriers I meant - just mentioning that because the feature I’m referring to in the picture isn’t the one referred to in the text.