Swanage met station

Posted: October 19, 2015 by tchannon in Surfacestation

Tim writes, on the way back home from a visit to a secluded bay I visited the small Swanage met site.

Swanage weather station.

This is a report, not a site citicism, it’s fair enough for what it is.

Arriving late in the day as the sun touches the local horizon is a bad time for photography, add in exhaustion from earlier, this was going to be a brief look.

The Swanage Met Office AWS reports hourly temperature and humidity, probably rainfall. As a station it is not synoptic, will be based on an old seaside town site, hence some furniture in the enclosure which has nothing to do with the Met Office.

Image

Figure 1 Swanage met station looking SE, this is two joined images .

The site is about 30 ft above sea level on an unstable sloping terrace then with a steep slope to a road, promenade, and sandy beach with breakwaters. Note the low trees in the background, have that windswept look. The land here is sheltered by a ridge from the south-west gales (setting sun is touching the ridge). The tree there implies a more southerly strength and on-shore summer breezes.

In the above enclosure is stone base with decorative post carrying compass points and is leaning, fortunately the instruments are upright. Further down the slope is an asphalt path showing severe stress ripples from ground movement.

Google maps include images from 1945, road layout is the same, beach hut area is still there, terraced housing higher up the slope was not there so it is recent.

A high chain link fence is supported on angle iron posts. This looks fairly new.

There are three rain gauges; Stevenson screen and a sensor I don’t recognise.

A Campbell-Stokes sunshine recorder is on a tall post as is usual at seaside resorts.

Aerial image from Bing, land looks flat, it isn’t.

50.613559° -1.958784°

Google Street view has a problem at the crossroads, gap in the coverage., you can though get a good look, this link might work for a web browser version, you will need to drag the street view icon onto the road near the met site.

 

Image

Figure 2. Campbell Stokes paper strip sunshine recorder. I expect this is for local records.

Image

Figure 3, the rain gauges. One seems to be data connected, is mounted via levelling screws, probably a Munro R102 .

A high fence will alter rain pattern and alter wind profile (keep in mind this is a minor site, not critical).

I didn’t win a coconut. Bet some strange things have over the years been found in gauges. Fence? Ah yes.

Image

Figure 4. What is this sensor? You can see the back of a solar panel, on the left is probably the battery box, and the right the electronics.

There is no visible site mains power feed to the site. I also didn’t spot a transmitter aerial, nor overhead comms line. The site power requirements will be minimal.

 

Image

Figure 5 Stevenson screen, poorly joined pair of images, were not intended for joining. These are PVC screens, likely manufacture will be mentioned in a later article. Grass looks normal for essentially parkland. Weeds under screen are plantains, typical of English lawns. Bottom right is the end of path paving.

Note the drip loops on the cables and plastic conduct descending from the box.

 

Image

Figure 6. The probable way the screen is clamped down onto the angle iron stand. (section of image in deep shadow is enhanced). Has to stay put in 100mph gusts.

The underneath of screens is of interest, needs to be kept clean and act as a barrier to ground heat, including radiative. A problem historically is poor cleaning and the painting of awkward to get at places. Today with AWS there is no daily human oversight.

.Image

Figure 7, top of inner screen at sunset

Image

Figure 8, site looking south. Ridge the other side of town ends in a cliff to the English Channel. We see the last rays of sun as it sinks below a ridge.

Waiting for a chain driven ferry half hour later we saw the sun go down again.

Image

Figure 9, thumbnail of Met Office Datapoint data from the site on the day. Temperature and humidity/dewpoint (pink trace) only.


Post by Tim

Comments
  1. As sites go, Tim, it is not bad, even by official station standards. Thanks for this – I always find station set-ups interesting – just to compare with my own

  2. tchannon says:

    Things on the way wanstead which will be of more than a passing interest to you.

  3. ivan says:

    I assume the WiFi antenna on the solar panel pole is the way they get the information from the station via some public network.

  4. tchannon says:

    WiFi?
    I’d be surprised for a reliable link. (third parties involved)

    The Met Office uses spectrum set aside for meteorological use, get involved with Ofcom, I don’t know is the actual usage for the surface network.

    WMO handbook. (there is a newer draft)
    Use of Radio Spectrum for Weather, Water and Climate Monitoring and Prediction
    Edition 2008
    https://www.wmo.int/pages/prog/www/ISS/Meetings/SG-RFC_Brasilia2008/documents/Draft_HDB_Meteorology_Climate_FINALf.pdf

  5. ivan says:

    Thanks tchannon. That document deals with such things as weather radar, communication with radiosondes and other very long range device communications.

    The reason I said WiFi is because I have installed several such units with antennas that are very like the one in your photo.
    http://www.asiarf.com/uploadfiles/product/1381051285.JPG is typical as is the one in the wikipedia article. https://en.wikipedia.org/wiki/Long-range_Wi-Fi#/media/File:WIFI_Amp_Setup.JPG

    The met office may not be using public WiFi but I would be very surprised if they weren’t using radio in the 2 to 4 GHz range especially for a non prime station.

  6. tchannon says:

    You are right it does suggest a dipole. Only one cable, looks right for coax.

    In effect the site is in a bowl, without a high gain is going to be short range.

    So for want of a better idea that’s a solar powered short range comms system. Aerial high enough to get over the fence.