My Stevenson Screen is finished

[PaulsInnerChild]

I have just finished my Stevenson Screen
I made it all out of red cedar and I have set the instruments at between 1.35 and 1.45 meters above the ground which is well within the range of 1.2 and 2 meters. The bulbs are 10 centimeters clear of the walls too.
:cheers:

http://img89.imageshack.us/img89/571/screen2ev8.jpg


http://img235.imageshack.us/img235/1460/instruments1dh2.jpg

[Claw Hama]

Nice job PIC but the location dosen't meet the requirements for official recording. Air flow is blocked by the fence, concrete on the ground etc you could have just hung the thermometer on the fence. Sorry to be a wet bulb but it all makes a difference if you are trying to get acurate readings.

[PaulsInnerChild]

Nice job PIC but the location dosen't meet the requirements for official recording. Air flow is blocked by the fence, concrete on the ground etc you could have just hung the thermometer on the fence. Sorry to be a wet bulb but it all makes a difference if you are trying to get acurate readings.

The Melbourne CBD is much worse. It is on the corner of a busy intersection.

Here is another classic http://www.norcalblogs.com/watts/images/lovelock_mig480.JPG
Not only is it surrounded by ashphalt but I just wonder how much the jet exhaust effects the readings.

[PaulsInnerChild]

I also come across this one a lot on the internet and I can't help noticing that huge overhanging eave not only on it but the surrounding buildings.

http://upload.wikimedia.org/wikipedia/commons/thumb/5/50/Stevenson_screen_in_Ikuta_Wooded_Area.jpg/450px-Stevenson_screen_in_Ikuta_Wooded_Area.jpg

[Claw Hama]

Mr Stevenson would be unhappy, I suppose they still give you a more accurate reading of that exact location rather than the ambient of the general area. Happy temps PIC.

[PaulsInnerChild]

Mr Stevenson would be unhappy, I suppose they still give you a more accurate reading of that exact location rather than the ambient of the general area. Happy temps PIC.

The low was 3.1 degreesC last night and it was pretty cold and breezy when I looked. (I also removed a nearby bush to improve air circulation)

:cheers:

[seafurymike]

I need to build one of these as i just bought a wireless weather station.
Does any one know if the Stevenson screen would reduce the wireless range of a transmitter if it was housed within the unit? Unfortunately the transmitter and temp sensor are all one unit.

[AlexS]

I doubt it would reduce the range, but does the transmitter generate any heat?

[PaulsInnerChild]

13.9c was the high today and I have not looked at the official record for out at the Ballarat Airport. But I am sure it would be not too far off.
When I just had the Stevenson Screen sitting on the table before I put it on the post last Saturday the high was 29.3 in my screen and 28.6 at the Airport.
I should expect the nights to be not quite as cold at my place largely due to a slight urban heat island effect ;

:cheers:

[PaulsInnerChild]

Ballarat Aerodrome recorded exactly the same reading I did yesterday at 13.9 degreesC
The minimum last night there was 2.7 and mine was 3.2. (The urban heat island effect probably accounted to the difference there) Looks like the screen is working well with the two Dobbie thermometers in them - the kind they use in BOM. I think there would be no point building a decent Stevenson Screen if you just put a Mickey Mouse thermometer in it

[Johncs]

I need to build one of these as i just bought a wireless weather station.
Does any one know if the Stevenson screen would reduce the wireless range of a transmitter if it was housed within the unit? Unfortunately the transmitter and temp sensor are all one unit.

I'm running my Internet connection via wireless from the house to the office. The lay of the land has made it tricky to avoid rooves, but it's been going througn three brick walls and a glass window: not very quickly, but it got through.

The latest improvement was to move a computer across the office to eliminate two walls, it's no going through a double brick wall at a nasty angle and near square-on to a glass door. I can now get 1.5 Mbytes/sec, about the same as my ADSL connexion.


Over distance, trees (especially when wet) and rain can cause problems: I recall a few years ago there was heavy rain between Melbourne and Geelong in April, it cut the roads off. That would make wireless hard.

[PaulsInnerChild]

This is the temperature data I measured in my Stevenson Screen over the past fortnight
The official Ballarat Aerodrome readings are in brackets
I live in a fairly build up area next to a shopping complex which would account for an urban heat island effect. Like I did not see a trace of white frost on the ground when it was -2.2 at the aerodrome in the open country.
I have a very small back yard, about five meters wide and seven and half meters deep but I have sited it well clear of the house. Even so my figures are pretty close to the Aerodrome readings given that is distance of about 10 kilometers separates us. .
Thursday
7.8 (5.1)
19.6 (19.6)
Friday
6.0 (3.8)
21.6 (23.4)
Saturday
11.3 (8.9)
29.4 (28.5)
Sunday
10.4 (10.4)
18.8 (17.1)
Monday
6.2 (4.9)
14.8 (14.8)
Tuesday
3.1 (2.2)
13.9 (13.9)
Wednesday
3.2 (2.8)
14.0 (13.0)
Thursday
1.3 (-2.2)
21.0 (20.2)
Friday
6.7 (5.0)
26.5 (25.1)
Saturday
13.3 (10.9)
24.4 (24.4)
Sunday
16.1 (16.1)
32.1 (29.7)
Monday
12.3 (9.1)
20.2 (18.0)
Tuesday
8.5 (7.9)
18.3 (17.4)
Wednesday
6.5(5.9)
23.7 (22.8)
Thursday
12.3 (12.1)
28.8 (27.7)