Synop sunshine hours calibration?

[Keith (Southend)]

I realise I'm about 6 miles to the NW of Shoeburyness (03693) but find the sunshine recorded there is quite a bit higher than mine (IntroMet, replacement bought in the last 6 months), . I wonder what the parameters are as it can often be quite hazy sunshine. I also have a Blake-Larsen which also records, sometimes in just bright skies, yet on the whole is less than the other two.

Has anyone made adjustments to anh factory settings of their sun recording quipment.?

Keith (Southend)

[Keith (Southend)]

################################################## # SYNOPS from 03693, Shoeburyness (United Kingdom) ################################################## ==

202504261200 AAXX 26124 03693 07960 00710 10133 20085 30229 40231 54001 60001 710// 333 55310 60005 91013 90710 91113==

202504261100 AAXX 26114 03693 25962 00807 10138 20079 30231 40233 50004 333 55310 60005 91009 90710 91112==

202504261000 AAXX 26104 03693 27950 00909 10127 20092 30231 40233 51009 710// 333 55310 60005 91011 90710 91112==

Very hazy, but Shoeburyness reports FULL sun hours.

Keith (Southend)

[Nick Gardner]

I've left the Instromet recorder on its factory setting. Is the Shoeburyness recorder right on the coast? Here along the south coast of Devon, the differences in sunshine amounts between the coast and just a few miles inland can be large with the coasts recording far more sunshine. Yesterday was a good example where I recorded pretty much unbroken sunshine all day but looking inland it was cloudy from convectional build up.  

The differences between the Instromet and the BL can be quite stark but I find overall these differences cancel each other out through the year. The Instromet records more in the autumn and winter and the BL more in the spring and summer.

I believe the Met Office uses KZ recorders which operate in a similar way to the BL.

Nick

Otter Valley, Devon.

[Keith (Southend)]

Hi Nick,

Thanks for your reply.

I've never got either the BL or the InstroMet (both old and new) ones to record as many hours as Shoeburyness.

Today the sunshine would have been almost identical as it was a layer of cirro-stratus. Shoeburyness was recording 55310 for every hour throughout the main part of the day.  I've tweaked my InstroMet about mid-day and the readings mirrored that of Shoeburyness. The BL you can make some adjustments, but never enough in my view. I agree that overall Shoeburyness should have more hours, but days like today should be like for like. Shoeburyness does lose the sun before me as there is a bank to the WNW of this site that would block the sun for the last 15 to 20 minutes.

Today Shoeburyness : 8.8 hours

My InstroMet: 8.01 (adjusted late morning so would be more)

My BL: 8.33

https://www.ogimet.com/display_synops2.php?lang=en&lugar=03693&tipo=ALL&ord=REV&nil=SI&fmt=txt&ano=2025&mes=04&day=25&hora=19&anof=2025&mesf=04&dayf=26&horaf=19&send=send

Basically, if there is a clearly defined shadow cast, sun is shining.?

I will monitor closely.

Regards

Keith (Southend

[Nick Gardner]

You can calibrate the BL to kingdom come by typing shift+CALI at the sensor monitor screen. Also, the daily text files can be easily amended if you're missing data. When I last spoke to Ole Larsen, he told me how to set up the calibration. The green line should match the red line when the sun is shining through the clearest of blue skies. Adjust the WIN (pink line) when there is fair weather cloud and the sun goes in, the red line should drop to the same distance to the other side of the pink line that the green line is away from it. I calibrate mine once in the late autumn and once in the late spring time. During prolonged dry weather the sensor glass can get dusty so a calibration check is handy to do. 

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Nick

Otter Valley, Devon.

[Keith (Southend)]

Thanks Nick, you reminded me about this. WHat I found was this pink curve you could move up/down but you couldn't bring it down just at the first and last few hours of the day, quite often the sun was still out but the threshold was too high at hese times. Correct me if I've missed something here. I have just adjusted mine to your settings 36.0, 4.8. Out of interest what are you autumn settings?

Many thanks

Keith (Southend)

[Nick Gardner]

I don't believe there is a way to alter the predicted sunlight curves at post-dawn and pre-dusk, they go up and down when you do the overall calibration. I wouldn't use my calibration settings, each sensor will be slightly different. You should calibrate around midday when the sun is shining through a cystal clear sky and no clouds (these add to the incoming light). I don't have any actual numeric settings for the seasons, I calibrate each time as I have just written.

Nick

Otter Valley, Devon.

[Keith (Southend)]

Thanks Nick,

The InstroMet sensor is my primary one I use for recording, but I will do some closer monitoring. Now I'm retired I'm home more now.

Regards

Keith (Southend)

[Keith (Southend)]

I found an anomaly with my new IntroMet. There is a cable that runs from the box to the display which has a small jack connector at both ends. Yesterday it stopped recording a couple of time, totalling about 50 minutes, and this morning it did the same. Basically the yellow light (Sun) goes off. By fiddling with the jack at the box end, basicalling pulling it very slightly out, the light comes back on and it records again. We're decorating the room so the drains are up, so to speak with my wires, bu this looks like an earth/grounding problem with the connection. I thought my sunshine was down! I can also check when it went off from the 5 minutes data intervals from the logger. Fortunately it's wall to wall sunshine here so should be NO gaps...

Keith (Southend)