Topic: Barani MS Pro vs SmartCellino radiation shield comparison

[hmderek]

Interesting. While I have also seen very little difference between the two shields, my data seems to indicate a better response time for the Barani. Very subtle though, so hard to make any hard statements.

[ypsinine]

my data from yesterday

M. [ You are not allowed to view attachments ]

This is interesting with regards to the "low sun in the horizon" effect with the Barani.
I looked up your location coordinates in the pdf and plotted them into the calculator:
https://www.timeanddate.com/sun/@43.6499225,13.3296084

If we look at these two time spans from your pdf that has the biggest T deviation:
9-10 -0,14
10-11 -0,14

15-16 -0,11
16-17 -0,19

According to the calculator linked above: for the 9th of October, the sun is between 17 and 34 degrees above the horizon during 09-11 clock.
And it is between 32 and 15 degrees above the horizon during 15-17 clock.

Maybe this overheating effect occurs in the Barani during this specific angle of the sun on the horizon, somewhere around 15 to 34 degrees, where the sun can somehow get into the shield sideways?
I also notice the Barani shows higher humidity. Perhaps this is related somehow.

[tobyportugal]

Finally, we're taking a rational approach to the problem! I had repeatedly asked for the height of the sun to be added.
With this link a CSV file is possible to be perfectly in phase with the data.

https://www.sunearthtools.com/dp/tools/pos_sun.php?lang=fr


On the subject of humidity, I'd like to repeat that I've spoken to Jan Barani about this on several occasions (in Portugal, humidity is important).
This was confirmed by someone at IPMA.
But nobody here is paying any attention.

[ypsinine]

I have been rather disappointed about the Barani performance compared to a lot of both professional and amateur weather stations around my area, none of which (as far as I know) use the Barani.
This feeling has been amplified around the hours during sunrise and sunset. That is why the SmartCellino has peaked my interest. Or maybe the correct choice at 60° N is an active shield like the Davis?
There is not much wind at my location either, which I think is part of the problem...

So for fun one week ago I put up an old TFA outdoor sensor on the north side of my property where it is shielded from the sun all day, just behind a shed in the garden.
Today after days of clouds there is finally a clear sky now and a good time to compare the two.

Barani vs always-shaded TFA sensor:
 [ You are not allowed to view attachments ]

0.9 degree C is too big a difference for me to feel comfortable about my setup.
At first I thought I had the Barani mounted too close to the ground at 185 cm so I raised it to 200 cm (also to be at the WMO recommended height) but I can't really see any difference - which makes sense if the height wasn't the problem to begin with, but rather the radiation hitting inside the shield at low sun altitudes.

edit: I will add that the picture was taken at 12:47 today and that puts the sun at 22 degrees above the horizon (60° N). The Meridian was just a minute before at 12:46 so the sun is already getting lower from this point onward.

[mauro63]

my data from yesterday

M. [ You are not allowed to view attachments ]

This is interesting with regards to the "low sun in the horizon" effect with the Barani.
I looked up your location coordinates in the pdf and plotted them into the calculator:
https://www.timeanddate.com/sun/@43.6499225,13.3296084

If we look at these two time spans from your pdf that has the biggest T deviation:
9-10 -0,14
10-11 -0,14

15-16 -0,11
16-17 -0,19

According to the calculator linked above: for the 9th of October, the sun is between 17 and 34 degrees above the horizon during 09-11 clock.
And it is between 32 and 15 degrees above the horizon during 15-17 clock.

Maybe this overheating effect occurs in the Barani during this specific angle of the sun on the horizon, somewhere around 15 to 34 degrees, where the sun can somehow get into the shield sideways?
I also notice the Barani shows higher humidity. Perhaps this is related somehow.

Thanks,

you could be right, and I thank you for the excellent research work, but we must take into account an important aspect, my position is affected by a strong value of site-specificity.

Even though I am on a meadow, in a hypothetical WMO classification my level introduces a notable uncertainty that must be added to the instrumental uncertainty, the proximity of medium-sized plants, and a house, even if a modest-sized villa about 10 meters away, puts me in a probable class 4.

There may be situations or conditions of particular disturbances that can mislead during the analysis phase.

M.

[mauro63]

I have been rather disappointed about the Barani performance compared to a lot of both professional and amateur weather stations around my area, none of which (as far as I know) use the Barani.
This feeling has been amplified around the hours during sunrise and sunset. That is why the SmartCellino has peaked my interest. Or maybe the correct choice at 60° N is an active shield like the Davis?
There is not much wind at my location either, which I think is part of the problem...

So for fun one week ago I put up an old TFA outdoor sensor on the north side of my property where it is shielded from the sun all day, just behind a shed in the garden.
Today after days of clouds there is finally a clear sky now and a good time to compare the two.

Barani vs always-shaded TFA sensor:
 [ You are not allowed to view attachments ]

0.9 degree C is too big a difference for me to feel comfortable about my setup.
At first I thought I had the Barani mounted too close to the ground at 185 cm so I raised it to 200 cm (also to be at the WMO recommended height) but I can't really see any difference - which makes sense if the height wasn't the problem to begin with, but rather the radiation hitting inside the shield at low sun altitudes.

edit: I will add that the picture was taken at 12:47 today and that puts the sun at 22 degrees above the horizon (60° N). The Meridian was just a minute before at 12:46 so the sun is already getting lower from this point onward.

Sorry but you can't compare a screen correctly positioned in the sun and a sensor placed in the shade, it's totally unscientific.

M.

[tobyportugal]

I have been rather disappointed about the Barani performance compared to a lot of both professional and amateur weather stations around my area, none of which (as far as I know) use the Barani.
This feeling has been amplified around the hours during sunrise and sunset. That is why the SmartCellino has peaked my interest. Or maybe the correct choice at 60° N is an active shield like the Davis?
There is not much wind at my location either, which I think is part of the problem...

So for fun one week ago I put up an old TFA outdoor sensor on the north side of my property where it is shielded from the sun all day, just behind a shed in the garden.
Today after days of clouds there is finally a clear sky now and a good time to compare the two.

Barani vs always-shaded TFA sensor:
 [ You are not allowed to view attachments ]

0.9 degree C is too big a difference for me to feel comfortable about my setup.
At first I thought I had the Barani mounted too close to the ground at 185 cm so I raised it to 200 cm (also to be at the WMO recommended height) but I can't really see any difference - which makes sense if the height wasn't the problem to begin with, but rather the radiation hitting inside the shield at low sun altitudes.

edit: I will add that the picture was taken at 12:47 today and that puts the sun at 22 degrees above the horizon (60° N). The Meridian was just a minute before at 12:46 so the sun is already getting lower from this point onward.

Wanting to compare your station with others, even in the region, is rather bizarre.
I think there are people here (Italy, France, Holland, Portugal, .... ) who have an impressive number of shelters (Barani, Apogée, Rad, Comet,...) and what do the majority say? I'll leave the talking to others.

[Jasper3012]

I have been rather disappointed about the Barani performance compared to a lot of both professional and amateur weather stations around my area, none of which (as far as I know) use the Barani.
This feeling has been amplified around the hours during sunrise and sunset. That is why the SmartCellino has peaked my interest. Or maybe the correct choice at 60° N is an active shield like the Davis?
There is not much wind at my location either, which I think is part of the problem...

So for fun one week ago I put up an old TFA outdoor sensor on the north side of my property where it is shielded from the sun all day, just behind a shed in the garden.
Today after days of clouds there is finally a clear sky now and a good time to compare the two.

Barani vs always-shaded TFA sensor:
 [ You are not allowed to view attachments ]

0.9 degree C is too big a difference for me to feel comfortable about my setup.
At first I thought I had the Barani mounted too close to the ground at 185 cm so I raised it to 200 cm (also to be at the WMO recommended height) but I can't really see any difference - which makes sense if the height wasn't the problem to begin with, but rather the radiation hitting inside the shield at low sun altitudes.

edit: I will add that the picture was taken at 12:47 today and that puts the sun at 22 degrees above the horizon (60° N). The Meridian was just a minute before at 12:46 so the sun is already getting lower from this point onward.

Don’t let a suspicion fool you into thinking the Barani is a poor shield, it is an excellent shield. The low sun thing is mostly a wind thing, I’ve gotten shortlasting 0.5-1C errors when the sun was 40 degrees in the sky but with no wind. On the other hand, I’ve had plenty of times with a very low sun angle but no error due to a breeze. Like Mauro said, your testing with a shaded sensor is pretty much worthless as shaded areas are significantly cooler than sunny areas, regardless of a radiation shield error. It’s almost certain that at least some of your 0.9C difference is explained by an actual difference in air temp.

[mauro63]

I have been rather disappointed about the Barani performance compared to a lot of both professional and amateur weather stations around my area, none of which (as far as I know) use the Barani.
This feeling has been amplified around the hours during sunrise and sunset. That is why the SmartCellino has peaked my interest. Or maybe the correct choice at 60° N is an active shield like the Davis?
There is not much wind at my location either, which I think is part of the problem...

So for fun one week ago I put up an old TFA outdoor sensor on the north side of my property where it is shielded from the sun all day, just behind a shed in the garden.
Today after days of clouds there is finally a clear sky now and a good time to compare the two.

Barani vs always-shaded TFA sensor:
 [ You are not allowed to view attachments ]

0.9 degree C is too big a difference for me to feel comfortable about my setup.
At first I thought I had the Barani mounted too close to the ground at 185 cm so I raised it to 200 cm (also to be at the WMO recommended height) but I can't really see any difference - which makes sense if the height wasn't the problem to begin with, but rather the radiation hitting inside the shield at low sun altitudes.

edit: I will add that the picture was taken at 12:47 today and that puts the sun at 22 degrees above the horizon (60° N). The Meridian was just a minute before at 12:46 so the sun is already getting lower from this point onward.

To be more precise and exhaustive, I will better explain the two different types of problem trying to be very practical and apologizing for any errors due to my rather approximate English.

- the comparison with nearby stations is useless, different positioning, different orography, different height and/or exposure, different roughness of the terrain and relative impact on ventilation etc. etc. make the comparison useless

- a sensor constantly in the shade will never be able to provide data on the air temperature if not in a frighteningly approximate way.
Solar screens were born with two main functions, to protect the sensor from rain, hail etc and to protect it from direct, diffuse and reflected solar radiation.
The air is transparent to radiation, it does not heat up in the sun, what heats up is everything it hits, lawns, roads, houses, water and obviously the screens and, if these are not of adequate quality, the sensors inside them.
Each of these components, and many others, has its own thermal characteristics, the soil and the sea, in particular, are the most important, they are those that determine, by convection, the temperature of the air already in the first layers above the ground, in decreasing measure as one moves away from it
If an area of ​​the ground is totally in shadow, the data on the temperature of the air above it are totally useless except for personal research purposes.

M.

[ypsinine]

Sorry but you can't compare a screen correctly positioned in the sun and a sensor placed in the shade, it's totally unscientific.

M.

I agree, it is unscientific. And I put it there mostly out of curiosity. 

Don’t let a suspicion fool you into thinking the Barani is a poor shield, it is an excellent shield. The low sun thing is mostly a wind thing, I’ve gotten shortlasting 0.5-1C errors when the sun was 40 degrees in the sky but with no wind. On the other hand, I’ve had plenty of times with a very low sun angle but no error due to a breeze. Like Mauro said, your testing with a shaded sensor is pretty much worthless as shaded areas are significantly cooler than sunny areas, regardless of a radiation shield error. It’s almost certain that at least some of your 0.9C difference is explained by an actual difference in air temp.

During the past half hour, the wind has increased from an average of 1 m/s to 1.5 m/s and funnily enough the Barani now shows 0.2 lower temp than the shaded sensor.
I think low winds are the problem in my location - you are probably right. Maybe I can somehow mount a fan to my shield. I will think about this...

[Meteorology fan]

@ypsinine - take a look at the Apogee TS100 and the Davis FARS24H. Plug a constant power supply into them, then you will see the differences in low wind conditions when you compare with the Barani Meteoshield Pro III. On aspirated shields nights also have an advantage. In Poland in winter, radiation errors can exceed as much as 2 degrees in snowy weather and low wind conditions, as well as lingering Arctic air and the presence of low-angle sunlight.

The important thing is to strip the Sensirion SHT35 filters and give analogous sensors to the Barani Meteoshield Pro III and Davis FARS24H or Apogee TS100. On a single mast, this can be duplicated further with high-end resistance sensors like PT100 and PT1000. Some diagrams below.

https://www.wetterladen.de/Bestrahlungsschutzschild-6831-mit-24-Stunden-Aktivbelueftung

https://www.apogeeinstruments.com/ts-100-ss-12-v-aspirated-radiation-shield-shield-only/

[Jasper3012]

Annoyingly, it’s a cloudy evening here, despite a lot of clear spells nearby and pretty much no wind. Could’ve been a good test to see whether there’s any difference between the shields with the dreaded low wind/low sun angle combination. I’ll post an update if anything changes.

[Meteorology fan]

Jasper3012 - it would be interesting to compare Davis FARS24H, Barani Meteoshield Pro III and Apogee TS100 and SmartCellino side by side long term. With analogous and accurate sensors at one altitude. The Apogee TS100 arrived a few days ago, I was persuaded by colleagues in Poland and I will be checking the Davis FARS24H and Barani Meteoshield Pro III long term. At my place I plan to put Sensirion SHT35 without filters and PT1000 calibrated with logger, but not before next week. In my opinion, the Apogee TS100 is several classes above the Barani Meteoshield Pro III after what I have seen from fellow testers.

[Jasper3012]

That’s the intention but I only have 2 sensors at the station now. The person that can get me a third is busy at the moment.

Correction: it’s my intention to get a 3rd sensor to install the Davis but I’m not getting an Apogee. I think I’d rather invest in upgrading my current Davis with a stronger fan and a battery that’s sufficient for it to run 24/7 even in the depths of winter.

[Meteorology fan]

I will be testing the long-term performance of the FARS in the Davis FARS24H against the Apogee TS100 under various conditions, having the Barani Gen III right next to it, to catch the possible shortcomings of each shield. Response time will also be interesting to investigate, as I am throwing in the TS100 PT1000 with its high accuracy class and low response time, plus remote recording every 1 minute and logger synchronisation every 1s with local time. Sensirion SHT35 as an additional sensor and curiosity without filters in Apogee, Davis and Barani.

For the Davis FARS24H I already have a fixed power supply arranged and a programmer for a fixed power supply and an additional spare battery. The Apogee TS100 will be hooked up to a 12V constant power supply with a manual voltage regulator, maybe in the future I will expand this with an additional pyranometer.

[mauro63]

I think should be useful to have some pictures about all installations on test

M.

[Jasper3012]

Already posted mine earlier in this thread, it’s pretty much as open as you can get. This is in favour of the Barani, as it generates higher wind speeds.

[mauro63]

Already posted mine earlier in this thread, it’s pretty much as open as you can get. This is in favour of the Barani, as it generates higher wind speeds.

I know, I'm referring to the others users, to give impressions or others we need to know the conditions about the installation, or are unuseful

M.

[mauro63]

Already posted mine earlier in this thread, it’s pretty much as open as you can get. This is in favour of the Barani, as it generates higher wind speeds.

You see,

going back to a previous post of mine, knowing the status of an installation is essential to be able to consider the data it publishes, the observations made, the defects found or the positive aspects, which can often be the result of a distorted vision, not because it is done in bad faith but because of an inability to manage the behavior of disturbances and unwanted thermal transfers, as wanted or not.

If we want to measure the air temperature, it is likely that with a Barani, purely as an example, we will have a data presumably quite close to the measurand, which is the air temperature, but if we want to compare different solar radiation shields, and even more so if they are of high and similar quality, the measurand is no longer the air temperature but the difference between their readings.

Ergo, if your station, in addition to the instrumental uncertainties, introduces a further uncertainty due to the installation, the amount of your uncertainty will be greater than the measurand, and when this happens you can stop wasting time, you are not measuring anything

Therefore, if I read negative comments, evidence of defects of one screen compared to another but I am not clear about the uncertainty of that installation, I cannot consider everything I read reliable.

M.

[Jasper3012]

Barely any wind here at the moment with clear sky and therefore a good moment to see the responsiveness of the shields... SC still seems to be slightly faster.

 [ You are not allowed to view attachments ]

[mauro63]

Barely any wind here at the moment with clear sky and therefore a good moment to see the responsiveness of the shields... SC still seems to be slightly faster.

 [ You are not allowed to view attachments ]

You see, this is also an extremely difficult situation to evaluate, because we need always starts from a basic concept, indisputable, but that some still do not accept, we do not really know the measurand.

You could be right, Siap could be more reactive, if in fact at that moment the air temperature is actually decreasing, and we do not know it, or it could be a mistake, the Siap could not adequately protect the sensor from night radiation.

The allies in fighting night radiation are the clouds and the wind, and you have neither of them at the moment.

So, always start from doubt, do not take for granted what you absolutely cannot demonstrate, this is a wonderful field, but it requires humility and respect.

It is preferable to say "in these conditions A is colder than B" or "B is warmer than A" as usually happens in comparisons carried out by official institutions, not "better", or "worse".

M.

[tobyportugal]

One example among many, just look for the documentation on metrology.

https://www.baranidesign.com/faq-articles/2022/7/28/how-to-properly-perform-solar-radiation-shield-comparisons-for-weather-stations

[Kallo78]

Finally, we're taking a rational approach to the problem! I had repeatedly asked for the height of the sun to be added.
With this link a CSV file is possible to be perfectly in phase with the data.

https://www.sunearthtools.com/dp/tools/pos_sun.php?lang=fr


On the subject of humidity, I'd like to repeat that I've spoken to Jan Barani about this on several occasions (in Portugal, humidity is important).
This was confirmed by someone at IPMA.
But nobody here is paying any attention.

It is not easy to represent the elevation line in a graph that already has 2 vertical axes. Do you know how to do this?

[Kallo78]

My Yesterday report


 [ You are not allowed to view attachments ]
 [ You are not allowed to view attachments ]

[tobyportugal]

It is not easy to represent the elevation line in a graph that already has 2 vertical axes. Do you know how to do this?

To my knowledge, it is not possible to have 3 vertical axes in an Excell graph.
There is a solution of superimposing two graphs, but with the large amplitude of the 3rd axis it's not very easy to read.
On the other hand, the most useful data is the spreadsheet data. With perfect dating, it's easy to see if an anomaly is recurring.
When I get back to Portugal, I'll post an example of the graph I made.
Edit: The clarity problem is due to the vertical amplitude on half of the horizontal axis, so it's not very precise.