Topic: Barani: too good to be true...

[Meteorology fan]

Wind gusts reach around 5-9 km/h in my valley today. As you can see, Barani keeps overheating for several hours after sunrise. If a front had passed at this point, Barani would have ended the day with an inflated maximum air temperature.

[ivano]

Wind gusts reach around 5-9 km/h in my valley today. As you can see, Barani keeps overheating for several hours after sunrise. If a front had passed at this point, Barani would have ended the day with an inflated maximum air temperature.

Hi, it distorts the temperature data in moments when the wind is very low or absent, compared to a ventilated screen, but this is obvious, try to think the opposite, on a day with higher winds 10/15 km/h would be the fars to distort the temperature value, therefore it is essential to design the weather station based on the place where it is installed, if it is an area where the wind is almost absent, it is obvious that you have to put a ventilated screen there, if instead it is located in a hum fairly ventilated area should be a passive screen,  [ You are not allowed to view attachments ]  if you look at the graph I can say that it is the fars that distorts the temperature data when the wind starts to blow  

[Jasper3012]

Wind gusts reach around 5-9 km/h in my valley today. As you can see, Barani keeps overheating for several hours after sunrise. If a front had passed at this point, Barani would have ended the day with an inflated maximum air temperature.

The FARS has the same kind of error but during the time of day where the max is actually recorded and on a much more frequent basis, so you end up with an error much more frequently than with the Barani.

[Jasper3012]

Second time in 24 h that the temp drops a lot quicker in the Barani compared to the FARS during a heavy shower, up to a 0.8C difference even (13.8C vs 14.6C). Not sure why this is? You'd expect the opposite with the active ventilation of the FARS generating a quicker response time.

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[bianconero57]

  what time constant of your sensors
because it continues to not be clear at all 
what do you have as a WMO reference 

[Jasper3012]

20 sec at 1 m/s , probe measures every 8 sec and the reported min and max are the lowest and highest 1 min averages

[Jasper3012]

Updated graph with the comparison. The graph itself should be clear but I'll explain it again here, the blue line is the difference in the recorded min, with a negative value representing a cooler value on the Barani and a positive value a cooler value on the FARS. In this case, you'll (mostly) see a positive value for the blue line, indicating that the FARS is usually cooler than the Barani. The red line is the same but for the recorded max, you'll see that the Barani usually gets a cooler value. The difference between the two with both min and max has been shrinking in recent days due to the very poor weather here, a lot of cloud and wind, which tends to generate more equal temps between the shields. The summer overall has been poor and that will have suppressed the difference between the shields. Nevertheless, the Barani has so far been the clear winner by day, with the FARS performing slightly better than the Barani by night.

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[Jasper3012]

Not directly relevant for this thread but to indicate how poor it has been here... which in turn does influence the comparison obviously. Very cool, wet and not much sun at all.

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[bianconero57]

  hmm is your probe from your Davis 24h shelter also the one with a constant of 20s/1m/s 

[Jasper3012]

Yes, the exact same probe as the MS Pro.

[Jasper3012]

First hot day of the year here with light wind (often around 5 km/h) and strong sunshine, so some of the most challenging conditions you’ll get here for a passive shield. Max of 30.4C on the Barani and 30.7C on the FARS, so it withstood the test very well. What I’ve noticed over the past few months during sunshine is the following: with 0-5 km/h of wind, the FARS often outperforms the Barani (although still only by a small margin 99% of the time), with 5-10 km/h there is very little difference between the shields and with 10 km/h+ the Barani outperforms the FARS (and by a bigger margin usually than the opposite at the 0-5 km/h scenario). This conclusion seems to match up rather well with what others in this thread have found so I honestly don’t think there’s that much more to add. Will keep updating this thread if I find some more interesting things to share.

[tobyportugal]

First hot day of the year here with light wind (often around 5 km/h) and strong sunshine, so some of the most challenging conditions you’ll get here for a passive shield. Max of 30.4C on the Barani and 30.7C on the FARS, so it withstood the test very well. What I’ve noticed over the past few months during sunshine is the following: with 0-5 km/h of wind, the FARS often outperforms the Barani (although still only by a small margin 99% of the time), with 5-10 km/h there is very little difference between the shields and with 10 km/h+ the Barani outperforms the FARS (and by a bigger margin usually than the opposite at the 0-5 km/h scenario). This conclusion seems to match up rather well with what others in this thread have found so I honestly don’t think there’s that much more to add. Will keep updating this thread if I find some more interesting things to share.

This is the reason for the development of FARS Barani.
As this is a "solar" FARS, it can be used without ventilation, which is not the case with "permanent" FARS.
The future will tell whether this technical choice is the ideal marriage of the two worlds (Passive/Active) without the constraints.

[Jasper3012]

I’m very skeptical about Barani’s FARS as that involves lots of electronics probably and Barani has a very poor record with that. Happy to be proven wrong but I don’t see why this FARS won’t start failing after 1-2 years like the MeteoHelix.

[Dador]

I have been testing Davis FARS together with Barani for a few days now. Both are at a height of 2 meters above the ground, on the same pole.

Place: Garden
Heigh: 2 meters above ground

FARS
Sesnor: Davis SHT31 (old version)
FAN: 12V, 29 CFM
Log interval: 5 min

BARANI
Sensor: Davis SHT31 (new version)
FAN: ----
Log interval: 5 min

27.07.2024

                 Barani              FARS
Tmax -      31,4*C            31,6*C
Tmin -       15,2*C            15,6*C
Tavg-         24,5*C            24,7*C

Below is yesterday's comparison chart. Wind speed is measured right next to the shields, by a Davis sensor.

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Below is a graph from an episode of heavy rain combined with wind. The rain fell intensely, briefly and at quite a large angle. The chart shows how FARS quite quickly after the precipitation passed, began to read about 1*C higher to Barani. This is where I believe that the shield has overcooled in Barani due to water getting inside. Evaporation lowered the temperature in Barani. In such a case, FARS, as a dry shield, read the current temperature better, even though it was higher.

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[Jasper3012]

Biggest error I've recorded to date this morning with the Barani, up to 1.1C. Wind was at 0 km/h with no cloud at all and a low sun angle, so very hostile for the Barani. No impact on the min and max but notable regardless.

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[Meteorology fan]

@Jasper3012 In winter and autumn, similar and larger measurement error in the Barani Gen III shield can persist during sunny weather for many days in Poland, projecting average and maximum values. In summer, it overlaps most of the time with the Davis FARS24H and Apogee TS100. In general, the Barani shield is not served by high weather with low winds, like any passive shield.

Barani also simply does not like low-angle sunlight, a fact that the shield maker has painstakingly hidden from customers and has not eliminated this problem in the Ms Pro III.

[bianconero57]

Barani also simply does not like low-angle sunlight, a fact that the shield maker has painstakingly hidden from customers and has not eliminated this problem in the Ms Pro III.

  and pass the criticism on to the manufacturer, right  just a question 

[Meteorology fan]

Barani knows this very well and nowhere does he indicate this, not even in small print and he should indicate under which conditions his shield does not present representative results.

[Jasper3012]

Today was the first day in 2.5 months of testing where the Barani had a higher max than the FARS, albeit only by 0.1C (29.5C vs 29.4C). There was again very little wind (<1 m/s) up until a moderate sea breeze arrived, after which the Barani returned to its standard 0.2-0.3C cooler than the FARS.

[Meteorology fan]

In my case, there are more such occurrences in the maximum to the detriment of the Ms Pro III. This is due to climate and location.

[Dador]

Biggest error I've recorded to date this morning with the Barani, up to 1.1C. Wind was at 0 km/h with no cloud at all and a low sun angle, so very hostile for the Barani. No impact on the min and max but notable regardless.

This morning I experienced a similar phenomenon.
Very little wind, full sun and FARS reading lower than Barani by 0.8*C for several minutes.

[Jasper3012]

Yes, this is a known problem by now. There’ll usually be very little impact on recorded min/max in summer, but I can imagine there being an impact on very calm and sunny winter days, due to the low sun angle even in the afternoon. Having said that, such days are non-existent here and therefore I don’t expect a measurable effect on the monthly averages, but this could be different in (more) continental climates. Graph below showing the deviation between the two shields over the past 10 days (red = FARS cooler, blue = Barani cooler), you can see that the Barani has been struggling lately due to low wind but overall still holding up very well.

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[Meteorology fan]

A colleague from the Netherlands is already testing against i.a. Barani. The new shield tested at meteodrenthe seems to be more resistant to rays from the side like Barani.

https://blog.meteodrenthe.nl/2024/07/29/unboxing-the-siapmicros-smart-cellino-radiation-shield/

https://www.siapmicros.com/en/smart-cellino-il-nuovo-schermo-di-riferimento-nella-misure-di-temperatura-e-umidita-dellaria/

[hmderek]

A colleague from the Netherlands is already testing against i.a. Barani. The new shield tested at meteodrenthe seems to be more resistant to rays from the side like Barani.

https://blog.meteodrenthe.nl/2024/07/29/unboxing-the-siapmicros-smart-cellino-radiation-shield/

https://www.siapmicros.com/en/smart-cellino-il-nuovo-schermo-di-riferimento-nella-misure-di-temperatura-e-umidita-dellaria/

Tbh it’s really hard to draw any conclusions from that graph because I’ve got some trees causing intermittent shading on the shields around that time of day. What you are seeing there is the Barani in the sun and the Siap+Micros just inside the shade.

[bianconero57]

  we're all going to ditch the brni for the new Smart toy