Detecting Cloudy or Clear night

[Zalmor]

Updated to the most recent ZIP update today.

Made the changes, restarted WD, still only showing the 'Cloudy night' and no weather conditions like rain during the night time hours using Temp in a Jar sensor.  Works fine during the daytime hours utilizing Davis VP solar sensor?

My testtags.php is showing the following also:

Code: [Select]

// $current_summary = 'Cloudy night' . "<br />" . 'Cloudy night ';
   $dayornight = 'Night'; // dayornight
   $timeofdaygreeting = 'Evening'; // E.g Morning, Afternoon, etc
   $weathercond = 'Cloudy night';
   $Currentsolardescription = 'Cloudy night ';
   $current_summary = $Currentsolardescription;

Any ideas as to why the weather conditions are not showing up at night time?

I don't have a clue as mine is working very well now. You might need to email windy to take a look at this thread.

No reply back from windy yet, must still be busy with his move to his new house which is Very nice to say the least.

For now I only enable it when I know there won't be any precipitation each night.

[TokKiwi]

Do you have the Davis weather conditions turned on in WD - I think this is in Control Panel - Summary Gif and Icon Conditions or some such. Try turning off.

[oldun]

I have just picked up this thread.
How about having two sensors each inside a half sphere mounted in a position to view the sky and sheltered from incipient terrestrial radiation, one half sphere painted mat black internally white externally
 ( the terrestrial reference ) the other white internally, black externally (the sky sensor).

Another simpler setup for those whom live in larger towns or cities would be to mount a visible light sensor for example a PIN diode inside a long say 1 m. large diameter tube (10cm.)  painted black inside and blocked off at the bottom end and maybe a simple lens at the other end with the sensor at the focal point. Pointed up vertically.
The rational for all this is that city "glow" (night time glow produced by street lights etc) is reflected back from clouds and not from clear skies, a long time constant would be needed to prevent transient short term illumination from producing unwanted artifacts. The dimensions given should negate the Lunar effect.
R

[Zalmor]

Do you have the Davis weather conditions turned on in WD - I think this is in Control Panel - Summary Gif and Icon Conditions or some such. Try turning off.

Turned them off, restarted WD, waited about 10 minutes .. showing 'Clear night'. 

[TechnoGuy]

So it is working. Yes or no?

[TokKiwi]

Turned them off, restarted WD, waited about 10 minutes .. showing 'Clear night'.  

That sounds positive!! I will check your website...

10mins later...
I like your website!  Still showing clear skies   Elmira is clear on the Doppler, so looking good!

I wonder if you can generate your WD Extra sensor graph and get that uploaded...?



Graeme

[Zalmor]

So it is working. Yes or no?

It is working, but no conditions show up like 'Light rain, Moderate rain' which will probably happen tonight (07/29) when I'm at work, don't show up like they do during the daytime hours.

[Zalmor]

That sounds positive!! I will check your website... 10mins later...
I like your website!  Still showing clear skies  Elmira is clear on the Doppler, so looking good!

I wonder if you can generate your WD Extra sensor graph and get that uploaded...?

Thanks for the comment concerning the website, always finding something to add and/or modify here.  

Just cleared and enabled the upload of http://southerin-ny.org/extrarealtimegraph.gif and http://southerin-ny.org/extrarealtimegraphmore.gif files at 08:30 am.

Second file link above shows the Temp in a Jar reading along with the Outside temperature uploaded every 10 minutes.

[TokKiwi]

Thanks - they will be good to follow as night draws near... as it should be now...

Much later now, the IR satellite pic shows cloud cover and it should be 1am there.  Your night time cloud sensor is saying mostly cloudy although there is very little temperature variation between the ambient and the sensor in a jar (0.3degF lower).  I thought this should have said cloudy.  At least it is starting to show relativity and indicate a varying cloud cover.  It takes a while to tweak the settings to get a good relative range for cloud types.  Keep it up.  Yes I was reminded about IE6 at work here...

[Zalmor]

Thanks - they will be good to follow as night draws near... as it should be now...

Much later now, the IR satellite pic shows cloud cover and it should be 1am there.  Your night time cloud sensor is saying mostly cloudy although there is very little temperature variation between the ambient and the sensor in a jar (0.3degF lower).  I thought this should have said cloudy.  At least it is starting to show relativity and indicate a varying cloud cover.  It takes a while to tweak the settings to get a good relative range for cloud types.  Keep it up.  Yes I was reminded about IE6 at work here...

Being located at the top of a hill the temperature can vary here on an average of +/- 2-3 degrees, especially like last night.  We had patches of mist/fog rolling over the tops of nearby hills which can last anywhere from 5-20 minutes depending on the wind speed.

Now if I can only get the precipitation to also show up during the night time hours I would be happy.  As it is now WD here writes:

Code: [Select]

// $current_summary = 'Cloudy night' . "<br />" . 'Cloudy night ';
   $dayornight = 'Night'; // dayornight
   $timeofdaygreeting = 'Evening'; // E.g Morning, Afternoon, etc
   $weathercond = 'Cloudy night';
   $Currentsolardescription = 'Cloudy night ';

'Cloudy night' for the $weathercond and $Currentsolardescription evening when it is actually raining and WD is recording the measurable rain increments.  Precipitation isn't showing up on the web site when it is raining here at night, unless that is the way night time cloud detector section is suppose to handle any precipitation by not showing measurable precipitation too.

This is what I'm trying to display is the cloud type and precipitation.

[dendrite]

It's been a year, but I'm going to bump this...

How are everyones' jars and readings handling? I've been thinking of doing this with my VP2 and an additional temp probe...

I have a soil station with soil temp, soil moisture, and leaf wetness (heated and used as precip detector) sensors already. My concern with using an additional Davis temp probe for the nighttime in-jar is the resolution of the sensor. My soil temp probe only measures in whole degrees Fahrenheit and I can't get it to report in tenths on the console like the regular ISS air temp.

Aside from that...I was thinking more about the hardware for this. How would a cheap, vacuum insulated Dewar flask work with a ~720nm IR filtered top (like for an IR camera)? This would freely let the IR pass through only the top and prevent the visible and UV portion of the spectrum. Then maybe it could even be used during the daytime?

[TokKiwi]

Hi Dendrite - the IR lens sounds like a great idea - mine is still running well - even better in the clear winter skies - I noticed I was getting around 6.3ēC difference last night, where in summer I was getting about 4.1ēC when I started the project.  My PE based vegetable fridge container upside down has spat the dummy and the PE without UV stabilisation has cracked up and was going to let the rain in...  I quickly covered it with a thinner sandwich plastic bag to keep the weather off!  Still working away happily, but I do need to upgrade it and make it more permanent.  I really like the idea of being able to tell WU, YoWindow and my visitors what the sky conditions are at night!!  I will follow up your suggestion and seek out an IR lens even if it is a pricy camera accessory.

TK

[dendrite]

Hi Dendrite - the IR lens sounds like a great idea - mine is still running well - even better in the clear winter skies - I noticed I was getting around 6.3ēC difference last night, where in summer I was getting about 4.1ēC when I started the project.  My PE based vegetable fridge container upside down has spat the dummy and the PE without UV stabilisation has cracked up and was going to let the rain in...  I quickly covered it with a thinner sandwich plastic bag to keep the weather off!  Still working away happily, but I do need to upgrade it and make it more permanent.  I really like the idea of being able to tell WU, YoWindow and my visitors what the sky conditions are at night!!  I will follow up your suggestion and seek out an IR lens even if it is a pricy camera accessory.

TK

I'm considering a stainless steel, double vacuum insulated can insulator from Thermos and an 82mm 720nm IR filter. The Thermos is 3" diameter for about US$13 and the 77mm to 82mm (~3" to 3.2") filters run about US$15-25 on ebay. The Davis probes are 2.5" (64mm) long so it should fit into the bottom nicely. I'd probably run the cord through the top between some silicone connecting the filter to the Thermos.

[TokKiwi]

The sensor is supposed to be attached to a black body that has good thermal density and is reflective to heat on the underside - ie white or silver.  I have used a small paint tin lid but it is still too large, and the lid has to see the sky for the heat loss to occur. It tries to lower its temperature to the same as the black sky which is at -273ēC via IR transmission.  If a cloud passes over, it limits this IR communication...

TK

[dendrite]

The sensor is supposed to be attached to a black body that has good thermal density and is reflective to heat on the underside - ie white or silver.  I have used a small paint tin lid but it is still too large, and the lid has to see the sky for the heat loss to occur. It tries to lower its temperature to the same as the black sky which is at -273ēC via IR transmission.  If a cloud passes over, it limits this IR communication...

TK

I understand the net radiation processes and blackbody physics, but wouldn't a well insulated jar (thermos) on the sides and bottom work just as well? With the IR filter on top the only longwave IR/heat gain or loss would be through the top. And yes, I planned to seal the Davis temp probe to a dense black, metal plate.

Of course if the bottom isn't insulated I'll have to modify the Thermos or come up with a different idea altogether. Here is the filter and Thermos I've been leaning towards...

http://cgi.ebay.com/82mm-82-mm-Infrared-Infra-Red-IR-Filter-720nm-720-F2V-/260500455774?pt=Camera_Filters

http://www.beveragefactory.com/draftbeer/accessories/thermos_2700p_beverage_can_insulator.html

Does everyone think these would work fine?


edit: the more I think about this I think going with a higher IR filter would be better...i.e. something like 1000nm. That would cut down on the shorter IR wavelengths taken in from the sun (helpful when transitioning from the nighttime jar to the daytime solar) while still getting all of the longwave IR. I think the Earth emits longwave at a max of about 10000nm and the sun/earth transition is at about 2000-3000nm (2-3 micrometers). I haven't seen any filters greater than 1000nm in my search yet.