<blockquote>
<p>It would be good to have satellites that gave current readings of skin temperature so that farmers could see if their crop was freezing or too hot</p>
</blockquote>
<p>This is not generally possible in near real time (&quot;live update&quot;), but satellites may still offer some useful information.  There are several problems:</p>
<ul>
<li>Satellites can measure skin temperature using infrared sensors only in the absence of clouds.  On average, 67% of Earth and 55% of land is covered in clouds (King et. al, 2013)  (of course, this number various strongly with time and place).  Therefore, much or most of the time, satellites cannot measure skin temperature instantly, but have to wait for a cloud-free moment.  However, dry nights (no cloud and not much water vapour) cool down more than humid or cloudy nights, so maybe during the most at-risk nights the radiometres can still give a clue.</li>
<li>To monitor in near-real time, you need to use either geostationary satellites or a very large swarm of low Earth Orbit satellites.
<ul>
<li>The spatial resolution of infrared channels in geostationary satellites is too poor.  Most geostationary imagers have resolutions of more than a kilometre.  The current Meteosat generation has 3×3 km² at sub satellite point and closer to 4×6 km² in central Europe.</li>
<li>A very large swarm would be costly, and the infrared resolution would still be dozens of metres.</li>
<li>High resolution imagers in any case only regard a small area at any time.</li>
</ul>
</li>
<li>In theory, microwave can be used to measure surface temperature in the presence of clouds (although for a thicker layer than infrared), but only with a good knowledge of surface emissivity (which is a function of soil moisture, among other things), and the spatial resolution of microwave sensors is much worse (&gt;10 km from low earth orbit, non-existent from geostationary orbit).</li>
</ul>
<p>A resolution of 1×1 km² from geostationary orbit would already be very ambitious, where 2×2 km² or more is more realistic.  I'm not sure if this is good enough for farmers for discriminating the skin temperature of their crops from the skin temperature of the general area, which may be quite different (heat loss in a clear night strongly depends on surface material).</p>
<p>Farmers who wish to monitor their crop temperature in real time should probably just use infrared cameras installed at their property or possibly with drones constantly flying in the air.  Whether this is cost-effective is beyond the scope of Earth Science SE.</p>
<blockquote>
<p>as well as for other global warming monitoring</p>
</blockquote>
<p>This is routinely done, but this does not need a high spatial resolution and it does not need to be in near real time.</p>
<hr />
<p>M. D. King, S. Platnick, W. P. Menzel, S. A. Ackerman and P. A. Hubanks, &quot;Spatial and Temporal Distribution of Clouds Observed by MODIS Onboard the Terra and Aqua Satellites,&quot; in IEEE Transactions on Geoscience and Remote Sensing, vol. 51, no. 7, pp. 3826-3852, July 2013, doi: 10.1109/TGRS.2012.2227333. <a href="https://ieeexplore.ieee.org/document/6422379" rel="nofollow noreferrer">Accessed online 5 April 2022</a>.</p>

CC BY-SA 4.0
2022-04-05T11:53:49.453Z
"On average, in the order of 70% of Earth is covered in clouds." - Citation needed.
Erik
CC BY-SA 4.0
2022-04-05T12:01:13.233Z
@Erik Citation added (67% rather than 70%, close enough).
gerrit
CC BY-SA 4.0
2022-04-05T17:26:04.050Z
One thing worth pointing out is that those worried about borderline freezes will often be favored to get data, as temperatures drop off (and frost forms) best in clear skies.  Here in Florida our danger nights to crops are almost always clear.  Experientially don't know if that's entirely true in places that are often nearer the wraparound moisture nearer the low pressure up more into the midlats, though imagine it is, because the first fronts of the year would feasibly tend to have lows more poleward likewise.  And of course such areas will be less a question of if than of when.
JeopardyTempest
CC BY-SA 4.0
2022-04-05T17:29:01.653Z
Also I think I tend to agree with trond in the end that 1 km resolution can still be quite good for farmers to get a rough idea of impacts, though of course may miss microscale features and such.
JeopardyTempest
CC BY-SA 4.0
2022-04-05T19:49:28.710Z
@JeopardyTempest That's true, clear nights are colder nights.  Maybe my answer is too pessimistic.  I've changed the formulation a bit.  For a huge farm in (say) Brazil perhaps it's valuable (although I don't know if the information "your crops may freeze in the next 2 hours" is actually actionable for such a farm, but that's another question).
gerrit
CC BY-SA 4.0
2022-04-06T02:03:41.020Z
Did you see about the Sentinel 3 ESA satellites? They are global and give a resolution of 0.3'C and 300m, its only mostly for ocean studies.
bandybabboon
CC BY-SA 4.0
2022-04-06T04:27:34.953Z
@LifeInTheTrees looks there are only 2 so far, and polar orbiting... so they cover a lot of the globe being antipodal, but wouldn't imagine they have the highest resolution at high angles, so maybe not really global to high time resolution to where they'd be reliable for farms each night.  (The footprint option, and the fact it takes nearly 2 hours to complete one 1,000 mile shift seems to agree?)  Maybe when the other two get up there in the coming years, better.  But I didn't know of the satellites! Here's their orbits: [3A](https://www.n2yo.com/?s=41335), [3B](https://www.n2yo.com/?s=43437)
JeopardyTempest
CC BY-SA 4.0
2022-04-06T07:34:16.577Z
@LifeInTheTrees They're pretty good, but they only pass twice a day or so (I'm not sure about the swath width, but in any case it's not in near real time).
gerrit
CC BY-SA 4.0
2022-04-05T08:18:07.370Z
2022-04-05T19:55:07.053Z
2022-04-05T19:55:07.053Z
gerrit
<p>Not, because the costs of satellite image provider are excessive, and the same idea can be exploited with drones (and in fact it is being commercially exploited, as it can be seen by accessing this report <a href="https://www.businessinsider.com/agricultural-drones-precision-mapping-spraying?r=US&amp;IR=T" rel="nofollow noreferrer">https://www.businessinsider.com/agricultural-drones-precision-mapping-spraying?r=US&amp;IR=T</a> ).</p>
<p>I suggest to have a look at this study:
<a href="https://www.researchgate.net/publication/341253627_Applications_of_UAV_Thermal_Imagery_in_Precision_Agriculture_State_of_the_Art_and_Future_Research_Outlook" rel="nofollow noreferrer">https://www.researchgate.net/publication/341253627_Applications_of_UAV_Thermal_Imagery_in_Precision_Agriculture_State_of_the_Art_and_Future_Research_Outlook</a>
to understand where we are in 2022 in terms of implementation of remote sensing and precision agriculture (we are quite ahead wrt to what OP question implies).</p>

CC BY-SA 4.0
2022-04-05T17:33:41.060Z
You mention drones being commercially exploited, it would help more to give examples.  Also may help to give a rough vision to the costs being excessive, rather than assume everyone would immediately agree with that idea.  Not saying your wrong, but details help give credence and support to ideas like these :-)
JeopardyTempest
CC BY-SA 4.0
2022-04-05T21:43:31.407Z
@JeopardyTempest added references
EarlGrey
CC BY-SA 4.0
2022-04-06T02:02:49.517Z
Did you see about the Sentinel 3 ESA satellites? They are global and give a resolution of 0.3'C and 300m,  420-1030Nm range
bandybabboon
CC BY-SA 4.0
2022-04-06T04:23:55.357Z
@EarlGrey awesome, that really lays weight behind your position, and is the kind of answer I think we in like math and science Stack Exchanges really enjoy, I sure do.  Thanks for taking that next step :)
JeopardyTempest
CC BY-SA 4.0
2022-04-06T06:57:11.887Z
@LifeInTheTrees there were some momentum around Sentinel-2, with even some infrastructure aimed specifically at agriculture, like this:
https://github.com/Sen2Agri
I am not updated in Sentinel 3, they provide daily data but if there are clouds the moment they should be above your field it is no-data day (so to be complemented by more expensive, at least on paper, drones? I do not have an opinion).
EarlGrey
CC BY-SA 4.0
2022-04-05T14:32:19.840Z
2022-04-05T21:44:37.673Z
2022-04-05T21:44:37.673Z
EarlGrey
<p>It would be good to have satellites that gave current readings of skin temperature so that farmers could see if their crop was freezing or too hot, as well as for other global warming monitoring. Would this be possible, why isn't there one?</p>

CC BY-SA 4.0
2022-04-04T05:22:36.700Z
I would think that's what infrared satellite can be used for if there's no clouds.  I'm pretty limited in satellite knowledge, but not sure if there's any band to specifically to give skin temperature if there's not.
JeopardyTempest
CC BY-SA 4.0
2022-04-04T05:49:14.423Z
How would the skin temperature of a plant differ from the air temperature at the location of the plant? If there isn't a difference, it would be easier & cheaper for the farmer to establish a system of temperature sensor around the farm that could be monitored via a screen or via a computer in the farmhouse. The computer could sound an alarm if the temperature varies from specified parameters.
Fred
CC BY-SA 4.0
2022-04-04T08:00:27.377Z
@Fred If a farmer was to select which land to grow a crop, he can see if there are early frosts in the satellite records and other climate info's. I want to see where it frosted today because all the cherry trees and apricots there may have been damaged, so I can find drought and frost effects locally.
bandybabboon
CC BY-SA 4.0
2022-04-04T08:04:35.927Z
@JeopardyTempest Yes indeed. So I checked the infra-red satellite and it states a range from -70'C clouds to -10 degrees clouds that give the cloud altitudes. It's a clear sky today and the terrestrial readings are grey. Perhaps there are other satellites which have HD narrow ranges of +40 to -20 which give ideas of frosts and forest fires and so on.
bandybabboon
CC BY-SA 4.0
2022-04-04T09:18:58.437Z
Ah, indeed, guess IR doesn't entirely go to true surface then.  I do see a site over here in the western Hemisphere that offers land surface derived temp for GOES: https://weather.cod.edu/satrad/?parms=global-northamerica-07-24-1-100-1&checked=map&colorbar=undefined  But can't find anything for Europe, only https://land.copernicus.eu/global/products/lst... which seems to be backed from the EU and include Eurosat, but unfortunately, as can often be the way over there, such data is not free (as is the case with the bulk of the European weather model) :-/  Maybe someone has something better.
JeopardyTempest
CC BY-SA 4.0
2022-04-04T11:45:53.687Z
Hey that's a cool topic, i haven't studied US vs EU weather systems commercialization and precision!!! I imagine that they are fairly similar? This is the EU IR satellite for weather https://www.meteo60.fr/satellites/infra-rouge Why aren't there images of i.e. the US using these kinds of camera and thermal precision? : https://www.google.com/search?q=thermal+imaging&tbm=isch
bandybabboon
CC BY-SA 4.0
2022-04-04T18:46:47.620Z
Right now the US (and Japanese) satellites offer much higher spatial and temporal resolution.  If you look through the options on that weather.cod.edu site, you'll find infrared, and can change the color scale to similar, and zoom in to very localized areas on the top left menus (such as https://weather.cod.edu/satrad/?parms=local-Orlando-dcphase-24-1-100-1&checked=map&colorbar=undefined).  EU is planning to launch high resolution satellites perhaps later this year: https://www.eumetsat.int/meteosat-third-generation
JeopardyTempest
CC BY-SA 4.0
2022-04-04T18:50:58.517Z
https://rammb-slider.cira.colostate.edu gives most of the products for most global satellites around the globe, you can play with that more.  But I don't see a land surface image option offered there for any of the satellites.  Doesn't mean it doesn't exist, since COD offers it, it clearly does for GOES, but only option I could find for Meteosat was the pay site by searching, and I don't know enough about such satellites to know if it's out there somewhere free or not.
JeopardyTempest
CC BY-SA 4.0
2022-04-05T08:20:38.243Z
@JeopardyTempest Even with MTG-FCI, most IR channels have a resolution of 2 km SSP (worse in Europe), with 2 channels at 1 km SSP, in the absence of clouds only.  Probably not good enough for farmers.
gerrit
CC BY-SA 4.0
2022-04-05T14:47:20.980Z
https://www.sciencedirect.com/science/article/abs/pii/003442579490023X
trond hansen
CC BY-SA 4.0
2022-04-05T15:29:43.693Z
@trondhansen That's a very old article.  There has got to be newer work on this; technology has changed a lot in the past 30 years.
gerrit
CC BY-SA 4.0
2022-04-05T15:51:53.557Z
@gerrit i too asume things has evolved maybe this question should be asked over at https://space.stackexchange.com/ long wave infra red radiated from the ground should be easy to observe from a satelite and a resolution of 1x1 km is still useful for the farmers,the temperature 5 km from where i live is about the same as here.
trond hansen
CC BY-SA 4.0
2022-04-05T15:56:46.140Z
@Fred My banana plants often experience frost damage, and I often see frost on roofs whenever the air temperature drops below +4 °C (39.2 °F). Air temperature at 1.5 meters above the ground (the proper height for a meteorological station) can be significantly higher or lower than surface temperature.
David Hammen
<temperature><satellites>
Skin temperature, live update satellites, are there any? If not, why not?
bandybabboon
# Skin temperature, live update satellites, are there any? If not, why not?

(Asked by: username_0 on 2022-04-04)

It would be good to have satellites that gave current readings of skin temperature so that farmers could see if their crop was freezing or too hot, as well as for other global warming monitoring. Would this be possible, why isn't there one?

**Tags:** temperature, satellites

> **Comments:**
> **username_1**: I would think that's what infrared satellite can be used for if there's no clouds.  I'm pretty limited in satellite knowledge, but not sure if there's any band to specifically to give skin temperature if there's not.  
> **username_2**: How would the skin temperature of a plant differ from the air temperature at the location of the plant? If there isn't a difference, it would be easier & cheaper for the farmer to establish a system of temperature sensor around the farm that could be monitored via a screen or via a computer in the farmhouse. The computer could sound an alarm if the temperature varies from specified parameters.  
> **username_0**: @username_2 If a farmer was to select which land to grow a crop, he can see if there are early frosts in the satellite records and other climate info's. I want to see where it frosted today because all the cherry trees and apricots there may have been damaged, so I can find drought and frost effects locally.  
> **username_0**: @username_1 Yes indeed. So I checked the infra-red satellite and it states a range from -70'C clouds to -10 degrees clouds that give the cloud altitudes. It's a clear sky today and the terrestrial readings are grey. Perhaps there are other satellites which have HD narrow ranges of +40 to -20 which give ideas of frosts and forest fires and so on.  
> **username_1**: Ah, indeed, guess IR doesn't entirely go to true surface then.  I do see a site over here in the western Hemisphere that offers land surface derived temp for GOES: https://weather.cod.edu/satrad/?parms=global-northamerica-07-24-1-100-1&checked=map&colorbar=undefined  But can't find anything for Europe, only https://land.copernicus.eu/global/products/lst... which seems to be backed from the EU and include Eurosat, but unfortunately, as can often be the way over there, such data is not free (as is the case with the bulk of the European weather model) :-/  Maybe someone has something better.  
> **username_0**: Hey that's a cool topic, i haven't studied US vs EU weather systems commercialization and precision!!! I imagine that they are fairly similar? This is the EU IR satellite for weather https://www.meteo60.fr/satellites/infra-rouge Why aren't there images of i.e. the US using these kinds of camera and thermal precision? : https://www.google.com/search?q=thermal+imaging&tbm=isch  
> **username_1**: Right now the US (and Japanese) satellites offer much higher spatial and temporal resolution.  If you look through the options on that weather.cod.edu site, you'll find infrared, and can change the color scale to similar, and zoom in to very localized areas on the top left menus (such as https://weather.cod.edu/satrad/?parms=local-Orlando-dcphase-24-1-100-1&checked=map&colorbar=undefined).  EU is planning to launch high resolution satellites perhaps later this year: https://www.eumetsat.int/meteosat-third-generation  
> **username_1**: https://rammb-slider.cira.colostate.edu gives most of the products for most global satellites around the globe, you can play with that more.  But I don't see a land surface image option offered there for any of the satellites.  Doesn't mean it doesn't exist, since COD offers it, it clearly does for GOES, but only option I could find for Meteosat was the pay site by searching, and I don't know enough about such satellites to know if it's out there somewhere free or not.  
> **username_3**: @username_1 Even with MTG-FCI, most IR channels have a resolution of 2 km SSP (worse in Europe), with 2 channels at 1 km SSP, in the absence of clouds only.  Probably not good enough for farmers.  
> **username_4**: https://www.sciencedirect.com/science/article/abs/pii/003442579490023X  
> **username_3**: @username_4 That's a very old article.  There has got to be newer work on this; technology has changed a lot in the past 30 years.  
> **username_4**: @username_3 i too asume things has evolved maybe this question should be asked over at https://space.stackexchange.com/ long wave infra red radiated from the ground should be easy to observe from a satelite and a resolution of 1x1 km is still useful for the farmers,the temperature 5 km from where i live is about the same as here.  
> **username_5**: @username_2 My banana plants often experience frost damage, and I often see frost on roofs whenever the air temperature drops below +4 °C (39.2 °F). Air temperature at 1.5 meters above the ground (the proper height for a meteorological station) can be significantly higher or lower than surface temperature.  

---

## 2 answers

### Answer by username_3 on 2022-04-05. Score: 4

> It would be good to have satellites that gave current readings of skin temperature so that farmers could see if their crop was freezing or too hot

This is not generally possible in near real time ("live update"), but satellites may still offer some useful information. There are several problems:

* Satellites can measure skin temperature using infrared sensors only in the absence of clouds. On average, 67% of Earth and 55% of land is covered in clouds (King et. al, 2013) (of course, this number various strongly with time and place). Therefore, much or most of the time, satellites cannot measure skin temperature instantly, but have to wait for a cloud-free moment. However, dry nights (no cloud and not much water vapour) cool down more than humid or cloudy nights, so maybe during the most at-risk nights the radiometres can still give a clue.
* To monitor in near-real time, you need to use either geostationary satellites or a very large swarm of low Earth Orbit satellites.
  + The spatial resolution of infrared channels in geostationary satellites is too poor. Most geostationary imagers have resolutions of more than a kilometre. The current Meteosat generation has 3×3 km² at sub satellite point and closer to 4×6 km² in central Europe.
  + A very large swarm would be costly, and the infrared resolution would still be dozens of metres.
  + High resolution imagers in any case only regard a small area at any time.
* In theory, microwave can be used to measure surface temperature in the presence of clouds (although for a thicker layer than infrared), but only with a good knowledge of surface emissivity (which is a function of soil moisture, among other things), and the spatial resolution of microwave sensors is much worse (>10 km from low earth orbit, non-existent from geostationary orbit).

A resolution of 1×1 km² from geostationary orbit would already be very ambitious, where 2×2 km² or more is more realistic. I'm not sure if this is good enough for farmers for discriminating the skin temperature of their crops from the skin temperature of the general area, which may be quite different (heat loss in a clear night strongly depends on surface material).

Farmers who wish to monitor their crop temperature in real time should probably just use infrared cameras installed at their property or possibly with drones constantly flying in the air. Whether this is cost-effective is beyond the scope of Earth Science SE.

> as well as for other global warming monitoring

This is routinely done, but this does not need a high spatial resolution and it does not need to be in near real time.

---

M. D. King, S. Platnick, W. P. Menzel, S. A. Ackerman and P. A. Hubanks, "Spatial and Temporal Distribution of Clouds Observed by MODIS Onboard the Terra and Aqua Satellites," in IEEE Transactions on Geoscience and Remote Sensing, vol. 51, no. 7, pp. 3826-3852, July 2013, doi: 10.1109/TGRS.2012.2227333. [Accessed online 5 April 2022](https://ieeexplore.ieee.org/document/6422379).

> **Comments:**
> **username_6**: "On average, in the order of 70% of Earth is covered in clouds." - Citation needed.  
> **username_3**: @username_6 Citation added (67% rather than 70%, close enough).  
> **username_1**: One thing worth pointing out is that those worried about borderline freezes will often be favored to get data, as temperatures drop off (and frost forms) best in clear skies.  Here in Florida our danger nights to crops are almost always clear.  Experientially don't know if that's entirely true in places that are often nearer the wraparound moisture nearer the low pressure up more into the midlats, though imagine it is, because the first fronts of the year would feasibly tend to have lows more poleward likewise.  And of course such areas will be less a question of if than of when.  
> **username_1**: Also I think I tend to agree with username_4 in the end that 1 km resolution can still be quite good for farmers to get a rough idea of impacts, though of course may miss microscale features and such.  
> **username_3**: @username_1 That's true, clear nights are colder nights.  Maybe my answer is too pessimistic.  I've changed the formulation a bit.  For a huge farm in (say) Brazil perhaps it's valuable (although I don't know if the information "your crops may freeze in the next 2 hours" is actually actionable for such a farm, but that's another question).  
> **username_0**: Did you see about the Sentinel 3 ESA satellites? They are global and give a resolution of 0.3'C and 300m, its only mostly for ocean studies.  
> **username_1**: @LifeInTheTrees looks there are only 2 so far, and polar orbiting... so they cover a lot of the globe being antipodal, but wouldn't imagine they have the highest resolution at high angles, so maybe not really global to high time resolution to where they'd be reliable for farms each night.  (The footprint option, and the fact it takes nearly 2 hours to complete one 1,000 mile shift seems to agree?)  Maybe when the other two get up there in the coming years, better.  But I didn't know of the satellites! Here's their orbits: [3A](https://www.n2yo.com/?s=41335), [3B](https://www.n2yo.com/?s=43437)  
> **username_3**: @LifeInTheTrees They're pretty good, but they only pass twice a day or so (I'm not sure about the swath width, but in any case it's not in near real time).  

---

### Answer by username_7 on 2022-04-05. Score: 2

Not, because the costs of satellite image provider are excessive, and the same idea can be exploited with drones (and in fact it is being commercially exploited, as it can be seen by accessing this report <https://www.businessinsider.com/agricultural-drones-precision-mapping-spraying?r=US&IR=T> ).

I suggest to have a look at this study:
<https://www.researchgate.net/publication/341253627_Applications_of_UAV_Thermal_Imagery_in_Precision_Agriculture_State_of_the_Art_and_Future_Research_Outlook>
to understand where we are in 2022 in terms of implementation of remote sensing and precision agriculture (we are quite ahead wrt to what OP question implies).

> **Comments:**
> **username_1**: You mention drones being commercially exploited, it would help more to give examples.  Also may help to give a rough vision to the costs being excessive, rather than assume everyone would immediately agree with that idea.  Not saying your wrong, but details help give credence and support to ideas like these :-)  
> **username_7**: @username_1 added references  
> **username_0**: Did you see about the Sentinel 3 ESA satellites? They are global and give a resolution of 0.3'C and 300m,  420-1030Nm range  
> **username_1**: @username_7 awesome, that really lays weight behind your position, and is the kind of answer I think we in like math and science Stack Exchanges really enjoy, I sure do.  Thanks for taking that next step :)  
> **username_7**: @LifeInTheTrees there were some momentum around Sentinel-2, with even some infrastructure aimed specifically at agriculture, like this: https://github.com/Sen2Agri I am not updated in Sentinel 3, they provide daily data but if there are clouds the moment they should be above your field it is no-data day (so to be complemented by more expensive, at least on paper, drones? I do not have an opinion).  

---

