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== Fundamental Question to all ==
Doesn't the magnetosphere interfere with "solar radiation"? Shouldnt the subtractions from space insolation include Earth magnetosphere caused reductions? Didnt see magnetosphere in intro paragraph of this topic. Or did i miss something? Thanks to all. Mike H. mlhootenoutlook


== Erroneous table? ==
==WARNING: ERRORS==
There are numerous major misconceptions and miss-statements in this article. It needs thorough reworking by experts knowledgeable in solar science. See [[NASA]] [[SORCE]] at http://lasp.colorado.edu/home/sorce/ etc.[[User:DLH|DLH]] ([[User talk:DLH|talk]]) 18:15, 1 January 2015 (UTC)


The table under [[Solar_irradiance#Applications]] is confusing at best and possibly profoundly erroneous. In general you cannot convert between power and energy without knowing time. In this table (pasted to the side), it appears the assumption is 24 hours per day of full sun, which is not true for any spot on earth. I suggest that we delete the entire table.
== References removed ==


{| class="wikitable" style="float:right;"
Recently [https://en.wikipedia.org/w/index.php?title=Solar_irradiance&type=revision&diff=675530146&oldid=675529927 this edit] by [[User:Lfstevens|Lfstevens]], removed what appears highly cited papers. However the entire manual references belong inline with the content. Thus, i suggest to remove all manual references, and if possible move them to the correct content. Maybe the editor can explain why remove only a few paper studies. [[User:Prokaryotes|prokaryotes]] ([[User talk:Prokaryotes|talk]]) 04:46, 15 August 2015 (UTC)
! colspan="6" |Conversion factor (multiply top row by factor to obtain side column)
|-
!
! W/m<sup>2</sup>
! kW·h/(m<sup>2</sup>·day)
! sun hours/day
! kWh/(m<sup>2</sup>·y)
! kWh/(kWp·y)
|-
! W/m<sup>2</sup>
| 1
| 41.66666
| 41.66666
| 0.1140796
| 0.1521061
|-
! kW·h/(m<sup>2</sup>·day)
| 0.024
| 1
| 1
| 0.0027379
| 0.0036505
|-
! sun hours/day
| 0.024
| 1
| 1
| 0.0027379
| 0.0036505
|-
! kWh/(m<sup>2</sup>·y)
| 8.765813
| 365.2422
| 365.2422
| 1
| 1.333333
|-
! kWh/(kWp·y)
| 6.574360
| 273.9316
| 273.9316
| 0.75
| 1
|}


I would love to hear your thoughts.
== Insolation vs Irradiance ==


--[[User:LRG|Lonny (LRG)]] ([[User talk:LRG|talk]]) 21:52, 9 April 2020 (UTC)
See ''What is the difference between insolation and solar irradiance?'' http://www.researchgate.net/post/What_is_the_difference_between_insolation_and_solar_irradiance [[User:Prokaryotes|prokaryotes]] ([[User talk:Prokaryotes|talk]]) 19:00, 15 August 2015 (UTC)
:I have no opinion about the answer, but perhaps we should look for something more authoritative? [[User:Lfstevens|Lfstevens]] ([[User talk:Lfstevens|talk]]) 07:04, 16 August 2015 (UTC)


:The table is correct. All quantities are (or are equivalent to) power per unit area. In the case of sun-hour/day, a sun-hour is defined as one hour of 1kW/m^2 irradiation per day = 1kWh/(m^2 day). In the case of kWh/(kWp year), it is equivalent to a measure of the average irradiance during a year. --[[User:Ita140188|Ita140188]] ([[User talk:Ita140188|talk]]) 03:15, 10 April 2020 (UTC)
This looks like a more credible source: http://www.volker-quaschning.de/articles/fundamentals1/index.php The distinction they make is "The total specific radiant power, or radiant flux, per area that reaches a Spectrum AM 0 (extraterrestrial) Spectrum AM 1.5 (terrestrial) receiver surface is called irradiance. Irradiance is measured in W/m² and has the symbol E. When integrating the irradiance over a certain time period it becomes solar irradiation. Irradiation is measured in either J/m² or Wh/m², and represented by the symbol H", so I think Irradiance is power per area, "solar irradiation" or insolation is energy per area. [[User:Chthonicdaemon|Chthonicdaemon]] ([[User talk:Chthonicdaemon|talk]]) 05:57, 28 September 2015 (UTC)
:Yes, Solar Irradiance and Insolation (Solar Irradiation) are often confused and their meanings and units are conflated in this article. The name of the article needs to be changed to include both ("Solar Irradiance and Irradiation" perhaps), or there should be two articles, one on Solar Irradiance and the other on Solar Irradiation (which is now the preferred way to refer to Insolation). Having them both in the same article might make sense because Irradiation is simply the integral of Irradiance over a given time interval. Indeed the www.volker-quaschning.de source cited here is more credible than the www.researchgate.net source. [[User:JDHeinzmann|JDHeinzmann]] ([[User talk:JDHeinzmann|talk]]) 11:38, 30 October 2015 (UTC)
::I would be strongly in favour of a separate article on insolation, which can depend on altitude, latitude, cloud cover, wavelength (UV insolation is considerably weaker than IR insolation), nearby reflectors, etc.
::Solar irradiance on the other hand is independent of all of those variables except wavelength, with "total" often meaning "over all wavelengths". Nominally it is the irradiance at [[top of atmosphere]], but since both the [[solar luminosity]] and distance of Earth from the Sun varies from day to day, different authors implicitly take it to be the mean over one or both of these factors, averaged over a specified period. For example the several articles in Haigh et al's book "The Sun, Solar Analogs and the Climate" use "solar iradiance", "total solar irradiance", and "bolometric irradiance" without definition making it unclear how they differ.
::A definition of solar irradiance I'd be fine with is the irradiance from the Sun at a distance of 1 AU from the Sun. (This definition is kept simple by modeling the Sun as a spherically symmetric radiator.) Equivalently solar irradiance is the quotient of [[solar luminosity]] by the area of a sphere of radius 1 AU cocentric with the Sun. These are to be understood as instantaneous notions; one can then speak of mean solar luminosity, and hence mean solar irradiance, averaged over a specified period of time. (The article [[Solar luminosity]] complicates the notion with a factor of ''k'' apparently on the assumption that the notion is defined as the annual mean where distance varies according to [[Kepler's Second Law]] while luminosity is either constant or an annual average.)
::My understanding of "total" in TSI, based on usage, is as a spectral notion, namely "integrated over all wavelengths"; thus one can say "UV solar irradiance" but not "UV total solar irradiance". Logically "total solar luminosity" would therefore also be a spectral notion, but instead "total" in that context is more often used redundantly to emphasize that luminosity is irradiance integrated over area.
::Meanwhile there are some egregious errors in this article, such as mixing up energy and power, but I would nevertheless suggest fixing the definitions before fixing the errors since the latter depend on the former. [[User:Vaughan Pratt|Vaughan Pratt]] ([[User talk:Vaughan Pratt|talk]]) 17:06, 13 December 2015 (UTC)


While I can glean/infer the meanings of these terms from the discussion, I'd instead suggest that we refer to an authoritative source and go with that. Can anyone provide one? [[User:Lfstevens|Lfstevens]] ([[User talk:Lfstevens|talk]]) 07:43, 14 December 2015 (UTC)
:I am not sure about how useful it is though. These quantities can be compared in terms of units, but they represent very different things, so a conversion table is not that useful in my opinion, and may be misleading. So personally I am ok with removing it. --[[User:Ita140188|Ita140188]] ([[User talk:Ita140188|talk]]) 03:18, 10 April 2020 (UTC)
:Confusion about this table is what brought me here. I would be in favor of removal. My confusion is rooted in the fact that 1kWp = 1kW/m^2. So where does the factor of .75 come from in converting kWh/(m2·y) to kWh/(kWp·y). I believe it should be one-to-one. [[User:Gilles Ottervanger|Gilles Ottervanger]] ([[User talk:Gilles Ottervanger|talk]]) 14:44, 9 October 2024 (UTC)


== Solar radiation is a synonym? ==
I've reworded the first part of the article to be more in line with the concept of irradiance, and linked to [[Irradiance]] to show the analogy. However, as I was searching for the uses of insolation, I came across [[Direct insolation]] which uses the "wrong" definition of insolation (the power instead of the energy). I suggest that we take it as we can, I feel that my edits have at least removed some blatantly incorrect units and perhaps harmonized the page a little better. I think part of the problem comes from the redirect from insolation, which I suppose used to be the name of the page. We'll have to go through all the other pages referencing insolation to fix that as well. [[User:Chthonicdaemon|Chthonicdaemon]] ([[User talk:Chthonicdaemon|talk]]) 08:26, 14 December 2015 (UTC)


Have I got it right when I say that ''solar radiation'' is a synonym for ''solar irradiation''? If so, I'd like to add it to the first sentence. The term does redirect here already. Pinging [[User:Bikesrcool]]. [[User:EMsmile|EMsmile]] ([[User talk:EMsmile|talk]]) 11:03, 19 April 2024 (UTC)


:Irradiance typically implies use of power flux units (power/area). Radiation is the generic or looser term as I understand; might be accompanied by units of power, energy, power/area, energy/area, power/solid angle, etc. [[User:Bikesrcool|Bikesrcool]] ([[User talk:Bikesrcool|talk]]) 12:26, 20 April 2024 (UTC)
Since when does irradiance not depend on "depend on altitude, latitude, cloud cover, wavelength, nearby reflectors, etc."? Irradiance (or radiant flux) is simply the radiant energy that crosses a specified plane per unit time and unit area. Of course this depends on the entire environment, including the source of the radiation.
::Thanks! I think we should explain this in the article, perhaps in a new section on definition or terminology? I mean it's a bit odd that "solar radiation" redirects to this article but is not explained explicitly w.r.t how it differs to solar irradiance. For what it's worth I posed the question to Chat GPT ("is solar radiation the same as solar irradiance?") and got this answer: "Solar radiation and solar irradiance are related concepts but not exactly the same.

::Solar radiation refers to the electromagnetic energy emitted by the Sun. This energy includes visible light, infrared radiation, ultraviolet radiation, and other forms of electromagnetic radiation.
My understanding has been that "insolation" means the same thing as "solar irradiance," i.e., the irradiance arriving at a surface (in this case the Earth's surface) that originated at the sun. However, the term "insolation" is used primarily in the land surface and solar energy communities. In my field (atmospheric radiative transfer), "irradiance" (the current SI term) or "radiative flux" (the older, now nonstandard term) are most widely used, so I may be wrong. I fail to see why anyone would want to know an instantaneous flux (J/m2). <small class="autosigned">—&nbsp;Preceding [[Wikipedia:Signatures|unsigned]] comment added by [[Special:Contributions/140.142.113.201|140.142.113.201]] ([[User talk:140.142.113.201|talk]]) 01:56, 1 June 2016 (UTC)</small><!-- Template:Unsigned IP --> <!--Autosigned by SineBot-->
::Solar irradiance, on the other hand, specifically refers to the power per unit area (typically measured in watts per square meter) of solar radiation received at a given location on Earth's surface. It represents the intensity of solar radiation incident on a surface.

::In simpler terms, solar radiation is the total energy emitted by the Sun, while solar irradiance is the amount of that energy received per unit area on the Earth's surface." [[User:EMsmile|EMsmile]] ([[User talk:EMsmile|talk]]) 16:23, 21 April 2024 (UTC)
== Units ==
The first sentence of the article says "Solar irradiance (also Insolation, from Latin insolare, to expose to the sun)[1][2] is the power per unit area produced by the Sun in the form of electromagnetic radiation" but the units stated further along are MJ/m<sup>2</sup>. There are also many ambiguous units like kWh/m<sup>2</sup>/day and such. I think the units should all be power/area as in the definition. [[User:Chthonicdaemon|Chthonicdaemon]] ([[User talk:Chthonicdaemon|talk]]) 04:30, 28 September 2015 (UTC)

== External links modified ==

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I have just added archive links to {{plural:2|one external link|2 external links}} on [[Solar irradiance]]. Please take a moment to review [https://en.wikipedia.org/w/index.php?diff=prev&oldid=699214365 my edit]. If necessary, add {{tlx|cbignore}} after the link to keep me from modifying it. Alternatively, you can add {{tlx|nobots|deny{{=}}InternetArchiveBot}} to keep me off the page altogether. I made the following changes:
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*Added archive https://web.archive.org/20140714124903/http://www.iea-pvps.org/pv/glossary.htm to http://www.iea-pvps.org/pv/glossary.htm#STC

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== External links modified ==

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I have just added archive links to {{plural:1|one external link|1 external links}} on [[Solar irradiance]]. Please take a moment to review [https://en.wikipedia.org/w/index.php?diff=prev&oldid=704719018 my edit]. If necessary, add {{tlx|cbignore}} after the link to keep me from modifying it. Alternatively, you can add {{tlx|nobots|deny{{=}}InternetArchiveBot}} to keep me off the page altogether. I made the following changes:
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== Solar potential maps ==

The Solar potential maps are interesting but it wasn't clear at all that the mapping between colors and irradiation amounts are not the same among them, potentially misleading readers. Suggest re-doing these maps such that the color/irradiation scale is the same. <small class="autosigned">—&nbsp;Preceding [[Wikipedia:Signatures|unsigned]] comment added by [[Special:Contributions/71.238.62.176|71.238.62.176]] ([[User talk:71.238.62.176|talk]]) 03:39, 8 March 2016 (UTC)</small><!-- Template:Unsigned IP --> <!--Autosigned by SineBot-->

== Proposal to add information on Global Solar Atlas ==
I tried to make some changes and improvements to this article, in part to update the information but also to include a reference to the Global Solar Atlas (http://globalsolaratlas.info), which is relatively new so therefore not yet well known. These edits were rolled back by another editor because they believed them to be spam, which they are not. However, I do have a potential Conflict of Interest in adding the reference because I was involved in creating the Global Solar Atlas. So I won't attempt to re-add these edits. However, I do think they are relevant, and would encourage someone else to view what I was trying to edit and add and see which of this they feel like adding themselves. Much of the information on this article could do with improving, and I'd be happy to get involved, but I'm wary now after having content deleted. Thanks. --[[User:O-Jay|O-Jay]] ([[User talk:O-Jay|talk]]) 18:58, 25 December 2016 (UTC)

== Incorrect formulas ==

Recently I corrected the formula for the declination, but the formula for the average insolation over a day is also incorrect and I can't find where the mistake in the construction of the formula is.
On this wiki the formula is <math>\overline Q ^{day} =\frac{S_0}{\pi}\frac{R_0^2}{R_E^2}[h_0\sin(\phi)\sin(\delta)+\cos(\phi)cos(\delta)sin(h_0)]
</math>, but the correct formula is: <math>\overline Q ^{day} =\frac{S_0}{\pi}\frac{R_0^2}{R_E^2}[\sin(\phi)\sin(\delta)+\cos(\phi)cos(\delta)sin(h_0)]
</math>(so without the h<sub>0</sub>)
<ref>http://www.azimuthproject.org/azimuth/show/Insolation#details</ref>
[[User:Xyfonix|Xyfonix]] ([[User talk:Xyfonix|talk]]) 08:36, 9 March 2017 (UTC)
{{Talk page reference}}
:The web page you cite says that it copied the formula from Wikipedia, specifically the [[Insolation]] article that was merged into this one. It is likely the author of that page made a mistake in copying. Actually doing the integration shows that the result with the h is the correct one. [[User:StarryGrandma|StarryGrandma]] ([[User talk:StarryGrandma|talk]]) 08:01, 10 March 2017 (UTC)
: A good reference for the calculation of the daily insolation is {{cite book|last= MacDonald |first=G. J. |editor=Gordon J. MacDonald; Luigi Sertorio |title=Global Climate and Ecosystem Change |url=https://books.google.com/books?id=M3UECAAAQBAJ&pg=PA49|date=2013 |publisher=Springer Science & Business Media |isbn=978-1-4899-2483-4 |pages=49–57 |chapter=Global Climate Change}} [[User:StarryGrandma|StarryGrandma]] ([[User talk:StarryGrandma|talk]]) 16:18, 10 March 2017 (UTC)

== Unit of measure "Suns" ==

The cited source does not refer to "Suns" as a unit of measure. This claim should be deleted or it should have a citation that clearly defines "Suns" as a COMMON unit of measure for irradiance. An internet search produced no results that refer to "Suns" as a measure of irradiance, much less as a common UOM. Furthermore, if there is such a UOM, it probably should not be capitalized. Almost all UOMs are not capitalized, even if they derive from a proper noun (e.g., watt, newton, ampere). [[User:HolyT|Holy]] ([[User talk:HolyT|talk]]) 23:16, 3 August 2017 (UTC)
:The only use of "sun" as a unit that I can find is on a [https://www.newport.com/t/introduction-to-solar-radiation company website] where it says "For Solar Simulators, it is convenient to describe the irradiance of the simulator in 'suns.' One 'sun' is equivalent to irradiance of one solar constant." The company sells solar simulators and the unit appears to refer to the equipment, not the sun itself, and is not 1000 w/m2. The original statement in the article as added in 2007 to the [[Insolation]] article before the merge is: "The insolation of the sun can also be expressed in Suns, where one Sun equals 1000 W/m<sup>2</sup> at the point of arrival. One Sun is a unit of power, not a standard value for actual insolation." No reference was given at the time. It does not seem to be a standard unit and may have been originally be meant to be an explanation rather than an actual unit. I think the whole paragraph can be removed. [[User:StarryGrandma|StarryGrandma]] ([[User talk:StarryGrandma|talk]]) 17:12, 4 August 2017 (UTC)

Agreed, that there is not enough general usage of the term, either in literature or in actual discussions of the topic. The lack of a definition by any solar industry heavyweight suggests this is just a term that perhaps an equipment maker or installer used to help describe the concept. Recommend removal. [[User:WardEnerWat|WardEnerWat]] ([[User talk:WardEnerWat|talk]]) 23:03, 13 September 2017 (UTC)
:I have removed it. [[User:StarryGrandma|StarryGrandma]] ([[User talk:StarryGrandma|talk]]) 20:51, 17 September 2017 (UTC)

Latest revision as of 14:44, 9 October 2024

Fundamental Question to all

[edit]

Doesn't the magnetosphere interfere with "solar radiation"? Shouldnt the subtractions from space insolation include Earth magnetosphere caused reductions? Didnt see magnetosphere in intro paragraph of this topic. Or did i miss something? Thanks to all. Mike H. mlhootenoutlook

Erroneous table?

[edit]

The table under Solar_irradiance#Applications is confusing at best and possibly profoundly erroneous. In general you cannot convert between power and energy without knowing time. In this table (pasted to the side), it appears the assumption is 24 hours per day of full sun, which is not true for any spot on earth. I suggest that we delete the entire table.

Conversion factor (multiply top row by factor to obtain side column)
W/m2 kW·h/(m2·day) sun hours/day kWh/(m2·y) kWh/(kWp·y)
W/m2 1 41.66666 41.66666 0.1140796 0.1521061
kW·h/(m2·day) 0.024 1 1 0.0027379 0.0036505
sun hours/day 0.024 1 1 0.0027379 0.0036505
kWh/(m2·y) 8.765813 365.2422 365.2422 1 1.333333
kWh/(kWp·y) 6.574360 273.9316 273.9316 0.75 1

I would love to hear your thoughts.

--Lonny (LRG) (talk) 21:52, 9 April 2020 (UTC)[reply]

The table is correct. All quantities are (or are equivalent to) power per unit area. In the case of sun-hour/day, a sun-hour is defined as one hour of 1kW/m^2 irradiation per day = 1kWh/(m^2 day). In the case of kWh/(kWp year), it is equivalent to a measure of the average irradiance during a year. --Ita140188 (talk) 03:15, 10 April 2020 (UTC)[reply]
I am not sure about how useful it is though. These quantities can be compared in terms of units, but they represent very different things, so a conversion table is not that useful in my opinion, and may be misleading. So personally I am ok with removing it. --Ita140188 (talk) 03:18, 10 April 2020 (UTC)[reply]
Confusion about this table is what brought me here. I would be in favor of removal. My confusion is rooted in the fact that 1kWp = 1kW/m^2. So where does the factor of .75 come from in converting kWh/(m2·y) to kWh/(kWp·y). I believe it should be one-to-one. Gilles Ottervanger (talk) 14:44, 9 October 2024 (UTC)[reply]

Solar radiation is a synonym?

[edit]

Have I got it right when I say that solar radiation is a synonym for solar irradiation? If so, I'd like to add it to the first sentence. The term does redirect here already. Pinging User:Bikesrcool. EMsmile (talk) 11:03, 19 April 2024 (UTC)[reply]

Irradiance typically implies use of power flux units (power/area). Radiation is the generic or looser term as I understand; might be accompanied by units of power, energy, power/area, energy/area, power/solid angle, etc. Bikesrcool (talk) 12:26, 20 April 2024 (UTC)[reply]
Thanks! I think we should explain this in the article, perhaps in a new section on definition or terminology? I mean it's a bit odd that "solar radiation" redirects to this article but is not explained explicitly w.r.t how it differs to solar irradiance. For what it's worth I posed the question to Chat GPT ("is solar radiation the same as solar irradiance?") and got this answer: "Solar radiation and solar irradiance are related concepts but not exactly the same.
Solar radiation refers to the electromagnetic energy emitted by the Sun. This energy includes visible light, infrared radiation, ultraviolet radiation, and other forms of electromagnetic radiation.
Solar irradiance, on the other hand, specifically refers to the power per unit area (typically measured in watts per square meter) of solar radiation received at a given location on Earth's surface. It represents the intensity of solar radiation incident on a surface.
In simpler terms, solar radiation is the total energy emitted by the Sun, while solar irradiance is the amount of that energy received per unit area on the Earth's surface." EMsmile (talk) 16:23, 21 April 2024 (UTC)[reply]
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