Talk:Solar constant

Units

Per what unit time seconds minutes? (William M. Connolley 12:46, 25 Mar 2005 (UTC)) W/m2.

Joules / second / meter sq, because W = J/s (Cruzlee 00:34, 18 June 2006 (UTC))

The solar constant is given in kilowatts which is wrong. Compare e.g. the German page Solarkonstante which says: "die Bestrahlungsstärke auf der Erde zwischen 1325 W/m² und 1420 W/m²."

Since I don't have an account I must leave the correction to someone else. (Erik). — Preceding unsigned comment added by 217.209.225.87 (talk) 19:44, 18 June 2011 (UTC)

No correction needed; the units are equivalent. For example, 1.366 kW/m² equals 1366 W/m². The solar constant can be stated either way. Hertz1888 (talk) 23:08, 18 June 2011 (UTC)

The statement at the end of para 3:

The approximate average value cited,<ref name=KoppLean11 /> 1.361 kW/m², is equivalent to 1.952 calories per minute per square centimeter, or 1.952 langleys (Ly)—or, in SI units— about 81.672 kJ/m² per minute.

does not compute. 1W is by definition 1J per second, so to convert W to J per minute just multiply by 60. The given 1.361 kW/m² is therefore exactly 81.66 kJ/m² per minute, not 81.672 as given here. Suggest:

The approximate average value cited,<ref name=KoppLean11 /> 1.361 kW/m², which is 81.66 kJ/m² per minute, is equivalent to approximately 1.952 calories per minute per square centimeter, or 1.952 langleys (Ly). 86.186.147.246 (talk) 13:03, 27 May 2013 (UTC)

 Done Good catch. Edit made (with minor wording change). Hertz1888 (talk) 03:24, 29 May 2013 (UTC)

There is still a problem because the minute is not an SI unit as implied here, the value in kW/m² is already SI. — Preceding unsigned comment added by Grandchant (talk • contribs) 10:10, 27 February 2014 (UTC)

This article should mention Gcs. There is a good description of measurement at http://www.springer.com/978-1-4471-4648-3 "extraterrestrial radiation fluctuates about 6.9 % during a year (from 1412.0 Wm-2 in January to 1321.0 Wm-2 in July) due to the Earth’s varying distance from the Sun" "The integration of the extraterrestrial spectrum over all wavelengths defines the solar constant Gsc. Thus, Gsc represents the flux density of incoming solar radiation on a unitary surface perpendicular to the rays at the mean Sun–Earth distance." "Based on data collected over 25 years from terrestrial to space observations, the actual best estimate of the average solar constant is GSC = 1366.1 Wm-2" 75.166.53.52 (talk) 22:26, 16 September 2016 (UTC)

although the scientific consensus is that solar variations do not play a major role in determining present-day observed climate change.

This appears to be misattributed. Dr Joanna D. Haigh is not talking about scientific consensus with The Sun and the Earth’s Climate Someone who cares needs to provide a real link to the "scientific consensus" regarding the solar constant to support this claim or this should be removed.

In fact Dr. Haigh writes, "The absolute radiometerscarried by satellites since the late 1970s have produced indisputable evidence that total solarirradiance varies systematically over the 11-year sunspot cycle, relegating to history the term “solar constant”, but it is difficult to explain how the apparent response to the Sun, seen inmany climate records, can be brought about by these rather small changes in radiation."

What she's saying is that SOLAR CONSTANT is really an old term and that new technologies are showing that the sun's output is not constant. Her viewpoint is not reflected here. How can we be so clumsy in our writing here?

Also, why must AGW theory be peppered into this topic anyway and why is it the leadin? It's unecessary clumsy and gives a very biased impression of Wikipedia. If this article is about the solar constant, it should be about the solar constant and if there is a minor tangental interest to AGW theory, we can point to that but to make AGW the centerpiece here is agenda driven. 174.49.84.214 (talk) 14:25, 8 November 2011 (UTC)

Also, when we cite something, we should not cite an entire website. It's very difficult to go dig through an entire site to find a reference. Citations should be discrete and follow standard format. All this citation says is Joanna Haig. This is horrible work and almost tantamount to defacing. Whoever did this did not care about Wikipedia and it's content, they just cared about getting their message out. We need to be neater. It's almost like people are trying to hide things.174.49.84.214 (talk) 14:29, 8 November 2011 (UTC)

Solar constant & solar variation

1. Solar constant is just a definition of solar irradiance at 1AU.
2. Solar variation encompasses all variations in the sun's output
3. Solar cycle is one type of solar variation

The solar constant has been disproven by satellite observations, the sun's output vary over time as described by Dr. Joanna Haigh of MetOffice.

Why do we have largely a ProAGW solar variation section in the solar constant page? Not only that but it's filled with missattributions and misquotes and very poorly referenced.174.49.84.214 (talk) 14:55, 8 November 2011 (UTC)

Talk:Solar_cycle#One_page_to_rule_them_all William M. Connolley (talk) 15:32, 8 November 2011 (UTC)

Thank you William M. Connolley. I, like others, contend that the solar cycle is big enough of a topic that it merits its own page and will keep less hands in the pot than there would be if it were moved to solar variation. If we merge solar cycle and solar variation we're going to get two different groups smashed together not to mention the AGW crowd who will also be present. We should have a summary of solar cycle within solar variation and direct to solar cycle.174.49.84.214 (talk) 15:52, 8 November 2011 (UTC)

However, that still begs the question of why we have a poorly written pro AGW solar variation section within the solar constant article when there is a full article on solar variation already.174.49.84.214 (talk) 15:52, 8 November 2011 (UTC)

Found it! William M. Connolley, On 2 October 2010, you added a whole ProAGW Variation Section taking the article from 5,000 bytes to 28,000 bytes. Why? This AGW stuff is entirely out of place and this is the solar constant not the solar variation page. Can you explain? I'd like to remove this entire section. It's poorly written. It's an AGW war now (by that I mean that editors have made swiss cheese to any cohesiveness the article might have had). It misquotes and miscites people. There is some good content onthere but it doesn't belong under SOLAR CONSTANT. Where do you suggest this be moved to? It seems to me you made the mess that you now purport to try to clean up. 174.49.84.214 (talk) 13:29, 9 November 2011 (UTC)

And under no circumstances should the AGW crowd do the combining: these topics are on stellar physics. Where they impact our climate we note those impacts and current scientific understanding from physicists and where we think those impacts relate to global warming we link out to climate change or global warming as appropriate but AGW should NOT be the leadin on these topics. I hope we can agree on that.174.49.84.214 (talk) 16:07, 8 November 2011 (UTC)

I believe the value for the solar constant here (1361 W/m^2) is not given full clarification. The value of 1360.8 discussed in Kopp and Lean (2011) is presented as a value valid for the solar cycle minima of 2008. It is intended to be valid as a minima, not as a generally valid solar constant. At very minumum, I believe the following changes should be considered:

1. If we are to leave the value of 1360.8 W/m^2, it should be noted as a minima in the 11-year solar cycle, with an amplitude of 1.6 W/m^2, as noted in the paper. This would suggest a mean solar constant of 1361.6 W/m^2
2. There must be a discussion of the various values used in other sources. Kopp and Lean is a valid source, but, for example, "Li, H., Lian, Y., Wang, X., Ma, W., & Zhao, L. (2011). Solar constant values for estimating solar radiation. Energy , 1785-1789." discusses other commonly used values of 1353-1373 W/m^2 and concludes that various values have different regions of validity. To neglect this variation does not necessarily detract from the validity of the article as stated, but it does cause confusion when attempting to cross-reference Wikipedia with other sources. 128.244.9.7 (talk) 02:06, 7 March 2012 (UTC)

Clarifying wording added to address first point. Since the difference between minimum and average is less than one part in 1000, the term "roughly" should cover giving the typical value with sufficient precision. However, the text now expressly identifies the "roughly 1361" value as corresponding to solar minimum. I have not addressed your second point, a discussion of values from other sources. That may or may not be within the scope of this article. Hertz1888 (talk) 03:56, 7 March 2012 (UTC)

Historical perspective

This historical perspective is basically a long quote from a book on the discovery of global warming and about sunspot cycles. It bears little to no relevance to the solar constant. What it is doing here is beyond me and by that I mean that it makes zero sense for this section to be here. It's not even historical to the solar constant!174.49.84.214 (talk) 17:49, 8 November 2011 (UTC)

Variation

It really appears that this whole section is just a bad rehash of the climate change debate and the role that the sun plays. With people just digging for any quote that they can to make their point. There are some decent quotes here on both sides of the argument but the debate is just in the wrong article page --- this whole section probably belongs under a solar influence section of the global warming controversy article (and let those guys go at it). This page is about the Solar Constant, a concept that is now largely disproven and then direct the reader to solar variation.174.49.84.214 (talk) 19:31, 8 November 2011 (UTC)

William M. Connolley. On 2 October 2010, you added a whole ProAGW Variation Section taking the article from 5,000 bytes to 28,000 bytes. Why? This AGW stuff is entirely out of place and this is the solar constant not the solar variation page. Can you explain? I'd like to remove this entire section. It's poorly written. It's an AGW war now (by that I mean that editors have made swiss cheese to any cohesiveness the article might have had). It misquotes and miscites people. There is some good content onthere but it doesn't belong under SOLAR CONSTANT. Where do you suggest this be moved to? It seems to me you made the mess that you now purport to try to clean up :-)174.49.84.214 (talk) 20:35, 8 November 2011 (UTC)

So No William M. Connolley, these pages should remain discrete but we should remove the proAGW clutter you added over a year ago. The ProAGW content on the solar constant page is wildly out of place and you should refrain from cluttering ancillary pages with ProAGW sections where none are merited.174.49.84.214 (talk) 21:24, 8 November 2011 (UTC)

Solar irradiance

I think, the right word for this article should be "solar irradiance" but I am not shure in english terms here, I hope, some people who understand this wil chage it, if I am right. --Nolanus (talk) 14:53, 22 May 2012 (UTC)

In English, "irradiance" refers to the ratio of power and area, that is, W/m². Any value for this ratio is an irradiance. Solar irradiance could refer to any irradiance measured anywhere in space. The term "Solar constant" refers specifically to the irradiance just outside Earth's atmosphere. So the title of the article is correct, because it refers to a particular irradiance, and not just any solar irradiance.----189.248.160.44 (talk) 21:52, 7 April 2017 (UTC)

"Solar constant"

The [1] SORCE mission calls the "solar constant" a "misconception". It is NOT a physical constant such as the CODATA maintained by NIST. The discussion mentions its variation and that it is NOT a "constant". Consequently, to clearly show that it is not a physical "constant", as used in the scientific world, I placed all occurances in quotes (except the main title.)DLH (talk) 19:06, 1 January 2015 (UTC)

I do not feel we are entitled to change the traditional presentation of the term on the basis of one published comment. I have instead rewritten the lead to explain at the outset that the solar constant is not constant, and not a physical constant as such, referencing the SORCE URL. I have also removed the repetitive scare quotes, which would seem to distract more than inform. Thanks for your other changes. Hertz1888 (talk) 19:59, 1 January 2015 (UTC)

The quotes provided are NOT "scare quotes". I provided the quotes are the formal method to distinguish unusual from conventional scientific usage. I followed the explicit formal usage established by the SORCE scientific team: It was not until long-duration measurements from space were available that changes in TSI were accurately measured and the misconception of a “solar constant” changed. Similarly, the Encyclopedia Brittanica uses: The “constant” is fairly constant, increasing by only 0.2 percent at the peak of each 11-year solar cycle. Following this usage, I have restored the quotes to at least one occurrence.DLH (talk) 22:26, 1 January 2015 (UTC)

That looks proper, putting the quotes around "constant" only. Hertz1888 (talk) 22:42, 1 January 2015 (UTC)

I agree, there is no need to stress that the Solar constant is not actually absolutely constant. It is understood that it is just a traditional way of referring to this mean value, which is useful in solar calculations. Nevertheless, I still added a clarification mentioning that it is not like Planck constant or the speed of light, which are real constants in physics.----189.248.160.44 (talk) 22:15, 7 April 2017 (UTC)

Nice picture but...

...it shows two curves. Presumably the black one integrates to 1667 Watt/m² and the red one integrates to 1661 Watt/m². The difference between the two curves should be explained. --Herbmuell (talk) 04:50, 6 January 2017 (UTC)

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