Diffuse Solar Radiation—A History
Question: Was the SURFRAD project originally designed to measure the Diffuse Solar radiation on our planet’s surface? I conclude ‘probably not.’ I explain why below.
First, some background: In 1896, an essay, titled “On the Influence of Carbonic Acid in the Air upon the Temperature of the Ground.” by Svante Arrhenius, was published in the Philosophical Magazine and Journal of Science.
This essay gave birth to the now popular idea, the greenhouse effect of the atmosphere (GHE), which had been conceived more than a half century earlier by Joseph Fourier.
This essay is a story about what I pondered about the data being measured and reported by a NOAA (National Ocean and Atmospheric Agency) project titled SURFRAD (Surface Radiation) begun in 1995. Of course, the project had to have been begun before this time because it had to have been designed and constructed before any radiations could have been measured.
This historical story began with the radiation balance calculation, reported by Arrhenius in his essay, involving the incoming radiation from the sun, ‘visible’ to our eyes, and the outgoing infrared radiation from the earth’s surfaces (ground), ‘invisible’ to our eyes and the controversy about the GHE it (his calculation) created.
Finally, by June 1, 1995, NOAA was reporting the measurements being made at 3 sites (Fort Peak, Montana; Bondville, Illinois; Goodwin Creek, Mississippi). Figure 1 is an example of one 24hr period of these measurements, being made each minute, were reported. There also is a data file of many, many numbers) which makes the data very challenging to generally digest without first studying the figures.
A critical part of my story is that, in Figure 1, only 5 of the 6 radiations listed in the legend were reported. This was also the case for the other two sites.
So, the first issue becomes about the missing diffuse radiation (brown line). The next critical issue of my story is that by December 1, a 4th site (Table Mountain, Colorado) had been added to the project and we see (Figure 2) all 6 radiations were reported.
However, at this time the Diffuse Solar at the 3 previous sites was still missing. By June 1, 1996 the Diffuse Solar was being reported at the Goodwin Creek site and by December 1, 1996 the Diffuse Solar was being reported at all 4 sites.
Based upon this ‘historical evidence’, I conclude that the SURFRAD project was probably not originally designed to measure the Diffuse Solar radiation.
Another reason for this conclusion is that when I shared a sample of the SURFRAD data with a friend (who can be forthright). He had been a chemical engineer for about 3 decades with DuPont, he asked: what was this Diffuse Solar radiation? From which I conclude that Diffuse Solar radiation might not be really obvious (or can be easily overlooked as being a fundamental radiation like the other 5).
To understand what I have concluded, as ‘a probably‘, I ask: Why does any scientist make a special effort to do any experiment?
My answer: a scientist does an experiments because it is not known what might be the result of the experiment. So, in this story it is not my intent to be critical of the NOAA scientists if they did design the project without designing an instrument to measure the Diffuse Solar radiation (I certainly do not know if this was the case).
However, based upon personal experiences, I can imagine it could have happened.
And to make the point that the obvious is easily overlooked, I am going to cut this story short, relative to what I had previously written in its first draft, in order to challenge (ask) any reader who is generally critical of the NOAA scientists (of whom it seems there are more than a few): what do you see in Figure 1 that points to the need of the 6th solar radiation—Diffuse Solar?
So, either answer this question by reporting your answer as a comment or cease making comments, or writing articles, critical of NOAA scientists. For the evidence is that if they didn’t design the project to measure the Diffuse Solar, they quickly did design and construct the instrument necessary to measure the Diffuse Solar radiation.
After giving someone a chance to correctly answer my question (once you see what can be seen, there should be no debate as to what the correct answer is), I will continue my story about what else I discovered, which I did not intend to discover when I began this essay. But be reminded, only one can be first.
PRINCIPIA SCIENTIFIC INTERNATIONAL, legally registered in the UK as a company 
incorporated for charitable purposes. Head Office: 27 Old Gloucester Street, London WC1N 3AX. Telephone:
Please DONATE TODAY To Help Our Non-Profit Mission To Defend The Scientific Method.
Trackback from your site.
DC
| #
Once again we have a PSI article barking up the wrong tree. The global mean surface temperatures of planets like Earth and Venus is not primarily determined by radiation of any kind. The correct physics is in my paper “Planetary Core and Surface Temperatures” derived from the laws of physics and supported by copious evidence on Earth and throughout the Solar System.
Reply
Michael D
| #
DC, I would love to read your work and watch any videos you have. Please let me know where to find them.
Reply
jerry krause
| #
Additional information about the SURFRAD project and the measusrement of the diffuse solar.
The downwelling Solar Radiation seems to have been initially only measured with an upward-viewing
Broadband pyranometer. A silicon pyranometer
(https://www.ncdc.noaa.gov/crn/instruments.html)
“Radiation measurements at SURFRAD stations cover the range of the electromagnetic spectrum that affects the earth/atmosphere system. Direct solar radiation is monitored with a Normal Incidence Pyrheliometer (or NIP) mounted on the solar tracker. Downwelling global solar radiation is measured by an upward-viewing broadband pyranometer. The diffuse, or sky component, of solar radiation is measured by a shaded Eppley 8-48 pyranometer mounted on a platform that is attached to the solar tracker. A ball shades the sensor of the diffuse pyranometer, thus allowing only the radiation scattered by the atmosphere to be measured.”
(https://catalog.data.gov/dataset/surface-radiation-budget-surfrad-network-1-hour-observations)
Station(s): Bondville, Fort Peck, Goodwin Creek, Table Mt., Desert Rock, Penn State
Parameter(s): net solar, total net
Date(s): Entire record
Description of Problem:
”Improvements to the processing code that enable a better calculation of net solar radiation have been implemented. Before this change, net solar radiation was computed using the global solar measurement as the downwelling component. If that parameter was missing, net solar, and thus total net radiation, was reported as missing. Now, net solar is computed using total solar (direct + diffuse) as the primary downwelling solar quantity, and if either direct or diffuse is missing, the global solar measurement is then used to compute net solar calculation.
All data from the time shaded pyranometers were added to the SURFRAD stations to July 4, 2002 (the date when the improved code became operational) were reprocessed. This was finished on July 22, 2002. The only effects on the data files are that the net solar and net radiation have been changed. No other variables have been affected. (https://www.esrl.noaa.gov/gmd/grad/surfrad/problems.html)
(https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2012JD017945) From abstract: “This paper compares Rsfrom 1995 to 2011 at collocated sites collected by the Surface Radiation Budget Network (SURFRAD), the U.S. Climate Reference Network (USCRN) and the AmeriFlux network. SURFRAD stations have measured separately the diffuse and direct components of Rs as well as Rs by a pyranometer, while Rs was measured by a pyranometer or a net radiometer at the USCRN and AmeriFlux sites. Rs can be calculated by summing the diffuse and direction radiation measurements. Rs measured by the summation technique was compared those measured by a pyranometer or a net radiometer at collocated sites
.
From Results: “Figure 2 shows as an example the time series of hourly data for the week of 13–19 July 2006 (days of year 194 to 200). This period is selected because (1) it was clear (cloud free) at all four locations on days 196 and 197 and (2) all the data were available during the period. Figure 3 shows the differences between hourly Rs collected by a pyranometer (or a net radiometer) and the component sum (direct plus diffuse) collected at the SURFRAD sites.”
I have studied SURFRAD at length and when I look specifically at the data of days 196 and 197, I have to conclude that these two days are far from ‘clear (cloud free) at all four locations. In fact I would be so bold to state that there are no cloud free atmospheres. In this comment I cannot illustrate why I conclude this figures cannot be submitted when making comments. But if John O’Sullivan considers it important enough to compare the eight 24hr periods with one of two I do consider that the data indicates are apparently cloudless, I would do so.
“Using the direct plus diffuse measurements at the SURFRAD sites as a reference, the hourly Rs collected by a pyranometer or a net radiometer at the three networks has a standard deviation varying from 1.3% to 7.5%, with an average of 3.9% ± 2.2%. Previous studies have shown that, under ideal conditions, Rs collected by a typical single pyranometer has a standard deviation of ∼2.5% (or an uncertainty of ±5% at 95% confidence level) and Rs calculated from diffuse and direct radiation component has a standard deviation error of ∼1% [Gueymard and Myers, 2008; Reda, 2011; Stoffel and Myers, 2010]. Our results are consistent with these past estimates, indicating all the instruments were well maintained and calibrated.”
I quote this because it seems that the designers of the instrumentation of this project did not initially include “a shaded Eppley 8-48 pyranometer mounted on a platform that is attached to the solar tracker. A ball shades the sensor of the diffuse pyranometer, thus allowing only the radiation scattered by the atmosphere to be measured.” (From a prevision quote.) And I doubt that the measurement of diffuse solar was added because of the improved precision of adding the diffuse solar to the direct-normal-solar to calculate the total downwelling solar instead of directly measuring it with an upward-viewing broadband pyranometer
Reply