In July 2013, Geoengineeringwatch.org made the claim that UVB levels were at incredibly high levels, or around 9 mw/cm2 (milliwatts per square centimeter). That was a rather extreme claim, as the levels of UVB in space are just 2.5 mw/cm2, and given that the atmosphere block a lot of that, it's impossible to get MORE UVB actually reaching the ground. So obviously this must be wrong.
The questions of WHY is was wrong were not immediately apparent, but they helpfully showed the instruments they were using, and it turned out that the most likely source of their error was that they were calculating UVB by subtracting UVA measured on one meter from UVA+UVB measured on another.
That would be fine, except that the UVA+UVB meter was actually measuring quite a bit more UVA than the UVA meter, so the end result was a vastly inflated UVB number.
This makes perfect sense. Even though it does not sound like a lot, the actual amount of extra radiation (reaching the surface)in those UVA bands is much higher than all the UVB radiation.
So that seemed to settle the matter. Unfortunately it was just brought up again:
http://www.geoengineeringwatch.org/record-shattering-uv-radiation-levels-finally-confirmed/
http://journal.frontiersin.org/Journal/10.3389/fenvs.2014.00019/full
And it does indeed say "Record solar UV irradiance in the tropical Andes", but what are these records? And how do they compare to the Geoengineering Watch figures? Their record levels of UVB were on one day, Jan 17, 2004, measured at around 5000m (16,400 ft).
So that's the new record. 0.815 mW/cm2. While the record GeoengineeringWatch is claiming is 9.0 mW/cm2. That's ten times higher than the value they say confirms their result.
Another metric used by the study is the ratio of UVA to UVB:
So far from "confirming" their original measurements, this study quite roundly debunks them.
The questions of WHY is was wrong were not immediately apparent, but they helpfully showed the instruments they were using, and it turned out that the most likely source of their error was that they were calculating UVB by subtracting UVA measured on one meter from UVA+UVB measured on another.
That would be fine, except that the UVA+UVB meter was actually measuring quite a bit more UVA than the UVA meter, so the end result was a vastly inflated UVB number.
I checked the two instruments he said he was using:
General Tools UVAB-513 for the UV AB measurement
Omega HHUV254SD for the UVA measurement.
Now the first device measures in the range 280 to 400 nm.
The second one measures in the range 240 to 390 nm with UVA+UVC sensors, the range for the UVA sensor alone is not specified.
However, it is clear that the upper limit of the Omega instrument is 390 nm.
That means that if you measure UVAB with the first instrument and subtract the UVA measured by the second instrument, the difference will not only include the UVB region but also the 390-400 nm region.
Which means that it is not possible to measure UVB by measuring UVAB and UVA with different instruments and just take the difference.
It's even worse if they used the UVAB-513 for both measurements:
UVA range as measured by its UVA sensor is 320 to 380 nm.
UVAB range measured by its UVAB sensor is 280 to 400 nm.
So if you take the difference you will not get the 280 to 320 region, but also the 380 to 400 nm region.
So the power difference will include UVB plus the power in the 380-400 nm region (which is pretty large).
That's why this measurement method is plainly wrong.
This makes perfect sense. Even though it does not sound like a lot, the actual amount of extra radiation (reaching the surface)in those UVA bands is much higher than all the UVB radiation.
So that seemed to settle the matter. Unfortunately it was just brought up again:
http://www.geoengineeringwatch.org/record-shattering-uv-radiation-levels-finally-confirmed/
The actual report is here:Over a year ago geoengineeringwatch.org reported on the extreme UV radiation levels that were already occurring around the globe due to the ongoing climate engineering. Many in academia flatly disputed our reports in spite of the fact that all of our data was and is based on actual metering with state of the art meters. The disinformation also did their best to dispute our reports but their attempts failed miserably. Now, finally, confirmation has come from a peer reviewed report.
http://journal.frontiersin.org/Journal/10.3389/fenvs.2014.00019/full
And it does indeed say "Record solar UV irradiance in the tropical Andes", but what are these records? And how do they compare to the Geoengineering Watch figures? Their record levels of UVB were on one day, Jan 17, 2004, measured at around 5000m (16,400 ft).
8.15 W/m2 is 815 µW/cm2, or 0.815 mW/cm2It peaked at ~8.15 W m−2, exceeding modeled clear-sky of UV-B = 6.4 W m−2, UVI = 66 for a modeled column ozone of 75 DU at 14:30 UTC (SZA = 30.5°).
So that's the new record. 0.815 mW/cm2. While the record GeoengineeringWatch is claiming is 9.0 mW/cm2. That's ten times higher than the value they say confirms their result.
Another metric used by the study is the ratio of UVA to UVB:
So we have a record value of 0.129, while the record Geoengineeringwatch is claiming is around 0.800These are the highest values ever recorded anywhere on Earth. Each major event was preceded by several days of rising UV-B/UV-A ratio, with the highest value (0.129) recorded on December 29, 2003
So far from "confirming" their original measurements, this study quite roundly debunks them.
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