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Archive for March, 2011

Circles and dimensions

March 28, 2011 Leave a comment

Gold appeared during a detailed technical web search, complete wrong context for what I wanted but one of the strangest happened upons ever for me.

I will present the cross check first, this has a very real basis.

The Wiltshire Heritage Museum is based in Devizes, Wiltshire. Not so far from here and now I must visit when the opportunity arises. I know the henge area, where my father grew up, know this from the times where our heritage was ours and not stolen by the exploiters.

http://www.wiltshireheritage.org.uk/

A bizarre artefact held Is the Bush Barrow “lozenge”

http://www.wiltshireheritage.org.uk/galleries/index.php?Action=3&obID=89&prevID=9

A new zealander has written his interpretation of what this is

http://www.celticnz.co.nz/BBLOZ/BBLOZWEB1.htm

Enjoy.

Out of politeness here is his home page where there is a lot more in articles

http://www.celticnz.co.nz/

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Categories: History Tags:

ERBS TSI

March 6, 2011 3 comments

As part of an ongoing investigation I looked at the ERBS TSI data. This dataset is not particularly interesting and  as with all satellite data is far too short to say much. One interesting snippet did appear.

Creating a rough model posed some problems but in practice was simple.

First was the data has a Y2K corrupted date which was kindly sorted out by V.

The sampling is irregular (scattered time points) which the software can usually handle if slowly. The result is unremarkable.

I’ve shown a fore and hindcast which indicates the model is stable and sane. It will be somewhat wrong.

A surprise came when I looked at a paper associated with the dataset where the final sentence of the conclusion is “The fact that the measurements increased with time relative to the proxies  suggests the existence of a second TSI variability component with an amplitude greater than 0.04% (0.5 Wm-2), and with a period greater or equal to approximately 20 years.”
A minor model component: 20.0432969909    3.69480925972    0.124480125667

Period just over 20 years, amplitude 0.125 * 2 * sqrt(2) = 0.35W p-p

With such short data that will be way out and TSI certainly is far more complex in the long term.

http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.81.834&rep=rep1&type=pdf

I’ve shown SORCE as well. This is not really TSI, is narrowband/is in my opinion incomplete [disputed, see comments]. It does however show the wide variation is measured values. Given the extreme difficulty in making these measurements the usual rule of thumb is sensible, the instrument must be at least an order more accurate and so for absolute maybe we know +-40W sq/m

Putting that into context 40W in 1360W is +-3% of absolute, not as easy as many will imagine and for a remote instrument is an intensely hostile environment would not be a surprise. Lets hope the instrument is returned to earth for post mission calibration checks. See the point?

“Validation of spacecraft active cavity radiometer total solar irradiance  [TSI] long-term measurement trends using proxy TSI least squares analyses

“aRobert Benjamin Lee III and bRobert S. Wilson
aNASA Langley Research Center, Atmospheric Sciences, MS 420, Hampton, VA 23681-2199
Science Application International Corp. (SAIC), One Enterprise Parkway, Hampton, VA 23666 ”

http://www.acrim.com/

A lot of interesting material on TSI  can be found here http://www.leif.org/research/

Categories: analysis, Modelling, solar