Speaking to some astronomer friends, they say the Pinatubo eruption effect was
certainly measurable as a (pretty much global) change in the extinction
properties of the atmosphere, adding an important "grey" aerosol contribution
to the usual reddening (one study). From New Zealand, once the particulates
reached them (after about 80 days), the extinction in the V-band around 550 nm
increased from 0.13 to 0.21 magnitude/airmass (similar to other temperature
sites both north and south - reference). A similar change was observed for the
eruption of El Chichon. These analyses suggest that the settling time for all
measurable extinction effects of these eruptions can be decades. You can see
the increase in extinction in the U, B, and V passbands very clearly in this
figure http://adsbit.harvard.edu/cgi-bin/t2...&filetype=.gif from the paper by
Burki et al., Astronomy and Astrophysics, 112, p. 383 (1995), available at
http://articles.adsabs.harvard.edu/f...6AS..112..383B A number of other
papers by observers at other locations confirm these results.
Robert Tulip
On Monday, 8 April 2019, 2:01:00 am AEST, Douglas MacMartin
<[email protected]> wrote:
There’s not that much ground-based astronomy in UV, relative to optical and IR
astronomy.
Impact on optical astronomy is straightforward; if you lose 5% of the direct
light, you need 5% longer integration time to get same number of photons.
Impact on IR astronomy is less obvious, as limited by the background from the
sky, which depends on water vapour and temperature through the atmospheric
column (with most telescopes being at 14000’ or so). Shouldn’t be hard to
estimate, I’ve never gotten someone interested enough to do the calculations
but I could try again (my other job is being on the design team for the Thirty
Meter Telescope).
I did ask people whether they noted anything after Pinatubo, and the answer I
got was no… that doesn’t mean there wasn’t an effect, but it wasn’t something
that the astronomy community by and large remembered.
From: [email protected] <[email protected]>On
Behalf Of Russell Seitz
Sent: Sunday, April 7, 2019 9:31 AM
To: geoengineering <[email protected]>
Subject: [geo] Re: SRM optical impacts
Why would reductions in the downwelling tropospheric light flux increase any
of the above? I'd instead ask instrumental astromomers what they think SO2
scattering would do in the UV , as they have a lot to lose from scattered
light, which can cost them contrast and degrade the signal to noise ratio in
interferometry and spectroscopy.
Try the Magellan and OWL teams
On Wednesday, April 3, 2019 at 7:47:35 AM UTC-4, Andrew Lockley wrote:
Has there been any investigation of SRM effects on vision? Eg perceived glare,
macular degeneration, corneal sunburn, vision development in infants, object
recognition when driving (and their equivalent in animals)?
Andrew Lockley
--
You received this message because you are subscribed to the Google Groups
"geoengineering" group.
To unsubscribe from this group and stop receiving emails from it, send an email
[email protected].
To post to this group, send email to [email protected].
Visit this group at https://groups.google.com/group/geoengineering.
For more options, visit https://groups.google.com/d/optout.
--
You received this message because you are subscribed to the Google Groups
"geoengineering" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to [email protected].
To post to this group, send email to [email protected].
Visit this group at https://groups.google.com/group/geoengineering.
For more options, visit https://groups.google.com/d/optout.
--
You received this message because you are subscribed to the Google Groups
"geoengineering" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to [email protected].
To post to this group, send email to [email protected].
Visit this group at https://groups.google.com/group/geoengineering.
For more options, visit https://groups.google.com/d/optout.
