Comments for AGW Observer

Comment on Papers on the Milankovitch cycles and climate by Ari Jokimäki

Ari Jokimäki — Mon, 10 Jun 2013 06:06:32 +0000

Thanks for the links, Bob. I have fixed the ADS links in your posts above. It seems that WordPress didn’t like the successive dots in the links. If you need to post further links to ADS, you can do either do it like you did above and I’ll fix the links or you can use A HREF HTML tag to include the link without putting the URL in the visible part of the tag, but instead paper name or something like I did above.

Comment on Papers on the Milankovitch cycles and climate by Bob Brand

Bob Brand — Mon, 10 Jun 2013 04:11:41 +0000

Ari Jokimäki,

You might add this page with forcing data to my comment above, if you wish. It is a useful resource for those reading up on Milankovic cycles:

http://www.ncdc.noaa.gov/paleo/forcing.html

Comment on Papers on the Milankovitch cycles and climate by Bob Brand

Bob Brand — Mon, 10 Jun 2013 03:53:45 +0000

Please excuse me - the strange URL's from Adsabs don't seem to work here. Maybe this link ought to work: Link to full text PDF of Quinn et al. (1991) It concerns: A THREE MILLION YEAR INTEGRATION OF THE EARTH'S ORBIT THOMAS R. QUINN Department of Astrophysics, Oxford University Ii is cited extensively, so if you google it you will find plenty of work referencing this seminal paper.

Comment on Papers on the Milankovitch cycles and climate by Bob Brand

Bob Brand — Mon, 10 Jun 2013 03:45:46 +0000

Shirley Nicholson,

You should read up on astronomical papers by Quinn et al. (1991) and in particular by Berger and Loutre of Louvain University in Belgium. They have calculated the changes in precession, obliquity and eccentricity with remarkable precision for millions of years into the past and into the future.

There can be little doubt about the regular changes in the inclination of the Earth’s axis, since these are consequences of planetary mechanics – large variations would mean an unstable solar system and planets disappearing into the void, or into the sun. However, the exact *timing* and interrelationship of precession, obliquity and eccentricity gets somewhat uncertain beyond ca. 10 or 20 million years into the past or into the future.

This is due to variations in the ocean tides on Earth and resonances between lunar and planetary orbits. You could start reading here:

A three million year integration of the earth’s orbit – Quinn et al. (1991)
Orbital, precessional, and insolation quantities for the Earth from -20 MYR to +10 MYR – Laskar et al. (1993)

http://www.dvfu.ru/meteo/library/243887.pdf
http://www.sciencemag.org/content/297/5585/1287.summary
https://pangea.stanford.edu/research/Oceans/GES205/MIS11FutureClimateModeling.pdf

Comment on Papers on precipitation and global warming by Ari Jokimäki

Ari Jokimäki — Thu, 23 May 2013 07:16:42 +0000

I added Zhang et al. (2007) and some regional studies.

Comment on Papers on tropopause height by jyyh

jyyh — Wed, 22 May 2013 05:23:22 +0000

might I add the cirrus cloud top method of determining the tropopause height is intuitive since the temperature starts to go up in the stratosphere. rawinsonde – cirrus top height might be a measure of water vapor exchange between troposphere and stratosphere. since it’s well known the overshooting tops of cumulonimbus clouds enter the stratosphere, indetifying trends in these (somewhat easy to identify from satellite photos might give an indication of how much water vapor enters stratosphere.

Comment on Papers on tropopause height by Another Week of Anthropocene Antics, May 12, 2013 – A Few Things Ill Considered

Tue, 14 May 2013 02:37:25 +0000

[…] 2013/05/07: AGWObserver: Papers on tropopause height […]

Comment on Papers on tropopause height by Ari Jokimäki

Ari Jokimäki — Sun, 12 May 2013 13:13:04 +0000

Thanks! I couldn't find journal where that paper has been published, so it might not be peer-reviewed document (could be some conference paper or such). I found some other papers from them and I added Lakkis et al. (2009) to the list as it seems to be quite similar to the paper you suggested.

Comment on Papers on the Milankovitch cycles and climate by Shirley Nicholson

Shirley Nicholson — Sun, 12 May 2013 03:17:44 +0000

Can anyone cite a critique of the Milankovich hypothesis written by an astronomer, one who specialises in celestial mechanics, and not by a geologist or paleo-climatologist? The little I know about this subject suggests, that the invariable approximations in the calculations lead to huge inaccuracies if the methods Milankovich used are projected over more than a few tens of thousands of years, and are therefore not valid for longer periods. Astronomy normally works by checking theoretical predictions by observation and correcting them when necessary, which does not happen here. While it is probably true that variations in the earth’s orbit round the sun affect the climate, I very much doubt if these variations could ever be calculated far into the past or projected far into the future. It is not satisfactory when geology and climate science are used to verify the astronomy, as usually seems to be the case here.

Comment on Papers on tropopause height by jyyh

jyyh — Sat, 11 May 2013 08:58:12 +0000

rawinsonde vs cirrus cloud tops in measuring the tropopause height over Beunos Aires: http://www.uca.edu.ar/uca/common/grupo72/files/Local_study_of_tropopause.pdf