The earth wobbles

The earth wobbles about in its rotation.  This was predicted long before it was observed, which is a story itself that I'll tell later.  For now, consider the earth and its rotation.  The north pole of the earth points towards the north star, and rotates once per day.  Open your right hand.  Your thumb points north, and when you close your fingers, they are moving in the direction of the earth's rotation.  With your arm making a right angle at the elbow, hand aiming away from your torso, you have an x-y coordinate system.  When you rotate your forearm, that moves your thumb in the x direction (positive or negative), when swing your arm forward/backward, that's the y direction.

The thing is, the earth (your thumb) doesn't always point in exactly the same direction.  There's a small bit of variation.  That's the wobble.  Since astronomers make their observations from the earth, it's very important to know exactly where the earth is pointing at any instant.  This lead (over 100 years ago) to the foundation of the IERS -- International Earth Rotation and Reference Systems Service.  Daily data from 1 January 1962 to (very nearly) the present are available at http://datacenter.iers.org/eop/-/somos/5Rgv/getTX/213/eopc04_08.62-now. 

Two things stand out to me in looking at this: There's a very slow tendency to increase x and y over time (increasing movement of the north rotational pole away from the original 0 point), and the more dramatic periodic variation.  The business of having slowly varying amplitude (size of the up and down) for the fast variations suggests a 'beat' is going on.  Namely, there are two different periodic variations going on.  When they're both at maximum, you get a large amplitude.  When they're at minimum, you've got a small amplitude.

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Amateurs on climate

Amateurs are the people who do something for the love of it, without getting paid for it.  I get paid for doing what I love, so don't get to be called an amateur*.  One of my favorite amateurs on climate is Jan Schloerer.  He was active in the Usenet group Sci.environment in the 1990s, and wrote a number of articles on climate for nonprofessionals.  A number of excellent articles.  He ok'd my posting them to my personal web site (I used to be on radix.net) and I'm now, finally, moving my personal site to www.grumbinescience.org.

Two of the great things about Jan as an amateur writer on climate was that he wrote for other people who also were not professionals, and that he paid a lot of attention to what was in the scientific literature, citing thoroughly where data and conclusions came from.  Therefore, even though it's 15-20 years since he wrote the articles, they remain relevant and correct as far as they go.  Good job Jan!

On a different side, Jan is (was?  nobody I know has heard from him in years) a very caring person.  When the US government shut down in the 1990s, he knew that I was working for it, so not being paid.  He offered to help me out financially if needed.  Fortunately it wasn't.  But he is/was the kind of person who speedily thought about the possibility that I could be in some difficulty, and offered help immediately if it might be needed.

Jan's articles (I'm not sure I have the most recent versions, so any errors are mine, not his, and the formatting is all my fault -- to be fixed Real Soon Now; updates will be coming):
Climate Basics
How we know humans are the source of the CO2 increase
Readings on climate change
CLIMAP -- the climate mapping project (1970s-early 1980s)
Methane

* Well, on my oceanography/glaciology/... work.  On other things I am indeed an amateur.  I hope in my amateur activities to approach Jan's level. 

Martin Luther King Jr. Day

I share the Reverend Dr. Martin Luther King Jr.'s dream.  Among other things, for people to be judged by the content of their character rather than the color of their skin.  It is an ideal.  Since that dream has still not been achieved more than 50 years after he gave the speech, it's apparently a challenging ideal.  Given events of the last few years, I'm not confident that we're closer to it than we were 20 years ago.  Maybe I was just that naive 20 years ago, maybe I just hear about more than I used to.  And maybe we as a nation have ceased the effort towards that ideal.  In many respects, though, it doesn't matter.  Something is only an ideal if you are approaching it ever more closely through time.  And that's not where we are.  It's only an ideal if, indeed, people actually agree that it is an ideal to strive for.

I also encourage all to read his letter from a Birmingham jail.  Not only is it a fine piece of writing, it mentions many specifics of our (USA) failure to live to our ideals as expressed in the Constitution and the Declaration of Independence.  The preamble to the constitution reads:

We the People of the United States, in Order to form a more perfect Union, establish Justice, insure domestic Tranquility, provide for the common defence, promote the general Welfare, and secure the Blessings of Liberty to ourselves and our Posterity, do ordain and establish this Constitution for the United States of America.

  It is not justice for the law to be applied differently based on the color of someone's skin, rather than the content of their character.  It does not ensure domestic Tranquility to make police forces comparable to occupying military forces.  Nor can the Blessings of Liberty be secured by treating part of your citizenry like 'other' -- not truly citizens, not really deserving of the Blessings of Liberty, or Justice.

I've seen some bizarre interpretations of the Constitution.  For some, since the constitution was written by slaveowners, slaves and their descendants are not included as part of 'We the People'.  Other absurdities on par with that abound.  But, if one wants to tread that route, be sure that all of your ancestors signed the Declaration.  None of mine did, so I incline to the interpretation that it is a) people and b) of the United States -- all citizens -- who should be (ideals again) included.  Even though for more than four score and seven years we treated part of our population as property.  The step forward in ideals is to include all our people.

About a century before letter from a Birmingham jail was Civil Disobedience, by Henry David Thoreau.  He was in jail, on grounds of his protest of his taxes going to support slavery.  For both men, there was this consistency, often lost by current people: They knew full well that in breaking unjust laws, they would likely go to jail for it.  That is part of engaging in civil disobedience.  When a friend visited Thoreau in jail, the friend asked "How can you be here?" (in jail).  Thoreau answered "How can you not be?"  A couple years ago, I testified in favor of giving civil protections to a class of people who were being discriminated against, not for reasons of their character.  I was astonished by one of the people testifying against the nondiscrimination law.  Not, sadly, because she was opposed, but because of her panic reaction to a later person noting that our names would be recorded and history would judge us.  If you argue that public law should be one way or the other, you should certainly be willing to be known for it!  Not even a threat of jail time.  Ideals mean little if you are not even willing to be known to hold them.

I don't have answers, but this year I'll be doing more towards achieving those, and below, ideals.

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Edging towards a climatology

I say edging towards climatology because the process of going from here, a state of not really knowing what the climatology is, to there, a state of having pretty solid knowledge, isn't one I like to take in a single jump.  Even if scientists in professional journals present their work as if we did it in one jump, we seldom do it this way.  Plus, for our purposes here, it's more meaningful to proceed in successive approximations

For data, I'm going to use the Climate Forecast System Reanalysis (v2).  I'll also be using the high resolution, in time and space, versions of the data.  This leads to some pretty big files (unpacked, it is about 2 Gb per month, and remember there'll be 360 months for a 30 year climatology).  So you might want to go with the lower resolution for your own initial exploration.

To start with, let's look at the 2 meter air temperature, where I've converted temperatures to Celsius (from Kelvin).  30 C = 86 F, 0 C = 32 F.  The total planetary range is a bit over 70 C from the very coldest areas (Antarctic Plateau -- below -40 C) to the warmest (pretty much the whole tropics).

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Happy Perihelion 2015!

I was late to with you a happy New Year for 2015, so hope the perihelion (our closest approach to the sun each year, typically January 3rd) passes well for everyone and kicks off a year of good events and health.

Year turnovers are good opportunities to look back at what I did the previous year (some good, some not so good, and not much blogging) and ponder what to do in the coming year (more good, less not so good, and more blogging).  In the blogging side of the coming year, I plan to be more regular in posting.  Part of that will be that I'll be less restrictive about scaring people with math.  I'll at least hide the scarier stuff at the bottom and give fair warning :-)

Two strains of posts will be new this year.  One will be, let's call it "Journal of Spectral Climatology".  Obviously not a peer-reviewed journal, but I'll be taking a whack at looking at climate not so much in terms of 'today's expected high temperature is ...' as 'in this part of the world, you expect summer to be this much warmer than winter'.  Or ditto for day versus night.  And then ... we'll see. For data source, I'm going to pound on the NCEP Climate Forecast System Reanalysis.  (that's where to get the data, for description of the sources, see Saha, Suranjana, and Coauthors, 2010: The NCEP Climate Forecast System Reanalysis. Bull. Amer. Meteor. Soc., 91, 1015.1057. doi: 10.1175/2010BAMS3001.1)

The second, call it "Journal of Hypothetical Climatology".  Two sides to this.  One is, I at least used to read a lot of science fiction, and there are many candidate places to ponder what climate would be like.  Mission of Gravity by Hal Clement is one I particularly like.  Rendezvous with Rama by Arthur C. Clark is another good candidate.  The other side is, getting an exact solution for the real earth's climate is impossible.  But there may be some hypothetical earths for which we can get exact answers.