GIStemp, A “Start Here” page
I have moved this page to https://chiefio.wordpress.com/gistemp/ in the top bar as the “GIStemp” tab (rather than being a ‘sticky page’). In the near future, I’ll cut the text here back to just this ‘relocation notice’ in case anyone has linked to this page.
Every journey begins with but a single step. This page is it for GIStemp deconstruction.
At present this is a work in progress. As I get through a chunk, I will update this persistent top level page with the appropriate links. It is likely to take a few months.
At present, I’m nearly done with STEP0, and I’ve started on STEP1 (which sounds much more impressive when you realize that STEP4_5 is really just a couple of new programs and some runs of the same code as STEP3, so there’s roughly STEP2 as a “big chunk” to go, and with Minus One, Zero, and One done that makes it about half way already…
STEP3 and STEP4_5 have had the scripts documented and the source code is up, but I have not yet done the FORTRAN deconstruction.
So please expect that there will be headers with no data, or links that fail; and that this shell will fill in over time. There is only one of me doing it part time for free, so the speed will not be what you might like.
You are welcome to help make it go faster by contributing time, coding skill, commentary, or even just beer. After all, my present motto is “Will Program for Beer!” (Hey, everybody needs a motivator…good management just chooses what they know will work; and since I’m management as well as grunt on this project…)
GIStemp has 6 formal steps (named 0 to 5) each run by a top level script. In the sections on each STEP, I go through that top level script in an overview page. that overview page will have links to the source code and commentary for each program inside that step. As these overviews get done, and as the code pages fill out, there will be links added to fill in this structure.
Right now the biggest hole is STEP2, but I hope to have something there soon. STEP1 source code is also lacking for now.
General Overview Steps
So how big is this puppy and where can I download a copy? What is the general impression of it?
For a bit more detail on the source download and a peek at the “README” file that comes with it, gistemp.txt, we have a starter peek.
And if you would like, you can look in a bit more depth at the ghcn data formats.
A list of things I’ve found that make me wonder.
First up, the issue of GIStemp cutting off data at 1880 and using an odd “baseline” period of 1950 to 1980. Is this a Cherry Pick? Were these dates picked deliberately to make warming trends look bigger than they really were (or to fabricate the trend entirely?)
Then there is the issue of false precision. How can you calculate 1/10 th of a degree C from data in whole degrees F? Mr. McGuire would NOT approve!
And then there is the issue of trying to dig a global trend out of a data series that only goes back a few years for most of the planet. Maybe you can get a 50 year trend for America, but not for most of the world. We just don’t have the data for the time period needed
To Be Done: Add entries.
The Code – Step by Step, Inch by Inch, Slowly He Turns…
Step Minus One
OK, you need to get the data and there is a pre-process to sort the Antarctic data if you get a fresh copy.
So how about those input files scattered about?
Once you have all the data and files, STEP0 processing does what again?
What does STEP1 look like in an overview sense?
What does STEP2 look like in an overview sense?
This step has several subscripts and FORTRAN programs
What does STEP3 look like in an overview of mostly just source code listings right now.
Some folks have asserted that since GIStemp uses an anomaly map for sea surface temperatures to adjust its internal anomaly map already computed, this means that GIStemp “uses satellite data”. After chasing this down for a while, I came to the conclusion that this stretches the truth quite a bit. Yes, it uses a partially satellite derived SST anomaly map as input to STEP4, but that isn’t quite the same as using direct satellite data.
What does STEP4 look like in an overview of mostly just source code listings right now.
What does STEP5 look like in an overview of mostly just source code listings right now.