Makefiles are machine-readable documentation that make your workflow reproducible.

The beauty of Make is that it’s simply a rigorous way of recording what you’re already doing. It doesn’t fundamentally change how you do something, but it encourages to you record each step in the process, enabling you (and your coworkers) to reproduce the entire process later.

I've been using Make like this on and off since my PhD. I could generate my whole thesis -- analyses and pictures -- just by typing "make". It would download required files, run analyses, create the pictures (B&W or color, depending on an environment flag), and run LaTeX to create a beautiful PDF.

Hello, I am a compiler.

Hellо, I am a compiler.

I just scanned thousands of lines of code while you were reading this sentence. I browsed through millions of possibilities of optimizing a single line of yours using hundreds of different optimization techniques based on a vast amount of academic research that you would spend years getting at. I won't feel any embarrassment, not even a slight ick, when I convert a three-line loop to thousands of instructions just to make it faster. I have no shame to go to great lengths of optimization or to do the dirtiest tricks. And if you don't want me to, maybe for a day or two, I'll behave and do it the way you like. I can transform the methods I'm using whenever you want, without even changing a single line of your code. I can even show you how your code would look in assembly, on different processor architectures and different operating systems and in different assembly conventions if you'd like. Yes, all in seconds. Because, you know, I can; and you know, you can't.

P.S. Oh, by the way you weren't using half of the code you wrote. I did you a favor and threw it away.

A satellite’s view of ship pollution

For more than a decade, scientists have observed “ship tracks” in natural-color satellite imagery of the ocean. These bright, linear trails amidst the cloud layers are created by particles and gases from ships. They are a visible manifestation of pollution from ship exhaust, and scientists can now see that ships have a more subtle, almost invisible, signature as well.

In 2009 I went to a summer school in Corsica, and one of the coolest things I did was measuring the concentration of NO2 in the atmosphere. We plugged a USB radiometer to a laptop, measured light at different angles, and from that we could know the concentration of NO2 -- we knew the sun radiation spectrum at the top of the atmosphere and the absorption signature of NO2, and from that it was just math.

We measured the concentration of a gas kilometers away using light. Light! Science is awesome.

Would penguins survive in the Arctic?

The original “penguin” was in fact the late great auk (Pinguinus impennis), once found in vast numbers around northern shores of the Atlantic.

Although no relation to southern hemisphere penguins, it was very similar in appearance, and filled much the same ecological niche as penguins, particularly the king penguins of the subantarctic region.

via Ian Bicking's G+ post:

A world before WSGI and Numpy

One problem at the time was that the Python web ecosystem was a mess: there was no WSGI, so the first version had 3 different interfaces: one for running it as CGI, another for Twisted, and a third one that I don't remember. Another problem was that there was no Numpy at that time. There was Numeric, the original Python array library, but it was slow with large arrays; and there was Numarray, created some time after, which was slow with small arrays. So I supported both at the time. In a sense I think this was good, because Pydap was very modular from the start. 

Me, talking about the history of Pydap to OceanDrivers. I surely don't miss these times.

RealClimate: 2012 Updates to model-observation comparions

The conclusion is the same as in each of the past few years; the models are on the low side of some changes, and on the high side of others, but despite short-term ups and downs, global warming continues much as predicted.

"Global warming continues much as predicted". I was asked earlier this week about global warming and if it was real, I gave a long elaborate answer with a "TL;DR: Yes."