# Bret's Skew-T/Ln p Graph

I spent some time creating a program to produce nice blank Skew-T/ln p graph paper so that meteorology students could practice plotting soundings and calculating atmospheric instability and other meteorological-type things. It turns out that there's a bit of math required to get the chart right.

Below you'll find links to some pre-generated blank charts in PDF format. Two are in color, and two are in black and white. Low-density versions have isotherm and dry adiabats drawn every 2 degrees, while the high-density versions have 1-degree separations.

Color | B&W | |
---|---|---|

Low Density | skewt-loc.pdf | skewt-lob.pdf |

High Density | skewt-hic.pdf | skewt-hib.pdf |

I have also posted the program that I wrote to create the blank diagrams so that you can see what the equations are like. (Some curves may have alternative versions of the equations in the literature, and you may want to know which I've chosen.) The documentation link below is a heavily annotated, nicely formatted version of the program for easy reading. The source code link allows you to download the code yourself.

The program is written in the
Literate Programming style developed by computer
scientist extraordinaire
Donald Knuth, author
of TeX and the foundational textbook
series *The Art of Computer Programming*.
(See the
journal article by Knuth for an overview of literate programming,
and the Literate Programming
Website for additional information.)

In order to compile the program, you will need the `ctangle`
utility to extract the `C` source from the `CWEB` file.
You can download the
CWEB Source Code, which is the package I use to write and
document most of the software I develop.
I also made use of the
FitCurves routine
written by Philip Schneider which appeared in the book
*Graphics Gems*.
This routine and the *Graphics Gems* 2D and 3D Vector C library
GGVecLib will also need to be compiled and linked with the program.

You may also find my Amortization Calculator or Blog interesting.