Issue 146 bugfix: costheta and sintheta calculations

[scrasmussen]

TYPE: bug fix

KEYWORDS: wind fields, latitude, longitude, boundary conditions

SOURCE: Soren Rasmussen, NCAR

DESCRIPTION OF CHANGES: Costheta and sintheta calculations were different when using one vs. multiple processes. To fix this lat and long fields are copied to global variables until costheta and sintheta are calculated. Slight changes to the bounds of certain calculations have been made

ISSUE: Fixes #146

TESTS CONDUCTED: Comparing results from original code, 1 vs. 36 images to the PR.

• Original: 1 vs 36 images

  

• 1 image (original) vs. 36 of PR Fix (note the orders of magnitude difference in the error color-bar needed to see any difference)

Checklist

• [X] Closes issue #146
• [ ] Tests added (unit tests and/or regression/integration tests)
• [X] Backwards compatible
• [ ] Requires new files? If so, how to generate them.
• [X] Fully documented

[gutmann]

very cool, I love how simple that change is in the end!