csyhuang/hn2016_falwa: Bugfix release v1.2.0: inconsistency in differential area computation in reference state calculation

Abstract

<p><strong>Important:</strong> This release fix a bug in computing the reference states #102 : the differential area to compute reference states, $a^2 \cos\phi \Delta\phi \Delta\lambda$ , was miscomputed as $a^2 \cos\phi (\Delta\phi)^2$ . This has not caused issues in results presented in our previous publications because we have been using ERA5 datasets with $\Delta\phi = \Delta\lambda$. Great thanks to Pragallva Barpanda for fixing the issue and also sharing her working example to preprocess model output for consumption of <code>QGField</code> downstream.</p> <p>Summary of changes:</p> <ol> <li>$\Delta\phi$ and $\Delta\lambda$ are precomputed in <code>QGField</code> object and passed into the F2PY modules as parameters</li> <li>Pragallva has included an example in <code>scripts/pre_process_data_in_hybrid_coordinates/</code> how to preprocess climate model output in hybrid coordinate for consumption of <code>QGField</code> downstream by (1) transforming the fields to pressure coordinates, and (2) do gridfill over underground" gridpoints using poisson solver (as how Clare did in MDTF project)</li> <li>Added <code>CONTRIBUTING.md</code> to include instructions for potential contributors.</li> </ol&gt