wde0924/SMUrF: SMUrF v1 for GMD submission

The SIF-based biospheric model offers an appliable solution to NEE over urban areas around the globe and helps separate biospheric fluxes from anthropogenic emissions. The methodology is based on [Wu et al., accepted]. Here we only included the exact version of the model script. *** For access to flux data or the latest model script, please check out http://dienwu.me/gmd2021/. 

Dien Wu, John C. Lin, Henrique F. Duarte, Vineet Yadav, Nicholas C. Parazoo, Tomohiro Oda, and Eric A. Kort: A Model for Urban Biogenic CO2 Fluxes: Solar-Induced Fluorescence for Modeling Urban biogenic Fluxes (SMUrF), accepted by Geoscientific Model Development. (https://gmd.copernicus.org/preprints/gmd-2020-301/)