Interactive Python Widget for Correcting WRF-Hydro Input Grids Nicholas Elmer1,2 and Andrew Molthan1,3 1NASA Short-term Prediction Research and Transition (SPoRT) Center, Huntsville, Ala. 2Department of Atmospheric Science, University of Alabama in Huntsville, Huntsville, Ala. 3Earth Science Office, NASA MSFC, Huntsville, Ala. January 23, 2017 Seventh Symposium on Advances in Modeling and Analysis using Python 97th AMS Annual Meeting, Seattle, Wash. WRF-Hydro System • WRF-Hydro (Gochis et al. 2013) is WRF hydrological extension package • Run in uncoupled or coupled mode • Contains column land surface, terrain routing, and channel routing modules • Supports multi-scale domains, so each module may require input grids at different spatial resolutions (NCAR 2017) (NCAR 2017) WRF-Hydro GIS Preprocessing Tool • Derives WRF-Hydro terrain routing and channel routing grids using ArcGIS hydrology tools • Channel routing grids include channel grid and lake grid. • Inputs: • WRF Preprocessing System (WPS) GEOGRID file • High-resolution Digital Elevation Model (DEM) • NCAR working to make tool 100% open- source Python • Preprocessing Tool Documentation: Sampson and Gochis 2015 Screen capture of WRF-Hydro GIS Preprocessing Tool within ArcGIS WRF-Hydro GIS Preprocessing Tool • Channel grid derived from high- resolution DEM (Sampson and Gochis 2015) WRF-Hydro GIS Preprocessing Tool • Channel grid derived from high- resolution DEM • Insert reservoirs/lakes using lake shapefile (Sampson and Gochis 2015) WRF-Hydro GIS Preprocessing Tool • Channel grid derived from high- resolution DEM • Insert reservoirs/lakes using lake Stream shapefile artifact • Lake polygon rasterized to mask channel grid • Lakes numbered 1 to n • Stream artifacts may result (Sampson and Gochis 2015) WRF-Hydro GIS Preprocessing Tool • Preprocessing Tool does not remove stream artifacts • Stream artifacts must be removed prior to running WRF-Hydro • Straightforward, programmatic method not available • Can be done interactively in Python using TkInter module Stream artifact Channel grid Lake grid TkInter – A Python Graphical User Interface • Provides basic Graphical User Interface (GUI) TkInter Widgets within Python Button • Contains classes which allow display, Canvas Checkbutton positioning, and control of widgets Entry • Wrapper functions for Tcl/Tk Frame Label • Importing TkInter LabelFrame Listbox OptionMenu PanedWindow Radiobutton Scale • Online documentation and resources: Scrollbar Spinbox • https://wiki.python.org/moin/TkInter Text • http://tkinter.unpythonic.net/wiki/ Tk • http://infohost.nmt.edu/tcc/help/pubs/tkinter/tkinter.pdf Toplevel *Spyder 2.3.8, Python 2.7, TkInter 8.5 Applying TkInter – Interactive Python Widget *Spyder 2.3.8, Python 2.7, TkInter 8.5 Interactive Python Widget Merged grid Lakegrid showing both number Full domain channels and lakes Lake Channel Node / outlet Land Lake location Lake inset