EEMT 1.0
Authors: Tyson L. Swetnam, Nicholas R. Callahan, Jon D. Pelletier, Craig Rasmussen, Nirav Merchant, Eric Lyons
Date
1 Background
As a proof of concept we developed a distributed computing workflow using open-source GIS tools (GDAL, SAGA, GRASS, and QGIS) and Makeflow to calculate traditional and topographically controlled "Effective Energy and Mass Transfer (EEMT)" (Rasmussen et al. 2015), which is a measure of the available free energy for physical and chemical work [units in mega joules per meter square over time: MJ m2 yr-1], at the surface of the critical zone (the near Earth surface environment which includes everything between crystalline bedrock and the atmospheric boundary layer).
To calculate EEMT we use a digital elevation model (DEM) and NASA's DAYMET 34-year (1980-2014) monthly averaged precipitation, vapor pressure, and temperature series for the contiguous 48 states. With the open-source GIS software we calculate the potential solar radiation of a DEM at any resolution, e.g. 1 to 90 m2, and upscale the lower resolution DAYMET climate data (1 km2) to the same resolution using a MT-CLIM simulation (upon which the DAYMET data are based). The user only needs to supply or define the input DEM and the workflow will distribute the job to an HPC through Makeflow. An output file tree is created with every upscaled climate and solar output file saved to sub-directories. Solar radiation is calculated for every day of the year at a high temporal step (3 minute interval) to avoid Jensen’s inequality; topographic shading in complex terrain and/or urban settings are turned on. Further, summary statistics are generated for each variable.
The goals of the project are to (1) make open-source GIS tools available through a Cyber-GIS data service, e.g. OpenTopography, using distributed computing to accelerate computation times, (2) allow users to generate scalable solar radiation models and EEMT models directly from OpenTopography data.
The availability of the dozens of open-source GIS tools in SAGA, GRASS, and QGIS via OpenTopography has far greater potential and a wider audience than the initial test project goal.
Currently the calculations use monthly average observations from the DAYMET weather service. A future option should allow the user to select either DAYMET or PRISM data to generate EEMT layers.
In this set of Wiki child-pages we provide in detail the procedures for (1) installing the dependencies and tools from source, (2) running the work flow in a terminal window, and (3) miscellaneous details related to the creation of tool from the Applied Concepts in Cyber-infrastructure (ACIC) course at the University of Arizona.
Figure: Daily global radiation (watts m-2) and hours of sunlight over Marshall Gulch in the Santa Catalina Mountains, Tucson AZ. Animations are for one year from January 1st to December 31st.
Unknown macro: {html}<div style="width: 960px; height: 720px; margin: 10px; position: relative;"><iframe allowfullscreen frameborder="0" style="width:960px; height:720px" src="https://www.lucidchart.com/documents/embeddedchart/3fc73d47-6d78-4ff0-ae5d-ea5a37ececae" id="VXU-WFW5jpR~"></iframe></div>