The Delta-X Framework: A Reality Check for Hydrodynamic, Sediment Transport and Ecogeomorphic Models
Marc Simard, Jet Propulsion Laboratory, Pasadena, CA, United States, Michael W Denbina, NASA Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, United States, Kyle A Wright, University of Texas at Austin, Dept. of Civil, Architectural, and Environmental Engineering, Austin, TX, United States and Daniel Jensen, Jet Propulsion Laboratory, California Institute of Technology, Pasadena, United States
Abstract:
Deltas are highly dynamic environments with hydrological and ecological processes operating at sub-tidal and seasonal timescales, and across vast landscape. Thus, it is difficult to collect the data efficiently calibrate numerical hydrological and eco-geomorphic models. In this presentation we demonstrate the large scale capabilities of airborne and spaceborne remote sensing to capture these processes with the intent of calibrating and validation model implementations. The Delta-X framework uses multiple airborne remote sensing measurements collected simultaneously, along with in situ field data to calibrate and validate models at sub-tidal timescales. Spaceborne remote sensing is used to capture seasonal and multi-year changes. We conducted two Delta-X demonstration campaigns in the Mississippi Delta during Spring 2015 and Fall 2016. The campaigns involved three aircrafts flying near-simultaneously and several in situ measurements of water level and plant structure. We also discuss the significant challenges of gathering and standardizing datasets from various sources. In fact, we find airborne remote sensing to be a formidable asset to verify consistency of in situ measurements.
We show the airborne remote sensing instruments are capable of accurately measure water surface elevation and slope within river channels, tide propagation across marshes, sediment transport across the delta. These unprecedented measurements challenge numerical models with a reality check at time and spatial scales relevant to deltaic environments. The remote sensing observations are those of the surface, corresponding to numerical model outputs -- water surface elevation and above ground vegetation structure. As such, assimilation of remote sensing products is used to invert or improve model inputs. An iterative approach can be used to solve for model input parameters by comparing remotely sensed measurements to model outputs.
A new set of Delta-X campaigns is planned for Spring and Fall 2020 to further our understanding of the hydrological and eco-geomorphic processes responsible for land building. Delta-X will deliver fully calibrated numerical models to predict vulnerability of the Mississippi delta to sea level rise.
