CaltechAUTHORS
Published March 1, 2026 | Version Published
Journal Article Open

Delta-X: An airborne remote sensing framework to calibrate hydrodynamic and ecogeomorphic processes responsible for land building in coastal deltas

Creators

  • 1. ROR icon Jet Propulsion Lab
  • 2. ROR icon Louisiana State University
  • 3. ROR icon Florida International University
  • 4. ROR icon Boston University
  • 5. ROR icon California Institute of Technology
  • 6. ROR icon The University of Texas at Austin
  • 7. ROR icon University of North Carolina at Chapel Hill

Abstract

Coastal river deltas are highly dynamic regions with hydrological processes that vary on hourly, daily, and seasonal timescales. Soil formation in deltas relies on the balance between mineral sediment deposition, erosion, and organic matter production, which are intricately controlled by vegetation and hydrodynamic conditions. The spatial complexity and rapid variations in flow, particularly due to tides, present a major challenge to spaceborne remote sensing achieving the required spatial resolution and temporal sampling. Here, we present an airborne remote sensing and in situ framework that measures parameters that are critical to calibrate and validate hydrodynamic, sediment transport, morphodynamic, and ecogeomorphic models. We discuss the measurements and models within the context of the NASA Earth Venture-Suborbital Delta-X mission, which implemented the framework in two deltaic regions of the Mississippi River Delta with contrasting hydrological regimes, namely the Atchafalaya (i.e., active, river-dominated) and Terrebonne (inactive, river-abandoned) basins that are undergoing land gain and land loss, respectively. The Delta-X framework uses two airborne radar instruments to monitor hydrodynamic processes, measuring water surface level and slope within channels, and tide-induced water level change within wetlands. In addition, an airborne imaging spectrometer provides estimates of suspended sediment concentrations in open water as well as vegetation type and aboveground biomass. We also discuss how the data are used to calibrate and validate the models that estimate sediment deposition and organic soil production, which build land to offset subsidence and sea level rise.

Copyright and License

© 2025 The Authors. Published by Elsevier Inc. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).

Acknowledgement

This work was carried out in part at the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration (80NM0018D0004). The NASA Delta-X project is funded by the Science Mission Directorate's Earth Science Division through the Earth Venture Suborbital-3 Program NNH17ZDA001N-EVS3. JN, JH, and LC were partially supported by NASA FINESST grants 80NSSC20K1645 (PI MPL) and 80NSSC20K1648 (PI CGF) and 80NSSC21K1612 (PI SF), respectively. We thank Gerard Salter for initial development of the bed-material load model and upscaling framework, and Gerard Salter and Gen Li for help with sediment transport measurements. We thank Matthew Weiser, Hope Vanderhider, Nilotpal Ghosh, and Xiaohui Zhu for help with in situ sampling and/or processing of samples in the laboratory. We also thank Paul Miller of Louisiana State University for providing detailed weather forecasts and guidance during the campaigns. We acknowledge the participation of the late William “Bill” Gibson who conducted field measurements during the Spring campaign 2021. We recognize the support of previous Delta-X managers, Ian McCubbin and Judy Lai-Norling, who supported the formulation and execution of the campaigns.We are grateful to all Delta-X team members and the airborne instrument and flight crews, without whom the mission would not have been successful. This is contribution number 2093 from the Institute of Environment at Florida International University.

Data Availability

The datasets from the in situ campaigns and the airborne campaigns, and all derived information, models, and model output for Delta-X are archived by the Oak Ridge National Laboratory (ORNL) Distributed Active Archive Center (DAAC) [https://daac.ornl.gov/get_data/].

Supplemental Material

Supplementary information about water quality sampling, the Delta-X science traceability matrix and interannual discharge trends.

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Additional details

Related works

Is supplemented by
Dataset: https://daac.ornl.gov/get_data/ (URL)

Funding

Jet Propulsion Laboratory
National Aeronautics and Space Administration
80NM0018D0004
National Aeronautics and Space Administration
NNH17ZDA001N-EVS3
National Aeronautics and Space Administration
80NSSC20K1645
National Aeronautics and Space Administration
80NSSC20K1648
National Aeronautics and Space Administration
80NSSC21K1612

Dates

Submitted
2025-03-04
Accepted
2025-12-12
Available
2025-12-16
Version of record

Caltech Custom Metadata

Caltech groups
Division of Geological and Planetary Sciences (GPS)
Publication Status
Published