ORNL DAAC Data Release - Delta-X Datasets on Derived Vegetation, Derived Biomass, & the Delft3D Hydrodynamic Model

[ORNL - blancohl]

The Oak Ridge National Laboratory Distributed Active Archive Center (ORNL DAAC) released a series of new datasets for the Delta-X mission recently.

Delta-X is a 5-year NASA Earth Venture Suborbital-3 mission to study the Mississippi River Delta in the United States, which is growing and sinking in different areas. River deltas and their wetlands are drowning as a result of sea level rise and reduced sediment inputs. The Delta-X mission will determine which parts will survive and continue to grow, and which parts will be lost. Delta-X begins with airborne and in situ data acquisition and carries through data analysis, model integration, and validation to predict the extent and spatial patterns of future deltaic land loss or gain.

More information about these datasets and the project can be found on the NASA Earthdata Delta-X mission page.

Delta-X AVIRIS-NG L3 Derived Vegetation Types, MRD, Louisiana, V2

This dataset provides maps of vegetation types for the Atchafalaya and Terrebonne basins in coastal Louisiana, U.S., derived from NASA's Next Generation Airborne Visible Infrared Imaging Spectrometer (AVIRIS-NG) imagery acquired during spring and fall of 2021 for the Delta-X campaign. Vegetation types were classified from Level-2B BRDF-adjusted surface reflectance. Local pixel reflectance spectra coincident with Delta-X field vegetation samples and vegetation plot data from Louisiana's Coastwide Reference Monitoring System (CRMS) were used to generate a machine learning-based model to classify vegetation types. This model was then applied to the AVIRIS-NG mosaic imagery to map vegetation types across the Atchafalaya and Terrebonne Basins. The data are provided in cloud optimized GeoTIFF (COG) format.

Delta-X AVIRIS-NG L3 Derived Herbaceous Belowground Biomass, MRD, Louisiana, V2

This dataset contains high-resolution (~5 m) gridded estimates of belowground biomass (BGB) in the Atchafalaya and Terrebonne basins of southern Louisiana, U.S., in August 2021. The Level 3 (L3) AVIRIS-NG-derived herbaceous aboveground biomass (AGB) and necromass (AGN) Version 3 products were used to predict the BGB. The AGB estimates were derived from the L2B BRDF-adjusted surface reflectance product, following atmospheric correction to produce L2 Hemispherical-Directional surface reflectance. An Ordinary Least Squares Regression (OLSR) model was derived, trained on field sample measurements (n=40) of aboveground biomass (AGB), aboveground necromass (AGN), and the natural logarithm-transformed total nitrogen (N). This dataset constitutes all available field samples where AGB, AGN, total N, and BGB were measured concurrently. Belowground biomass is an essential component of organic accretion but cannot be directly measured by airborne instruments. This model infers BGB from its relationships with aboveground plant mass and foliar N concentrations. This model was applied to landscape-scale maps derived from AVIRIS-NG data to estimate BGB for the August 2021 peak biomass collection period. The data are provided in cloud optimized GeoTIFF (COG) format.

The following three datasets employed the Delft3D Flexible Mesh (FM) hydrodynamic model used to investigate water levels, water movement, and changing salinity levels through space and time across the complex estuaries of the Mississippi River Delta.

Delta-X: Delft3D FM, Extended Domain Hydrodynamic Model

This dataset contains Delft3D Flexible Mesh (FM) hydrodynamic model setup and results for the Atchafalaya and Terrebonne basins in coastal Louisiana, U.S.. The model domain spans from Bayou Lafourche in eastern Terrebonne Bay, encompasses Atchafalaya Bay, and extends westward to Vermilion Bay. Separate simulations were conducted for spring and fall, each covering a 31-day period. Both simulations were calibrated and validated using Delta-X airborne remote sensing data and in situ measurements. The dataset includes the full set of hydrodynamic model input files for each seasonal simulation, along with a netCDF output file for each model run. Using the provided input files, users can reproduce the simulations and obtain results identical to those in the output netCDF files included in this dataset.

Delta-X: Delft3D FM, Weighted Mean Hydroperiod, MRD, Louisiana, USA

This dataset provides the weighted average hydroperiod derived from two Delft3D FM model simulations representing the low discharge (fall 2021) and high discharge (spring 2021) seasons. Each model was run for 31 days, excluding a 1-day warm-up period from the analysis. The weights for each model were derived from the long-term probability density function (PDF) of the Atchafalaya River discharge. Hydroperiod, which quantifies the frequency of inundation at each model grid cell, is computed by analyzing the water level time series and identifying periods when the water depth does not exceed the model-defined wet/dry threshold of 5 cm.

Delta-X: Delft3D FM, Weighted Mean Salinity, MRD, Louisiana, USA

This dataset provides the weighted averaged salinity derived from two Delft3D Flexible Mesh (FM) model simulations representing the low discharge (fall 2021) and high discharge (spring 2021) seasons. The weights for each model were determined using the probability density function of the Atchafalaya River discharge. Each model was run for 31 days, excluding a 1-day warm-up period from the analysis. Salinity is calculated by applying a weighted average to the salinity values at each grid cell in the final time step of each simulation. The data are provided in netCDF format.

Citations:
Jensen, D. J., Castañeda-Moya, E., Solohin, E., Thompson, D. R., & Simard, M. (2025). Delta-X AVIRIS-NG L3 Derived Vegetation Types, MRD, Louisiana, V2 (Version 2). ORNL Distributed Active Archive Center. https://doi.org/10.3334/ORNLDAAC/2457

Jensen, D. J., Castañeda-Moya, E., Solohin, E., & Simard, M. (2025). Delta-X: AVIRIS-NG L3 Derived Herbaceous Belowground Biomass, MRD, LA, USA (Version 1). ORNL Distributed Active Archive Center. https://doi.org/10.3334/ORNLDAAC/2456

Payandeh, A. R., Simard, M., & Jones, C. (2025). Delta-X: Delft3D FM, Extended Domain Hydrodynamic Model (Version 1). ORNL Distributed Active Archive Center. https://doi.org/10.3334/ORNLDAAC/2464

Payandeh, A. R., Simard, M., & Jones, C. (2025). Delta-X: Delft3D FM, Weighted Mean Hydroperiod, MRD, Louisiana, USA (Version 1). ORNL Distributed Active Archive Center. https://doi.org/10.3334/ORNLDAAC/2421

Payandeh, A. R., Simard, M., & Jones, C. (2025). Delta-X: Delft3D FM, Weighted Mean Salinity, MRD, Louisiana, USA (Version 1). ORNL Distributed Active Archive Center. https://doi.org/10.3334/ORNLDAAC/2420