NASA N80INA airplane superimposed on a map

AirSWOT is an airborne instrument for supporting the SWOT mission. AirSWOT data help the engineering team better understand the natural properties of the Earth surfaces that SWOT will observe so that the SWOT design can be better tailored to the science objectives of the mission. AirSWOT data will also be used to help calibrate and validate SWOT data and can be used additionally for science studies in their own right.

It has been integrated with a B200 Super King Air aircraft operated by NASA Armstrong Flight Research Center. AirSWOT is designed to make interferometric measurements similar to those that will be made in space by SWOT. For example, AirSWOT gathers data over science targets for:

  • Water elevation mapping
  • Surface characterization (i.e., backscatter and coherence time) and classification (e.g., land vs. water)
  • Understanding signals affected by vegetation
  • Validation of water discharge algorithms

AirSWOT plays a key role in SWOT mission development. It allows scientists and engineers to study interferometric data before launch and thus be prepared to effectively interpret SWOT data after launch. In addition, AirSWOT campaigns will be flown during the SWOT mission to calibrate and validate data collected by the satellite.

Ka-band SWOT Phenomenology Airborne Radar

The core of AirSWOT is the Ka-band SWOT Phenomenology Airborne Radar (KaSPAR). It collects two swaths of across-track interferometry data - between nadir and 1 km and between 1 km and 5 km, respectively - which can be used to obtain centimeter-level topographic maps of water surfaces. In addition, KaSPAR has an along-track interferometer that can be used to measure the temporal decorrelation of water surfaces, as well as the water radial velocity.

Complementary Measurements

In addition to the KaSPAR measurements, AirSWOT will provide complementary measurements using:

  • Digital Camera System. For validation of surface water extent and for characterization of terrain type, simultaneous measurements will be collected using a color-infrared (CIR) Digital Camera System.
  • Precision Inertial Measurement Unit (IMU). Precision attitude and positioning information will be collected using an Applanix POSAV 610 integrated GNSS/IMU system.

The initial development of AirSWOT was funded by the NASA SBIR program. The KaSPAR radar design and many subsystems were developed by Remote Sensing Solutions (RSS). Integration, testing, processor development and validation of the AirSWOT operational system was done under joint funding from NASA ESTO under the Instrument Incubator Program and the SWOT project by a team of JPL, RSS engineers and SWOT science team members.



Estimating River Discharge with Swath Altimetry: A Proof of Concept Using AirSWOT Observations
(2019), Tuozzolo, S., Lind, G., Overstreet, B., Mangano, J., Fonstad, M., Hagemann, M., Frasson, R.P.M., Larnier, K., Garambois, P.‐A., Monnier, J., and Durand, M.

AirSWOT Measurements of River Water Surface Elevation and Slope: Tanana River, AK
(2017), Altenau, E.H., Pavelsky, T.M, Moller, D., Lion, C., Pitcher, L.H., Allen, G., Bates, P.D., Calmant, S., Durand, M., and Smith, L.C.

Meeting Presentations and Posters

Recent AirSWOT Results for Lakes and Wetlands
(2018), Pitcher, L., Smith, L., Pavelsky, T., Moller, D., Gleason, C., Fayne, J., Cooley, S., Humphries-Altenau, E., and Allen, G.

Recent AirSWOT Results for Rivers
(2018), Altenau, E., Pitcher, L., and Tuozzolo, S.

+ more

Preliminary Ka-band returns from 2017 NASA ABoVE AirSWOT Flight Campaigns
(2018), Smith, L., Fayne, J., and Kyzivat, E.

Highly Nominal U.S. Post-Launch Cal/Val Plan
(2017), Pavelsky, T. and Minear, T.

2017 AirSWOT Flights and SWOT Cal/Val Activities
(2017), Smith, L., Gleason, C., Pietroniro, A., Pavelsky, T. and Minear, T.

Summer 2017 Experiments
(2017), Smith, L. and Minear, T.

Updated AirSWOT and Field Results
(2017), Minear, T.

Novel AirSWOT Measurements of River Height and Slope, Tanana River, AK
(2016), Altenau, E.H., Pavelsky, T., Moller, D., Lion, C., Pitcher, L.H., Allen, G.H., Bates, P.D., Calmant, S., Durand, M.T., and Smith, L.C.

Characterizing AirSWOT Elevation Accuracy on the Willamette River, Oregon
(2016), Tuozzolo, S., Overstreet, B.T., Mangano, J., Minear, J.T., Stringham, C., Chen, C.W., Pavelsky, T., Frasson, R.P.M., Fonstad, M.A., Wei, R., and Durand, M.T.

AirSWOT Hydrology
(2016), Pavelsky, T., Durand, M., Rodriguez, E., Michailovsky, C., and Humphries, E.

Preliminary Results from the 2015 AirSWOT Campaign: Tanana River, Alaska
(2016), Altenau, E., Pavelsky, T., Lion, C., Pitcher, L., Allen, G., Bates, P., Butman, D., Calmant, S., Durand, M., Moller, D., and Smith, L.

AirSWOT for Discharge Algorithm Validation: Sacramento & Willamette Flights, March 2015
(2015), Durand, M.

Piute Ponds, Edwards AFB: The World’s Most Convenient AirSWOT Calibration/Validation Site
(2015), Smith, L.

AirSWOT Alaska Summary
(2015), Pavelsky, T.

Science from AirSWOT
(2015), Pavelsky, T.

Proposed Ocean AirSWOT or SWOT Cal/Val Sites in France
(2015), Morrow, R.

AirSWOT Instrument Engineering and Programmatic Status
(2015), Sadowy, G.

AirSWOT Applications Demonstration Project
(2014), Michailovsky, C.

Testing the SSH Observability of HF Dynamics in the Bay of Biscay: Perspective of a Quasi-synoptic AirSWOT Experiment
(2014), Ayoub, N. and De Mey, P.

Validation of the AirSWOT Data Collected during the French Campaigns
(2013), Calmant, S.

AirSWOT/SWOT Contributions to the Hydrodynamic Study of the Garonne River
(2013), Biancamaria, S., Dartus, D., Monnier, J., Roux, H., Ricci, S., Rogel, P., Goutal, N., and Garambois, P-A.

Calibration and Validation of SWOT and AirSWOT Data: Water Surface Elevations and Derivatives
(2013), Fulton, J., Bjerklie, D., Minear, T., Wright, S., and Farqharson, G.

AirSWOT 2012 Field Experiment Off the Southern California Coast
(2011), Chao, Y. and Rodriguez, E.

AirSWOT - Hydrology in France
(2011), Calmant, S.

The Uniqueness of AirSWOT Measurements
(2010), Moller, D., Carswell, J., Rodriguez, E., and Esteban-Fernandez, D.

Potential AirSWOT & CalVal French Oceanography Sites

AirSWOT Technology and Campaign Logistics
(2010), Moller, D.


Development and Comprehensive Validation of SWOT River Discharge Algorithms from AirSWOT, Simulator, and Field Measurements
(2017) Plan to 1) perform comprehensive validation of four existing algorithms; 2) develop a novel synergistic algorithm and provide an open source user platform to deliver discharge products; and 3) develop these algorithms for deployment at river basin scales.