Surface Water and Ocean Topography

NASA/CNES oceanography mission (2022–Present)

Surface Water and Ocean Topography

Rendering of the SWOT satellite

Names| SWOT
WATER HM[1]
Mission type| Hydrology / Oceanography
Operator| NASA / CNES
COSPAR ID| 2022-173A
SATCAT no.| 54754
Mission duration| Planned:
3 years
Elapsed:
2 years, 6 months and 4 days
Spacecraft properties
Manufacturer| Thales Alenia Space
Launch mass| 2,200 kg (4,900 lb)[2]
Dimensions| 14.9 × 5 × 5 m (49 × 16 × 16 ft)[2]
Power| 8,000 watts[2]
Start of mission
Launch date| December 16, 2022, 11:46 UTC[3]
Rocket| Falcon 9 Block 5 B1071-6
Launch site| Vandenberg, SLC-4E
Contractor| SpaceX
Orbital parameters
Reference system| Geocentric
Regime| Low Earth orbit
Periapsis altitude| 857 km (533 mi)
Apoapsis altitude| 857 km (533 mi)
Inclination| 77.6°
Period| 102.89 minutes
Repeat interval| 1 sidereal day
| Instruments

KaRIn| Ka-band Radar Interferometer
AMR-C| Advanced Microwave Radiometer-C
Altimeter| Nadir Altimeter
DORIS| Doppler Orbitography and Radiopositioning Integrated by Satellites
GPSP| Global Positioning System Payload
LRA| Laser Retro-reflector Assembly
Telecom| X-band Telecom

Alternate SWOT Mission Patch by NASA

The Surface Water and Ocean Topography (SWOT) mission is a satellite altimeter jointly developed and operated by NASA and CNES, the French space agency, in partnership with the Canadian Space Agency (CSA) and UK Space Agency (UKSA).[4] The objectives of the mission are to make the first global survey of the Earth's surface water, to observe the fine details of the ocean surface topography, and to measure how terrestrial surface water bodies change over time.

While past satellite missions like the Jason series altimeters (TOPEX/Poseidon, Jason-1, Jason-2, Jason-3) have provided variation in river and lake water surface elevations at select locations, SWOT will provide the first truly global observations of changing water levels, stream slopes, and inundation extents in rivers, lakes, and floodplains. In the world's oceans, SWOT will observe ocean circulation at unprecedented scales of 15–25 km (9.3–15.5 mi), approximately an order of magnitude finer than current satellites. It does this using synthetic aperture radar interferometry.[5] Because it uses wide-swath altimetry technology, SWOT will almost completely observe the world's oceans and freshwater bodies with repeated high-resolution elevation measurements, allowing observations of variations.

## Context

[edit]

SWOT builds on a long-standing partnership between NASA and CNES to measure the surface of the ocean using radar altimetry. This partnership began with the TOPEX/Poseidon mission (launched in 1992) and continued with the Jason series. SWOT brings together the hydrology and oceanography communities and will extend the precise, high-resolution surface topography observations into the coastal and estuarine regions.

## Scientific objectives

[edit]

The mission's science goals are to:

* Provide sea surface heights and terrestrial water heights over a 120 km (75 mi) wide swath with a ±10 km (6.2 mi) gap at the nadir track.
* Over the deep oceans, provide sea surface heights within each swath with a posting every 2 km × 2 km (1.2 mi × 1.2 mi), and a precision not to exceed 2.7 cm (1.1 in) at 1 km × 1 km (0.62 mi × 0.62 mi), or 1.35 cm (0.53 in) at 2 km × 2 km (1.2 mi × 1.2 mi) when averaged over the area.
* Over land, download the raw data for ground processing and produce a water mask able to resolve 100 m (330 ft) wide rivers and 250 m × 250 m (820 ft × 820 ft) lakes and reservoirs.[6] Associated with this mask will be water level elevations with an accuracy of 10 cm (3.9 in) for water bodies whose non-vegetated surface area exceeds 1 km2 (0.39 sq mi). The slope accuracy is 1.7 cm/km (1.1 in/mi) over a maximum 10 km (6.2 mi) of flow distance.[7]
* The satellite will overfly Earth from 78° S to 78° N, covering at least 86% of the globe.

SWOT’s orbit extends from 78° S to 78° N, covering at least 86% of the globe in its three-year-long mission. SWOT revisits the same path all over the Earth every 21 days in 292 unique orbits.[8][9]

## Applications

[edit]

SWOT is designed for the study and monitoring of inland waters and the oceans, such as:[10]

Management of water-sharing issues

The sharing of river water often causes friction between neighboring states, especially when there is no common technology for verification. SWOT will provide global information as input for systems monitoring transboundary river basins, including measurements of variations in reservoir water storage and estimates of river discharge.

More accurate weather and climate forecasting

SWOT will enable more accurate weather and climate forecasting, especially seasonally. The quality of weather and climate forecasting largely depends on numerical modeling that uses the state of the ocean surface and the hydrological conditions of catchment areas in their initial and boundary conditions.

Managing freshwater for urban, industrial, and agricultural consumption

Accurate knowledge of sources of available water is a key factor in decision-making for organizations involved in the distribution of water for agricultural, urban, and industrial needs. Data from SWOT will contribute at a global level by providing water supply services and distribution companies with information about major reservoirs and the largest rivers and catchment areas, thus enabling them to plan the management of water stocks further into the future.

Improved flood modeling

Flooding, whether from rivers overflowing their banks or in coastal regions, is among the most costly natural disasters. Altimetry data from the SWOT mission will make it possible to measure the 3-dimensional shape of flood waves, track floodwater levels, and improve measurements of local topographic details in floodplains. All of these will improve prediction capabilities for future floods.

Coastal ocean dynamics

Coastal ocean dynamics are important for many societal applications. They have smaller spatial and temporal scales than the dynamics of the open ocean and require finer-scale monitoring. SWOT will provide global, high-resolution observations in coastal regions for observing coastal currents and storm surges. While SWOT is not designed to monitor the fast temporal changes of the coastal processes, the swath coverage will allow us to characterize the spatial structure of their dynamics when they occur within the swath.

Reducing environmental risk and contributing to public policy-making

More generally, SWOT will help improve our knowledge of Earth's water cycle and ocean circulation, enhance our observation capacity by collecting unique data on water storage and fluxes and making them freely available, and help us better understand the physics that drives surface water and ocean dynamics. Water resources, natural risks (floods, climate change, hurricane forecasting, etc.), biodiversity, health (preventing the propagation of water-borne diseases), the agricultural sector, energy (including the management of electricity production and offshore gas and oil rigs), territorial development; all these areas and more stand to benefit from this new satellite mission.

## Sensor payload

[edit]

Diagram of SWOT data collection

The primary instrument on SWOT is the Ka-band Radar Interferometer (KaRIn), which uses synthetic-aperture radar (SAR) technology, especially SAR interferometry.[11] Because SWOT operates at Ka-band's relatively short wavelengths, 11–7 mm (27–43 GHz) – compared to the Ku-band Jason series, 25–17 mm (12–18 GHz) – and at near-nadir incidence angles (<5°), it is designed to be uniquely appropriate for measuring water surface elevations and inundation extents.[citation needed]

The satellite will fly two radar antennas at either end of a 10 m (33 ft) mast, allowing it to measure the elevation of the surface across a 120 km (75 mi) wide swath. The new radar system is smaller than, but similar to, the one that flew on NASA's Shuttle Radar Topography Mission (SRTM), which made high-resolution measurements of Earth's land surface in 2000.[12]

A conventional nadir radar altimeter will also be flown, and measure just beneath the satellite, as was done on the Topex/Poseidon, Jason series, and SARAL missions. It is a "Jason-class" altimeter.[13]

## History

[edit]

Mating of SWOT Payload on satellite platform made in Thales Alenia Space Cannes Center

SWOT was developed by an international group of hydrologists and oceanographers to provide a better understanding of the world's oceans and its terrestrial surface waters.[14] It will give scientists their first comprehensive view of Earth's freshwater bodies from space and much more detailed measurements of the ocean surface than ever before.[15] By 2019 the mission hardware was under active construction, algorithms to produce hydrology and oceanography data products were under final development, and calibration/validation methods and post-launch activities were being finalized. The spacecraft launched on a SpaceX Falcon 9 on 16 December 2022.[3]

The mating of the payload made by Jet Propulsion Laboratory (JPL) took place on 11 August 2021 at Thales Alenia Space Cannes Center, France.

## See also

[edit]

* Spaceflight portal

* Jason-3

## References

[edit]

1. ^ "SWOT (Surface Water Ocean Topography)". eoPortal.org. Retrieved 26 August 2024.
2. ^ a b c "SWOT: Quick Facts". jpl.nasa.gov. NASA / JPL. Retrieved 26 August 2024.
3. ^ a b "Live coverage: SpaceX ready to launch U.S.-French environmental satellite". spaceflightnow.com. 16 December 2022. Retrieved 16 December 2022.
4. ^ Bains, Navdeep (7 March 2016). "2016-17 Report on Plans and Priorities". Canadian Space Agency. Retrieved 18 December 2022.
5. ^ Rodriguez, Ernesto; Fernandez, Daniel Esteban; Peral, Eva; Chen, Curtis W.; De Bleser, Jan-Willem; Williams, Brent (15 September 2017). "Wide-Swath Altimetry: A Review". In Stammer, Detlef; Cazenave, Anny (eds.). Satellite Altimetry Over Oceans and Land Surfaces. CRC Press. doi:10.1201/9781315151779. ISBN 978-1-315-15177-9.
6. ^ Fjørtoft, Roger; Callahan, Phil; Rodriguez, Ernesto; Desroches, Damien (21 July 2013). "Processing of KaRIn/SWOT Data". Root. Retrieved 2 November 2022.
7. ^ Biancamaria, Sylvain; Lettenmaier, Dennis P.; Pavelsky, Tamlin M. (1 March 2016). "The SWOT Mission and Its Capabilities for Land Hydrology" (PDF). Surveys in Geophysics. 37 (2): 307–337\. Bibcode:2016SGeo...37..307B. doi:10.1007/s10712-015-9346-y. ISSN 0169-3298. S2CID 130786322.
8. ^ Hamoudzadeh, Alireza; Ravanelli, Roberta; Crespi, Mattia (31 March 2024). "SWOT Level 2 Lake Single-Pass Product: The L2_HR_LakeSP Data Preliminary Analysis for Water Level Monitoring". Remote Sensing. 16 (7): 1244. doi:10.3390/rs16071244. ISSN 2072-4292.
9. ^ "Swath Visualizer | Mission". NASA SWOT. Retrieved 15 January 2023.
10. ^ Fu, Lee-Lueng; Pavelsky, Tamlin; Cretaux, Jean-Francois; Morrow, Rosemary; Farrar, J. Thomas; Vaze, Parag; Sengenes, Pierre; Vinogradova-Shiffer, Nadya; Sylvestre-Baron, Annick; Picot, Nicolas; Dibarboure, Gerald (28 February 2024). "The Surface Water and Ocean Topography Mission: A Breakthrough in Radar Remote Sensing of the Ocean and Land Surface Water". Geophysical Research Letters. 51 (4). doi:10.1029/2023GL107652. ISSN 0094-8276.
11. ^ "SWOT: Technology". swot.jpl.nasa.gov. Archived from the original on 24 July 2009. Retrieved 19 April 2017. This article incorporates text from this source, which is in the public domain.
12. ^ "NASA's Shuttle Radar Topography Mission". www2.jpl.nasa.gov. Retrieved 18 December 2022. This article incorporates text from this source, which is in the public domain.
13. ^ "Flight Systems | Mission - NASA SWOT". Retrieved 1 November 2023.
14. ^ "SWOT Science". swot.jpl.nasa.gov. Archived from the original on 18 June 2019. Retrieved 18 December 2022. This article incorporates text from this source, which is in the public domain.
15. ^ "The Surface Water and Ocean Topography Mission". swot.jpl.nasa.gov. Archived from the original on 23 June 2018. Retrieved 18 December 2022. This article incorporates text from this source, which is in the public domain.

## External links

[edit]

* Surface Water and Ocean Topography at NASA.gov
* Ocean Surface Topography from Space at NASA.gov
* Cnes project Library at CNES.fr
* AVISO+ portal for SWOT

* v
* t
* e

← 2021

Orbital launches in 2022

2023 →

January|

* Starlink G4-5 (49 satellites)
* ION-SCV 004 (LabSat, STORK-1, STORK-2, SW1FT), Capella 7, Capella 8, ICEYE X14, ICEYE X16, USA-320, USA-321, USA-322, USA-323, DEWA SAT-1, Flock 4x × 44, Kepler × 4, Lemur-2 × 5, Nepal PQ-1
* Lemur-2 Krywe, STORK-3, TechEdSat-13, Unicorn-1, Unicorn-2 × 4
* Shiyan 13
* Starlink G4-6 (49 satellites)
* USA-324 / GSSAP-5, USA-325 / GSSAP-6
* CSG-2

February|

* USA-326
* Starlink G4-7 (49 satellites)
* Kosmos 2553 / Neitron №1
* OneWeb L13 (34 satellites)
* EOS-04 / RISAT-1A
* Progress MS-19
* Cygnus NG-17 (KITSUNE)
* Starlink G4-8 (46 satellites)
* Starlink G4-11 (50 satellites)
* Jilin-1 Gaofen-03D × 9, Jilin-1 Mofang-02A 01

March|

* GOES-18 / GOES-T
* Starlink G4-9 (47 satellites)
* Noor 2
* Starlink G4-10 (48 satellites)
* SpaceBEE × 16, SpaceBEE NZ × 4
* Yaogan 34-02
* Soyuz MS-21
* Starlink G4-12 (53 satellites)
* Meridian-M 10

April|

* ION-SCV 005 (KSF2 × 4), EnMAP, Lynk Tower 01, MP42 / Tiger-3, ÑuSat × 5, SpaceBEE × 12
* Gaofen 3-03
* Kosmos 2554 / Lotos-S1 №5
* Axiom Mission 1
* ChinaSat 6D
* USA-327 / NOSS-3 9A, NOSS-3 9B
* Starlink G4-14 (53 satellites)
* SpaceX Crew-4
* Kosmos 2555 / EO MKA №2
* Starlink G4-16 (53 satellites)
* Jilin-1 Gaofen-03D × 4, Jilin-1 Gaofen-04A

May|

* SpaceBEE × 16, SpaceBEE NZ × 8, Unicorn-2F
* Jilin-1 Kuanfu-01C, Jilin-1 Gaofen-03D × 7
* Starlink G4-17 (53 satellites)
* Tianzhou 4
* Jilin-1 Mofang-01A†
* Starlink G4-13 (53 satellites)
* Starlink G4-15 (53 satellites)
* Starlink G4-18 (53 satellites)
* Kosmos 2556 / Bars-M 3L
* Boe OFT-2
* ION-SCV 006 (SBUDNIC), SHERPA AC1, Vigoride-3, ICEYE × 5, ÑuSat × 4, Lemur-2 × 5, Platform 1, PTD-3

June|

* Progress MS-20
* Shenzhou 14
* TROPICS 02†, TROPICS 04†
* Starlink G4-19 (53 satellites)
* CMS-02 or GSAT-24
* Yaogan 35-02 (3 satellites)
* CAPSTONE

July|

* USA-337
* Kosmos 2557 / GLONASS-K 16L
* Starlink G4-21 (53 satellites)
* Starlink G3-1 (46 satellites)
* Tianlian II-03
* SpaceX CRS-25 (TUMnanoSAT)
* Starlink G4-22 (53 satellites)
* Starlink G3-2 (46 satellites)
* Wentian
* Starlink G4-25 (53 satellites)
* Yaogan 35-03 (3 satellites)

August|

* Kosmos 2558 / Nivelir №3
* USA-335 / RASR-4
* USA-336 / SBIRS GEO-6
* Chinese reusable experimental spacecraft
* Danuri
* EOS-02 / Microsat-2A†, AzaadiSAT†
* Starlink G4-26 (52 satellites)
* Jilin-1 Gaofen-03D × 10, Jilin-1 Hongwai-01A × 6
* Starlink G3-3 (46 satellites)
* Yaogan 35-04 (3 satellites)
* Starlink G4-27 (53 satellites)
* Starlink G4-23 (54 satellites)
* Starlink G3-4 (46 satellites)

September|

* Yaogan 33-02
* Starlink G4-20 (51 satellites)
* Yaogan 35-05 (3 satellites)
* Eutelsat Konnect VHTS
* Starlink G4-2 (34 satellites)
* ChinaSat 1E
* Starlink G4-34 (54 satellites)
* Soyuz MS-22
* KH-11 19/NROL-91
* Shiyan 14, Shiyan 15
* Starlink G4-35 (52 satellites)
* Yaogan 36-01 (3 satellites)
* Shiyan 16A, Shiyan 16B, Shiyan 17

October|

* TechEdSat-15
* SES-20, SES-21
* SpaceX Crew-5
* Starlink G4-29 (52 satellites)
* Galaxy 33, Galaxy 34
* GLONASS-K 17L
* RAISE-3†, KOSEN-2†, MAGNARO†, MITSUBA†, WASEDA-SAT-ZERO†
* Huanjing 2E
* Yaogan 36-02 (3 satellites)
* Hotbird 13F
* Starlink G4-36 (54 satellites)
* OneWeb L14 (36 satellites)
* Gonets-M × 3
* Progress MS-21
* Starlink G4-31 (53 satellites)
* Shiyan 20C
* Mengtian

November|

* LDPE-2, USA-339 / Shepherd Demonstration, USA-340, USA-341, USA-344 / USUVL
* Kosmos 2563 / EKS-6
* Hotbird 13G
* MATS
* ChinaSat 19
* Cygnus NG-18 (SpaceTuna1)
* NOAA-21, LOFTID
* Yunhai-3 01
* Tianzhou 5
* Galaxy 31, Galaxy 32
* Yaogan 34-03
* Jilin-1 Gaofen-03D × 5
* Artemis I (ArgoMoon, BioSentinel, CuSP, EQUULEUS, LunaH-Map, Lunar IceCube, LunIR, Near-Earth Asteroid Scout, OMOTENASHI, Team Miles)
* Eutelsat 10B
* EOS-06 / Oceansat-3, Astrocast × 4
* SpaceX CRS-26
* Yaogan 36-03 (3 satellites)
* Kosmos 2564 / GLONASS-M 761
* Shenzhou 15
* Kosmos 2565 / Lotos-S1 №6 (Kosmos 2566)
* Oceansat-3

December|

* Gaofen 5-01A
* OneWeb L15 (40 satellites)
* Jilin-1 Gaofen-03D × 7, Jilin-1 Pingtai-01A 01
* Hakuto-R Mission 1 (Rashid), Lunar Flashlight
* Shiyan 20A, Shiyan 20B
* Galaxy 35, Galaxy 36, MTG-I1
* Yaogan 36-04 (3 satellites)
* Shiyan 21
* SWOT
* O3b mPOWER 1, O3b mPOWER 2
* Starlink G4-37 (54 satellites)
* Pléiades Neo 5†, Pléiades Neo 6†
* Gaofen 11-04
* Starlink G5-1 (54 satellites)
* Shiyan 10-02
* EROS-C3

Launches are separated by dots ( • ), payloads by commas ( , ), multiple names for the same satellite by slashes ( / ).
Crewed flights are underlined. Launch failures are marked with the † sign. Payloads deployed from other spacecraft are (enclosed in parentheses).
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