OSTM/Jason-2, or Ocean Surface Topography Mission/Jason-2 satellite, [ 1 ] was an international worldly concern observation satellite altimeter joint deputation for ocean open height measurements between NASA and CNES. It was the third base satellite in a series started in 1992 by the NASA/CNES TOPEX/Poseidon mission [ 2 ] and continued by the NASA/CNES Jason-1 mission launched in 2001. [ 3 ]
history [edit ]
Like its two predecessors, OSTM/Jason-2 used high-precision ocean altimetry to measure the distance between the satellite and the ocean coat to within a few centimeters. These very accurate observations of variations in sea surface stature — besides known as ocean topography — provide information about global sea level, the accelerate and focus of ocean currents, and heat stored in the ocean.
Reading: OSTM/Jason-2 – Wikipedia
Jason-2 was built by Thales Alenia Space using a Proteus platform, under a contract from CNES, arsenic well as the independent Jason-2 instrument, the Poseidon-3 altimeter ( successor to the Poseidon and Poseidon 2 altimeter on-board TOPEX/Poseidon and Jason-1 ). Scientists consider the 15-plus-year climate data phonograph record that this mission extended to be critical to understanding how ocean circulation is linked to ball-shaped climate change. OSTM/Jason-2 was launched on 20 June 2008, at 07:46 UTC, from Space Launch Complex 2W at Vandenberg Air Force Base in California, by a Delta II 7320 rocket. [ 4 ] The spacecraft separated from the rocket 55 minutes subsequently. [ 5 ] It was placed in a 1,336 kilometer ( 830 security service ) circular, non-sun-synchronous scope at an inclination of 66.0° to Earth ‘s equator, allowing it to monitor 95 % of Earth ‘s ice-free ocean every 10 days. Jason-1 was moved to the inverse side of ground from Jason-2 and now flies over the same region of the ocean that Jason-2 flew over five days earlier. [ 6 ] Jason-1 ‘s grind tracks fall midway between those of Jason-2, which are about 315 km ( 196 mi ) apart at the equator. This interleave tandem deputation provided twice the number of measurements of the ocean ‘s surface, bringing smaller features such as ocean eddies into opinion. The bicycle-built-for-two mission besides helped pave the way for a future ocean altimeter mission that would collect much more detail data with its single instrument than the two Jason satellites did together. With OSTM/Jason-2, ocean altimetry made the transition from research into operational mode. responsibility for collecting these measurements moved from the space agencies to the world ‘s weather and climate bode agencies, which use them for short-range, seasonal worker, and long-range weather and climate forecast. [ 7 ]
science objectives [edit ]
- Extend the time series of ocean surface topography measurements beyond TOPEX/Poseidon and Jason-1 to accomplish two decades of observations
- Provide a minimum of three years of global ocean surface topography measurement
- Determine the variability of ocean circulation at decadal time scales from combined data record of TOPEX/Poseidon and Jason-1
- Improve the measure of the time-averaged ocean circulation
- Improve the measure of global sea-level change
- Improve open ocean tide models
Ocean altimetry [edit ]
“ Spaceborne radar altimeters have proven to be superb tools for mapping ocean-surface topography, the hills and valleys of the ocean surface. These instruments send a microwave pulsation to the ocean ‘s come on and meter how hanker it takes to return. A microwave radiometer corrects any delay that may be caused by water vapor in the atmosphere. other corrections are besides required to account for the influence of electrons in the ionosphere and the dry air batch of the atmosphere. Combining these data with the accurate localization of the spacecraft makes it possible to determine sea-surface stature to within a few centimetres ( about one inch ). The military capability and determine of the returning sign besides provides information on wind amphetamine and the height of ocean waves. These data are used in ocean models to calculate the amphetamine and commission of ocean currents and the measure and location of heat stored in the ocean, which, in turn, reveals ball-shaped climate variations “. [ 8 ]
Atomic clock synchronization [edit ]
Another cargo aboard Jason-2 is the T2L2 ( Time Transfer by Laser Link ) instrument. T2L2 is used to synchronize nuclear clocks at prime stations, and to calibrate the on-board clock of the Jason-2 DORIS instrument. On 6 November 2008, CNES reported the T2L2 legal document was working well. [ 9 ]
joint attempt [edit ]
Jason 2 merely before launching OSTM/Jason-2 was a joint campaign by four organizations. [ 10 ] The mission participants were :
CNES provided the spacecraft, NASA and CNES jointly provided the warhead instruments, and NASA ‘s launch Services Program at the Kennedy Space Center was responsible for the launching management and countdown operations. After completing the on-orbit commission of the spacecraft, CNES handed over operation and control of the spacecraft to NOAA in October 2008. [ 11 ] CNES processed, distributed, and archived the research-quality data products that became available in 2009. EUMETSAT processed and distributed operational data received by its ground place to users in Europe and archived that datum. NOAA processed and distributed operational data received by its anchor stations to non-European users and archived that data along with the CNES datum products. NOAA and EUMETSAT both generated near-real-time data products and distributed them to users. NASA evaluated the performance of the follow instruments : the Advanced Microwave Radiometer ( AMR ), the Global Positioning System cargo, and the Laser Retroreflector Assembly ( LRA ). NASA and CNES besides validated scientific data products together. NASA ‘s Jet Propulsion Laboratory in Pasadena, California, managed the mission for NASA ‘s Science Mission Directorate in Washington, D.C .
Prior similar missions [edit ]
OSTM/Jason-2 ‘s harbinger TOPEX/Poseidon caught the largest El Niño in a hundred seen in this image from 1 December 1997. The two previous altimetry missions, TOPEX/Poseidon and Jason-1, led to major advances in the skill of physical oceanography and in climate studies. [ 12 ] Their 15-year data record of ocean coat topography provided the foremost opportunity to observe and understand the global variety of ocean circulation and sea flush. Their results improved scientific understanding of the character of the ocean in climate change and improved weather and climate predictions. Data from these missions were used to improve ocean models, forecast hurricane saturation, and identify and track large ocean/atmosphere phenomena such as El Niño and La Niña. The data was besides used in daily applications a divers as routing ships, improving the safety and efficiency of offshore industry operations, managing fisheries and tracking marine mammals. Some of the areas in which TOPEX/Poseidon and Jason-1 have made major contributions, [ 13 ] and to which OSTM/Jason-2 continued to add, are :
- Ocean variability
The missions revealed the surprise unevenness of the ocean, how much it changes from temper to season, class to year, decade to ten and on tied longer clock scales. They ended the traditional notion of a quasi-steady, large-scale pattern of ball-shaped ocean circulation by proving that the ocean is changing quickly on all scales, from huge features such as El Nino and La Nina, which can cover the entire equatorial Pacific, to tiny eddies swirling off the big Gulf Stream in the Atlantic Ocean .
- Sea level change
Measurements by TOPEX/Poseidon and Jason-1 show that mean sea level has been rising by about 3 mm ( 0.12 inches ) a class since 1993. This is about doubly the estimates from tide gauges for the previous hundred, indicating a possible recent acceleration in the rate of sea level wax. The datum record from these altimetry missions has given scientists significant insights into how ball-shaped sea horizontal surface is affected by natural climate variability, deoxyadenosine monophosphate well as by homo activities .
- Planetary waves
TOPEX/Poseidon and Jason-1 made clear the importance of planetary-scale waves, such as Rossby and Kelvin waves. Thousands of kilometres wide, these waves are driven by wind under the influence of Earth ‘s rotation and are important mechanisms for transmitting climate signals across the boastfully ocean basins. At high latitudes, they travel twice equally fast as scientists believed previously, showing the ocean responds much more cursorily to climate changes than was known before these missions .
- Ocean tides
The precise measurements of TOPEX/Poseidon ‘s and Jason-1 have brought cognition of ocean tides to an unprecedented flush. The change of water charge due to tidal gesticulate in the deep ocean is known everywhere on the globe to within 2.5 centimetres ( one column inch ). This new cognition has revised notions about how tide dissipate. alternatively of losing all their energy over shoal seas near the coasts, as previously believed, about one third of tidal energy is actually lost to the deep ocean. There, the energy is consumed by mixing water of different properties, a fundamental mechanism in the physics governing the general circulation of the ocean .
- Ocean models
TOPEX/Poseidon and Jason-1 observations provided the first global datum for improving the performance of the numerical ocean models that are a cardinal component of climate prediction models .
Data use and benefits [edit ]
Validated data products in support of better weather, climate and ocean forecasts were distributed to the public within a few hours of observation. Beginning in 2009, other data products for climate inquiry were made available a few days to a few weeks after observations were taken by the satellite. Altimetry data have a wide variety show of uses from basic scientific research on climate to ship routing. Applications include :
end of deputation [edit ]
The OSTM/Jason-2 mission concluded on 1 October 2019, after NASA and its mission partners made the decision to decommission the spacecraft upon discovering significant holocene deterioration of the spacecraft ‘s power systems. [ 14 ] The decommission of the satellite took some days ; the final decommission activities on the satellite ended 9 October 2019, with the satellite rendered amply inactive. [ 15 ] Because Jason-2 is orbiting at an elevation of over 1,300 km ( 810 nautical mile ), NASA estimates that it will remain in eye socket for at least 500 to 1,000 years after decommissioning. [ 15 ]
future [edit ]
The fourth spacecraft to be part of the Ocean Surface Topography Mission is Jason-3. Like its predecessors, the elementary instrument aboard Jason-3 is a radar altimeter. extra instruments include : [ 16 ]
- A microwave radiometer
- DORIS (Doppler Orbitography and Radiopositioning Integrated by Satellite)
- A Laser Retroreflector Array (LRA)
- A Global Positioning System (GPS) receiver
Jason-3 launched from Vandenberg Air Force Base on board a SpaceX Falcon 9 v1.1 establish fomite in 2016. [ 17 ] The satellite was shipped to Vandenberg Air Force Base on 18 June 2015, [ 18 ] and after delays due to a June 2015 Falcon 9 launch failure, the mission was launched 17 January 2016 at 18:42:18 UTC. [ 19 ] [ 20 ] The technologies and data-sets pioneered by Jason-1, OSTM/Jason-2, and Jason-3, will be continued through the Sentinel-6 /Jason-CS satellites, planned for establish in 2020 and 2025. [ 14 ]
See besides [edit ]
References [edit ]
Media related to Ocean Surface Topography Mission at Wikimedia Commons