Cyclone Global Navigation Satellite System

Last updated

CYGNSS
CYGNSS concept art.jpeg
Concept art of CYGNSS above a hurricane
Mission typeWeather research
Operator NASA
COSPAR ID 2016-078A , 2016-078B , 2016-078C , 2016-078D , 2016-078E , 2016-078F , 2016-078G , 2016-078H
SATCAT no. 41884, 41885, 41886, 41887, 41888, 41889, 41890, 41891
Website cygnss-michigan.org
Mission durationPlanned: 2 years
Elapsed: 7 years, 10 months, 19 days
Spacecraft properties
Manufacturer
Launch mass28.9 kg (64 lb) each [1] [2]
Dimensions163.5 × 52.1 × 22.9 cm (64.4 × 20.5 × 9.0 in) [1]
(L x W x D)
Power34.7 watts
Start of mission
Launch dateDecember 15, 2016, 13:37:21 (2016-12-15UTC13:37:21)  UTC [3]
Rocket Pegasus XL F43 [2]
Launch site Cape Canaveral ( Stargazer )
Contractor Orbital ATK
Entered serviceMarch 23, 2017 [4]
Orbital parameters
Reference system Geocentric
Regime Low Earth
Semi-major axis 6,903 km (4,289 mi)
Eccentricity 0.00162
Perigee altitude 514 km (319 mi)
Apogee altitude 536 km (333 mi)
Inclination 35 degrees
Period 95.1 minutes
Epoch April 15, 2017, 22:21:25 UTC [5]
Instruments
Delay Doppler Mapping Instrument

The Cyclone Global Navigation Satellite System (CYGNSS) is a space-based system developed by the University of Michigan and Southwest Research Institute with the aim of improving hurricane forecasting by better understanding the interactions between the sea and the air near the core of a storm.

Contents

In June 2012, NASA sponsored the project for $152 million with the University of Michigan leading its development. [6] [7] Other participants in CYGNSS' development include the Southwest Research Institute, Sierra Nevada Corporation, and Surrey Satellite Technology. [8]

The plan was to build a constellation of eight micro-satellites to be launched simultaneously in a single launch vehicle [9] into low Earth orbit, [7] [10] at 500 km altitude. [11] The program was scheduled to launch December 12, 2016, and then observe two hurricane seasons. [12] [13] Problems with a pump on the launching aircraft prevented this first launch, but a second launch attempt took place successfully on December 15, 2016. In 2022, one of the satellites, FM06, abruptly ceased operations. [14]

Overview

Forecasting the tracks of tropical cyclones since 1990 has improved by approximately 50%; however, in the same time period there has not been a corresponding improvement in forecasting the intensity of these storms. A better understanding of the inner core of tropical storms could lead to better forecasts; however, current sensors are unable to gather a sufficient quality of data on the inner core due to obscuration from rain bands surrounding it and to infrequent sampling. In order to improve the models used in intensity forecasts, better data are required. [15] [16]

CYGNSS will measure the ocean surface wind field using a bi-static scatterometry technique based on Global Navigation Satellite Systems (GNSS) signals, primarily GPS. [15] [16] Each satellite receives both direct GPS signals and signals reflected from the Earth's surface; the direct signals pinpoint the microsatellite position and provide a timing reference, while the reflected or "scattered" signals provide information about the condition of the sea's surface. Sea surface roughness corresponds to wind speed. [11] Using a network of eight small satellites enables frequent observations: the mean revisit time is predicted to be 7 hours. [15] [16] The eight microsatellites orbit at an inclination of 35°, and are each capable of measuring 4 simultaneous reflections, resulting in 32 wind measurements per second across the globe. [11]

CYGNSS is the first of NASA's Earth Venture-class spaceborne missions, part of NASA's Earth Science System Pathfinder program; [8] the previous EV selections were divided among five airborne remote sensing missions. The two-year mission launched on December 15, 2016, after postponements from November 2016, [17] and December 12, 2016. [12] [18]

Science goal

The CYGNSS science goal is to understand the coupling between ocean surface properties, moist atmospheric thermodynamics, radiation, and convective dynamics in the inner core of a tropical cyclone. [11] To achieve this goal, the system will measure ocean surface wind speed in all precipitating conditions, including those experienced in the eyewall. The mission will also measure ocean surface wind speed in the storm's inner core with sufficient frequency to resolve genesis and rapid intensification. As secondary goal, the project will support the operational hurricane forecast community by producing and providing ocean surface wind speed data products. [11]

Instruments

Each CYGNSS satellite carries a Delay Doppler Mapping Instrument (DDMI), consisting of:

The instrument receives GPS signals scattered by the ocean surface for the purposes of bi-static scatterometry. [11]

Launch and early orbit operations

Launch of CYGNSS on a Pegasus-XL Launch of Pegasus F43 from Stargazer (KSC-20161215-PH LAL02 0005).jpg
Launch of CYGNSS on a Pegasus-XL

The CYGNSS mission was launched on December 15, 2016, at 13:37:21 UTC from a single Pegasus XL air-launched rocket. The rocket was deployed from a customized Lockheed L-1011 aircraft, Orbital ATK 's Stargazer , from a position 201 kilometers (125 mi) off the coast of Cape Canaveral, Florida. [3] [19] A launch attempt on December 12 was aborted due to problems with the hydraulic system that separates the Pegasus rocket from the carrier aircraft. [20] After launch, the eight microsats were released into orbit beginning at 13:50 UTC and ending at 13:52 UTC by a deployment module attached to the Pegasus third stage. Successful radio contact with the first microsat was made at 16:42 UTC. [21] The eighth microsat was successfully contacted at 20:30 UTC. [22] By the end of the day on December 15, all eight microsats had their solar arrays deployed and were sun-pointed with batteries charging in safe condition, ready to begin engineering commissioning. [23]

Use of Differential Drag to Adjust Satellite Spacing

CYGNSS measurements of Hurricane Jose on September 17, 2017. The calm eye is visible inside the ring of strong winds in the eyewall. Wind Hurricane-Jose storm-centered 2017-09-17.jpg
CYGNSS measurements of Hurricane Jose on September 17, 2017. The calm eye is visible inside the ring of strong winds in the eyewall.

Early mission operations focused on engineering commissioning of the satellites [24] and adjustments to the spacing between them. Their relative spacing is important for achieving the desired spatial and temporal sampling. [25] Inter-satellite spacing is controlled by adjusting spacecraft orientation and, as a result, the difference in atmospheric drag between satellites. This technique is referred to as differential drag. An increase in drag lowers a satellite's altitude and increases its orbital velocity. [26] The distance between spacecraft changes as a result of their relative velocities. This is an alternate way of managing the spacing between a constellation of satellites, as opposed to using traditional active propulsion, and is significantly lower cost. It allows for more satellites to be built for the same net cost, resulting in more frequent sampling of short lived, extreme weather events like tropical cyclones. [16] Differential drag maneuvers were conducted throughout the first year-and-a-half of on-orbit operations, and have resulted in a well-dispersed constellation that is able to make measurements with the desired sampling properties. [27] [28]

Wind Observations over the Ocean

Wind speed measurements are made by CYGNSS in a manner analogous to that of previous spaceborne ocean wind sensing radars, by detecting changes in surface roughness caused by near surface wind stress. [29] [30] The quality of the measurements is determined by comparisons to nearly coincident observations by other wind sensors. Comparisons at low to moderate wind speeds (below 20 m/s, 45 mph, 72 km/h) are made to the NOAA Global Data Assimilation System numerical reanalysis wind product and indicate an uncertainty in CYGNSS winds of 1.4 m/s (3 mph; 5 km/h), with higher uncertainty at high wind speeds. [31] Above 45 mph, and in particular for measurements made within tropical cyclones, comparisons are made to nearly coincident observations by wind sensing instruments on NOAA P-3 hurricane hunter aircraft which were flown into hurricanes in coordination with satellite overpasses by CYGNSS. [32] The comparisons indicate an uncertainty in CYGNSS winds of 11%. [33] As was the case at lower wind speeds, the uncertainty increases with wind speed. CYGNSS ocean wind speed measurements are currently being incorporated into hurricane numerical forecast models [34] [35] [36] [37] and storm surge models [38] to assess the improvement in their performance. Images of recent and archival ocean wind measurements, both globally and centered on individual storms, are available at Archived January 21, 2019, at the Wayback Machine . Numerical data files of ocean wind speed measurements are available at .

Observations over Land

CYGNSS measurements of land surface scattering for the month of December 2017. Changes in soil moisture and the extent of inland waterways affect the measurements. SNR Global 2018-12.png
CYGNSS measurements of land surface scattering for the month of December 2017. Changes in soil moisture and the extent of inland waterways affect the measurements.

CYGNSS operates continuously, over both ocean and land, and the land measurements also contain useful information. The measurements are sensitive to surface soil moisture and to the presence and extent of inland water bodies. [27] Soil moisture has been estimated using CYGNSS data at numerous sites in the continental U.S. and is found to be in close agreement with independent measurements made by ground sensors and by another satellite. [39] [40] Numerical data files of soil moisture measurements are available at . The ability of CYGNSS land data to detect and map the extent of flood inundation under dense forest canopies has also been demonstrated [41] and this capability has been used to produce time lapse images of flooding in and around Houston and Havana after landfalls by Hurricanes Harvey and Irma, respectively. [42]

See also

Related Research Articles

<span class="mw-page-title-main">EUMETSAT</span> European intergovernmental organisation

The European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT) is an intergovernmental organisation created through an international convention agreed by a current total of 30 European Member States.

<span class="mw-page-title-main">Jason-1</span> Satellite oceanography mission

Jason-1 was a satellite altimeter oceanography mission. It sought to monitor global ocean circulation, study the ties between the ocean and the atmosphere, improve global climate forecasts and predictions, and monitor events such as El Niño and ocean eddies. Jason-1 was launched in 2001 and it was followed by OSTM/Jason-2 in 2008, and Jason-3 in 2016 – the Jason satellite series. Jason-1 was launched alongside the TIMED spacecraft.

<span class="mw-page-title-main">Satellite geodesy</span> Measurement of the Earth using satellites

Satellite geodesy is geodesy by means of artificial satellites—the measurement of the form and dimensions of Earth, the location of objects on its surface and the figure of the Earth's gravity field by means of artificial satellite techniques. It belongs to the broader field of space geodesy. Traditional astronomical geodesy is not commonly considered a part of satellite geodesy, although there is considerable overlap between the techniques.

A scatterometer or diffusionmeter is a scientific instrument to measure the return of a beam of light or radar waves scattered by diffusion in a medium such as air. Diffusionmeters using visible light are found in airports or along roads to measure horizontal visibility. Radar scatterometers use radio or microwaves to determine the normalized radar cross section of a surface. They are often mounted on weather satellites to find wind speed and direction, and are used in industries to analyze the roughness of surfaces.

<span class="mw-page-title-main">ADM-Aeolus</span> Wind-measuring satellite

Aeolus, or, in full, Atmospheric Dynamics Mission-Aeolus (ADM-Aeolus), was an Earth observation satellite operated by the European Space Agency (ESA). It was built by Airbus Defence and Space, launched on 22 August 2018, and operated until it was deorbited and re-entered the atmosphere over Antarctica on 28 July 2023. ADM-Aeolus was the first satellite with equipment capable of performing global wind-component-profile observation and provided much-needed information to improve weather forecasting. Aeolus was the first satellite capable of observing what the winds are doing on Earth, from the surface of the planet and into the stratosphere 30 km high.

<span class="mw-page-title-main">QuikSCAT</span> Earth observation satellite

The NASA QuikSCAT was an Earth observation satellite carrying the SeaWinds scatterometer. Its primary mission was to measure the surface wind speed and direction over the ice-free global oceans via its effect on water waves. Observations from QuikSCAT had a wide array of applications, and contributed to climatological studies, weather forecasting, meteorology, oceanographic research, marine safety, commercial fishing, tracking large icebergs, and studies of land and sea ice, among others. This SeaWinds scatterometer is referred to as the QuikSCAT scatterometer to distinguish it from the nearly identical SeaWinds scatterometer flown on the ADEOS-2 satellite.

<span class="mw-page-title-main">Rapid intensification</span> Dramatic increase in a tropical cyclones strength

Rapid intensification (RI) is any process wherein a tropical cyclone strengthens dramatically in a short period of time. Tropical cyclone forecasting agencies utilize differing thresholds for designating rapid intensification events, though the most widely used definition stipulates an increase in the maximum sustained winds of a tropical cyclone of at least 30 knots in a 24-hour period. However, periods of rapid intensification often last longer than a day. About 20–30% of all tropical cyclones undergo rapid intensification, including a majority of tropical cyclones with peak wind speeds exceeding 51 m/s.

<span class="mw-page-title-main">GNSS reflectometry</span> Earth observation technology

GNSS reflectometry involves making measurements from the reflections from the Earth of navigation signals from Global Navigation Satellite Systems such as GPS. The idea of using reflected GNSS signals for earth observation was first proposed in 1993 by Martin-Neira. It was also investigated by researchers at NASA Langley Research Center and is also known as GPS reflectometry.

<span class="mw-page-title-main">Tropical cyclone observation</span>

Tropical cyclone observation has been carried out over the past couple of centuries in various ways. The passage of typhoons, hurricanes, as well as other tropical cyclones have been detected by word of mouth from sailors recently coming to port or by radio transmissions from ships at sea, from sediment deposits in near shore estuaries, to the wiping out of cities near the coastline. Since World War II, advances in technology have included using planes to survey the ocean basins, satellites to monitor the world's oceans from outer space using a variety of methods, radars to monitor their progress near the coastline, and recently the introduction of unmanned aerial vehicles to penetrate storms. Recent studies have concentrated on studying hurricane impacts lying within rocks or near shore lake sediments, which are branches of a new field known as paleotempestology. This article details the various methods employed in the creation of the hurricane database, as well as reconstructions necessary for reanalysis of past storms used in projects such as the Atlantic hurricane reanalysis.

<span class="mw-page-title-main">Tropical cyclone forecasting</span> Science of forecasting how a tropical cyclone moves and its effects

Tropical cyclone forecasting is the science of forecasting where a tropical cyclone's center, and its effects, are expected to be at some point in the future. There are several elements to tropical cyclone forecasting: track forecasting, intensity forecasting, rainfall forecasting, storm surge, tornado, and seasonal forecasting. While skill is increasing in regard to track forecasting, intensity forecasting skill remains unchanged over the past several years. Seasonal forecasting began in the 1980s in the Atlantic basin and has spread into other basins in the years since.

<span class="mw-page-title-main">Tropical cyclone track forecasting</span> Predicting where a tropical cyclone is going to track over the next five days, every 6 to 12 hours

Tropical cyclone track forecasting involves predicting where a tropical cyclone is going to track over the next five days, every 6 to 12 hours. The history of tropical cyclone track forecasting has evolved from a single-station approach to a comprehensive approach which uses a variety of meteorological tools and methods to make predictions. The weather of a particular location can show signs of the approaching tropical cyclone, such as increasing swell, increasing cloudiness, falling barometric pressure, increasing tides, squalls and heavy rainfall.

The Cooperative Institute for Meteorological Satellite Studies (CIMSS) is a research institute where scientists study the use of data from geostationary and polar orbit weather satellites to improve forecasts of weather (including tropical cyclones and severe storms. CIMSS was formed through a Memorandum of Understanding between the University of Wisconsin–Madison, the National Oceanic and Atmospheric Administration and the National Aeronautics and Space Administration. CIMSS parent organization, the Space Science and Engineering Center is a primary developer and operator of environmental satellite technologies.

<span class="mw-page-title-main">OSTM/Jason-2</span> International Earth observation satellite mission

OSTM/Jason-2, or Ocean Surface Topography Mission/Jason-2 satellite, was an international Earth observation satellite altimeter joint mission for sea surface height measurements between NASA and CNES. It was the third satellite in a series started in 1992 by the NASA/CNES TOPEX/Poseidon mission and continued by the NASA/CNES Jason-1 mission launched in 2001.

<span class="mw-page-title-main">Radio occultation</span> Remote sensing technique

Radio occultation (RO) is a remote sensing technique used for measuring the physical properties of a planetary atmosphere or ring system. Satellites carrying onboard GNSS-Radio occultation instruments include CHAMP, GRACE and GRACE-FO, MetOp and the recently launched COSMIC-2.

<span class="mw-page-title-main">Surface Water and Ocean Topography</span> NASA/CNES oceanography mission (2022–Present)

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). 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.

<span class="mw-page-title-main">Soil Moisture Active Passive</span> NASA earth monitoring satellite that measures global soil moisture

Soil Moisture Active Passive (SMAP) is a NASA environmental monitoring satellite that measures soil moisture across the planet. It is designed to collect a global 'snapshot' of soil moisture every 2 to 3 days. With this frequency, changes from specific storms can be measured while also assessing impacts across seasons of the year. SMAP was launched on 31 January 2015. It was one of the first Earth observation satellites developed by NASA in response to the National Research Council's Decadal Survey.

<span class="mw-page-title-main">ISS-RapidScat</span>

ISS-RapidScat was an instrument mounted to the International Space Station'sColumbus module that measured wind speeds. It was launched aboard SpaceX CRS-4 in September 2014 and operated until August 2016. ISS-RapidScat was a scatterometer designed to support weather forecasting by bouncing microwaves off the ocean's surface to measure wind speed via wind waves. It featured a 75 cm (30 in) rotating radar dish that operated at 13.4 GHz. It could collect data between 51.6 degrees north and south latitude, with a swath 900 km wide (560 mi).

<span class="mw-page-title-main">Space-based measurements of carbon dioxide</span> Used to help answer questions about Earths carbon cycle

Space-based measurements of carbon dioxide are used to help answer questions about Earth's carbon cycle. There are a variety of active and planned instruments for measuring carbon dioxide in Earth's atmosphere from space. The first satellite mission designed to measure CO2 was the Interferometric Monitor for Greenhouse Gases (IMG) on board the ADEOS I satellite in 1996. This mission lasted less than a year. Since then, additional space-based measurements have begun, including those from two high-precision satellites. Different instrument designs may reflect different primary missions.

<span class="mw-page-title-main">TROPICS (spacecraft constellation)</span> NASA mission

TROPICS(Time-Resolved Observations of Precipitation structure and storm Intensity with a Constellation of Smallsats) is a 2023 NASA constellation of six small satellites, 3U CubeSats, that will measure temperature and moisture profiles and precipitation in tropical systems with unprecedented temporal frequency. This data will enable scientists to study the dynamic processes that occur in the inner core of the storm resulting in rapid genesis and intensification. William Blackwell of the Massachusetts Institute of Technology's Lincoln Laboratory in Lexington, Massachusetts is the principal investigator. The constellation was initially planned to be delivered to orbit on three launches between June and July 2022. Due to the loss of the first two satellites after a launch failure in June 2022, the first satellites were delivered to orbit aboard a Rocket Lab Electron rocket on 7 May 2023.

<span class="mw-page-title-main">Sentinel-6 Michael Freilich</span> Earth observation satellite

The Sentinel-6 Michael Freilich (S6MF) or Sentinel-6A is a radar altimeter satellite developed in partnership between several European and American organizations. It is part of the Jason satellite series and is named after Michael Freilich. S6MF includes synthetic-aperture radar altimetry techniques to improve ocean topography measurements, in addition to rivers and lakes. The spacecraft entered service in mid 2021 and is expected to operate for 5.5 years.

References

  1. 1 2 "CYGNSS Press Kit" (PDF). NASA. December 16, 2016. Archived from the original (PDF) on May 8, 2018. Retrieved April 17, 2017.
  2. 1 2 Graham, William (December 15, 2016). "Pegasus launches CYGNSS constellation following Stargazer release". NASA Spaceflight. Retrieved April 17, 2017.
  3. 1 2 Clark, Stephen (December 15, 2016). "Flock of 'microsats' launched to measure winds inside hurricanes". Spaceflight Now. Retrieved April 16, 2017.
  4. ↑ "NASA's CYGNSS Satellite Constellation Enters Science Operations Phase". NASA. March 31, 2017. Archived from the original on June 29, 2017. Retrieved April 16, 2017.
  5. ↑ "CYGNSS - Orbit". Heavens-Above. April 15, 2017.
  6. ↑ "U-M To Lead $152M NASA Satellite Project". Associated Press. June 19, 2012. Retrieved June 22, 2012.
  7. 1 2 Clark, Stephen (June 21, 2012). "NASA funds satellite mission to measure hurricane winds". SpaceflightNow. Retrieved June 22, 2012.
  8. 1 2 "NASA Selects Low Cost, High Science Earth Venture Space System". NASA. June 18, 2012. Retrieved June 24, 2012.
  9. ↑ "U-M to Lead $150M NASA Hurricane Prediction Project". University of Michigan. June 19, 2012. Archived from the original on June 23, 2012. Retrieved November 14, 2016.
  10. ↑ Aldridge, James (June 21, 2012). "NASA taps SwRI on research effort to map hurricanes". San Antonio Business Journal. Retrieved June 22, 2012.
  11. 1 2 3 4 5 6 "CYGNSS Factsheet October 2014". Archived August 4, 2016, at the Wayback Machine University of Michigan. Retrieved: September 27, 2015.
  12. 1 2 "CYGNSS Mission". University of Michigan . Retrieved February 11, 2016.
  13. ↑ "University of Michigan, NASA team up for hurricane satellite project". Michigan Radio. June 19, 2012. Retrieved April 11, 2023.
  14. ↑ "Notes from the Field - Happy Sixth Birthday to the CYGNSS Constellation". NASA Earth Observatory. December 15, 2022. Retrieved October 3, 2023.
  15. 1 2 3 "CYGNSS." Archived March 15, 2013, at the Wayback Machine University of Michigan. Retrieved: August 15, 2015
  16. 1 2 3 4 Ruf, Christopher S.; Atlas, Robert; Chang, Paul S.; Clarizia, Maria Paola; Garrison, James L.; Gleason, Scott; Katzberg, Stephen J.; Jelenak, Zorana; Johnson, Joel T. (June 26, 2015). "New Ocean Winds Satellite Mission to Probe Hurricanes and Tropical Convection". Bulletin of the American Meteorological Society. 97 (3): 385–395. Bibcode:2016BAMS...97..385R. doi: 10.1175/BAMS-D-14-00218.1 . ISSN   0003-0007. S2CID   10991111.
  17. ↑ "Missions - CYGNSS". NASA. April 30, 2013. Archived from the original on April 7, 2014. Retrieved September 8, 2013.
  18. ↑ Leone, Dan (June 19, 2012). "NASA To Fund Wind-monitoring Smallsat Constellation". Space News. Archived from the original on February 3, 2013. Retrieved June 22, 2012.
  19. ↑ "NASA Hurricane Science Satellites sent into Orbit by Air-Launched Pegasus Rocket". Spaceflight 101. December 15, 2016. Retrieved April 16, 2017.
  20. ↑ "'Valiant Troubleshooting in the Air' - CYGNSS Hurricane Mission". blogs.nasa.gov. December 12, 2016. Retrieved December 12, 2016.
  21. ↑ Allen, Bob (December 15, 2016). "First CYGNSS micro-satellite is healthy!". NASA. Retrieved April 16, 2017.
  22. ↑ Atkinson, Joseph (December 15, 2016). "Eight for Eight! All Satellites Contacted!". NASA. Retrieved April 16, 2017.
  23. ↑ Ruf, Chris (December 15, 2016). "A Message From CYGNSS Principal Investigator Chris Ruf". NASA. Retrieved April 16, 2017.
  24. ↑ Killough, Ronnie; Scherrer, John; Rose, Randall; Brody, Antonina; Redfern, Jillian; Smith, Keith; Ruf, Christopher; Yee, Terrance (August 9, 2017). "CYGNSS Launch and Early Ops: Parenting Octuplets". AIAA/USU Conference on Small Satellites.
  25. ↑ Bussy-Virat, C. D.; Ruf, C. S.; Ridley, A. J. (2018). "Relationship Between Temporal and Spatial Resolution for a Constellation of GNSS-R Satellites". IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing. 12: 16–25. doi:10.1109/JSTARS.2018.2833426. ISSN   1939-1404. S2CID   19175653.
  26. ↑ Finley, T.; Rose, D. (2014). Astrodynamics 2013: Proceedings of the AAS/AIAA Astrodynamics Specialist Conference held 11-15 August 2013, Hilton Head, South Carolina, U.S.A. Vol. 150. American Institute of Aeronautics and Astronautics. pp. 1397–1411. ISBN   978-087703605-0.
  27. 1 2 Ruf, Christopher; Ridley, Aaron; Nave, Kyle; Morris, Mary G.; Lang, Timothy; Chew, Clara; Balasubramaniam, Rajeswari (June 8, 2018). "A New Paradigm in Earth Environmental Monitoring with the CYGNSS Small Satellite Constellation". Scientific Reports. 8 (1): 8782. Bibcode:2018NatSR...8.8782R. doi:10.1038/s41598-018-27127-4. ISSN   2045-2322. PMC   5993737 . PMID   29884899.
  28. ↑ Bussy-Virat, C. D.; Ridley, A. J.; Masher, A.; Nave, K.; Intelisano, M. (2018). "Assessment of the Differential Drag Maneuver Operations on the CYGNSS Constellation". IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing. 12: 7–15. doi:10.1109/JSTARS.2018.2878158. ISSN   1939-1404. S2CID   59234996.
  29. ↑ Jones, W. Linwood; Schroeder, Lyle C.; Boggs, Dale H.; Bracalente, Emedio M.; Brown, Robert A.; Dome, George J.; Pierson, Willard J.; Wentz, Frank J. (1982). "The SEASAT-A satellite scatterometer: The geophysical evaluation of remotely sensed wind vectors over the ocean". Journal of Geophysical Research: Oceans. 87 (C5): 3297–3317. Bibcode:1982JGR....87.3297J. doi:10.1029/JC087iC05p03297. ISSN   2156-2202.
  30. ↑ Zavorotny, V.U.; Voronovich, A.G. (2000). "Scattering of GPS signals from the ocean with wind remote sensing application" (PDF). IEEE Transactions on Geoscience and Remote Sensing. 38 (2): 951–964. Bibcode:2000ITGRS..38..951Z. doi:10.1109/36.841977. ISSN   0196-2892.
  31. ↑ Ruf, C. S.; Gleason, S.; McKague, D. S. (2018). "Assessment of CYGNSS Wind Speed Retrieval Uncertainty" (PDF). IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing. 12: 87–97. doi:10.1109/JSTARS.2018.2825948. ISSN   1939-1404. S2CID   13966928.
  32. ↑ "Notes from the Field - Flying into Hurricane Harvey". earthobservatory.nasa.gov. January 20, 2019. Retrieved January 20, 2019.
  33. ↑ "Notes from the Field - Two year anniversary of CYGNSS on orbit". earthobservatory.nasa.gov. January 20, 2019. Retrieved January 20, 2019.
  34. ↑ Zhang, S.; Pu, Z. (2017). "Impact of CYGNSS ocean surface wind speeds on numerical simulations of a hurricane in observing system simulation experiments". Journal of Atmospheric and Oceanic Technology. 34 (2): 375–383. Bibcode:2017JAtOT..34..375Z. doi: 10.1175/jtech-d-16-0144.1 .
  35. ↑ Annane, Bachir (2018). "A Study of the HWRF Analysis and Forecast Impact of Realistically Simulated CYGNSS Observations Assimilated as Scalar Wind Speeds and as VAM Wind Vectors". Monthly Weather Review. 146 (7): 2221–2236. Bibcode:2018MWRv..146.2221A. doi: 10.1175/mwr-d-17-0240.1 .
  36. ↑ Leidner, S. (2018). "Variational Analysis of Simulated Ocean Surface Winds from the Cyclone Global Navigation Satellite System (CYGNSS) and Evaluation using a Regional OSSE". Journal of Atmospheric and Oceanic Technology. 35 (8): 1571–1584. Bibcode:2018JAtOT..35.1571L. doi: 10.1175/jtech-d-17-0136.1 .
  37. ↑ Cui, Z., Z. Pu, C. Ruf, V. Tallapragada, 2019a: Impact of CYGNSS Data on Tropical Cyclone Analysis and Forecasts Using the Operational HWRF. 23rd IOAS-ALOS Conference, AMS Annual Mtg, Jan 6-10, 2019, Phoenix, AZ.
  38. ↑ Warnock, April; Ruf, Chris; Morris, Mary (2017). "Storm surge prediction with cygnss winds". 2017 IEEE International Geoscience and Remote Sensing Symposium (IGARSS). pp. 2975–2978. doi:10.1109/IGARSS.2017.8127624. ISBN   978-1-5090-4951-6. S2CID   25898619.
  39. ↑ Kim, Hyunglok; Lakshmi, Venkat (2018). "Use of Cyclone Global Navigation Satellite System (CyGNSS) Observations for Estimation of Soil Moisture". Geophysical Research Letters. 45 (16): 8272–8282. Bibcode:2018GeoRL..45.8272K. doi: 10.1029/2018GL078923 . ISSN   1944-8007. S2CID   53379291.
  40. ↑ Chew, C. C.; Small, E. E. (May 5, 2018). "Soil Moisture Sensing Using Spaceborne GNSS Reflections: Comparison of CYGNSS Reflectivity to SMAP Soil Moisture". Geophysical Research Letters. 45 (9): 4049–4057. Bibcode:2018GeoRL..45.4049C. doi: 10.1029/2018gl077905 . ISSN   0094-8276. S2CID   134962064.
  41. ↑ Jensen, Katherine; McDonald, Kyle; Podest, Erika; Rodriguez-Alvarez, Nereida; Horna, Viviana; Steiner, Nicholas (September 7, 2018). "Assessing L-Band GNSS-Reflectometry and Imaging Radar for Detecting Sub-Canopy Inundation Dynamics in a Tropical Wetlands Complex". Remote Sensing. 10 (9): 1431. Bibcode:2018RemS...10.1431J. doi: 10.3390/rs10091431 . ISSN   2072-4292.
  42. ↑ Chew, Clara; Reager, John T.; Small, Erica (June 19, 2018). "CYGNSS data map flood inundation during the 2017 Atlantic hurricane season". Scientific Reports. 8 (1): 9336. Bibcode:2018NatSR...8.9336C. doi:10.1038/s41598-018-27673-x. ISSN   2045-2322. PMC   6008409 . PMID   29921941.
This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.