Mr. Parag V. Vaze Profile

Parag V. Vaze

Project Manager at Jet Propulsion Lab

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Publications (7)

Proceedings Article | 18 October 2019 Presentation

Development status and performance of the NASA payload for the Sentinel-6 mission (Conference Presentation)

Parag Vaze

Proceedings Volume 11151, 111510D (2019) https://doi.org/10.1117/12.2537016

KEYWORDS: Radiometry, Satellites, Humidity, Weather forecasting, Climatology, Synthetic aperture radar, Microwave radiation, Earth's atmosphere, Satellite navigation systems, Climate change

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The Sentinel-6 (S6) Mission will provide continuity of ocean topography measurements beyond TOPEX-Poseidon (launched in 1992), Jason-1 (2001), OSTM/Jason-2 (2008), and Jason-3 (2016) for determining ocean circulation, climate change and sea level rise. Unlike past Jason missions, S6 will also contribute atmospheric temperature and humidity profile measurement in near real time to support operational weather forecasting. The S6 mission consists of two satellites to be launched approximately 5 years apart to extend measurement continuity for at least another decade. This mission will serve both the operational user community and also enable the continuation of multi-decadal ocean topography measurements for ocean circulation and climate studies. The first S6 satellite is planned to launch by the end of 2020 with a suite of instruments similar to the prior Jason series missions. Sentinel-6 is a cooperative mission with contributions from NASA, NOAA, ESA, and EUMETSAT. The ocean altimetry science payload is similar to the prior Jason missions, including a nadir altimeter, water vapor radiometer and precision orbit determination system instruments. The nadir altimeter is contributed by ESA and EUMETSAT and comprises a new dual-frequency (C and Ku band) synthetic aperture radar (SAR) altimeter (Poseidon-4). The NASA-provided payload is managed and developed by the Jet Propulsion Laboratory (JPL). It consists of the Advanced Microwave Radiometer for Climate (AMR-C) instrument that includes a new on-board absolute Supplemental Calibration Subsystem (SCS). The SCS is a key evolution of the radiometer instrument that will enable a significant improvement in the sea surface height measurement stability. The AMR-C provides the water vapor path delay correction to the ocean height measurement from the Poseidon-4 Radar Altimeter. The AMR-C is further enhanced by an experimental High-Resolution Microwave Radiometer (HRMR) that will demonstrate the capability of high frequency (90, 130, 166 GHz) radiometer channels for extending the wet path delay measurements into the coastal zone with ~5x finer spatial resolution compared with the traditional low-frequency AMR channels. The NASA payload also contains a Laser Retroflector Array (LRA) that supports ground-based laser tracking for precise orbit determination validation. As a secondary mission objective, S6 will also characterize atmospheric temperature and humidity profiles by measuring bending angles of GNSS signals occulted by the Earth’s atmosphere. These measurement products will be ground-processed within three hours of acquisition on board the satellite and made available for ingestion into national weather service models to support weather forecasting capabilities. This measurement is provided by the NASA-provided Global Navigation Satellite System for Radio Occultation (GNSS-RO) instrument. We present a description of the overall mission and focus on the NASA payload architecture, development status and (pre and post) launch expected performances.

Proceedings Article | 18 October 2019 Presentation

SWOT: development of the wide-swath surface water altimetry mission for oceanography and hydrology (Conference Presentation)

Parag Vaze

Proceedings Volume 11151, 111510E (2019) https://doi.org/10.1117/12.2537017

KEYWORDS: Radar, Hydrology, Oceanography, Satellites, Climate change, Knowledge management, Space operations, Calibration, Interferometry, Spatial resolution

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A new satellite mission called Surface Water and Ocean Topography (SWOT) is being developed jointly by the U.S. National Aeronautics and Space Administration and France’s Centre National d’Etudes Spatiales. Based on the success of conventional nadir-looking altimetry missions in the past, SWOT will utilize the technique of radar interferometry for making wide-swath altimetric measurements of the elevation of surface water on land and the ocean’s surface topography. The new measurements will provide information on the changing ocean currents that are key to the prediction of climate change, as well as the shifting fresh water resources resulting from the dynamic water cycle. The noise level of conventional radar altimeters limits the along-track spatial resolution to 50-100 km over the oceans. The large spacing between the satellite ground tracks limits the resolution of two-dimensional gridded data to 200 km. Yet most of the kinetic energy of ocean circulation takes place at the scales unresolved by conventional altimetry. SWOT observations will provide the critical new information at these scales for developing and testing ocean models that are designed for predicting future climate change. In contrast to ocean observations, land surface water measurements are limited mostly to in situ networks of gauges. While radar altimetry over surface waters has demonstrated the potential of this technique in land hydrology, a number of limitations exist. Raw radar altimetry echoes reflected from land surface are complex, with multiple peaks caused by multiple reflections from water, vegetation canopy and rough topography, resulting in much less valid data over land than over the ocean. Yet one of the most threatening consequences of a warming climate is the shifting water resources. Monitoring the global water on land is critical for assessing the storage and discharge of lakes and rivers. The technology of SWOT is based on the heritage of the Shuttle Radar Topography Mission (SRTM) that successfully mapped the elevation of global land topography from a 10-day space shuttle mission. A higher frequency at Ka band (~35 GHz) is chosen for the radar to achieve high precision with a much shorter inteferometry baseline of 10 m. Small near-nadir look angles (~ 4 degrees), required for minimizing elevation errors, limit the swath width to 120 km. An orbit with inclination of 78 degrees and 22 day repeat period was chosen for gapless coverage and good tidal aliasing properties. With this configuration, SWOT is expected to achieve 1 cm precision at 1 km x 1 km pixels over the ocean and 10 cm precision over 50 m x 50 m pixels over land waters. Other payloads of the mission include a conventional dual-frequency altimeter for calibration to large-scale ocean topography, a water-vapor radiometer for correcting range delay caused by water vapor over the ocean, and precision orbit determination package (GPS, DORIS, and laser retroreflector). SWOT is currently being developed for a planned launch in 2021. This presentation will describe the current SWOT mission status, including technical development challenges regarding the Payload Instrument, Spacecraft, ground data system and calibration/validation plans.

Proceedings Article | 19 November 2012 Paper

Surface Water and Ocean Topography (SWOT) mission

Lee-Lueng Fu, Steven Neeck, Parag Vaze, Eric Lindstrom

Proceedings Volume 8533, 85330G (2012) https://doi.org/10.1117/12.981151

KEYWORDS: Space operations, Radar, Neodymium, Hydrology, Antennas, Ka band, Receivers, Spatial resolution, Global Positioning System, Radiometry

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Proceedings Article | 13 October 2010 Paper

The Jason-3 Mission: completing the transition of ocean altimetry from research to operations

Joseph Green, Eric Thouvenot, Steven Neeck, Francois Parisot, Gerard Zaouche, Angelo Wade, Michael Mignogno, Veronique Couderc, Parag Vaze, Walid Bannoura

Proceedings Volume 7826, 78260Y (2010) https://doi.org/10.1117/12.868543

KEYWORDS: Satellites, Global Positioning System, Lead, Microwave radiation, Radiometry, Doppler effect, Retroreflectors, Data modeling, Space operations, Meteorological satellites

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The Jason-3 mission is planned as a follow-on mission to the Ocean Surface Topography Mission/Jason-2, to continue the core satellite altimetry measurements for physical oceanography. In addition, a key long-term vision of the founders of this measurement will come to reality: the transitioning from research to operational applications of this valuable measurement. Jason-3 builds upon the heritage of foundational and transitional missions such as SEASAT (1978), GEOSAT (1985), TOPEX/Poseidon (T/P, 1992), Jason-1 (2001) and OSTM/Jason-2 (2008), which have led to the understanding and development of a wide range of oceanographic applications of satellite altimetry. With the successful development and operation of the TOPEX/Poseidon and Jason-1 missions, the Franco-American cooperation in ocean altimetry has grown with a steady vision of expanding this measurement towards operational applications. As such, the T/P and Jason-1 missions were developed by NASA and CNES, and subsequently NOAA and EUMETSAT have taken on key partnership roles by providing mission operations services for the OSTM/Jason-2 project. For Jason-3, NOAA and EUMETSAT are the lead agencies with CNES and NASA as key partners providing mission development support. With a planned project start in early 2010 and a launch target of mid-2013, Jason-3 is planned as a recurring mission from OSTM/Jason-2 to minimize satellite development risk as well as to ensure the continuity of measurements after OSTM/Jason-2. The Jason-3 satellite is planned to operate at the same 1336 km, 66 deg. inclination reference orbit with essentially the same on-board instrumentation as OSTM/Jason-2. The instrument suite will consist of a dual-frequency Nadir Altimeter, a Microwave Radiometer, and three Precision Orbit Determination instruments (Global Positioning System - GPS, Doppler Orbitography and Radio-positioning Integrated by Satellite -DORIS, and Laser Retroreflector Array - LRA). Fulfilling the goals of moving satellite altimetry onto routine operations will require a close cooperation and coordination of international, multi-agency mission managers, designers, engineers, scientists and operational systems developers. This paper presents the Jason-3 mission formulation and development plans, and highlights the key aspects of making this multidimensional project move towards reality.

Proceedings Article | 13 October 2010 Paper

The Surface Water and Ocean Topography Mission: a mission concept to study the world's oceans and fresh water

Thierry Lafon, Parag Vaze, Vincent Albuys, Juliette Lambin, Ernesto Rodriguez, Alain Mallet, Daniel Esteban-Fernandez

Proceedings Volume 7826, 782613 (2010) https://doi.org/10.1117/12.868439

KEYWORDS: Hydrology, Radar, Oceanography, Satellites, Interferometers, Data processing, Antennas, Data storage, Earth sciences, Ka band

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The Surface Water and Ocean Topography (SWOT) is a planned satellite mission to study the world's oceans and terrestrial surface water bodies. The SWOT mission concept has been proposed jointly by the global Hydrology and Oceanography science communities to make the first global survey of the Earth's surface water, observe the fine details of the ocean's surface topography, and measure how water bodies change over time. SWOT was one of 15 missions listed in the 2007 National Research Council's Decadal Survey for Earth science as a mission that NASA should implement in the incoming decade. This mission concept builds upon the heritage of prior missions and technologies such as Topex/Poseidon, Jason-1/ 2, the Shuttle Radar Topography Mission (SRTM), and the initial development of the Wide Swatch Ocean Altimeter intended for the Ocean Surface Topography Mission/Jason-2. The key measurement capability for SWOT is provided by a Ka-band synthetic aperture radar interferometer (KaRIn). With an orbit altitude of 970 km, the KaRIn instrument provides a high-resolution swath width of 120 km enabling global coverage (~90%) of the world's ocean's and fresh water bodies. The KaRIn measurement is being designed to provide a spatial resolution of 1 km for the oceans (after on-board processing), and 100 m for land water, both at centimetric accuracy. An additional instrument suite similar to the Jason series will complement KaRIn: a Ku-band nadir altimeter, a Microwave Radiometer and Precision Orbit Determination (POD) systems. To enable this challenging measurement performance, the SWOT mission concept is designed to overcome several challenges, such as very high raw data rate (320 Mbps), large on-board data volumes, high power demand, stringent pointing and stability requirements, and ground data processing systems, to produce meaningful science data products to our user community. The SWOT mission concept is being developed as a cooperative effort between NASA and CNES. This paper presents the initial end-to-end mission concept as well as the current plans to develop and implement this challenging mission in the future.

Proceedings Article | 13 October 2010 Paper

The Surface Water and Ocean Topography Mission: centimetric spaceborne radar interferometry

Lee-Lueng Fu, Parag Vaze, D. Esteban-Fernandez, Ernesto Rodriguez, Douglas Alsdorf

Proceedings Volume 7826, 782615 (2010) https://doi.org/10.1117/12.868535

KEYWORDS: Radar, Interferometry, Radio propagation, Calibration, Troposphere, Signal to noise ratio, Antennas, Spatial resolution, Interferometers, Radiometry

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Proceedings Article | 9 October 2008 Paper

The Ocean Surface Topography Mission (OSTM)

Parag Vaze, Steven Neeck

Proceedings Volume 7106, 710603 (2008) https://doi.org/10.1117/12.803677

KEYWORDS: Satellites, Space operations, Receivers, Global Positioning System, Climatology, Radiometry, Radar, Microwave radiation, Antennas, Climate change

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The Ocean Surface Topography Mission (OSTM), also known as Jason-2, will extend into the next decade the continuous climate data record of sea surface height measurements begun in 1992 by the joint NASA/Centre National d'Etudes Spatiales (CNES) TOPEX/Poseidon mission and continued by the NASA/CNES Jason-1 mission in 2001. This multi-decadal record has already helped scientists study the issue of global sea level rise and better understand how ocean circulation and climate change are related. With OSTM, high-precision ocean altimetry has come of age. The mission will serve as a bridge to transition the collection of these measurements to the world's weather and climate forecasting agencies. The agencies will use them for short- and seasonal-to-long-range weather and climate forecasting. OSTM is designed to last at least three years. It will be placed in the same orbit (1,336 kilometers) as Jason-1 and will move along the same ground track at an inclination of 66 degrees to the equator. It will repeat its ground track every 10 days, covering 95 percent of the world's ice-free oceans. A tandem mission between Jason-1 and OSTM will be conducted to further improve tide models in coastal and shallow seas, and to better understand the dynamics of ocean currents and eddies. OSTM is an international and interagency mission developed and operated as a four-party collaboration among NASA, the National Oceanic and Atmospheric Administration (NOAA), CNES, and the European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT). CNES is providing the spacecraft, NASA and CNES are jointly providing the payload instruments and NASA is providing the launch vehicle. After completing the onorbit commissioning of the spacecraft, CNES will hand over operation and control of the spacecraft to NOAA. NOAA and EUMETSAT will generate the near-real-time products and distribute them to users. OSTM was launched from Vandenberg Air Force Base, California on June 20, 2008. Launch and Early Orbit Operations (LEOP) and the on-orbit Assessment Phase have been completed. Preliminary science data show excellent performance.

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