Geodesy in the 21st century Shimon Wdowinski University of Miami Susan Eriksson UNAVCO
Remote sensing at UM • CSTARS • Geodesy and space-geodesy • What is geodesy? • Historical perspective • Space-based technologies • Applications • Lithosphere (Solid Earth) • Hydrosphere • Cryosphere • Atmosphere&Ionosphere • Summary Presentation Content
CSTARS at UMCenter for Southeastern Tropical Advanced Remote Sensing A Satellite Data Reception (X-band) and Analysis Facility for Environmental Monitoring in the Southeastern US, Gulf of Mexico, Caribbean Basin and Equatorial Atlantic • Applications • environmental monitoring • storm prediction • volcanic eruptions • pollution • natural hazards • change detection • homeland security
Collection for October 2002 and April 2007 (all satellites) 1-week in April 2007 – 420 acquisitions
Volcano Monitoring Studies of hazardous volcanoes in México, Central America and the Caribbean Monitor eruption pre-cursors
Monitoring of Pollution 2001 oil spill off northern Spanish Coast (Imaged by ENVISAT ASAR) “Prestige” position
Storm monitoring Hurricane Francis Terra_2004-09-04 15:53 Hurricane Floyd Radarsat-1 - 1999
RADARSAT Ocean Winds Wind speed retrieval in tropical storms Estimates of wave breaking, surface roughness, and wave properties in tropical storms Courtesy: D. Thompson, JHU/APL
New Orleans Flooding & Subsidence Dixon et al. (2006)
Double bounce effect Wetland InSAR Water level changes in the Everglades (south Florida)
CSTARS Current and Planned Satellite Reception • PHASE 1: • RADARSAT-1 • ERS-2 • SPOT 2/4/5 • ENVISAT • TERRA/MODIS • PHASE 2: • LANDSAT • RADARSAT-2 • ALOS/PALSAR • TerraSAR-X • SEAWINDS & WINDSAT • IKONOS • QuickBird RADARSAT-1 IKONOS
Geodesy in the 21st century Space geodesy has application in areas of great societal impact such as climate change, water resources, and natural hazards and disasters. New Orleans subsidence Sea level change
Geodesy Geodesy is the science of accurately measuring the Earth’s size, shape, orientation, gravitational field and the variations of these quantities with time.
Geodesy Geodesy is one of the most ancient Earth Science disciplines with roots in the Greek era (600-100 BC). Eratosthenes (276 BC - 194 BC) measured the shade angle between Alexandria and Syene (Egypt) and distance. He calculated the Earth’s circumference as 252,000 strades (roughly 46,000 km, only 15% higher than the current estimate).
Space Geodesy Space or satellite geodesy completely revolutionized the field of geodesy in both accuracy and availability of measurements. This era began in the 1970’s with the utilization of exciting radio-telescope technologies (Very Long Baseline Interferometry –VLBI). Initial accuracies – 5-10 cm. Current accuracies – sub-cm.
Space geodetic technologies Positioning techniques Global Navigation Satellite Systems (GNSS) Altimetry Interferometric Synthetic Aperture Radar (InSAR) Gravity missions
Positioning techniques Very Long Baseline Interferometry (VLBI) Satellite Laser Ranging Lunar Laser Ranging Doppler Orbit determination and Radiopositioning Integrated on Satellite (DORIS)
Global Navigation Satellite Systems (GNSS) • GLObal NAvigatsionnaya Sputnikovaya Sistema (GLONASS) • Galileo (European, 1st launched 2005) • Beidou-1(China, test launch 2000) • IRNSS (India, in planning) Global Positioning System (GPS)
Altimetry SeaSAT GeoSAT TOPEX/Posiedon Jason-1 ERS-2 ENVISAT ICESAT CryoSAT
Repeat path data acquisition Interferometric Synthetic Aperture Radar (InSAR) SeaSAT ERS-1/2 JERS-1 RADARSAT-1 ENVISAT ALOS RADARSAT-2 TerraSAR-X COSMO-SkyMed Calculating phase changes
Gravity missions LAGEOS-1 LAGEOS-1/2 Ajisai CHAMP GRACE GOCE GRACE Measurements of small changes in the Earth’s gravitational field
Tectonic plate motion Revel-1 (Sella et al., 2004) Observations: VLBI, SLR, DORIS, GPS
Elastic rebound theory Earthquake deformation cycle GPS time series
Earthquake induced deformation M=6.6 B, 2003 Bam earthquake (Iran)
Seismicity and hazard at subduction zones Slow slip events
Magmatic induced deformation GPS, InSAR Magmatic inflation prior to eruptions
Geoid determination Long term geoid shape reflecting mass distribution within the Earth
Short-term changes of the geoid reflect mainly water and ice mass redistribution Global and regional water budget
Glacier Flow InSAR measurement
Subsidence – aquifer system deformation Las Vegas - Subsidence due to water extraction
River and lakes water levels Remote monitoring of water resources
Soil moisture Soil moisture is critical for vegetation growth and survival. It can be monitored by InSAR and GPS.
Wetlands are fragile and important ecosystem that depends on sufficient water supply. Wetland water level changes InSAR monitoring of water resources (Everglades, south Florida)
Urban and infrastructure subsidence New Orleans subsidence (2002-2004) prior to Hurricane Katrina
Hydrocarbon production Surface subsidence due to oil extraction
Landslides Ground movements in Berkley Hill, near San Francisco (InSAR monitoring)
Bathymetry Seafloor determination using satellite altimetry
Perceptible water Measuring the Atmosphere and Ionosphere Total Electron Content GPS measurements are sensitive to changes in the atmosphere and ionosphere.
Conclusions • Space geodetic techniques can measure small changes of the Earth’s solid and aquatic surfaces with cm- and sub-cm level accuracy • The measurement can be applied to a variety of application, including • Lithosphere (earthquakes, volcanoes, subsidence) • Hydrosphere (oceans, rivers, lakes, wetlands) • Cryosphere (icecap, glaciers) • Atmosphere & Ionosphere (Perceptible water, TEC) • Antroposphere (urban subsidence, oil fields) • Space geodesy provide critical measurements for societal important issue, such as global climate change, sea level rise and natural hazard mitigation.