Satellite OrbitsSlide 2Atmospheric Remote Sensing Sensors, Satellite Platforms, and OrbitsSlide 4Types of orbitsSlide 6Slide 7Geosynchronous Meteorological Satellites WMO Member StatesLow Earth Orbit ConceptsSun-Synchronous Polar OrbitSun-Synchronous Orbit of TerraSpacing Between Adjacent Landsat 5 or 7 Orbit Tracks at the EquatorTiming of Adjacent Landsat 5 or 7 Coverage TracksPolar-Orbiting Satellite in Low Earth Orbit (LEO)Tropical Rainfall Measuring Mission Orbit (Precessing)TRMM CoverageDefinition of Orbital Period of a SatelliteOrbital Characteristics of Selected Missions Low Earth Orbit & Precessing MissionsEllipseKepler’s lawsPeriod of orbitSlide 22Geostationary Image (GOES-8)Slide 24Space-time samplingSlide 26Slide 27Slide 28Slide 29Slide 30Scanning techniquesSlide 32Satellite OrbitsSatellite Satellite Meteorology/ClimatologyMeteorology/ClimatologyProfessor Menglin JinProfessor Menglin JinSatellite OrbitsAt what location is the satellite looking?At what location is the satellite looking?When is the satellite looking at a given When is the satellite looking at a given location?location?How often is the satellite looking at a How often is the satellite looking at a given location?given location?At what angle is the satellite viewing a At what angle is the satellite viewing a given location?given location?Atmospheric Remote Sensing Sensors, Satellite Platforms, and OrbitsAtmospheric Remote Sensing Sensors, Satellite Platforms, and OrbitsSatellite orbits and platformsSatellite orbits and platforms•Low Earth orbitLow Earth orbit–Sunsynchronous and repeat coverageSunsynchronous and repeat coverage–PrecessingPrecessing•Geosynchronous orbitGeosynchronous orbitSensor scanning modesSensor scanning modes•Whiskbroom and pushbroom scannersWhiskbroom and pushbroom scanners•Active and passive microwave radiometersActive and passive microwave radiometersOrbital parameters can be tuned to produce particular, useful orbits• Geostationary• Geosynchronous• Sunsynchronous• AltimetricSpecial OrbitsTypes of orbitsSunsynchronous orbitsSunsynchronous orbits: An orbit in which the : An orbit in which the satellite passes every location at the same time satellite passes every location at the same time each dayeach day•Noon satellites: pass over near noon and midnightNoon satellites: pass over near noon and midnight•Morning satellites: pass over near dawn and duskMorning satellites: pass over near dawn and dusk•Often referred to as “polar orbiters” because of the Often referred to as “polar orbiters” because of the high latitudes they crosshigh latitudes they cross•Usually orbit within several hundred to a few Usually orbit within several hundred to a few thousand km from Earththousand km from EarthTypes of orbitsGeostationary (geosynchronous) orbitsGeostationary (geosynchronous) orbits: : An An orbit which places the satellite above the orbit which places the satellite above the same location at all timessame location at all times•Must be orbiting approximately 36,000 km Must be orbiting approximately 36,000 km above the Earthabove the Earth•Satellite can only “see” one hemisphereSatellite can only “see” one hemisphere• Ascending and descending orbits should cross at 90º – Designed so that orthogonal components of surface slope will have equal accuracy• Orbital inclination depends on location of altimetric needsAltimetric OrbitsSectorSatellites in Orbit (+mode)Operator LocationLaunch dateStatusMTSAT-1R (Op) Japan 140°E 2/26/05 Fully functionalMTSAT-2 (B) Japan 145°E 2/18/06 Back-up to MTSAT-1RGOES-9 (B) USA/NOAA 160°E 5/99Dissemination not activatedEast-PacificGOES-11 (Op) USA/NOAA 135°E 5/00 GOES-WestGOES-10 (B) USA/NOAA 60°W 4/97 South America coverageGOES-12 (Op) USA/NOAA 75°W 7/01 GOES-EastGOES-13 (P) USA/NOAA 89.5°W 5/06 In commissioningMeteosat-6 (B) EUMETSAT 10°E 11/93 Rapid scan anomalyMeteosat-7 (B) EUMETSAT 0°E 2/97 To be relocated to 57.5°EMeteosat-8 (Op) EUMETSAT 3.4°W 8/28/02 EUMETCASTMeteosat-9 (P) EUMETSAT 6.5°W 12/21/05 In commissioningMeteosat-5 (Op) EUMETSAT 63°E 3/91Functional but high inclination modeGOMS-N1 (B) Russia 76°E 11/94 Standby since 9/98FY-2C (Op) China/CMA 105°E 10/19/04 FunctionalKalpana-1 (Op) India 74°E 9/12/02 DedicatedINSAT-3A (Op) India 93.5°E 4/10/03 OperationalWest-PacificWest-AtlanticEast-AtlanticIndian OceanGeosynchronous Meteorological SatellitesWMO Member StatesLow Earth Orbit ConceptsEquatorSouth PoleGround trackAscending nodeInclination angleDescending nodeOrbitPerigeeApogeeOrbitSun-Synchronous Polar OrbitSatellite OrbitEarth Revolution•Satellite orbit precesses (retrograde)–360° in one year•Maintains equatorial illumination angle constant throughout the year–~10:30 AM in this exampleEquatorial illumination angleSun-Synchronous Orbit of TerraSpacing Between Adjacent Landsat 5 or 7 Orbit Tracks at the EquatorTiming of Adjacent Landsat 5 or 7 Coverage TracksAdjacent swaths are imaged 7 days apartPolar-Orbiting Satellite in Low Earth Orbit (LEO)Example from AquaA precessing low-A precessing low-inclination (35inclination (35°°), low-), low-altitude (350 km) orbit altitude (350 km) orbit to achieve high spatial to achieve high spatial resolution and capture resolution and capture the diurnal variation of the diurnal variation of tropical rainfalltropical rainfall–Raised to 402 km in Raised to 402 km in August 2001 August 2001 Tropical Rainfall Measuring Mission Orbit (Precessing)TRMM Coverage1 day coverage 2 day coverageThe orbital period of a satellite around a The orbital period of a satellite around a planet is given byplanet is given bywhere where 00= orbital period (sec)= orbital period (sec)RRpp==planet radius (6380 km for Earth)planet radius (6380 km for Earth)HH==orbit altitude above planet’s surface (km)orbit altitude above planet’s surface (km)ggss==acceleration due to gravity (0.00981 km sacceleration due to gravity (0.00981 km s-2-2 for Earth)for Earth)Definition of Orbital Period of a Satellite T0  2( RpH )RpH gsRp2SatelliteAltitude(km)Inclination(°)Orbital Period(min)Repeat CoverageOrbits/dayJason-11336 66 112.3 10 12.8Meteor-3M/SAGE III1020 99.5 105.5 13.7Landsat 1-3907-915 99.2 103.1 18 14.0SPOT832 98.7 101.5 26 14.2NOAA850 98-99 102-104 11 14.0QuikScat803 98.6 100.9 14.3ACRIMSAT720 98.1 99.1 14.5Landsat 4-7705 98.2 98.8 16 14.6Terra,