Interpretation of Polar-orbiting Satellite Observations. Atmospheric Instrumentation

Transcription

1 Interpretation of Polar-orbiting Satellite Observations

2 Outline Polar-Orbiting Observations: Review of Polar-Orbiting Satellite Systems Overview of Currently Active Satellites / Sensors Overview of Sensor Scanning Strategies Visible (VIS) Imagery Infrared (IR) Imagery Microwave (MW) Imagery Precipitation Imagery Cloud / Aerosol Imagery Temperature / Humidity Soundings Surface Winds

3 Modern Polar-Orbiting Satellite Systems Polar-Orbiting: Circle the planet in an almost north-south orbit passing close to both poles Orbit is at altitudes of about 900 km Orbit is usually sun synchronous - passes over the same location at the same local time each day Provides view over a swath ~ km wide Good spatial resolution low altitude Poor temporal resolution twice per day Polar Orbit ~900 km

4 Modern Polar-Orbiting Satellite Systems Multiple Satellites: NOAA-xx // DMSP-Fxx // SNPP JPSS-x // NASA Numerous polar-orbiting satellites capable of monitoring weather and climate have been developed and launched by various organizations (we will focus on U.S. organizations) NOAA 15 / 16 / 17 / 18 / 19 Fifth generation operational satellites NOAA only program NOAA-15 was launched in MAY 1998 ACTIVE NOAA-16 was launched in SEP 2000 DEAD NOAA-17 was launched in JUN 2002 DEAD NOAA-18 was launched in MAY 2005 ACTIVE NOAA-19 was launched in FEB 2009 ACTIVE NOAA 19 Weather / Climate Instruments: Advanced Very High Resolution Radiometer (AVHRR) VIS and IR imagery Advanced Microwave Sounding Unit (AMSU) Liquid / Ice Water Content High Resolution Infrared Sounder (HIRS) Temperature / Humidity soundings

5 Modern Polar-Orbiting Satellite Systems Multiple Satellites: NOAA-xx // DMSP-Fxx // SNPP JPSS-x // NASA Numerous polar-orbiting satellites capable of monitoring weather and climate have been developed and launched by various organizations (we will focus on U.S. organizations) DMSP F15 / F16 / F17 / F18 / F19 / F-20 Fifth generation operational satellites Joint NOAA and DoD program F-15 was launched in DEC 1999 DEAD F-16 was launched in OCT 2003 ACTIVE F-17 was launched in NOV 2006 ACTIVE F-18 was launched in OCT 2008 ACTIVE F-19 was launched in APR 2014 DEAD F-20 anticipated launch in 2020 DMSP F19 Weather / Climate Instruments: Optical Line-scan System (OLS) VIS and IR imagery Special Sensor Microwave Imager (SSMI) Liquid / Ice Water Content Special Sensor Microwave Temperature (SSMT) Temperature soundings Special Sensor Microwave Temperature 2 (SSMT2) Humidity soundings Multiple space weather sensors (some classified)

6 Modern Polar-Orbiting Satellite Systems Multiple Satellites: NOAA-xx // DMSP-Fxx // SNPP / JPSS-x // NASA Numerous polar-orbiting satellites capable of monitoring weather and climate have been developed and launched by various organizations (we will focus on U.S. organizations) SNPP / JPSS 1 / 2 / 3 / 4 Sixth generation operational satellites Joint NOAA and NASA program SNPP was launched in OCT 2011 ACTIVE JPSS-1 anticipated launch in 2017 JPSS-2 anticipated launch in 2021 JPSS-3 anticipated launch in 2026 JPSS-4 anticipated launch in 2031 JPSS 1 Weather / Climate Instruments: Visible Infrared Imager Radiometer Suite (VIIRS ) VIS and IR imagery Land Cover / Biomass Advance Technology Microwave Sounder (ATMS) Liquid / Ice Water Content Temperature / Humidity soundings Cloud and Earth Radiant Energy System (CERES) Upward SW / LW irradiance Ozone Mapping and Profiler Suite (OPMS) Ozone soundings

7 Modern Polar-Orbiting Satellite Systems Multiple Satellites: NOAA-xx // DMSP-Fxx // SNPP / JPSS-x // NASA Numerous polar-orbiting satellites capable of monitoring weather and climate have been developed and launched by various organizations (we will focus on U.S. organizations) NASA Weather / Climate Satellites Numerous research satellites Satellite Launch Status End Date Primary Mission TRMM Nov 1997 DEAD Apr 2015 Precipitation Radar Landsat-7 Jan 1999 ACTIVE > 2016 Land / Vegetation Type Terra Dec 1999 ACTIVE > 2016 High resolution VIS/IR Imager Aqua May 2002 ACTIVE > 2016 High resolution VIS/IR Imager Coriolis Jan 2003 ACTIVE > 2016 Oceanic Surface Winds Aura Jul 2004 ACTIVE > 2016 High resolution VIS/IR Imager CALIPSO Apr 2006 ACTIVE > 2016 Cloud Aerosol Profiler Cloud-Sat Apr 2006 ACTIVE > 2016 Cloud Radar JASON-2 Oct 2008 ACTIVE > 2016 Ocean Waves GPM-Core Feb 2014 ACTIVE > 2017 Precipitation Radar OCO-2 Jul 2014 ACTIVE > 2017 CO 2 Profiler SMAP Jan 2015 ACTIVE > 2018 Soil Moisture DSCOVR Jan 2015 ACTIVE > 2020 Earth s Radiation Budget

8 Scanning Strategies Cross-Track Scanning: Most popular method Scanning mirror rotates to collect observations within a line from one side of the swath to the other side Mirror rotates back and a new line is scanned Swath width is defined by the instrument s angular field of view

9 Scanning Strategies Along-Track Scanning: Instrument has no moving parts Each ground cell has its own dedicated sensor, with a fixed orientation, such that a full swath is observed simultaneously Individual sensor for each cell (pixel) Swath width is defined by the number of adjacent sensors within the instrument s angular field of view Angular Field of View Ground Resolution Cell

10 Scanning Strategies Conical Scanning: Scanning mirror rotates at an angle to the vertical axis (e.g., 45 ) Observations are obtained along a conical arc ahead of the satellite along its ground track Scanning mirror sweeps across its angular field of view (e.g., 102 ) to observe along a single arc line Mirror rotates back and a new arc line is scanned Swath width is defined by the instrument s angular field of view

11 Scanning Strategies Why Different Scanning Types? Multiple instruments on a satellite GPM-Core Satellite Multiple Sensors Multiple Scanning Strategies Power consumption Sensor type Active Transmits a pulse Passive Observes emitted radiation Type of radiation being detected (VIS / IR / MW) Scientific properties of the phenomena being observed (clouds / temperature)

12 Visible (VIS) Imagery AVHRR: [ NOAA satellites ] Scanning: Cross-track Swath width: 2900 km Resolution: 1100 m Channels: 2 VIS (4 IR) MODIS: [ NASA Terra / Aqua / Aura satellites ] Scanning: Along-track Swath width: 2230 km Resolution: 250 m Channels: 9 VIS (27 IR) OLS: [ DMSP satellites ] Scanning: Cross-track Swath width: 2960 km Resolution: 560 m Channels: 2 VIS (1 IR) VIIRS: [ SNPP / JPSS satellites ] Scanning: Cross-track Swath width: 3000 km Resolution: 375 m Channels: 8 VIS (14 IR)

13 Visible (VIS) Imagery MODIS VIS Imagery

14 Visible (VIS) Imagery MODIS VIS Imagery Wildfires near Los Angeles

15 Infrared (IR) Imagery AVHRR: [ NOAA satellites ] Scanning: Cross-track Swath width: 2900 km Resolution: 1100 m Channels: 4 IR (2 VIS) MODIS: [ NASA Terra / Aqua / Aura satellites ] Scanning: Along-track Swath width: 2230 km Resolution: 250 m Channels: 27 IR (9 VIS) OLS: [ DMSP satellites ] Scanning: Cross-track Swath width: 2960 km Resolution: 560 m Channels: 1 IR (2 VIS) Volcanic Eruption AVHRR IR 10.8 μm VIIRS: [ SNPP / JPSS satellites ] Scanning: Cross-track Swath width: 3000 km Resolution: 375 m Channels: 14 IR (8 VIS)

16 Infrared (IR) Imagery Overshooting convection AVHRR VIS Overshooting convection AVHRR IR

17 Infrared (IR) Imagery

18 Microwave (MW) Imagery AMSU: [ NOAA satellites ] Scanning: Cross-track Swath width: 2250 km Resolution: 48 km Channels: 4* (22-GHz / 37-GHz / 54-GHz / 85-GHz) SSMI: [ DMSP satellites ] Scanning: Conical Swath width: 1700 km Resolution: 25 km Channels: 6* (19-GHz / 22-GHz / 37-GHz / 54-GHz / 85-GHz / 183-GHz) ATMS: [ SNPP / JPSS satellites ] Scanning: Cross-track Swath width: 2200 km Resolution: 16 km Channels: 5* (22-GHz / 37-GHz / 54-GHz / 85-GHz / 183-GHz) * Each sensor actually observes multiple sub-channels around these primary channels

19 Total Precipitable Water: Microwave (MW) Imagery Defined as the sum of all water (vapor, liquid, and ice) in an atmospheric column Computed from a linear combination of the 19-GHz, 22-GHz, 37-GHz, and 183-GHz channels Available only over oceans Oceans have a spatially-uniform signal easy to remove Land exhibits a non-uniform signal hard to remove Similar to the water vapor (WV) imagery obtained from GOES satellites Imagery from multiple satellites can be combined to produce composite animations

20 Shallow Convection: Microwave (MW) Imagery The 37-GHz channel is primarily sensitive to liquid water Precipitating clouds (with liquid water) appear warm compared to a relatively cold ocean Reliable only over oceans Oceans exhibit a cold signal easy to remove Land exhibits a much warmer signal harder to remove Hurricane Matthew 10/04/ UTC SSMI 37-GHz

21 Microwave (MW) Imagery Deep Convection: The 85-GHz channel is primarily sensitive to ice water Precipitating clouds (with ice water) appear warm compared to a relatively cold surface Reliable over oceans and land Should be compared with 37-GHz imagery to distinguish deep and shallow convection Hurricane Matthew 10/04/ UTC SSMI 85-GHz

22 Temperature Anomalies: Microwave (MW) Imagery The 54-GHz channels provide estimates of air temperature at levels between hpa Deep convection (latent heat release) appears warm compared to a colder environment Strong subsidence (adiabatic warming) appears warm compared to a colder environment Useful in diagnosing warm buoyant updrafts and tropical cyclone warm cores Hurricane Matthew 10/04/ UTC AMSU 54-GHz

23 GPM-Core: [ NASA satellite ] Vertical Profiling Precipitation Radar Scanning: Cross-track Swath width: 245 km (13.6 GHz) 125 km (35.6 GHz) Resolution: 5 km (horizontal) (ground) 250 m (vertical) Channels: 2 (13.6-GHz / Ku-band) (35.6-GHz / Ka-band) Non-Doppler Non-Polarimetric Precipitation Imagery

24 Precipitation Imagery GPM-Core Precipitation Radar ---- Hurricane Matthew

25 Cloud-Sat: [ NASA satellite ] Vertical Profiling Cloud Radar Scanning: Along-track Swath width: 1.4 km (cross-track) Resolution: 2.0 km (along-track) (ground) 500 m (vertical) Channels: 1 (94-GHz / W-band) Cloud / Aerosol Imagery Non-Doppler Non-Polarimetric

26 Cloud / Aerosol Imagery CALIPSO: [ NASA satellite ] Scanning: Along-track Aerosol Profiler / Cloud Top Height Swath width: 70 m (cross-track) Resolution: 333 m (along-track) 30 m (vertical) Channels: 2 (532 nm / 1064 nm)

27 Cloud / Aerosol Imagery

28 Temperature / Humidity Soundings HIRS: [ NOAA satellites ] Scanning: Cross-track Swath width: 2200 km Resolution: 10 km (horizontal) Channels: 19 IR (1 VIS) ATMS Sounder Weighting Functions (16 Channels) SSMT/2: [ DMSP satellites ] Scanning: Cross-track Swath width: 1500 km Resolution: 48 km (horizontal) Channels: 12 IR ATMS: [ SNPP / JPSS satellites ] Scanning: Cross-track Swath width: 2200 km Resolution: 32 km (horizontal) Channels: 16 IR

29 Temperature / Humidity Soundings Weather Balloon Sounding GOES Sounder Sounding ATMS Sounder Sounding

30 Surface Winds WindSat: [ NASA Coriolis satellite ] Scanning: Conical Surface Winds (Ocean only) Swath width: 1000 km Resolution: 15 km (horizontal) Channels: 5 (7-GHz / 11-GHz / 19-GHz / 2-GHz / 37-GHz)

31 Surface Winds

32 Summary Polar-Orbiting Observations: Review of Polar-Orbiting Satellite Systems Overview of Currently Active Satellites / Sensors Overview of Sensor Scanning Strategies Visible (VIS) Imagery Infrared (IR) Imagery Microwave (MW) Imagery Precipitation Imagery Cloud / Aerosol Imagery Temperature / Humidity Soundings Surface Winds