1 / 19

Section 3 Remote sensing of global change

Section 3 Remote sensing of global change. El niño Global Change Instructor: Dr. Cheng-Chien Liu Department of Earth Sciences National Cheng Kung University Office: Building of Earth Sciences, room 30206 Voice: +886-6-2757575 ext. 65422 E-mail: ccliu88@mail.ncku.edu.tw

may
Télécharger la présentation

Section 3 Remote sensing of global change

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Section 3 Remote sensing of global change El niño Global Change Instructor: Dr. Cheng-Chien Liu Department of Earth Sciences National Cheng Kung University Office: Building of Earth Sciences, room 30206 Voice: +886-6-2757575 ext. 65422 E-mail: ccliu88@mail.ncku.edu.tw Office hours: Monday 14:00 – 17:00, Wednesday 9:00 – 12:00 URL: http://mail.ncku.edu.tw./~ccliu88/ Last updated: 25 April 2005

  2. Introduction • El Niño • El Niño was named by people who fish off the western coast of Central America to refer to the warm current that invades their coastal waters around Christmas time • Significance • Air-sea interaction  climate change • El Niño  a typical example of air-sea interaction  short term climate change • El Niño  disrupt fisheries and bring severe weather events worldwide

  3. Mechanism of El Niño • Conditions of atmosphere and ocean during the normal year and El Niño (Fig. 1, 2) • A short videohttp://svs.gsfc.nasa.gov/vis/a000000/a000200/a000287/a000287.mpg

  4. Fig. 3.1.1 Fig. 1 Conditions of atmosphere and ocean during the normal year and El Niño. Source: http://140.115.123.30/gis/globalc/fig/06-10.gif

  5. Fig. 3.1.2 Fig. 2 Conditions of atmosphere and ocean during the normal year and El Niño. Source: http://svs.gsfc.nasa.gov/stories/elnino_20030114/norm_3dm.jpgand http://svs.gsfc.nasa.gov/stories/elnino_20030114/el_nino_3dm.jpg

  6. Consequences • An immense pacific bloom • Along the equatorial Pacific • During El Niño  nearly a complete lack of plankton • During La Niña  enormous plankton bloom • A short video 1 (12 Month Sequence) • http://svs.gsfc.nasa.gov/stories/biosphere/movies/Bio_Globe_Pacific_1.mov • A short video 2 (22 Month Sequence) • http://svs.gsfc.nasa.gov/stories/biosphere/movies/Bio_Pacific_1.mov

  7. Fig 3 Fig. 3 Along the equatorial Pacific during El Niño and La Niña. Source: http://svs.gsfc.nasa.gov/stories/elnino/index.html

  8. Consequences (cont.) • The carbon connection - physical and biological processes • Plankton bloom  biologic change  CO2 change • El Niño cut the amount of CO2 released into the atmosphere by 700 million metric tons • A short video 1 • http://svs.gsfc.nasa.gov/stories/elnino/COphy.mov • A short video 2 • http://svs.gsfc.nasa.gov/stories/elnino/CObio.mov

  9. Remote sensing techniques for studying El Niño – SST • Sensor • Advanced Very High Resolution Radiometer (AVHRR) • Channel 1: 0.58-0.68 mm • Channel 2: 0.725-1.0 mm • Channel 3: 3.55-3.93 mm • Channel 4: 10.3-11.3 mm • Channel 5: 11.4-12.4 mm • Mission

  10. Table 1 Satellite # Dates Pass # of bands NOAA-6 6/79 - 11/86 am 4 NOAA-7 8/81 - 6/86 pm 5 NOAA-8 5/83 - 10/85 am 4 NOAA-9 2/85 - 11/88 pm 5 NOAA-10 11/86 - 9/91 am 4 NOAA-11 11/88 - 9/94 pm 5 NOAA-12 5/91 - 12/94 am 5 NOAA-13 failed pm n/a NOAA-14 12/94 - present pm 5 NOAA-15 5/98 - present am 5 NOAA-16 9/00 - present pm 6 Table 1 Continuous observation of SST by AVHRR on boarded NOAApolar-orbiting satellite seriesSource: http://edc.usgs.gov/products/satellite/avhrr.html

  11. Remote sensing techniques for studying El Niño – SST (cont.) • Principle • Compute actual scene radiance from satellite counts • E=S*C + I • Find scene "temperature" (uncorrected) from radiance • T=temperature in degrees Kelvin • E=scene radiance as computed above • nu=central wave number of the channel (cm^-1, listed in the NOAA Polar Orbiter Data Users Guide) • C1=2*pi*Planck's Constant* c(speed of light)^2 • C2=c * Planck's Constant / Boltzmann Constant

  12. Remote sensing techniques for studying El Niño – SST (cont.) • Principle (cont.) • Correct for atmospheric effects and sensor artifacts • SST = a + b*T4 + c*(T4-T5)*Tsurf + d*(sec([[theta]])-1)*(T4-T5) + e*lifetime • T4 and T5 are the temperature measurements for channels 4 and 5 respectively • a,b,c,d, and e predetermined by comparing AVHRR radiance values to in situ temperature measurements taken from buoys. • Tsurf is an a priori estimate of the actual SST made from a precompiled composite SST map of the same area. • theta is the satellite zenith angle • lifetime is the number of days since the launch of the satellite, used to calibrate drift of the sensor response over time.

  13. Remote sensing techniques for studying El Niño – SST (cont.) • Measurements (0.50C) • NEW Rotating Globe Animation showing El Niño and La Niña events (1996-1999) using TOPEX/POSEIDON and Pathfinder SST Data Sets • http://podaac.jpl.nasa.gov/sst/movies/rotating_globe.mov • Animation showing El Niño and La Niña events (1996-1999) using AVHRR Oceans Pathfinder and TOPEX/ Poseidon Data Sets • http://podaac.jpl.nasa.gov/sst/movies/epacific_75q.mov

  14. Remote sensing techniques for studying El Niño – SST (cont.) • Useful links • Pathfinder SST • http://podaac.jpl.nasa.gov/sst/ • SST Measurement with the AVHRR • http://www.ae.utexas.edu/courses/ase389/midterm/duncan/duncan.html#channels • AVHRR: A Brief Reference Guide • http://www.ngdc.noaa.gov/seg/globsys/avhrr2.shtml • Data • AVHRR Stitched Orbits • http://edcdaacftp.cr.usgs.gov/html/avhrr_orbits.html • NASA-Earth Observing System Data Gateway • http://edcimswww.cr.usgs.gov/pub/imswelcome/

  15. Remote sensing techniques for studying El Niño – SSH • Sensor: Altimeter • An instrument that measures altimetry • Aneroid altimeters measure air pressure • Radar or laser altimeters time returning microwaves or light

  16. Remote sensing techniques for studying El Niño – SSH (cont.) • Mission: • TOPEX/Poseidon (August 10, 1992 – present) • Jason-1 (December 07, 2001 – present) • The Tandem Mission Flash animation • http://topex-www.jpl.nasa.gov/mission/gary-interview3.mov • GRACE (March 17, 2002) • Gravity Recovery and Climate Experiment, is flying two identical spacecraft about 220 kilometers apart in a 500-kilometer polar orbit, and over its 5-year lifetime will produce an accurate map of the geoid. The geoid, the manifestation of the Earth's gravity field, is the basic figure on which all altimetry data is based. • OSTM (Proposed Launch: 2005) • OSTM - Ocean Surface Topography Mission, is a follow-on to Jason-1. (operational mode)

  17. Remote sensing techniques for studying El Niño – SSH (cont.) • Principle • TOPEX/Poseidon Instruments • http://topex-www.jpl.nasa.gov/gallery/tiffs/videos/topomeas.mov • Measurements

  18. Remote sensing techniques for studying El Niño – SSH (cont.) • Useful links • TOPEX/Poseidon • http://topex-www.jpl.nasa.gov/mission/topex.html • Jason-1 • http://topex-www.jpl.nasa.gov/mission/jason-1.html • GRACE • http://www.csr.utexas.edu/grace/

  19. Questions • What are the abnormal events of climate during 1982/83 El Niño around the world?

More Related