1. Lecture 6 (10/14) METR 1111 Satellites Doing Something Different

2. What are satellites? Satellite – Any object that orbits around another object (You’ve got to like these intensive definitions)

3. What can satellites do? Man-made satellites are designed to carry out a wide range of tasks Take images, relay signals, etc First introduced over 40 years ago with the Russian satellite Sputnik Currently, over 8000 satellites orbiting Earth Most are not much bigger than a softball, but some are the size of a small car.

4. 4 Main Types of Satellites Geosynchronous Orbiting – stays over same spot on earth (rotates at same speed as land under it) Polar Orbiting – pole to pole orbit Low Earth Orbiting – very low orbit Elliptical Orbiting – elongated pole to pole orbit

5. Geosynchronous Orbiting Geosynchronous – a satellite in an equatorial or near equatorial orbit Has the same angular velocity of the earth Geostationary satellite - a type of geosynchronous satellite that is in a west to east orbit at an altitude of 35,786 km above the equator. Why can it only be at this altitude?

6. Geostationary Satellites Ans: At this altitude it encircles the earth once every 24 hours, making its speed in orbit synchronous (or in sync) with earth’s rotation Balance between gravitational force pulling it towards Earth and centripetal force away from it Stays over same geographic area 24/7 Examples: GOES East and West – take images of clouds from space from same vantage point.

7. GOES GOES – Geostationary Operational Environmental Satellite Observes the atmosphere in different wavelengths Visible – captures visible light (useless at night but valuable during day) Infrared – captures emitted long and short wave radiation Water Vapor – Just an infrared detector that’s extra-sensitive to water vapor

8. Current GOES Images http://www.rap.ucar.edu/weather/satellite/

9. Polar Orbiting Satellites Polar-Orbiting Satellite – a satellite with an orbit that lies in a plane passing through the center of the earth that traverses polar latitudes. POES (Polar-Orbiting Operational Environmental Satellite)

10. More on POES Polar orbiting satellites orbit earth in a couple hours. They cover the entire earth with data breaks between paths 2 or 3 polar orbiting satellites can work together to minimize data breaks.

11. Another Interesting Satellite TRMM – Tropical Rainfall Measuring Mission First satellite to carry a weather radar Main web site: http://trmm.gsfc.nasa.gov/http://trmm.gsfc.nasa.gov/ Images: http://trmm.gsfc.nasa.gov/images_dir/hurrican e.html http://trmm.gsfc.nasa.gov/images_dir/hurrican e.html Animations: http://trmm.gsfc.nasa.gov/images_dir/anim_hurric ane.html http://trmm.gsfc.nasa.gov/images_dir/anim_hurric ane.html

12. Satellite derived winds: can track a cloud’s movement and get approx. winds at an estimated height. Not as reliable as rawinsondes but it gives us more observations http://cimss.ssec.wisc.edu/tropic/real- time/europe/winds/winds.htmlhttp://cimss.ssec.wisc.edu/tropic/real- time/europe/winds/winds.html

13. Satellite Derived Indices Great for forecasting severe weather and precipitation Based on soundings that GOES makes Not as accurate as rawinsondes, but again, it helps fill data voids and gives big picture http://orbit- net.nesdis.noaa.gov/goes/soundings/html/fie lds.htmlhttp://orbit- net.nesdis.noaa.gov/goes/soundings/html/fie lds.html

14. Satellite-Derived Soundings Gives you soundings every hour instead of every 12 hours http://orbit- net.nesdis.noaa.gov/goes/soundings/skewt/h tml/http://orbit- net.nesdis.noaa.gov/goes/soundings/skewt/h tml/

15. For next time Read Ch 9 – Hurricanes - REAL WEATHER! (I’m wishing for something interesting) Homework 6 is posted Reminder: Your grade is affected by your attendance. This is my one call to make sure you turn in anything you have not given me yet