Why Stick Jason Up There, Anyway?

The TOPEX/POSEIDON satellite is and the Jason-1 satellite soon will be using all the equipment you just read about to measure and understand the complex and ever-changing topography of the ocean. Knowing the topography of the ocean and how it is changing enables (helps) meteorologists to predict the weather better and oceanographers to understand the way the ocean works and why. This helps fishers to fish better and boats to sail better. Even the Coast Guard uses this information. They use it to find boats and planes on the ocean floor (these, of course are boats and planes that have sunk!).

Understanding the topography of the ocean means understanding the shape of the surface of the ocean--the hills and valleys. It also means understanding the way heat flows in the ocean. The ocean holds most of the heat in the Earth's hydrosphere. The heat in the top three meters of the ocean is equal to the amount of heat stored in the whole atmosphere. This heat is pushed around by wind and the ocean currents. It affects the weather and climate considerably. It has always been a challenge to oceanographers to figure out how these currents move and how they affect the weather. These currents can be figured out by studying the topography of the ocean, which is the height of the ocean surface compared to the Earth's geoid (click on the "Satellite Altimetry" link to your left to see a picture of the geoid).

Scientists standing next to Jason-1 give you a good idea of just how big this satellite is.

We've only scanned the top layer here you might say, but if you wish to examine Jason-1 and space oceanography more closely, here are some topics to look up: altimeter, radiometer, radiowaves, electromagnetic radiation, CNES/AVISO, NASA/JPL, surface geostrophic currents, equi-geopotential surfaces, topography.

Questions that come to mind are:

1. Why is there a particular velocity needed to escape the pull of gravity?

2. How exactly does a radiometer work? How about an altimeter?

3. How does the Earth's atmosphere affect the readings of the instruments on Jason?

4. What other factors must be taken into account that would alter Jason's data readings?

5. How have TOPEX/POSEIDON or Jason-1 affected your life today?

Critical Thinking Questions:

6. What other things could the information received from Jason-1 be used for?

7. What other kinds of data could Jason-1 collect?