Making 3-D models of TOPEX/Poseidon
Sea Surface Topography Images


Concepts:

    Girl holding 3D TOPEX model
  1. The ocean surface varies in height, the surface is is not all at one "level."
  2. Warm water expands. For the ocean this results in an elevated surface over a large area.
  3. Cold water contracts. For the ocean, this means a depressed surface.
  4. The Pacific Ocean is not the same temperature year after year.
  5. A characteristic of the El Niño is warm, expanded water, with elevated sea surface in the equatorial Pacific Ocean.
  6. A characteristic of the La Niña is cold, contracted water, with lower sea surface in the equatorial Pacific Ocean.
  7. El Niño and La Niña are two ocean phases that occur every 5-7 years but their strengths vary.
  8. Warm and cold regions in the ocean influence rainfall patterns.
  9. Warm water causes increased evaporation and more rainfall.
  10. Cold water causes decreased evaporation and less rainfall.
(see end of page for standards)

Abstract: In this activity layers of foam-type poster boards were cut out, assembled and painted to match two TOPEX/Poseidon satellite images of sea surface height. The November 10, 1997 image was used to model El Niño conditions, and the January 8, 2000 image was used to model La Niña conditions. The result is two 3-D models which illustrate the elevations and depressions of the sea surface in the Pacific Ocean during the two phases of ENSO.

Introduction: Layers of painted cardboard or thick, foam-type, poster boards have been used for years to make 3-dimensional models of the ocean floor and various terrestrial landscapes. The purpose of this activity was to use the same process to make 3-dimensional models showing the elevations and depressions of the Pacific Ocean based on TOPEX/Poseidon satellite images. Stacked or elevated layers of poster board were used to represent pools of warmer than normal sea surface temperatures (SST's). Depressions, or cut away portions of poster board were used to represent cooler than normal SST's. The intended result was to create a display which included a matched pair of 3-dimensional models, one El Niño and one La Niña.

Materials:

  • 20 x 30 foam-type poster boards, or similar sized pieces of corrugated cardboard. (See note at end of page for cheaper options) One sheet of poster board or cardboard was used for each layer.
  • TOPEX/Poseidon satellite images enlarged to 20-inches in diameter
    • November 10, 1997 - El Niño conditions
    • January 8, 2000 - La Niña conditions
  • White glue
  • Utility knife
  • Single-edged razor blade
  • Acrylic paints, brushes
Methods:
  1. TOPEX/Poseidon satellite images were downloaded from the JPL/NASA website (http://sealevel.jpl.nasa.gov/) and enlarged to fit the size of the poster board using Adobe Photoshop.
    Image from 11/10/97 Image from 01/08/00
  2. The enlarged images were printed as nine overlapping 8 1/2 x 11 "tiles" using Adobe PageMaker, then taped together to form two poster-size templates, one template each for El Niño and La Niña.
  3. Each sea surface elevation depicted on the satellite image was identified using the colorbar below and a number was assigned to each color on the template. (The colorbar can also be found on the JPL/NASA TOPEX/Poseidon website, near the bottom of the page.)
    colorbar
  4. A template was then placed directly on a piece of foam poster board. One elevation at a time was traced directly from the template to the poster board using a sharp pencil. The deepest depression (coldest water) was marked on the first layer of poster board, then working layer-by-layer each was marked until the highest elevation (warmest water) layer was reached. Pressing the pencil firmly made a visible impression or groove on the poster board, which was then easily outlined with a pen or pencil. If you want to short cut this step, use the prepared templates.
  5. A utility knife was used to cut the poster board shapes, and a razor blade was used to help clean up the edges.
  6. A wide paint brush was used to evenly distribute white glue between each layer, and a heavy weight (pile of textbooks) was placed on the top to hold the layers together until the glue dried (overnight).
  7. When the glue was completely dry, each model was painted with a different color for each depth range using the JPL/NASA colorbar as a guide.

Results:

Girl with completed 3D models

The student with her two 3-dimensional models. On the left is her model of La Niña, based on the January 8, 2000 TOPEX/Poseidon satellite image. On the right (in her left hand) is her model of El Niño, November 10, 1997 TOPEX/Poseidon image.


3D Models


A close-up look at the El Niño model (left) and La Niña model (right). The completed models were approximately 20 inches (52 cm) in diamter. The models were created in partial fulfillment of Malibu High School's Honors Marine Biology program, a 12th grade elective course.


Standards:
High School, Grade 9-12 Earth Science section:
page 59 - Standard 5 - Heating of Earth's surface and atmosphere by the sun drives convection within the atmosphere and oceans, producing winds and ocean currents.
page 59 - Standard 6 - Climate is the long-term average of a region's weather and depends on many factors.

Note: Foam-type poster board in 20 x 30 inch sheets is rather expensive. The best values are found at the major office discount stores. In class we regularly use recycled foam boards, soliciting them from the various other academic departments on campus that routinely discard unclaimed old student projects. Corrugated cardboard is by far the cheaper way to go, but to get a smooth look the corrugated edges need to be filled in with wallboard compound before painting. Students that have talent working with clay or other media could apply their expertise to this project as well.

Creator:
Robert Perry and Robin Baltrushes
Malibu High School, and UCLA OceanGLOBE