*SITE SAMPLER

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LESSON PLAN: PAGE 1

TOPIC: Interpreting Features on Radar Maps

1) Knowledge:

• describe the purposes and characteristics of radar produced images.

2) Skills:

• read, analyze and interpret radar produced images.
• identify features on maps using clues such as shape, size, pattern, color, and texture

• Interpreting Radar Maps: Overview
• Interpreting Doppler Radar Maps- United States
• Interpreting Radar Satellite Altimetry
• Base map of USA (not provided)
• Base map of South Indian Ocean (not provided)

Part A: Introduction

1. Distribute the overview article on radar maps.
2. Pose the question: "What is Radar?" i.e. an acronym

Part B: Doppler Radar

1. Divide the class into pairs.
2. Distribute the ‘same day’ Doppler Radar maps of the regions of the USA
3. Explain the color code.
4. Have students: a) plot the precipitation on a base map of the USA; b) interpret the probable locations of the areas of i- high and low pressure, ii- weather fronts
5. Review answers: volunteers put sketches on blackboard

Part C: Radar Satellite Altimetry                                                                 

1. Divide the class into pairs.
2. Distribute the Radar Maps of the South Indian Ocean
3. Explain the significance of the location  i.e. meeting of tectonic plates
4. Have students: a) plot the ridges and basins on a base map of the South Indian Ocean; b) interpret the probable locations of the areas of i- Indian Plate, ii- African Plate
5. Review answers: volunteers put sketches on blackboard

LESSON PLAN: PAGE 2

• Approximately two 55 minute periods.

• Completion of task marks for mapping.

• Collect most recent Doppler Radar images from internet reference
• View alternate maps of South Indian Ocean from internet reference.
• Show land use and describe the operation of a farm.
• Identify Canada’s contribution to geotechnology through Radarsat.

• Internet: Weather Channel   http://www.weather.com/weather/maps

STUDENT DOCUMENTS: PAGE 1

Radar is an acronym for RAdio Detection And Ranging. An electronic instrument is used to detect distant objects and measure their range by how they scatter or reflect radio energy. Precipitation and clouds are detected by measuring the strength of the electromagnetic signal reflected back. Doppler radar and NEXRAD are examples.

Doppler Radar is weather radar that measures direction and speed of a moving object, such as drops of precipitation, by determining whether atmospheric motion is horizontally toward or away from the radar. Using the Doppler effect, it measures the velocity of particles. Named for J. Christian Doppler, an Austrian physicist, who in 1842 explained why the whistle of an approaching train had a higher pitch than the same whistle when the train was going away.

These map show any radar-detected precipitation in the United States. It is made through the compilation of over 140 local Doppler radar maps. The color of the precipitation corresponds to the rate at which it is falling.

The colors range from greens corresponding to lighter precipitation to yellow, orange, and red corresponding to heavier precipitation.

Satellite altimetry offers the possibility to measure sea surface heights globally. Sea surface height is determined by measuring the distance between a satellite and the sea surface using radar, after computing the location of the satellite during themeasurement and a number of atmospheric corrections the sea surface height is known.

Satellite altimetry is used for:

• Oceanography: Since currents are detectable as slopes in the sea surface, the worlds ocean currents can be detected and monitored. Small scale features are visible as well, like eddies, which are generated by the large scale currents (by the Gulf Stream, for example). Altimeter data is also used for tide modeling.

• Geophysics: Density differences in the Earth's crust cause local differences in gravity (gravity anomalies). These affect the topography of the sea surface. The sea surface is always perpendicular to the (local) gravity so a "mountain" in local gravity shows up as a "hill" in the sea surface. This "mountain" can be both a real subsurface seamount or island, or it may be a local increase in density in the Earth's crust. An accurate determination of the constant part of the sea surface (as opposed to the time-dependant part, mostly due to oceanographic influences) is made by averaging as much data as possible from as many satellites as possible.

STUDENT DOCUMENTS: PAGE 2

STUDENT DOCUMENTS: PAGE 3

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