# Presentation: 773343

## Exploring Change Over Time 

- Introduction
- Engage and Explore
- Explain
- Elaborate
- Evaluate

**Exploring Change Over Time**** **
**with *****L******a******n******d******s******a******t***

## Studying Earth from Space

**Studying Earth from Space**

**Notes:**
NASA’s Earth Science primary mission, simply put, is studying Earth from Space.

## Slide 3

**Notes:**
Travel to space is a compelling subject! These astronauts recently launched on the space shuttle. And the legacy of travel to the moon is still a big part of our culture today.

STS114-S-002 (March 2004) --- These seven astronauts take a break from training to pose for the STS-114 crew portrait. In front are astronauts Eileen M. Collins (right), commander; Wendy B. Lawrence, mission specialist; and James M. Kelly, pilot. In back are astronauts Stephen K. Robinson (left), Andrew S. W. Thomas, Charles J. Camarda, and Soichi Noguchi, all mission specialists. Noguchi represents Japan Aerospace Exploration Agency (JAXA).

## Slide 4

**Notes:**
As interesting and exciting as this is however, all the astronauts speak of how drawn they are to the view of earth from space.

AS11-40-5903 (20 July 1969) --- Astronaut Edwin E. Aldrin, Jr., lunar module pilot, walks on the surface of the Moon near the leg of the Lunar Module (LM) "Eagle" during the Apollo 11 exravehicular activity (EVA). Astronaut Neil A. Armstrong, commander, took this photograph with a 70mm lunar surface camera. While astronauts Armstrong and Aldrin descended in the Lunar Module (LM) "Eagle" to explore the Sea of Tranquility region of the Moon, astronaut Michael Collins, command module pilot, remained with the Command and Service Module (CSM) "Columbia" in lunar orbit

## Slide 5

**Notes:**
This was recognized very early on, as depicted in this artwork.

Apollo lunar landing commerative artwork. View depicts an Apollo era astronaut standing on the lunar surface, facing the viewer, with an Earthrise reflected in his visor. Directly behind him, is the lunar lander.

## Slide 6

**Notes:**
And the first images of Earth  from the moon are credited with helping to launch the environmental movement in our country...

AS11-44-6552 (July 1969) --- This view of the Earth rising over the Moon's horizon was taken from the Apollo spacecraft. The lunar terrain pictured is in the area of Smyth's Sea on the nearside. Coordinates of the center of the terrain are 85 degrees east longitude and 3 degrees north latitude. While astronaut Neil A. Armstrong, commander; and Edwin E. Aldrin, Jr., lunar module pilot, descended in the Lunar Module (LM) "Eagle" to explore the Sea of Tranquility region of the Moon, astronaut Michael Collins remained with the Command and Service Modules (CSM) "Columbia" in lunar orbit.

## Slide 7

**Notes:**
After all, Earth is still the only planet we know that can sustain life.
View of earth visible from Apollo 8 spacecraft during lunar orbital mission

## Why NASA Looks at Earth

- NASA has a mission *to understand and protect our home planet.*
- The goal is to understand the Earth system and apply Earth system science to improve prediction of             climate, weather,                           and natural hazards.

**Notes:**
So, we had better try to understand it, and what makes life sustainable here. The official language puts it this way.

## Research Questions

- How is the global Earth system changing?
- What are the primary causes of change in the Earth System?
- How does the Earth system respond to natural and human-induced changes?
- What are the consequences of change in the Earth systems for human civilization?
- How can we predict future changes in the Earth system?

**Notes:**
The five ESE research questions are: 
All ESE funded research is supposed to be clearly tied to these questions. Translated: Measure and describe changes on Earth; What makes it go?; How does Earth react to change?; So what?; What’s next?

## Providing Global Measurements

***ERBS***

***Grace***

**Jason**

***SeaWiFS***

***EO-1***

**Notes:**
NASA uses lots of satellites to study Earth. (NASA also uses ground-based, airborne, and balloon data.) 

## What’s Special About Landsat

- Primary mission to map Earth’s land surface
- Over 30 years of data
- 16 day repeat
- 30-meter resolution
- Many free educational products

**Notes:**
Today we focus on one of these satellite missions, Landsat.

## What can students do with Landsat images and data?

- What can *students* do with Landsat images and data?

**Notes:**
And we will be addressing this question

## Study their own neighborhoods from the perspective of space 
Appreciate the regional context in which local phenomena occur
Map land cover types 
Check the health of watersheds
Measure the extent of natural hazards (floods, drought, hurricane and tornado damage) 
Estimate plant photosynthetic activity
Appreciate how the Landsat sensor works
Map and quantify change over time including urban growth 
...and more

- Students Can...

- Study their own neighborhoods from the perspective of space
- Appreciate the regional context in which local phenomena occur
- Map land cover types
- Check the health of watersheds
- Measure the extent of natural hazards (floods, drought, hurricane and tornado damage)
- Estimate plant photosynthetic activity
- Appreciate how the Landsat sensor works
*Map and quantify change over time including urban growth *
- ...and more

## Map and Quantify Change Over Time   (including urban growth)

**Notes:**
We try to map all of our Landsat educational materials to the National Standards. This is an example.

## Exploring Change Over Time 

- Engage and Explore
- Explain
- Elaborate
- Evaluate

**Exploring Change Over Time**** **
**with *****L******a******n******d******s******a******t***

## Exploring Landsat Images: Does This Look Familiar?

*Exploring Landsat Images: Does This Look Familiar?*

**Notes:**
Sample satellite images are scattered about the room. People are asked to move from image to image, identifying as best they can land features, landmarks, etc. See if they recognize places, and think about how it is that they were able to decide what they were seeing (Color? Shape? Proximity to known objects? Etc.). Groups move from table to table. This is an engagement piece, designed to just get people thinking about what a satellite image looks like, and what kinds of things show up, and a sense of the scale for the imagery used. Optional: include other kinds of maps also (topographic, aerial photographs, conventional road maps, geological map, etc.) Ask: what is the value of these respective kinds of maps? What are the strengths and weaknesses of each? Build on this as these maps are used in analysis of a place.

## Landforms Quiz!

**Landforms Quiz!**

**Notes:**
So now you start to get the idea that the colors have meaning, and the images contain data. Let’s see how good you are at identifying some basic landforms found on Earth: this slide show is on your cd. You can of course create your own version using images you choose from any number of websites featuring satellite images.

## Landsat Movies

*Landsat Movies*

## Exploring Change Over Time 

- Engage and Explore
- Explain
- Elaborate
- Evaluate

**Exploring Change Over Time**** **
**with *****L******a******n******d******s******a******t***

## How Landsat Images are Made

## More than just a pretty picture

**Notes:**
But those are pretty weird looking maps, and it wasn’t always easy to pick out things. And why do they use such strange colors, anyway?
We’ll spend the next few minutes getting an introduction to how these images are made. IMPORTANT: Do not expect to internalize all this information at this stage: this is just an introduction. We can work with your group to delve into this material in greater depth in the future, if you are interested.

## Think About Cameras vs. Sensors

*Photographs* are taken in the visible portion of  the spectrum.
*Photographs* are registered chemically on paper.
*Sensors* measure data in certain segments of EMS (visible or not), digitally record that, and then people *convert* this to color.

## Electromagnetic Spectrum

*From Imagers (Echo the Bat)*

**Notes:**
Let’s think for just a minute about the Electromagnetic spectrum: Everything emits radiation. And, everything illumined by our sun reflects radiation. It is this radiation that brings color to our lives: we see various wavelengths of the visible portion of the spectrum and our brains process this information, making it possible for us to see and process color. But our sensors (eyes) are not able to see in other parts of the spectrum. Remote sensors allow us to “see” in other parts of the spectrum. (That is, we cannot see outside the visible spectrum--x-ray, gamma ray, radio waves, for example). Think about bee guides we cannot see with our own eyes, but when we use infrared images, they become visible.

Important point! Different objects absorb and reflect different wavelengths. For example, green vegetation reflects in the infrared quite well.  This is why we can use remote sensing technology to observe our world in new ways. 

Engineers and scientists collaborate to design sensors to measure specific parts of the EMS in order to measure certain things: land vs. ocean vs. atmosphere.

## Seeing (infra)Red

- Chlorophyll strongly absorbs radiation in the red and blue wavelengths but reflects green wavelengths. (This is why healthy vegetation appears green.)

- The internal structure of healthy leaves act as excellent diffuse reflectors of near-infrared wavelengths.

- Measuring and monitoring the near-IR reflectance is one way that scientists can determine how healthy (or unhealthy) vegetation may be.

**Notes:**
Color in Leaves:  A chemical compound in leaves called chlorophyll strongly absorbs radiation in the red and blue wavelengths but reflects green wavelengths. Leaves appear "greenest" to us in the summer, when chlorophyll content is at its maximum. In autumn, there is less chlorophyll in the leaves, so there is less absorption and proportionately more reflection of the red wavelengths, making the leaves appear red or yellow (yellow is a combination of red and green wavelengths). The internal structure of healthy leaves act as excellent diffuse reflectors of near-infrared wavelengths. If our eyes were sensitive to near-infrared, trees would appear extremely bright to us at these wavelengths. In fact, measuring and monitoring the near-IR reflectance is one way that scientists can determine how healthy (or unhealthy) vegetation may be.

## How we do Remote Sensing 

**Notes:**
Sensors on board satellites read amounts of reflected energy transmitted to them. These sensors are “remotely sensing” the energy of objects below. This information is stored and converted to picture format.

This diagram illustrates the entire process of remote sensing. We’ll be stepping through part of  this process today, in order to gain an understanding of what might or might not be available or accomplished via remote sensing, and to enable you to begin to understand more about what an image means when you look at one. 

## Sensor senses some segment of the Electromagnetic Spectrum

- Reads the “spectral signature” of the surface that is reflecting/emitting light

## Sensors Record Intensity of

- Reflected Energy Numerically

## The amount of the reflected energy or intensity is recorded for each pixel, in each band, on a scale of 0-255.

**Notes:**
For Landsat, there are 7 bands of data. Each band of data provides a record of the amount of energy reflected in a specific portion of the electromagnetic spectrum. For example band 4 measures the intensity of Near Infrared energy reflected, and  Band 3 measures the intensity of green light reflected. For each pixel in each band of data, there is a numerical value given to the amount of energy reflected from the Earth’s surface for that 30 X 30 meter square. 

WHY IS THIS IMPORTANT? Because of the numerical values, scientists can use software programs (for example Geographic Information Systems, or “GIS”), and write algorithms to quantify land cover and land use from these data. They use this information to study many aspects of our planet, from disease to forest fire, to agribusiness, flood predictions, etc.

This kind of information is not attainable with conventional photographs.

## Assigning Colors to Bands

- Assigning **C****o****l****o****r****s** to Bands

## Slide 30

**Notes:**
On your CD this movie is called, “Onion skin”

## Slide 31

**Notes:**
On your CD this movie is called, “Onion skin”

## 3,2,1

- Visible

- Infrared

- Green Data is shown as Green

- Blue Data is shown as Blue

- Red Data is shown as Red

**Notes:**
Here is an example of part of a Landsat “scene.” Note that all seven bands of data are in grey scale, even those that represent visible portions of the spectrum (blue, green or red reflected light), until we assign a color to the data. In this case we assigned the color blue to the band that represents blue light, the color green to the band representing green light, and red to the band of data representing red light. This produces what is called a “true color” image, akin to what one would see if they could ride atop one of these satellites (and used super-powered binoculars!)

## 4,3,2

- Visible

- Infrared

- NIR Data is shown as Red

- Red Data is shown as Green

- Green Data is shown as Blue

**Notes:**
Sometimes, to make things easier for our eyes to see, we use “false color.” One typical band combination for this is 4,3,2. Here band 4 (the near infra red) is assigned the color red. Band 3 (representing light reflecting in the red portion of the spectrum) is assigned the color green, and band 2 (what you and I would see as green) is assigned the color blue. 

Why do this? Recall that healthy vegetation reflects strongly in the near infra-red. If we color vegetation red, our eyes pick that out most clearly. In 4,3,2 combinations, the blue-green indicates the built environment (roads, pavement, buildings). Black or dark blue indicates water (or cloud shadows!)

## Producing...more than just a pretty picture!

**Notes:**
Mt Etna erupting shows some of the value of using more than one kind of band combination...
We couldn’t possibly accomplish this “color compositing” in a timely fashion if we had to do it manually. Image processing software including MultiSpec generates a satellite image using three spectral bands (wavelength ranges) of data, (whichever ones a user chooses to use) and combines them to create a color composite image. 

Now you know that a satellite image  is much more than a picture. Each pixel has a numeric representation of the amount of energy reflected in each of three selected wavelengths. And this information can be used to make numerous measurements. 

Possible teacher/student exercise: 
By adding up the number of pixels or squares in a grid overlay on an image, students can calculate the area of land cover type in a scene.  For example, if red in a false-color image represents vegetation, students can count the number of red pixels and multiply that number by the area of each pixel to determine the total area covered with vegetation.

## Time to Think!

- What did I just ***see***?

- What did I ***learn***?

- ...What am I ***thinking***?

**Notes:**
Process questions. 3-5 minutes use journals to write quick answers to these
What did I just see? 
What did I learn?
What am I thinking?

## What can students do with Landsat images and data?

- What can *students* do with Landsat images and data?

**Notes:**
OK., so now you know a bit about what goes into these images. How might we use this in a classroom?

## Getting to Know Your Landsat Image 

- Getting to Know Your Landsat Image

**...****a hands-on activity**

**Notes:**
Now let’s look at one classroom activity that can be used to examine a number of these subjects in greater detail. Turn to Section 2 in your note book, and find, “Getting to know your satellite imagery and GLOBE study site.”

## Quantifying Land Cover Change with Landsat 

*Quantifying Land Cover Change with Landsat** *

**Notes:**
OK Now that you’ve become a bit more familiar with images, let’s see how we might be able to use these images in a classroom to quantify landscape scale changes over time. In section 2 of your notebook, locate “Quantifying Land Cover Change with Landsat”

## Time to Think!

- What did I just ***see***?

- What did I ***learn***?

- ...What am I ***thinking***?

**Notes:**
Process questions. 3-5 minutes use journals to write quick answers to these
What did I just see? 
What did I learn?
What am I thinking?

## Exploring Change Over Time 

- Engage and Explore
- Explain
- Elaborate
- Evaluate

**Exploring Change Over Time**** **
**with *****L******a******n******d******s******a******t***

## So What?

- <date/time>

**Notes:**
So, we get lots of beautiful images, but how do scientists use this information to study our planet?

## How Scientists and Others Use Landsat

**Notes:**
See power point on your cd (“Why Landsat”);  follow along with notes in notebook if you like.

## Integration with Your Curriculum

**Notes:**
Time to think about how you might use what you have learned to day, within the context of your school’s curriculum

## Students can...

**Notes:**
First, let’s recall a few ways students might use this sort of data and imagery.

## Students can...

- Study their own neighborhoods from the perspective of space

## Students can...

- Measure the extent of natural hazards (floods, drought, hurricane and tornado damage)

**Notes:**
First image:
Four days after Maryland's strongest-ever tornado severely damaged the town of La Plata, authorities continued to count the cost of the storm. In the latest tally, 860 homes and 194 business were damaged or destroyed, and the total cost of the damage is expected to exceed $100 million. 

The above image was acquired by the Enhanced Thematic Mapper plus (ETM+), aboard Landsat 7, one minute before Earth Observer-1 (which produced an image with the Advanced Land Imager (ALI) instrument) passed over La Plata on May 1, 2002. Although the ETM+ does not have quite the same resolution or sensitivity as the ALI (a maximum or 15 meters per pixel for the ETM+, and a maximum of 10 meters per pixel for the ALI), it has a much wider field-of-view. The scene shows the entire length of the tornado's path?roughly 39 km (24 miles). 

Second image:
On Sunday, April 28, an F4 tornado cut an east-west path through La Plata, Maryland, killing 3 and injuring more than 100. These two images show a 6 x 17.8 km area centered on the town. The top image was acquired on May 12, 2001, and the bottom on May 3, 2002. The bands used for the image portray vegetation in red, and bare fields and urban areas in blue-green. The dark turquoise swath cutting across the 2002 image is the track of the tornado, where the vegetation was ripped up and removed. 

These images were acquired on May 3, 2002, and May 12, 2001 by the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) on NASA's Terra satellite. With its 14 spectral bands from the visible to the thermal infrared wavelength region, and its high spatial resolution of 15 to 90 meters (about 50 to 300 feet), ASTER will image Earth for the next six years to map and monitor the changing surface of our planet. 

## Students can...

- Aftermath of Hurricane Floyd September 1999 (Landsat 7 ETM+)

- Assess turbidity due to sediment load

**Notes:**
"Following Hurricane Floyd, record-breaking rains continued to soak the area, washing mountains of sediment and waste into the water system. Now rivers and tributaries along the Atlantic are choked and major ecological changes are happening," said Gene Feldman, of NASA's Goddard Space Flight Center, Greenbelt, MD. 

"Periodically, levels of dissolved oxygen in the water have dropped dramatically as organic matter decomposes, and aquatic life has been threatened in dozens of estuaries and peripheral habitats, commonly referred to as 'dead zones.' The current changes in the area may have lasting repercussions for hundreds of thousands of people," he said. 

The image above, from Landsat 7, shows the sediment washed into the ocean from hurricane Floyd's rains.

## Slide 48

## Slide 49

## Landsat Images and Software

- NASA’s Landsat Image Gallery: http://landsat.gsfc.nasa.gov
- USGS’s Landsat Image Gallery:  http://landsat7.usgs.gov/gallery/index.php

- Free Software for quantitative analysis of Landsat scenes:  *MultiSpec *at

- http://dynamo.ecn.purdue.edu/~biehl/MultiSpec/

## Where to get Landsat Data

- Landsat 7 Data Sets:
- http://landsat.gsfc.nasa.gov/education/l7downloads/index.html
- Global Visualization Viewer:
- http://glovis.usgs.gov
- Global Land Cover Facility: http://glcf.umiacs.umd.edu/index.shtml
- Landsat.org:
- http://www.landsat.org

**Notes:**
Note the url for Landsat 7 data sets is ....l7 downloads....that is a letter “L” followed by a number “7” --hard to see on the screen no matter what font I choose!

## New York City subsets

- http://landsat.gsfc.nasa.gov/education/l7downloads
- http://change.gsfc.nasa.gov

## Exploring Change Over Time 

- Engage and Explore
- Explain
- Elaborate
- Evaluate

**Exploring Change Over Time**** **
**with *****L******a******n******d******s******a******t***

## Journal/Discussion Questions

*What did I see/learn?*
*What was interesting?*
*What connections did I see to my work?*
*What do I want to learn more about?*
*What was confusing?*

## Landsat Education Staff

- Jeannie Allen
- SSAI
- Education and Outreach Specialist
- Jeallen@pop900.gsfc.NASA.gov

- Anita Davis
- SSAI
- Education and Outreach Coordinator
- Adavis@pop900.gsfc.NASA.gov

**Notes:**
Don’t hesitate to contact us with follow up questions!!!

## Depending upon the band combination and colors assigned, land cover appears in various colors.

**Notes:**
Addendum slide.

## National Aeronautics and Space Administration

-  http:www.nasa.gov