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Introduction to Earth Observation

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[Optional: slide introducing presenters]

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What is Earth Observation?

Earth observation involves collecting imagery and measurements of the surface of the Earth from the vantage point of space.

Specially designed instruments on-board satellites orbit the Earth taking measurements - giant cameras, radars, and even lasers!

Provides info for research in many fields: meteorology, oceanography, ecology, glaciology, atmospheric science (to name a few!)

'Earthrise' - Apollo 8 Mission, 1968

When we say earth observation, what do we mean? Well it is the ways we collect information about the physical, chemical and biological systems of Earth from the vantage point of space.

We send specially designed instruments up into space to orbit the Earth on satellites, taking measurements as they go. These include giant cameras, radars, and even lasers!

Earth observation provides information for research in fields including meteorology, oceanography, ecology, glaciology, atmospheric science and many more!

This picture shows the very first ‘Earth Observation’ – an iconic image, taken in 1968 by the Apollo 8 mission, showing ‘Earthrise’ from the Moon. From this moment onwards, humankind has become more and more obsessed with observing the Earth from space and so we have sent more and more satellites and instruments up into orbit to do just that – meaning we now have a approx. 50years of measurements from space over which we can observe annual, seasonal and daily changes. But obviously no info on longer timescales than this.

Image credits

Earthrise – creative commons license - https://www.flickr.com/photos/thomasappere/46531570361

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Definition: something in orbit around the Earth (or another planet!)
Fun Fact! The Earth itself is a natural satellite, orbiting the Sun
Thousands of man made satellite orbit the earth
Give a bird's eye view of the Earth

What is a satellite?

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Is it a satellite?

NEED TO ADD ANIMATIONS SO COME IN ONE AT A TIME FOLLOWED BY YES/NO

Is it a satellite? (could ask students to put their hands up for yes / no)

The international space station - YES

GPS – NO, but it uses satellites

The Moon – YES

The voyager probe – NO, it’s not in orbit!

Satellite phone – NO, but it uses satellites

Hubble space telescope – YES

Picture credits:

Moon – Gregory H. Revera https://commons.wikimedia.org/wiki/File:FullMoon2010.jpg#filelinks

Hubble space telescope – NASA https://www.nasa.gov/mission_pages/hubble/story/index.html

Voyager probe – NASA https://www.flickr.com/photos/121483302@N02/14813876421

Satellite phone - https://commons.wikimedia.org/wiki/File:3_Satellite_phones.jpg

ISS – NASA Johnson https://www.flickr.com/photos/nasa2explore/31763901878

GPS – public domain https://freesvg.org/gps-satnav-on

Tick and cross – vector stock image https://www.vectorstock.com/royalty-free-vector/green-tick-symbol-and-red-cross-sign-in-circle-vector-21387737

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Is it a satellite?

NEED TO ADD ANIMATIONS SO COME IN ONE AT A TIME FOLLOWED BY YES/NO

Is it a satellite? (could ask students to put their hands up for yes / no)

The international space station - YES

GPS – NO, but it uses satellites

The Moon – YES

The voyager probe – NO, it’s not in orbit!

Satellite phone – NO, but it uses satellites

Hubble space telescope – YES

Picture credits:

Moon – Gregory H. Revera https://commons.wikimedia.org/wiki/File:FullMoon2010.jpg#filelinks

Hubble space telescope – NASA https://www.nasa.gov/mission_pages/hubble/story/index.html

Voyager probe – NASA https://www.flickr.com/photos/121483302@N02/14813876421

Satellite phone - https://commons.wikimedia.org/wiki/File:3_Satellite_phones.jpg

ISS – NASA Johnson https://www.flickr.com/photos/nasa2explore/31763901878

GPS – public domain https://freesvg.org/gps-satnav-on

Tick and cross – vector stock image https://www.vectorstock.com/royalty-free-vector/green-tick-symbol-and-red-cross-sign-in-circle-vector-21387737

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Is it a satellite?

NEED TO ADD ANIMATIONS SO COME IN ONE AT A TIME FOLLOWED BY YES/NO

Is it a satellite? (could ask students to put their hands up for yes / no)

The international space station - YES

GPS – NO, but it uses satellites

The Moon – YES

The voyager probe – NO, it’s not in orbit!

Satellite phone – NO, but it uses satellites

Hubble space telescope – YES

Picture credits:

Moon – Gregory H. Revera https://commons.wikimedia.org/wiki/File:FullMoon2010.jpg#filelinks

Hubble space telescope – NASA https://www.nasa.gov/mission_pages/hubble/story/index.html

Voyager probe – NASA https://www.flickr.com/photos/121483302@N02/14813876421

Satellite phone - https://commons.wikimedia.org/wiki/File:3_Satellite_phones.jpg

ISS – NASA Johnson https://www.flickr.com/photos/nasa2explore/31763901878

GPS – public domain https://freesvg.org/gps-satnav-on

Tick and cross – vector stock image https://www.vectorstock.com/royalty-free-vector/green-tick-symbol-and-red-cross-sign-in-circle-vector-21387737

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Is it a satellite?

NEED TO ADD ANIMATIONS SO COME IN ONE AT A TIME FOLLOWED BY YES/NO

Is it a satellite? (could ask students to put their hands up for yes / no)

The international space station - YES

GPS – NO, but it uses satellites

The Moon – YES

The voyager probe – NO, it’s not in orbit!

Satellite phone – NO, but it uses satellites

Hubble space telescope – YES

Picture credits:

Moon – Gregory H. Revera https://commons.wikimedia.org/wiki/File:FullMoon2010.jpg#filelinks

Hubble space telescope – NASA https://www.nasa.gov/mission_pages/hubble/story/index.html

Voyager probe – NASA https://www.flickr.com/photos/121483302@N02/14813876421

Satellite phone - https://commons.wikimedia.org/wiki/File:3_Satellite_phones.jpg

ISS – NASA Johnson https://www.flickr.com/photos/nasa2explore/31763901878

GPS – public domain https://freesvg.org/gps-satnav-on

Tick and cross – vector stock image https://www.vectorstock.com/royalty-free-vector/green-tick-symbol-and-red-cross-sign-in-circle-vector-21387737

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Is it a satellite?

NEED TO ADD ANIMATIONS SO COME IN ONE AT A TIME FOLLOWED BY YES/NO

Is it a satellite? (could ask students to put their hands up for yes / no)

The international space station - YES

GPS – NO, but it uses satellites

The Moon – YES

The voyager probe – NO, it’s not in orbit!

Satellite phone – NO, but it uses satellites

Hubble space telescope – YES

Picture credits:

Moon – Gregory H. Revera https://commons.wikimedia.org/wiki/File:FullMoon2010.jpg#filelinks

Hubble space telescope – NASA https://www.nasa.gov/mission_pages/hubble/story/index.html

Voyager probe – NASA https://www.flickr.com/photos/121483302@N02/14813876421

Satellite phone - https://commons.wikimedia.org/wiki/File:3_Satellite_phones.jpg

ISS – NASA Johnson https://www.flickr.com/photos/nasa2explore/31763901878

GPS – public domain https://freesvg.org/gps-satnav-on

Tick and cross – vector stock image https://www.vectorstock.com/royalty-free-vector/green-tick-symbol-and-red-cross-sign-in-circle-vector-21387737

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Is it a satellite?

NEED TO ADD ANIMATIONS SO COME IN ONE AT A TIME FOLLOWED BY YES/NO

Is it a satellite? (could ask students to put their hands up for yes / no)

The international space station - YES

GPS – NO, but it uses satellites

The Moon – YES

The voyager probe – NO, it’s not in orbit!

Satellite phone – NO, but it uses satellites

Hubble space telescope – YES

Picture credits:

Moon – Gregory H. Revera https://commons.wikimedia.org/wiki/File:FullMoon2010.jpg#filelinks

Hubble space telescope – NASA https://www.nasa.gov/mission_pages/hubble/story/index.html

Voyager probe – NASA https://www.flickr.com/photos/121483302@N02/14813876421

Satellite phone - https://commons.wikimedia.org/wiki/File:3_Satellite_phones.jpg

ISS – NASA Johnson https://www.flickr.com/photos/nasa2explore/31763901878

GPS – public domain https://freesvg.org/gps-satnav-on

Tick and cross – vector stock image https://www.vectorstock.com/royalty-free-vector/green-tick-symbol-and-red-cross-sign-in-circle-vector-21387737

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Is it a satellite?

NEED TO ADD ANIMATIONS SO COME IN ONE AT A TIME FOLLOWED BY YES/NO

Is it a satellite? (could ask students to put their hands up for yes / no)

The international space station - YES

GPS – NO, but it uses satellites

The Moon – YES

The voyager probe – NO, it’s not in orbit!

Satellite phone – NO, but it uses satellites

Hubble space telescope – YES

Picture credits:

Moon – Gregory H. Revera https://commons.wikimedia.org/wiki/File:FullMoon2010.jpg#filelinks

Hubble space telescope – NASA https://www.nasa.gov/mission_pages/hubble/story/index.html

Voyager probe – NASA https://www.flickr.com/photos/121483302@N02/14813876421

Satellite phone - https://commons.wikimedia.org/wiki/File:3_Satellite_phones.jpg

ISS – NASA Johnson https://www.flickr.com/photos/nasa2explore/31763901878

GPS – public domain https://freesvg.org/gps-satnav-on

Tick and cross – vector stock image https://www.vectorstock.com/royalty-free-vector/green-tick-symbol-and-red-cross-sign-in-circle-vector-21387737

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Is it a satellite?

NEED TO ADD ANIMATIONS SO COME IN ONE AT A TIME FOLLOWED BY YES/NO

Is it a satellite? (could ask students to put their hands up for yes / no)

The international space station - YES

GPS – NO, but it uses satellites

The Moon – YES

The voyager probe – NO, it’s not in orbit!

Satellite phone – NO, but it uses satellites

Hubble space telescope – YES

Picture credits:

Moon – Gregory H. Revera https://commons.wikimedia.org/wiki/File:FullMoon2010.jpg#filelinks

Hubble space telescope – NASA https://www.nasa.gov/mission_pages/hubble/story/index.html

Voyager probe – NASA https://www.flickr.com/photos/121483302@N02/14813876421

Satellite phone - https://commons.wikimedia.org/wiki/File:3_Satellite_phones.jpg

ISS – NASA Johnson https://www.flickr.com/photos/nasa2explore/31763901878

GPS – public domain https://freesvg.org/gps-satnav-on

Tick and cross – vector stock image https://www.vectorstock.com/royalty-free-vector/green-tick-symbol-and-red-cross-sign-in-circle-vector-21387737

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Is it a satellite?

NEED TO ADD ANIMATIONS SO COME IN ONE AT A TIME FOLLOWED BY YES/NO

Is it a satellite? (could ask students to put their hands up for yes / no)

The international space station - YES

GPS – NO, but it uses satellites

The Moon – YES

The voyager probe – NO, it’s not in orbit!

Satellite phone – NO, but it uses satellites

Hubble space telescope – YES

Picture credits:

Moon – Gregory H. Revera https://commons.wikimedia.org/wiki/File:FullMoon2010.jpg#filelinks

Hubble space telescope – NASA https://www.nasa.gov/mission_pages/hubble/story/index.html

Voyager probe – NASA https://www.flickr.com/photos/121483302@N02/14813876421

Satellite phone - https://commons.wikimedia.org/wiki/File:3_Satellite_phones.jpg

ISS – NASA Johnson https://www.flickr.com/photos/nasa2explore/31763901878

GPS – public domain https://freesvg.org/gps-satnav-on

Tick and cross – vector stock image https://www.vectorstock.com/royalty-free-vector/green-tick-symbol-and-red-cross-sign-in-circle-vector-21387737

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Is it a satellite?

NEED TO ADD ANIMATIONS SO COME IN ONE AT A TIME FOLLOWED BY YES/NO

Is it a satellite? (could ask students to put their hands up for yes / no)

The international space station - YES

GPS – NO, but it uses satellites

The Moon – YES

The voyager probe – NO, it’s not in orbit!

Satellite phone – NO, but it uses satellites

Hubble space telescope – YES

Picture credits:

Moon – Gregory H. Revera https://commons.wikimedia.org/wiki/File:FullMoon2010.jpg#filelinks

Hubble space telescope – NASA https://www.nasa.gov/mission_pages/hubble/story/index.html

Voyager probe – NASA https://www.flickr.com/photos/121483302@N02/14813876421

Satellite phone - https://commons.wikimedia.org/wiki/File:3_Satellite_phones.jpg

ISS – NASA Johnson https://www.flickr.com/photos/nasa2explore/31763901878

GPS – public domain https://freesvg.org/gps-satnav-on

Tick and cross – vector stock image https://www.vectorstock.com/royalty-free-vector/green-tick-symbol-and-red-cross-sign-in-circle-vector-21387737

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Is it a satellite?

NEED TO ADD ANIMATIONS SO COME IN ONE AT A TIME FOLLOWED BY YES/NO

Is it a satellite? (could ask students to put their hands up for yes / no)

The international space station - YES

GPS – NO, but it uses satellites

The Moon – YES

The voyager probe – NO, it’s not in orbit!

Satellite phone – NO, but it uses satellites

Hubble space telescope – YES

Picture credits:

Moon – Gregory H. Revera https://commons.wikimedia.org/wiki/File:FullMoon2010.jpg#filelinks

Hubble space telescope – NASA https://www.nasa.gov/mission_pages/hubble/story/index.html

Voyager probe – NASA https://www.flickr.com/photos/121483302@N02/14813876421

Satellite phone - https://commons.wikimedia.org/wiki/File:3_Satellite_phones.jpg

ISS – NASA Johnson https://www.flickr.com/photos/nasa2explore/31763901878

GPS – public domain https://freesvg.org/gps-satnav-on

Tick and cross – vector stock image https://www.vectorstock.com/royalty-free-vector/green-tick-symbol-and-red-cross-sign-in-circle-vector-21387737

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Is it a satellite?

Is it a satellite? (could ask students to put their hands up for yes / no)

The international space station - YES

GPS – NO, but it uses satellites

The Moon – YES

The voyager probe – NO, it’s not in orbit!

Satellite phone – NO, but it uses satellites

Hubble space telescope – YES

Picture credits:

Moon – Gregory H. Revera https://commons.wikimedia.org/wiki/File:FullMoon2010.jpg#filelinks

Hubble space telescope – NASA https://www.nasa.gov/mission_pages/hubble/story/index.html

Voyager probe – NASA https://www.flickr.com/photos/121483302@N02/14813876421

Satellite phone - https://commons.wikimedia.org/wiki/File:3_Satellite_phones.jpg

ISS – NASA Johnson https://www.flickr.com/photos/nasa2explore/31763901878

GPS – public domain https://freesvg.org/gps-satnav-on

Tick and cross – vector stock image https://www.vectorstock.com/royalty-free-vector/green-tick-symbol-and-red-cross-sign-in-circle-vector-21387737

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What are (artificial) satellites used for?

Space stations - home for astronauts, space laboratory

Telecommunications - TV and radio, satellite phones

GPS or SatNav - navigation

Earth observation - weather monitoring, scientific research, cartography (e.g. Google maps)

Space observation (space telescopes) - stars, planets, space phenomena

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Where on Earth..?

1.

Eiffel Tower,

A quick quiz

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Where on Earth..?

1.

Eiffel Tower,

Eiffel Tower, Paris

Image from very high-resolution WorldView-2 Satellite

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2.

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2.

Antarctica

This is actually a mosaic image made up of lots of smaller satellite images, because Antarctica is so big!

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3.

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3.

Mount Everest

Image from very high-resolution GeoEye-1 Satellite

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4.

Bonus: Can you identify some man-made and natural features?

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4.

London, UK

Image from the Sentinel-2 satellite (10m resolution)

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5.

What do you think the bright orange feature is?

Can you identify any other interesting features?

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5.

La Palma, Canary Islands

During an eruption of the Cumbre Vieja volcano!

This is an infrared image, meaning it can detect the lava flow due to its heat causing it to appear very bright.

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6.

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6.

Sahara Desert, Algeria

Optical image from Japan's ALOS satellite. The pattern of the sand is caused by wind forming sand dunes. The dark black / purple area is a large expanse of rock!

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7.

What is the main feature you can see in this image?

Where do you think this could be?

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7.

Hurricane Katrina, Gulf of Mexico

This is a satellite image of hurricane Katrina in 2005 in the Gulf of Mexico, starting to move across the southern states of the USA.

Sometimes cloud and weather can block satellite images, but in some cases, like this one, you want to track the cloud and weather in order to warn those that may be affected.

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8.

This is a tougher one... but think about the main features you can identify in the image. Are they man-made or natural?

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8.

Istanbul, Turkey

This is a radar image, meaning it uses microwaves to capture information rather than measuring visible light (as in the optical sensors!). This is why it appears in black and white. All areas of water are very dark because water absorbs the microwaves!

These white dots are boats!

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Different types of EO satellite

~36,000km above Earth
'Hover' above a single point
Applications: Weather observations, telecommunications, satellite navigation

Intro to EO

Geostationary

Polar Orbiting

700-800km above Earth
Orbit Earth several times per day
Applications: Detailed mapping of the Earth, monitoring changes in vegetation, ice cover, pollution, clouds ...

Geostationary satellites

These satellites are in orbits at an altitude of 36,000km . At this altitude, they orbit the Earth at exactly the same speed that the Earth spins around its axis, so it effectively hovers above the same region on Earth.

This is vital for observing changes in meteorological phenomena (weather) and movement of cloud masses. For example, it is Europe’s Meteosat satellites that supply the images we are used to seeing in TV weather forecasts.

Communications satellites are also often put in gsostationary orbit so tat Earth-based satellite antanenas do not have to rotate to track them but can point permanently at the position in the sky where the satellite is – this is why the satellite dish on your roof at home can stay pointing in the same direction all the time!

Navigation satellites – like those ones used to power your GPS – are often also in geostationary orbit to enhance GPS accuracy.

One disadvantage of geostationary orbits is the fact that being at such a high altitude reduces the resolution of the data / images they can collect.

Polar-orbiting satellites

These orbit the earth at much lower altitudes – 700-800km – and with each pass, such observation satellites fly over a narrow zone allowing them to obtain very detailed images.

In a 24-hour period, these satellites orbit the Earth several times, passing over the poles as they do so. Because the Earth is also spinning around its axis, with each pass they fly over a different area. This video shows the European Space Agency’s sentinel-1 satellite constellation, and between the pair of satellites they can image the whole Earth in 6 days. Some satellites like MODIS can achieve this in as little as one day!

Most of our dedicated Earth Observation satellite missions are placed in polar orbit, because the lower altitude allows them to take more detailed pictures/measurements of the Earth’s surface.

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Different types of EO sensor

Work like a camera, taking pictures from space!
Measures sunlight reflected off the Earth’s surface
Produces images like we see on Google Earth

Intro to EO

Passive Sensors

Credit: NASA Earth Observatory

To our eyes, visible light emitted by the sun appears white. In fact it is composed of a mixture of primary colours, as is clear when we look at a rainbow or light passing through a glass prism. Each of these colours (red, orange, yellow, green, blue and purple) has its own specific wavelengths.

Passive sensors on EO satellites can record the amount of light with each of these different wavelengths that is either reflected or emitted from the Earth’s surface. The human eye is only able to perceive visible light, but there are lots of different types of light waves that we cannot see ourselves, but that satellites can detect – such as the much longer radio waves and microwaves that we use to transmit the radio all across the country or power our microwave ovens.

Image credits

Diagram from ESA watching over the earth worksheets (need to check whether we can use this…)

Sun – clip art

Camera – check

Satellite image – NASA Earth observatory (need to check whether can use)

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Different types of EO sensor

Like a camera... using FLASH! Send a signal down to earth and record what bounces back
Similar to a camera using flash or how bat’s navigate in the dark with echolocation

Intro to EO

Active Sensors

Credit: NASA Earth Observatory

Credit: ESA

Time-lapse animation of images of the Kangerdlugssuaq ice stream (Greenland) taken from March to May 2011. The animation shows the ice stream advancing steadily at a speed of about 35 m per day, until a 9 sq km piece of the glacier broke into icebergs during 19-22 May. Credits: ESA

Radar

Radar instruments do not measure sunlight reflected by the Earth. Instead they send out their own signal down to Earth, and then detect the echo of the signal that comes back to the satellite. Depending on the nature of the ground surface,, the signal bounces back with varying intensity. And so by recording these variations we are able to map differences in the surface properties. E.g. a still water surface (e.g. lake) will cause the radar signal will reflect very strongly away from the satellite, so a very small signal will be detected.

Altimetry

Altimeters send out pulses of either radar or laser light, and record the time taken for that light to return back to the satellite. We know the speed of light (because it is a constant), and so if we know the time taken for the signal to return, we can calculate the distance that that light ahs travelled – and hence the surface height of the Earth.

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What will we learn today?

What can we measure with satellite imagery?

City night light
Vegatation and other land cover changes

Using interactive worksheet web app to do fun activities!

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Hands on with Data

City Lights at Night

What can you measure using satellite data?

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City Lights at Night

Light sources at night:

How does the population size of a city influence the demand for city lights?

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City Lights at Night

Light sources at night:

streetlights, buildings, vehicles, industrial facilities...

How does the population size of a city influence the demand for city lights?

Generally, more population, greater need for infrastructure, night time activity and extensive urban development

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City Lights at Night

City light is detectable from space!

Lets look at what urban lights look like from space

Light sources at night:

streetlights, buildings, vehicles, industrial facilities...

How does the population size of a city influence the demand for city lights?

When populations are larger there is a greater need for infrastructure and nighttime activity increases.

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City Lights at Night

Nighttime light satellite data shows where people live and work by capturing the lights from cities and other sources of artificial illumination.

Lets look at what urban lights look like from space

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City Lights at Night

Nighttime light satellite data shows where people live and work by capturing the lights from cities and other sources of artificial illumination.

Lets look at what urban lights look like from space

Can you find where big cities are from the nighttime light imagery?

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The Atmosphere from Space

ACTIVITY 1: LET'S LOOK AT NIGHT LIGHT SATELLITE OBSERVATIONS FROM SPACE!

Follow the app link: https://satschool.streamlit.app/

Navigate to Activity 1 app: From the main menu, select "Introduction," then click the right arrow icon three times to reach the 4th page.

Answer the questions

Ask if you need help!

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Intro to EO

What can scientists measure with EO data?

Vegetation Change

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Intro to EO

Reasons for the changes in vegetation?

Amazon Rainforest

Lets check out what vegetation from space looks like

2000

2019

Deforestation

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Lets check out what vegetation from space looks like

Intro to EO

Kythira, Greece

Forest Fire

Reasons for the changes in vegetation?

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Intro to EO

Reasons for the changes in vegetation?

Amazon Rainforest

Lets check out what vegetation from space looks like

Kythira, Greece

Deforestation

Forest Fire

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Intro to EO

Land cover map

Satellite images can be used to create landcover maps

Land covers that can be mapped include forests, cities, farms, deserts and oceans!

<-check out the legend

Land cover maps are useful for decision makers and species conservation.

Two examples of how we can observe changes in vegetation.

1- Timelapse shows progressive deforestation in the Amazon rainforest

2- Series of images shows the greek island of Kythira in 2017 at the end of a very hot summer in Southern Europe. The images are taken with the Sentinel-2 satellite that takes pictures of the Earth with both visible and infrared light. This shows a false colour image using the infrared wavelengths, which makes vegetation appear red. On 4 August you can see the start of a fire on the island, with a plume of grey smoke. Then 5 days later you can see a huge burn scar visible across the western part of the island. This destroyed more than 2000 hectares of farmland.

Image Credits

Deforestation - NASA Earth Observatory (processed by L. Dauphin, using Landsat data from USGS)

Wildfires – creative commons ESA - https://commons.wikimedia.org/wiki/File:Kythira_wildfires_ESA382811.gif

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The Atmosphere from Space

ACTIVITY 2: LET'S LOOK AT LAND COVER CHANGES!

Follow the app link: https://satschool.streamlit.app/

Navigate to Activity 2 app: From the main menu, choose "Land."

Ask if you need help!

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Hands on with Data

What have we learnt today?

What a satellite is and what it can measure

What different colors on the night light observation tells us

Analysed changes in vegetation and crop types from satellites