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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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ACTIVITY 1: Is it a satellite?

Intro to EO

A satellite can be defined as anything in orbit around the Earth (or another planet!).

International Space Station
GPS Navigation
The Moon
Landsat-9
Voyager 1 probe
Satellite Phone
Hubble Space Telescope

Task 1 : Take a look at the following objects and decide - is it a satellite?

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Is it a satellite?

International

Space Station

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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International

Space Station

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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International

Space Station

GPS Navigation

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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International

Space Station

GPS Navigation

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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International

Space Station

GPS Navigation

The Moon

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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International

Space Station

GPS Navigation

The Moon

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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International

Space Station

GPS Navigation

The Moon

Voyager 1 Probe

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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International

Space Station

GPS Navigation

The Moon

Voyager 1 Probe

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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International

Space Station

GPS Navigation

The Moon

Satellite Phone

Voyager 1 Probe

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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International

Space Station

GPS Navigation

The Moon

Satellite Phone

Voyager 1 Probe

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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International

Space Station

GPS Navigation

The Moon

Satellite Phone

Hubble Space Telescope

Voyager 1 Probe

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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International

Space Station

GPS Navigation

The Moon

Voyager 1 Probe

Satellite Phone

Hubble Space Telescope

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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ACTIVITY 2: Explore the Satellites Orbiting Earth

Intro to EO

Spend a couple of minutes panning around and exploring what you see!

Name
Object type
Can you find out any other information about the object?

Task 1 : Zoom to the UK and select one of the objects flying overhead and write down its:

e.g. when it was launched? What was it designed for? Who owns it?

(satellite/rocket body/debris)

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ACTIVITY 2: Explore the Satellites Orbiting Earth

Intro to EO

Task 2: Search for Sentinel 2A in the top left panel. Pan around the Earth to find where this satellite is flying (it appears as a small green icon) and click on the icon to see more information - write down:

Where is it flying over?
What is its period? (minutes)

Hint: This is the time it takes for the satellite to complete one single orbit of Earth. The time is given in minutes.

Hint: You will need to look for details of the apogee - height of the satellite above Earth at the point in its orbit where it is furthest from Earth.

c. How high above Earth does it fly? (km)

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ACTIVITY 2: Explore the Satellites Orbiting Earth

Intro to EO

Task 3 : Toggle the 'debris' box to look at all the space debris. Discuss with a partner and write down.

What do you think all of this debris has come from?
Can you think of any risks caused by the debris?

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BONUS ACTIVITY: Tracking Satellites using Ground Radar

Intro to EO

Remember to toggle the ‘instruments’ box!

Why do you think it is helpful to track objects in space?
How many ground radar instruments can you count?
In what country is the most southernly ground radar instrument?

Ground radar instruments are used to track the movement of objects in space.

Task 4 : Toggle the ‘instruments’ box to see where ground radar instruments are located and the range in which they can detect objects.

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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. Flatter surfaces (e.g. water) reflect away the microwaves and rougher areas reflect more back to the detector (e.g. buildings and boats).

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 can scientists measure with EO data?

Intro to EO

Weather Patterns

Meteosat in geostationary orbit over Europe/Africa

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Intro to EO

Changes in Vegetation

Wildfires (Kythira, Greece)

Deforestation (Amazon Rainforest)

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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Intro to EO

Arctic Sea Ice Cover

We have a continuous daily satellite record of Arctic sea ice extent since 1979.

40-year record shows huge reduction in summer sea ice cover as a result of human-induced ocean and atmospheric warming.

Credit: ESA - CC BY-SA 3.0 IGO

Satellites have given us a continuous daily record of Arctic sea ice extent since 1979! Each year, sea ice cover goes through a cycle in the Arctic – growing over the winter months as there is very little sunlight and temperatures are very low – and then shrinking in the summer months as warmer temperatures causes the ice to melt.

Using this over 40 year satellite record, we can see how the warming air and ocean temperatures in the Arctic as a result of human-induced climate change have caused a huge reduction in sea ice cover – particularly in the summer months.

The image on the left shows sea ice each day of the year in 1979, and on the right each day in 2016. Notice how much less ice there is in august and September 2016 compared to the same month in 1979. 40 years ago you couldn’t have dreamt about sailing in a ship across the Arctic ocean, but nowadays the sea ice is melting much further north, opening up passages across the ocean for ships to travel.

Image credits

Credit: ESA - CC BY-SA 3.0 IGO

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Intro to EO

Air Pollution

The Sentinel-5P satellite measures levels of nitrogen dioxide (NO2) in the atmosphere, which is produced by the burning of fossil fuels.

Here we can see a sharp drop in pollution levels across China in early 2020 in response to the Covid-19 lockdown.

Credit: Copernicus Sentinel data (2019-20), processed by ESA

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Intro to EO

Wildlife

Gray whales along the Mexican coast

Elephants in South Africa

Penguins in Antarctica

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Earth Observation and Climate Change

Credit: ESA - CC BY-SA 3.0 IGO

The climate crisis is the most urgent challenge faced by humankind – affecting every region, continent, and ocean on Earth. Space has an untapped potential to make a difference in tackling the threats and challenges we face.

Satellites watch over Earth continuously, helping us to monitor, understand, model, predict and act on climate change and its related challenges. They give us a reliable 40+ year record of change and are especially useful for monitoring remote and inaccessible areas like the polar regions, where changes to the climate are the most extreme!

Play 2 min video from ESA

European Space Agency’s Climate Change Initiative – established to use EO satellite data to track changes in the climate and provide robust and transparent access to global climate data for scientists and the general public. It focuses on measuring 22 ‘essential climate variables’, including greenhouse gases, clouds, glaciers, land cover, sea level and sea surface temperature. ESA CCI – would really encourage all of you to go onto this web app and explore for yourself some of the amazing satellite imagery that can tell us how our planet has been changing over the past 40 years.

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[insert 2-3 sentence summary of what you do]

What do I use satellite data for?

Intro to EO

[Pic to illustrate what you do]

[Pic of you]

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ACTIVITY 3: Earth Observation Memory Game

Intro to EO

This works like a traditional memory card game, but with a challenging twist! The pairs of satellite images are not identical. Instead, they are before and after images of a location that has experienced a type of land change.

Your first challenge is to find the matching image pairs of the same location—then try again and see if you can improve your time! Start trying with four pairs, and if that's too easy - try six or eight pairs!

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ACTIVITY 3: Earth Observation Memory Game

Intro to EO

Task 1: Pick one of six locations and write down:

Where in the world has this pair of images been taken?
Describe the main geographical features (natural/man-made) you see in the satellite images.
Which satellite image in the pair do you think was taken first?
What has changed between the two images in this location?

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Intro to EO

What have we learnt today?

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Task 1: Write ‘I wonder about…’, relating to something you wonder from what you have learnt about studying earth observation.

Task 2: What have you learnt now that you didn't know before?

I wonder...

Intro to EO

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Intro to EO

Thank you for listening!

For my specific research, I use one of NASA’s latest satellites – called ICESat-2.

And I use data from this really cool NASA satellite, called ICESat-2, that was specifically designed to monitor elevation changes of the ice surface in the polar regions. It works by sending down small pulses of laser light 10,000 times a second, each containing billions of photons, and by measuring precisely how long it takes for the individual photons to travel from the spacecraft, down to the Earth and back again, allows us to work out the height of the surface beneath ICESat-2. The fundamental concept of this is relatively simple (going back to our physics triangles), if we know the speed of light (constant for all EM waves), and the time taken for the light to travel to the surface of the Earth and bounce back to reach the satellite, then we can calculate the distance of the surface away from the satellite (and hence it’s elevation). These measurements are sensitive to millimetres of elevation change, which is pretty mind-boggling considering the satellite is flying around 481km above the Earth’s surface.

By repeatedly taking measurements of surface elevation of the ice sheet and ice shelves, we can identify areas where the mass balance of the ice sheet is changing  thinning indicates we are losing mass, and where does that ice mass go? Well, it flows right into the oceans and contributes to sea level rise around the globe.