Earth from space: image of the week

[jacqmans]

Wildfires rage across Athens
13/08/2024

Firefighters in Greece are battling a rapidly spreading wildfire that has swept across several neighbourhoods in Athens, Greece, on Monday. Thousands of residents have been evacuated as the massive fire reached the suburbs of Athens, with some flames reaching heights of 25 m.

This image shows the fires surrounding Athens on 12 August 2024, captured by the Copernicus Sentinel-2 mission. This image has been processed in a way that highlights vegetation in red, while the burned areas can be seen in black. The estimated affected area exceeds 100 sq km.

In response to the fires, the Copernicus Emergency Management Service was activated to cover the fire event affecting the Attica Region. Copernicus EMS Rapid Mapping was requested to provide an initial rough estimate, as well as emergency mapping of the fire’s extent and damage assessment.

The Copernicus Sentinel-2 mission is based on a constellation of two identical satellites, each carrying an innovative wide swath high-resolution multispectral imager with 13 spectral bands for monitoring changes in Earth’s land and vegetation.

[jacqmans]

Earth from Space: Sentinel-2 captures Sentinel-2
06/09/2024

The Copernicus Sentinel-2B satellite captured this image over Europe’s Spaceport in French Guiana on 2 September, just ahead of the Sentinel-2C launch.

Europe's Spaceport is situated in the northeast of South America in French Guiana, an overseas department of France. The spaceport lies northwest of Kourou, a coastal town on the estuary of the Kourou River, both visible near the centre of the image. After running for 144 km, the river flows into the Atlantic Ocean. The brownish hue of its muddy waters is most likely the result of sediment gathered from the nearby forest.

White, sandy beaches stretch along the ocean coast north of Kourou, while the riverbank and the interior regions are mostly covered by mangroves and dense tropical rainforest.

The spaceport is home to the ESA-developed Ariane and Vega rocket families, whose launch pads can be spotted in the top left corner of the image.

Thanks to its geographical position near the equator, the spaceport is ideally placed as launchers benefit from increased velocity owing to the ‘slingshot’ effect, created by the speed of Earth’s rotation.

From here, the third Copernicus Sentinel-2 satellite, Sentinel-2C, launched on 5 September aboard the final Vega rocket.

The Sentinel-2 mission is based on a constellation of two identical satellites flying in the same orbit but 180° apart: currently Sentinel-2A and Sentinel-2B. With Sentinel-2C now in orbit, it will soon replace its predecessor, Sentinel-2A, prolonging the life of the mission and ensuring a continuous supply of data for Copernicus, the Earth observation component of the EU Space Programme.

Sentinel-2 data are currently being used for a broad range of applications, including agriculture, water quality monitoring, methane emissions detection and natural disaster management, including wildfires, volcanic eruptions and floods.

[jacqmans]

Earth from Space: Adriatic bloom
13/09/2024

This Copernicus Sentinel-2 image captures algal bloom swirls in the north Adriatic Sea, along the coast of Italy.


An algal bloom describes the rapid growth of phytoplankton – microscopic marine plants that drift on or near the sea surface. The chlorophyll that phytoplankton use for photosynthesis collectively tints the surrounding waters, providing a means of detecting these tiny organisms from space with certain satellite sensors.

With its 13 spectral channels, Copernicus Sentinel-2’s imager can be used to detect the extent and evolution of these blooms. In this image from 12 August 2024, the emerald-green streaks, eddies and whirls of the bloom, mixed by winds and currents, are clearly visible and cover an area of around 9000 sq km.

Algal blooms are a natural and essential part of ocean life. Warm weather, with surface water temperatures reaching 29°C, and calm seas in July and August 2024 led to an increase in mucilage in the Adriatic Sea. Here, white threads of mucilage can be spotted across the bloom. Currents and winds contributed to concentrating the mucilage into visible patches along the coast, interfering with fishing activities and making the waters less attractive for swimmers.

Satellite data like those from Sentinel-2 can be used to track the growth and spread of blooms and can help local authorities to implement timely strategies to reduce the impact on tourism and fishing.

[jacqmans]

Earth from Space: Burning Man festival
20/09/2024

The Copernicus Sentinel-2 mission has snapped a souvenir of the Burning Man festival in the Black Rock desert in Nevada.

Covering about 2600 sq km, the Black Rock Desert is an arid region of lava beds and alkali flats in northwestern Nevada. The picture, acquired on 26 August 2024, captures the white, sandy area in the southwestern part of the desert, where the Burning Man festival takes place annually.

Over 70 000 people gathered from 25 August to 2 September at Black Rock for the desert-based event. This image, taken from orbit on the second day of the event, shows the area of camper vans and tents grouped together for the week-long art and self-expression festival, which involves music, stunning art installations, experimental and interactive sculptures, and art cars, among others.

The name comes from its culminating ceremony, featuring the symbolic burning of a large wooden effigy, referred to as the Man, located at the dead centre of this temporary settlement.

Like most of Nevada, the Black Rock Desert lies within the Great Basin Desert, the largest in the US, covering an arid expanse of some 492 000 sq km. The Great Basin is noted for its internal drainage system, in which precipitation never reaches an outlet to the sea.

Stretching and uplifting of Earth's crust over the past 17 million years have resulted in a recurrent pattern of valleys and rugged north-south mountain ranges, like those visible in brown around the sandy area.

The Copernicus Sentinel-2 mission is based on a constellation of two identical satellites flying in the same orbit but 180° apart, to cover all of Earth’s land and coastal waters every five days.

On 5 September 2024, the third satellite in the mission, Sentinel-2C, was launched into orbit to join its siblings and ensure the continuous provision of high-resolution data from the mission.

Less than two weeks after launch, Sentinel-2C has delivered its stunning first images, proving that the satellite is not only working as expected, but has already surpassed expectations.

[jacqmans]

Earth from Space: Northern Territory, Australia
27/09/2024

This image captured by the Copernicus Sentinel-1 mission reveals the impact of severe flooding following heavy rain that hit Australia’s Northern Territory in March 2024.

According to the Australian Bureau of Meteorology, March 2024 was the second wettest March on record for the territory, with rainfall far exceeding the average. To make matters worse, tropical cyclone Megan struck the already drenched area, further exacerbating the situation.

This false-colour radar image combines data from two acquisitions, one from 10 March prior to the rainfall, and one from 22 March after the downpour. Flooded areas are highlighted in red, while dark areas represent permanent water bodies or fields that are frequently submerged.

Tarrabool Lake, the large dark patch in the bottom right, is a seasonal lake whose water level fluctuates. Its swampy wetlands and the nearby tropical forests provide an essential habitat for small mammals, reptiles, and numerous bird species. 

Although fed by various creeks, Creswell Creek, flowing down from the northeast, is its main water source and appears to have overflowed, as did most rivers in the area.

Owing to their importance as a breeding site for waterbirds, Tarrabool Lake and the Eva Downs swamp system are listed as an Important Bird Area by BirdLife International, as is Lake Woods, a large ephemeral freshwater wetland, visible as a black patch in the top left corner.

Typically around 350 sq km, Lake Woods can expand significantly during periods of seasonal heavy rainfall, supporting up to 116 000 waterbirds when fully inundated.

Copernicus Sentinel-1’s radar ability to ‘see’ through clouds and rain, and in darkness, makes it particularly useful for monitoring floods. These images can offer immediate information on the extent of inundation, aiding relief efforts. Also, after such events, satellite images are a valuable resource for assessing damage and planning restoration.

[jacqmans]

Earth from Space: Kunshan, China
04/10/2024

This Copernicus Sentinel-2 image captures the intricate blend of natural, rural and urban landscapes around Kunshan, a city in eastern China.

Situated in the heart of the Yangtze River Delta region in Jiangsu Province, Kunshan is home to about 1.6 million people. It nestles between the major hubs of Shanghai to the east and Suzhou to the west.

Kunshan covers over 900 sq km of mostly flat terrain. Owing to its low-lying geography, the city has historically been prone to flooding, a challenge exacerbated by rapid urbanisation. In response, Kunshan has implemented a polder system consisting of dikes with waterways managed through gates and pumps.

Zooming into the urban areas, the smaller red buildings typically indicate houses, while larger white and light-blue buildings denote factories and warehouses.

Kunshan is also known for its well-preserved ancient water towns, including Zhouzhuang, the most famous in China. Dating back more than 900 years, Zhouzhuang, at the bottom centre of the image, is known for its ancient houses and scenic waterways.

The city is also dotted with numerous lakes, the largest of which visible in the image include Dianshan Lake, partially visible in the bottom centre, Cheng Lake to its left, and Yangcheng Lake at the city edge in the top left.

Yangcheng Lake is an important freshwater resource for the whole province and is famous for the Chinese mitten crab, which is considered a delicacy. The rectangular crab farming ponds are clear to see in the middle of the lake, while water plants stand out in bright green.

Rivers and forests cover more than a quarter of the city. The Wusong River, visible in light green across the centre of the image, winds through the city, while smaller rivers form a grid-like pattern.

Covering an area of around 15 sq km, Forest Park, an ecological wetland filled with a variety of plants, and Tinglin Park, known for its lush green peak and pristine waters, offer scenic escapes from the urban centre.

[jacqmans]

Earth from Space: Hardap Dam, Namibia
11/10/2024

Resembling a Martian-like surface, this Copernicus Sentinel-2 image shows part of the Hardap region in south-central Namibia on the western edge of the Kalahari Desert.

Hardap is a hot and arid region, where groundwater is difficult to obtain. Its name reflects the importance of the Hardap Dam, Namibia’s second largest dam, visible in blue in the centre of the image. The various blue hues denote the presence of sediment in the water.   

With a surface area of 25 sq km, the dam supplies electricity and water to the whole area and the reservoir is home to numerous examples of Namibia’s wildlife.

The dam controls the flow of the Fish River, which can be seen snaking its way across the image. In this false-colour image, captured on 28 August 2024, the Copernicus Sentinel-2’s near-infrared channel was used to highlight vegetation in red, which appears mainly concentrated south of the dam along the river.

Agricultural fields can be spotted on the floodplain below the dam, where mainly vegetables and citrus fruits are grown. The different shades of red show the state of the crops: the brighter the red, the healthier is the vegetation.

About 20 km southeast of the dam, on the eastern bank of the river, lies the town of Mariental, the region’s capital. Its urban environment can be seen as a blend of red and grey dots. Near Mariental, the rocky plain of the Central Highland merges with the dry, sandy soil of the western limits of the Kalahari Desert.

The entire western Kalahari is characterised by long chains of sand dunes. Some of these dunes can be seen in shades of yellow in the top-right corner and appear surprisingly parallel and uniform.

On the right side of the image, the landscape is dotted with dry lake beds known as salt pans, seen as gleaming white circles.

Roads can be identified as white lines cutting sharply across the landscape.

[jacqmans]

Earth from Space: Riyadh, Saudi Arabia
18/10/2024

The Copernicus Sentinel-2 mission takes us over Riyadh, the capital city of Saudi Arabia.

Situated in the central region of Saudi Arabia, Riyadh serves as the nation’s legislative, financial, administrative, diplomatic and commercial hub, home to over seven million inhabitants.

Covering an area of around 1550 sq km, the city sits at approximately 600 m above sea level on the eastern part of the Najd plateau in the Arabian Peninsula. Like much of Saudi Arabia, Riyadh has a desert climate with extreme summer temperatures that can reach up to 50°C.

The image prominently features the city’s grid-like street system, which consists of square blocks measuring around two km one each side, forming an extensive network across the urban landscape.

Riyadh is served by the King Khalid International Airport, located approximately 35 km north of the city, visible in the top left of the image.

Moving southeast, the flower-like pattern of the Sand Sports Park construction site stands out against the orange, sandy terrain. Spanning more than 17 million sq m, the park is part of the large-scale Sports Boulevard Project, a linear park extending 135 km across the city. The project will connect over 50 sports sites and feature cycling and pedestrian pathways, equestrian and hiking trails, as well as several entertainment venues.

The city also has several large stadiums, including the King Fahd International Stadium, identifiable by its white circular structure, which can be spotted by zooming in south of the Sand Sports Park.

Towards the south, the industrial part of the city can be identified with bright white rooftops.

This image, captured on 14 September 2024, is part of the stunning initial set of images delivered by Copernicus Sentinel-2C, the third satellite in the Sentinel-2 mission. Sentinel-2C joined its twin satellites in orbit on 5 September 2024, to ensure the continuous delivery of high-resolution imagery for the Copernicus programme.

[jacqmans]

Autumn hues captured from space
08/11/2024

The colours of autumn across the western border of North Macedonia and Greece are captured in this Copernicus Sentinel-2 image from 27 October 2024.

From the Baba Mountains and the Pelister National Park in North Macedonia to the Verno/Vitsi mountains in northern Greece, the predominant tree species are the European beech at higher altitudes and oak at mid and lower altitudes. The result of this combination is the stunning mix of brown, red and green hues typical of the autumn season. The intensity of colours varies with altitude.

The densely packed rectangles of urban areas and cultivated land stand out in sharp contrast on the eastern side of the mountains.

[jacqmans]

Earth from Space: ‘Angry husband’ eruption
22/11/2024

This Copernicus Sentinel-2 image from 13 November 2024 shows the Lewotobi Laki Laki volcano eruption on the island of Flores in southern Indonesia.

Mount Lewotobi Laki Laki started spewing ash and smoke on 4 November 2024. It has, so far, killed at least ten people and forced authorities to issue large-scale evacuations. The volcanic ash cloud also caused hundreds of flights to be cancelled. The image clearly depicts the huge plume of ash and smoke spewing from the volcano and drifting westwards.

Laki Laki is one of two adjacent stratovolcanoes on Mount Lewotobi. The volcano summits, which are less than 2 km apart, are known locally as the husband-and-wife mountains. Laki Laki means man, while its taller and broader spouse to its southeast is called Perempuan, or woman. While Perempuan has been dormant for decades, Laki Laki is one of the most active volcanoes in Indonesia.

The country is prone to earthquakes, landslides and volcanic activity because it sits along the 'Ring of Fire', a continuous string of volcanoes and fault lines circling the Pacific Ocean.

The Copernicus Sentinel-2’s shortwave infrared channels, that detect heat sources, have been used in the processing of this image to display the activity on the volcano. The lava flowing from the crater is highlighted in orange and red.

Satellite data are an excellent means to monitor eruptions. Once an eruption begins, optical and radar instruments can capture the lava flows, mudslides, ground fissures and earthquakes.

Furthermore, atmospheric sensors can identify and measure the gases and aerosols released by the eruption, follow the spread and movement of volcanic plumes, and help to assess the environmental impact and possible hazards to aviation.

[catdlr]

Although this is a video about radar, it is related to Sentinel and illustrates how many of these images are collected.

How do radar satellites work?

Nov 28, 2024  #ESA #Sentinel #Satellite
Radar allows us to see through what would otherwise be invisible. By sending out radio waves that bounce off objects and return as echoes, radar creates a detailed picture of our surrounding world.

This technology is everywhere: from guiding air traffic and enabling self-driving cars to tracking the movements of athletes. But its reach doesn’t stop there—radar is also transforming how we observe our Earth from space.

Satellites like the Copernicus Sentinel-1 mission use radar to see through clouds, darkness and any weather conditions. This capability is invaluable for detecting subtle changes on Earth’s surface—changes that are often hidden from the human eye. Discover how radar technology is helping us unlock these hidden insights about our planet.

Credit: ESA - European Space Agency