Stratospheric clouds and gravitational waves over Antarctica
This image from the atmospheric lidar, captured on 2 August 2024, offers a profile of polar stratospheric clouds over Antarctica. The grey strip below, as featured in all of the images, is the corresponding area captured in the infrared by EarthCARE’s multispectral imager instrument, which gives natural visual context to all of the instruments’ data. Polar stratospheric clouds are crucial contributors to the depletion of stratospheric ozone during winter and spring. These clouds serve as surfaces for chemical reactions that generate chlorine free-radicals, which actively destroy ozone molecules in the stratosphere. This process is a key factor in the formation of the infamous ozone hole over Antarctica.
The jagged shape of the clouds in the centre-right is likely to be caused by gravity waves. Gravity waves form when air is forced upwards into a layer of stable air and gravity drags the air back down, creating a ripple effect – like the ripples of waves in the ocean. These waves transfer energy and momentum from the lower atmosphere to the upper atmosphere, influencing weather patterns, general atmospheric circulation and impact the formation of polar stratospheric clouds.
Source: ESA / https://www.esa.int/ESA_Multimedia/Images/2024/08/Stratospheric_clouds_and_gravity_waves_over_Antarctica

Aerosols and storms over North America
This profile, captured on 4 August by the atmospheric lidar, is a strip over North America. Here, the presence of tropical storm Debby is clear to see over the Gulf of Mexico, as are large convective clouds further north. As these clouds are optically very thick, as can be seen in the multispectral imager information, the lidar captures details of the cloud tops, but cannot see below them. Additionally, a striking red layer of aerosols is visible in the central part of the profile. These aerosols have been carried by the wind from forest fires that have been burning for a number of weeks in several regions of Canada. Smoke from forest fires plays a complex role in climate change, with both immediate and long-term effects that can disrupt weather patterns, accelerate global warming, as well as impact air quality when close to the ground.
Beneath this dense layer of smoke lies a more diffuse concentration of aerosols, originating from a variety of sources.
Source: ESA / https://www.esa.int/ESA_Multimedia/Images/2024/08/Aerosols_and_storms_over_North_America

Different aerosols and clouds over the Atlantic
This profile, captured on 3 August 2024 by the atmospheric lidar over the mid-Atlantic, is particularly rich in information. High-altitude cirrus clouds, deep convection clouds and low, thin clouds all feature in this profile. There are also two different types of aerosol: marine aerosols that include salt spray from the ocean, and a thick layer of dust blowing off the African Sahara desert. Understanding the complex relationship of these clouds and aerosols in the Tropics is fundamental to understanding Earth’s climate and how it will change.
Source: ESA / https://www.esa.int/ESA_Multimedia/Images/2024/08/Different_aerosols_and_clouds_over_the_Atlantic

Aerosols over Africa
This image, from the atmospheric lidar on 2 August 2024, is a strip over Africa. As well as high convection clouds, the most prominent feature here is a very dense layer of aerosols from biomass burning, which is common at this time of the year over large parts of the continent. These fires are mostly ignited to remove forest or last year’s crop growth and make way for cleared agricultural land.
Source: ESA / https://www.esa.int/ESA_Multimedia/Images/2024/08/Aerosols_over_Africa

The ground stations of the European research infrastructure ACTRIS play an important role in calibrating the data from the EarthCARE satellite: they have been established and expanded in recent years to analyse aerosol particles and clouds using remote sensing instruments such as lidar and radar. Around 50 stations in Europe and overseas are involved in the atmo4ACTRIS measurement campaign. Photo: Tilo Arnhold, TROPOS