Scheduled for launch in 2025, the European Space Agency’s (ESA) Carbon Dioxide Monitoring Mission (CO2M) will measure the amount of carbon dioxide released into the atmosphere through human activity. The payload includes a treasure trove of photonics technologies:
- * a telescope with polarization scrambler and entrance slit homogenizer
- * a reflective collimator, common for all bands
- * glass (VIS/NIR) and silicon (SWIR-1/SWIR-2) imagers
- * Mercury-Cadmium-Telluride CMOS detectors in SWIR
- * Si CMOS detectors in VIS-NIR
The effort is among the latest in a long list featuring European photonics companies and organizations that are gathering and providing invaluable insights about environmental changes, adding precision and depth to our understanding of the Earth’s changing climate and playing a pivotal role in shaping the future of climate observation and environmental preservation strategies. Here, we highlight many of them.
Assessing the market
These companies and organizations seek to solve complex challenges that address increasing concern about the global impact of climate change, which is driving the demand for quality and precision data on Essential Climate Variables (ECVs; see “Measuring climate changes”). A recent market report1 projects the environmental monitoring market will grow from USD $12.4 billion in 2023 to USD $18.9 billion by 2032, a compound annual growth rate of 5.40%.
Measuring climate changes
The Global Climate Observing System (GCOS) currently specifies 55 Essential Climate Variables (ECVs) in three main categories and subcategories:2
1. Atmosphere
a. Surface, Upper air: includes precipitation, pressure, temperature, and wind speed and direction at different altitudes
b. Upper Atmosphere: covers aerosols, carbon dioxide, methane and other greenhouse gases, and ozone
2. Land
a. Hydrosphere: e.g., groundwater and lakes
b. Cryosphere: e.g., glaciers and ice sheets
c. Biosphere: e.g., above-ground biomass, albedo (the fraction of light that the Earth’s surface reflects), and surface temperature
d. Anthroposphere: the part of the Earth system that is made or modified by humans for use in human activities and human habitats); i.e., greenhouse gas fluxes and water use
3. Oceans
a. Physical: e.g., ocean surface heat flux, sea ice and level, surface currents, salinity, and temperature
b. Biogeochemical: e.g., inorganic carbon, nitrous oxide, oxygen
c. Biological/ecosystems: i.e., marine habitats and plankton
Satellite-based systems
An effective way of obtaining ECV data is via LiDAR and hyperspectral imaging technology on board aerial systems and satellites, where broader coverage provides a more detailed picture of Earth’s changing temperature, sea levels, atmospheric gases, and declining ice and forest cover.
With the reduction in costs and increase in launch availability, today’s satellites are often deployed in low Earth orbits (LEO) as constellations only 500 to 1000 kilometers above the Earth, which, compared with satellites in high or medium Earth orbits, enables them to capture smaller areas with enhanced detail.
The European Space Agency (ESA) has been at the forefront of satellite-based climate monitoring programs since 1999 with the Aeolus mission, the first satellite capable of performing global wind-component-profile observation. Aeolus’s payload was the ALADIN instrument (Atmospheric Laser Doppler Instrument), a direct detection ultraviolet laser LiDAR consisting of a transmitter, a Mie receiver to determine winds from aerosol and cloud backscatter, a Rayleigh receiver (Fabry-Perot etalon) to determine winds from molecular backscatter, and a 1.5-m-diameter Cassegrain telescope.
In 2012, ESA established the Copernicus program, which included seven Sentinel missions that provided all-weather, day-and-night radar imaging for land and ocean services; high-resolution optical imaging of vegetation, soil and water cover, inland waterways, and coastal areas; and data on sea and land ECVs. Future Sentinel missions will provide data on atmospheric composition monitoring of nitrogen dioxide, ozone, sulfur dioxide, formaldehyde, glyoxal, and aerosols. Monitoring will be achieved via UV-visible and NIR infrared spectrometry with an 8 km spatial resolution and 60-minute repeat cycles.
In parallel, companies like Satellogic, founded in 2012 and based in Barcelona, provide affordable and high-quality data from space to enable organizations to track daily changes on the Earth’s surface with sub-meter resolutions. The company currently has 34 operational satellites in orbit providing multispectral imaging of the Earth with a spatial resolution of 0.70 to 0.99 m.
Critically, Satellogic’s proprietary multispectral cameras allow the monitoring of selected points of interest weekly, and the use of different spectral bands provides expanded insight into the level of environmental damage, especially of the biosphere.
The future of climate observation
The European Space Agency is planning various Quantum Missions (2023-2031) that will use a new generation of quantum sensors to enhance the measurement of ECVs as well as helping to scale up scientific and industrial R&D and creating a vibrant and innovative European ecosystem in quantum technology.
One of the objectives is to improve the measurement of gravity because tiny variations in the strength of the Earth’s gravity field have been shown to affect dwindling freshwater resources, the loss of ice mass from ice sheets and glaciers, and changes in sea-level, and therefore on climate change.
The idea for future quantum sensors is to combine the principles of current gravimetry measurements with cold atom interferometry, which involves using lasers to freeze atoms within the instrument to near absolute zero (-273.15°C). Then, switching off the lasers allows the atoms to move freely in response to the strength of the gravity field. Measuring the phase difference through interferometry as the atoms ‘fall’ according to the pull of gravity will provide measurements of the gravity field as the satellite orbits around Earth.
Although the theory of using quantum gravity sensors in space to measure gravity is relatively simple, until now, the challenge is to develop a robust satellite technology that provides the mission lifetime and high-resolution coverage required. To this end, ESA is working with NASA on the MAGIC gravity constellation, whose objective is to measure variations in the Earth’s gravitational field with a close temporal frequency (every three days) and a spatial resolution of 100 km.
Read more: https://www.laserfocusworld.com/executive-forum/article/55000844/epic-european-photonics-industry-consortium-photonics-innovations-in-climate-observation-a-view-from-europe
