Photonics Innovations Driving Climate Observation: A European Perspective

Introduction

Climate change is one of the most pressing challenges facing our planet, and accurate monitoring and measurement of essential climate variables (ECVs) is crucial in understanding and addressing this global issue. Fortunately, European photonics companies and organizations are at the forefront of developing innovative technologies that provide invaluable insights into environmental science. This article explores the pivotal role of photonics in climate observation, highlighting the contributions of various European entities.

Assessing the Market and Essential Climate Variables

The increasing concern over the global impact of climate change is driving the demand for high-quality and precise data on ECVs. The Global Climate Observing System (GCOS) currently specifies 55 ECVs across three main categories: atmosphere, land, and oceans (see "Measuring Climate Changes" box).

A recent market report projects that the environmental monitoring market will grow from USD $12.4 billion in 2023 to USD $18.9 billion by 2032, with a compound annual growth rate of 5.40%. This growth highlights the increasing importance of climate observation technologies and the vital role played by photonics innovations.

Satellite-based Systems and Hyperspectral Imaging

One effective way of obtaining ECV data is through LiDAR and hyperspectral imaging technology on board aerial systems and satellites. Satellite-based systems provide broader coverage, enabling a more detailed picture of Earth's changing temperature, sea levels, atmospheric gases, and declining ice and forest cover.

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. More recently, the Copernicus program, established in 2012, includes seven Sentinel missions that provide all-weather, day-and-night radar imaging for land and ocean services, high-resolution optical imaging, and data on sea and land ECVs.

Companies like Satellogic, based in Barcelona, provide affordable and high-quality data from space, enabling organizations to track daily changes on Earth's surface with sub-meter resolutions. Satellogic's proprietary multispectral cameras allow for weekly monitoring of selected points of interest, and the use of different spectral bands provides expanded insight into environmental damage, particularly in the biosphere (see Fig. 1).

FIGURE 1. La Palma wildfire, July 2023. Left: February 2021 (Source: PNOA). Right: July 2023 (Source: Satellogic). Red hues represent healthy vegetation, and dark hues represent burned areas.

Hyperspectral cameras also play a crucial role in climate monitoring. NIREOS, an Italian company, designs and manufactures interferometers, hyperspectral cameras, and photodetectors. Their HERA range of hyperspectral cameras (see Fig. 2) captures hyperspectral images over a wide spectral range (400–2200 nm) with high spectral and spatial resolutions, aiding scientists in tracking and understanding climate patterns, characterizing microplastics, and assessing vegetation health.

FIGURE 2. The NIREOS HERA eSWIR (1100-2200 nm) hyperspectral camera.

Infrared Cameras and Cloud Observation

Infrared cameras and cloud observation technologies are essential for monitoring atmospheric conditions and their impact on climate change. Reuniwatt, a French company based on Reunion Island, has patented an infrared all-sky imager called Sky InSight, which continuously tracks and forecasts cloud cover (see Fig. 3). This device has been used in projects like DYVALOCCA, aimed at monitoring the evolution of clouds and evaluating their effects on water and light availability in dense evergreen forests particularly vulnerable to climate change.

FIGURE 3. Reuniwatt’s Sky InSight used during the DYVALOCCA campaign in Bambidie, Gabon.

Optical Filters and Components

Optical filters and components play a vital role in climate change monitoring by manipulating light wavelengths and enhancing the accuracy of satellite-based observations. Companies like HOYA, Iridian Spectral Technologies, Tecnottica Consonni (see Fig. 4), and Vortex Optical Coatings manufacture custom optical filters, filter arrays, and components for Earth observation instruments, enabling precise imaging and monitoring of climate changes, natural disasters, and sustainable resource use.

FIGURE 4. The NEMO-HD microsatellite for Earth monitoring and observation.

Sensors and Substrate Materials

Photonics-based sensors are crucial for capturing detailed insights into temperature changes, sea-level rise, greenhouse gas concentrations, and ecosystem dynamics. The French university Versailles Saint-Quentin-en-Yvelines launched the UVSQ-SAT mini-satellite in 2023 to demonstrate technologies for broadband measurements of Earth Radiation Budget (ERB) and Solar Spectral Irradiance (SSI) in the Herzberg continuum, with Nanovation contributing its groundbreaking gallium (III) oxide (Ga2O3) UVC sensors.

New Infrared Technologies (NIT) and Mapsi Photonics are contributing to air quality monitoring by developing infrared detectors and filters for detecting gases like methane, carbon dioxide, and ammonia.

FIGURE 5. Longwave-infrared (LWIR) narrowband filters from Mapsi.

Substrate materials, such as SCHOTT's ZERODUR near-zero thermal expansion glass-ceramic (see Fig. 6), provide the foundation for precise and reliable satellite imaging systems. These specialized materials enable the creation of high-resolution cameras and mirrors essential for monitoring environmental changes, as seen in the Meteosat Third Generation (MTG) satellite system.

FIGURE 6. A ZERODUR 1.2-m mirror.

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 and create a vibrant and innovative European ecosystem in quantum technology.

One objective is to improve the measurement of gravity, as tiny variations in the Earth's gravity field affect freshwater resources, ice mass loss, and sea-level changes, all of which are linked to climate change. The idea is to combine current gravimetry measurements with cold atom interferometry, using lasers to freeze atoms within the instrument to near absolute zero and then measuring the phase difference as the atoms 'fall' according to the pull of gravity.

Although the theory is relatively simple, the challenge lies in developing robust satellite technology that provides the required mission lifetime and high-resolution coverage. To this end, ESA is working with NASA on the MAGIC gravity constellation, aiming to measure variations in the Earth's gravitational field with a close temporal frequency (every three days) and a spatial resolution of 100 km.

Conclusion

European photonics companies and organizations are at the forefront of developing innovative technologies that provide invaluable insights into environmental science and climate change monitoring. From satellite-based systems and hyperspectral imaging to infrared cameras, optical filters and components, sensors, and specialized substrate materials, photonics innovations are driving climate observation efforts. Additionally, future quantum missions aim to further enhance the measurement of ECVs, contributing to a deeper understanding of our planet's changing climate and shaping future environmental preservation strategies.

Reference

[2] J. Picot-Clémente, "Photonics innovations in climate observation: A view from Europe," EPIC - European Photonics Industry Consortium, Apr. 1, 2024.