The Small Mobile Ozone Lidar with eXtended capability (SMOL-X) is a compact, autonomous ozone differential absorption lidar developed at NASA Jet Propulsion Laboratory in support of the NASA Upper Atmospheric Composition Observations Program. SMOL-X has operated nominally since its installation in February, and by August 10, was able to detect the first sign of ozone depletion.
News and Events
In October 2025, the Fourier-transform infrared spectrometer (FTS) installed at the Onsala Space Observatory, located close to Gothenburg, Sweden (57.4° N, 11.93° E), was formally accepted into the NDACC network.
ESA publishes an Announcement of Opportunity (AO) for the calibration and validation of ALTIUS, due November 1, 2026.
This introduction to the special issue "Achievements and perspectives of the Network for the Detection of Atmospheric Composition Change after 35 years of operation” provides an overview of important research findings achieved under the NDACC objectives. The future of NDACC is discussed in the light of the evolution of the scientific questions, evolving collaborations with partners and Cooperating Networks, and the current landscape of gaps in satellite and ground-based observations.
Jonas et al. studied the evolution of ozone in the Arctic over the 2000–2024 period in the stratosphere (about 10 to 50 km) to assess the expected recovery of the ozone layer following the diminution of ozone-depleting substances. They merge ground-based data sets within spatially coherent regions to reduce uncertainties and obtain positive trends for the total column everywhere in the Arctic and for the middle and upper stratosphere over Canada, but no significant trends in the lower stratosphere.
Formaldehyde (HCHO) is a key atmospheric indicator of air pollution. The new TEMPO (Tropospheric Emissions: Monitoring of Pollution) satellite instrument provides hourly measurements of HCHO across North America. To check how accurate these measurements are, Ortega et al. compared them with ground-based data from two instruments, Fourier Transform InfraRed (FTIR) and Pandora, at sites in Boulder, Mexico City, and Toronto, where these instruments are co-located. They found good agreement between FTIR and Pandora, especially when Pandora instruments are properly calibrated. Using both data sets, they evaluated TEMPO and found that it consistently underestimates HCHO by about 30%, but it successfully captures daily pollution patterns. This highlights the value of combining satellite and ground-based data to improve air quality monitoring.
A recent article by Sergey Khaykin et al. was highlighted in the January 24, 2026 Featured News of the ESA earth online media platform. The Atmospheric Chemistry and Physics (ACP) article shows synergetic observations from the spaceborne lidar ATLID onboard EarthCARE and several suborbital techniques, including NDACC lidars, to characterize the evolution of the 2024 Ruang Volcanic eruption.
The 2026 Annual NDACC Steering Committee Meeting will take place in Bern, Switzerland from 31 August - 3 September 2026, with a site visit planned to Jungfraujoch on 4 September.
The Symposium celebrated 35 years of successful NDACC/NDSC science and operations. It took place from October 27-30, 2025 in Virginia Beach, VA, USA. This was only the third meeting of the larger NDACC community.
A shortened, one-and-a-half-day, Steering Committee (SC) meeting followed the Symposium on October 30 - 31 at Virginia Beach, VA, USA.