SASS (Subsonics Assessment) Ozone and NOx Experiment (SONEX) Merge Data Files

SONEX_Merge_DC8_Data is all of the project generated merge files for the SONEX suborbital campaign. Types of merges include 1- and 5-minute, aerosol composition-based, H2O2-based, HNO3-based, hydrocarbon-based, NO-based, and PAN-based merges. Data collection for this product is complete. The SASS (Subsonics Assessment) Ozone and NOx Experiment (SONEX) was an international, multi-organizational mission that took place in October-November 1997. NASA was the US sponsor of SONEX that partnered with POLINAT-2 (Pollution from Aircraft Emissions in the North Atlantic Flight Corridor) funded by the German DLR (Deutsches Zentrum für Luft- und Raumfahrt) or German Aerospace Agency. NASA flew the DC-8 aircraft out of NASA/Ames Research Center. DLR operated an instrumented Falcon 20 aircraft. The staging locations for NAFC sampling were primarily Bangor, Maine (US), and Shannon, Ireland. Subsonic aircraft emissions impact several aspects of atmospheric composition: nitrogen oxides (NOx), CO, and hydrocarbons from emissions can perturb upper tropospheric/lower stratospheric (UT/LS) ozone; water vapor, soot, and sulfur oxides (SOx) emitted by aircraft may perturb clouds and aerosols, changing UT/LS radiative forcing and global temperature. In SONEX and POLINAT, flights were conducted in the vicinity of the North Atlantic Flight Coordinator (NAFC) to observe the impact of aircraft emissions on NOx and ozone (O3). The DC-8 aircraft payload (Singh et al., 1999) primarily measured in-situ CO, CO2, hydrocarbons/halocarbons, O3, aerosols (Dibb et al., 2000), OH/HO2, water vapor, nitric acid (Talbot et al., 1999), photolysis rates, temperature, pressure, winds, NOx, and NOy. Three sampling approaches were implemented during SONEX. First, special meteorological (Fuelberg et al., 2000) were developed to allow targeted sampling for air parcels affected by aircraft emissions and various meteorological events, e.g., convection, lightning (Jeker et al., 2000), stratospheric intrusions (Cho et al., 2000). Second, because the NAFC had not been extensively sampled in the past, it was important for SONEX to characterize the climatology of trace species like CN (Wang et al., 2000), NOx and NOy (Koike et al., 2000). Third, tracers (Simpson et al., 2000; Thompson et al., 1999) and model sensitivity studies (Meijer et al., 2000) were employed for Air Mass Identification. This sampling strategy answered the following questions: Where and when are air masses found with the greatest aircraft influence? When and where was stratospheric air sampled? SONEX showed a substantial impact of aircraft emissions on UT/LS NOx and CN in the vicinity of fresh aircraft emissions. However, during October-November 1997 over the NAFC, UT/LS NOx was dominated by surface emissions redistributed by convection and augmented by lightning.

Data and Resources

Additional Info

Field	Value
Maintainer	Earthdata Forum
Last Updated	September 22, 2026, 20:51 (UTC)
Created	April 1, 2025, 18:44 (UTC)
accessLevel	public
bureauCode	{026:00}
catalog_conformsTo	https://project-open-data.cio.gov/v1.1/schema
harvest_object_id	b1912b26-999c-46c2-9edb-6377b40a425f
harvest_source_id	b99e41c6-fe79-4c19-bbc3-9b6c8111bfac
harvest_source_title	Science Discovery Engine
identifier	10.5067/ASDC/SUBORBITAL/SONEX_Merge_DC8_Data_1
license	https://www.usa.gov/government-works
modified	2026-09-14T22:16:02Z
programCode	{026:000}
publisher	NASA/LARC/SD/ASDC
resource-type	Dataset
source_datajson_identifier	true
source_hash	195d9403cb72492c4aaf311004bde75804dadc18242f8b4c2a891947d268b9a1
source_schema_version	1.1
spatial	["CARTESIAN", [{"WestBoundingCoordinate": -178.2, "EastBoundingCoordinate": 148.2, "SouthBoundingCoordinate": 19.89, "NorthBoundingCoordinate": 69.13}]], Minimum Altitude, Maximum Altitude, 0 km, 38.5 km
temporal	1997-10-07/1997-11-12
theme	{"Earth Science"}