Western North America Back Trajectory Data for Ozone Source Analysis

Hourly, 15-day backward airmass trajectories simulate source-receptor relationships for ozone observations over Western North America from 1994 to 2021. The dataset, generated by NASA's LARC ASDC using the FLEXPART model driven by ERA5 reanalysis, provides global simulations at 1° x 1° spatial resolution from the surface to 20 km altitude. It supports analysis of source contributions to tropospheric ozone across diurnal, seasonal, and decadal timescales.

Use Cases

• Identifying geographic source regions and atmospheric layers contributing to high ozone events at specific receptor locations.
• Analyzing decadal trends in ozone transport patterns using the 28-year time series of gridded ozone observations.
• Investigating seasonal or diurnal variations in source contributions to tropospheric ozone across different vertical layers.
• Supporting source contribution analyses for other atmospheric components if co-located observations exist at the defined receptor sites.

Strengths

• Covers a 28-year period (1994-2021) of ozone observations, enabling long-term trend analysis.
• Provides high-resolution simulations with hourly temporal and 1° x 1° spatial granularity.
• Includes vertical coverage from the surface up to 20 km above ground level.

Limitations

• Specific column names, row counts, and dataset size are unknown across all sources.
• Conflicting 'last updated' dates exist between platforms (2002-12-31 vs. 2026-03-12), creating uncertainty about metadata freshness.

Provenance

Source

NASA Langley Research Center Atmospheric Science Data Center (LARC_ASDC)

Collection Method

Simulations using the FLEXPART Lagrangian particle dispersion model driven by ERA5 reanalysis data.

Time Range

1994-2021

Freshness

2026-03-12 19:53:28.232824

Geography

Global simulations with receptor locations focused on Western North America (WNA).