HIRDLS/Aura N2O5 Zonal Fourier Coefficients, 2004-2007

HIRDLS/Aura Level 3 data provides dinitrogen pentoxide (N2O5) concentrations expressed as zonal Fourier coefficients. The dataset covers approximately 3 years of mission data across 1-degree latitude bands from -64 to 80 degrees at 121 pressure levels. NASA produced this version 7 product using a Kalman filter approach on Level 2 profiles.

Use Cases

• Model global atmospheric N2O5 distribution based on zonal Fourier coefficients.
• Analyze diurnal variations in atmospheric chemistry using separate ascending (daytime) and descending (nighttime) orbit node data.
• Study vertical profiles of trace gases across the 82.5 to 1.0 hPa pressure range.
• Reconstruct longitude-specific values from the stored mean and sine/cosine coefficients.

Strengths

• Provides the entire mission (~3 years) of HIRDLS data.
• Offers high vertical resolution with 121 pressure levels and about 1 km spacing.
• Coefficients allow computation of values at any longitude, increasing utility.

Limitations

• Column-level documentation is absent; field semantics must be inferred after download.
• Row count is unknown, which may limit suitability assessment.

Provenance

Source

National Aeronautics and Space Administration

Collection Method

Coefficients computed from HIRDLS Level 2 profiles with a Kalman filter approach using both forward and backward passes in time.

Time Range

Approximately 3 years (the entire HIRDLS mission).

Freshness

Last updated 2026-03-13 01:29:13.002673; freshness should be verified.

Geography

Global coverage from -64 to 80 degrees latitude.