HIRDLS Satellite Geopotential Height Zonal Fourier Coefficients

HIRDLS/Aura satellite data provides geopotential height expressed as zonal Fourier coefficients across 1-degree latitude bands from -64 to 80 degrees. The dataset contains the entire ~3-year mission record, processed to Level 3 by the GES DISC using a Kalman filter on Level 2 profiles. Data is stored in HDF-EOS5 format with separate fields for ascending, descending, and combined orbit nodes.

Use Cases

• Reconstructing 3D geopotential height fields at any longitude using the provided mean and up to 7 sine/cosine coefficients.
• Analyzing stratospheric wave activity by examining the amplitude and phase of the zonal Fourier coefficients across 121 pressure levels.
• Comparing daytime (ascending) and nighttime (descending) atmospheric states using the separate orbit node data fields.
• Studying vertical atmospheric structure from 1000 to 0.01 hPa with a resolution of 24 levels per decade (~1 km).

Strengths

• Covers the entire ~3-year HIRDLS mission, providing a complete temporal record.
• Offers high vertical resolution with data on 121 pressure levels from 1000 to 0.01 hPa.
• Includes precision estimates via the root-mean-square of differences between estimated fields and input data.

Limitations

• Temporal coverage ends in 2008, making the data stale for contemporary climate studies.
• Latitudinal coverage is limited from -64 to 80 degrees, excluding the polar caps.
• Data is stored in the specialized HDF-EOS5 format, requiring specific libraries for access and analysis.

Provenance

Source

GES DISC (Goddard Earth Sciences Data and Information Services Center), NASA.

Collection Method

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

Time Range

Covers the entire HIRDLS mission duration (~3 years), circa 2005-2008.

Freshness

Last updated in 2008; mission data is historical.

Geography

Global zonal coverage in 1-degree latitude bands from -64 to 80 degrees.