HIRDLS Satellite Water Vapor Zonal Fourier Coefficients

HIRDLS/Aura satellite data provides water vapor measurements expressed as zonal Fourier coefficients across 121 pressure levels. The dataset contains the entire mission's data, approximately 3 years, processed with a Kalman filter approach. It was produced by the GES DISC and last updated in March 2008.

Use Cases

• Reconstructing global water vapor fields at any longitude using the provided mean and up to 7 sine and cosine coefficients.
• Analyzing vertical profiles of water vapor from 200 to 10 hPa pressure levels with 1 km resolution.
• Comparing daytime (ascending) and nighttime (descending) orbit node water vapor patterns using the separate data fields.
• Assessing data precision by analyzing the root-mean-square differences between estimated fields and input data.
• Studying zonal mean atmospheric structure across 1-degree latitude bands from -64 to 80 degrees.

Strengths

• Covers the entire HIRDLS mission, approximately 3 years of data.
• Provides data on a detailed vertical grid of 121 pressure levels with about 1 km resolution.
• Coefficients allow for longitudinal reconstruction, offering more detail than zonal means alone.

Limitations

• Temporal coverage ends in 2008, making the data stale for contemporary climate analysis.
• Spatial coverage is limited to latitudes between -64 and 80 degrees, excluding the polar regions.
• Data is stored in the specialized HDF-EOS5 format, which may require specific libraries to read.

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, approximately 3 years (specific start date unknown).

Freshness

Last updated in March 2008; no ongoing updates indicated.

Geography

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