M. Joan Alexander Research Scientist

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HIRDLS: High Resolution Dynamics Limb Sounder

HIRDLS is an infrared limb sounder, launched on the NASA Aura satellite in 2004. HIRDLS measures a suite of atmospheric constituents and retrieves atmospheric temperature from measurements of CO2. Gravity waves can be clearly observed in HIRDLS temperature measurements.


HIRDLS observations of a mountain wave event over the Patagonian Andes. These are vertical cross-sections as a function of horizontal distance (west to east) and altitude. The colors represent temperature anomalies which oscillate positive to negative in the wave pattern. The white line shows the underlying topography in km exaggerated by a factor of 5. [Alexander et al., 2008].

The HIRDLS homepage is http://www.eos.ucar.edu/hirdls/

My research for HIRDLS is related to the detection of atmospheric waves in the HIRDLS temperature measurements. The HIRDLS measurements should provide valuable data on large horizontal scale gravity waves similar to CRISTA, but with improved horizontal and vertical resolution. We are currently analyzing CRISTA measurements in preparation for the HIRDLS data.