Use of the occultations for observing the Earth’s atmosphere and climate meanwhile comprises solar, lunar, stellar, navigation and satellite-crosslink methods, employing the electromagnetic spectrum from UV to Radio signals, to obtain atmospheric parameters from bending angle, refractivity, pressure, geopotential height, temperature, water vapour and ozone via a multitude of important trace species to particulate species such as aerosols and cloud liquid water. Ionospheric electron density is sensed as well.

Occultation methods share the unique properties of self-calibration, high accuracy and vertical resolution, global coverage, and, if using radio signals, all-weather capability. They thus bear great utility for meteorology and climate science, and other fields.

The OPAC-IROWG-1 2013 Workshop brought together members from the different sub-communities and users of occultation data. The present AMT special issue is dedicated to the results of this conference.