− Since the GPS/MET mission was launched in 1995, an extensive dataset of spaceborne GPS radio occultation (RO) soundings have been derived and compared to in-situ measurements and numerical model analyses. The launch of the Constellation Observing System for Meteorology Ionosphere and Climate (COSMIC) introduces several thousand more profiles daily, which has attracted much wider attention in ...

Measuring greenhouse gas (GHG) profiles with global coverage and high accuracy and vertical resolution in the upper troposphere and lower stratosphere (UTLS) is key for improved monitoring of GHG concentrations in the free atmosphere. In this respect a new satellite mission concept adding an infrared-laser part to the already well studied microwave occultation technique exploits the joint propa...

The development of small, high-performance instruments to receive Global Positioning System (GPS) signals has created an opportunity for active remote sounding of the Earth’s atmosphere by radio occultation techniques. A prototype demonstration of this capability has been provided by the GPS Meteorology (GPS/MET) experiment. Although it was shown that high vertical resolution profiles of atmosp...

I review recent activity in the field of intermediate polars, concentrating on: the mode of accretion (disc-fed, disc-overflow or discless); accretion curtains (the transition region and the accretion footprint); X-ray pulse profiles (occultation and absorption effects); accretion columns (mass determinations, line-broadening, the soft X-ray component), and outbursts in intermediate polars.

Intermediate polars range from systems which accrete entirely via discs (e.g. EX Hya) through systems which combine disc and disc-overrow accretion (e.g. FO Aqr) to discless accretors (e.g. RX 1712{ 24). The accretion curtain model provides a good description of the optical spin-pulses, while in the X-ray regime, occultation combines with absorption to create complex pulse-prooles.