The THAW (Temperature, Humidity and Winds near the Tropopause) project was led by Prof. Geraint Vaghaun (NCAS, University of Manchester) utilising a combination of vertically pointing Doppler radar data from the MST radar near Aberystwyth and a series of radiosonde and research aircraft flights in the tropopause region. The project used the FAAM BAE 146 aircraft to:

• Measure fine-scale vertical temperature structure in the vicinity of the tropopause, to test a model for VHF radar reflection being developed at Manchester.

• Compare wind and turbulence measurements with the MST radar, to better enable quantitative derivation of turbulence parameters from the radar echo spectra.

• Characterise the performance of the Buck research CR-2 hygrometer in the upper troposphere, with special emphasis on measuring supersaturation in the vicinity of the cirrus clouds.

The MST radar was operated in two modes during this period with higher vertical resolution measurements at 150 m resolution interspersed with the 300 m vertical resolution data - these are available in the standard MST radar version 3 dataset linked within this collection.