id	summary	reporter	owner	description	type	status	priority	milestone	component	version	resolution	keywords	cc
509	Modifications to 1d WOPT code	Ian Culverwell	Ian Culverwell	"As a result of some further R&D on the wave optics propagator in ROPP, Sean Healy (ECMWF) proposes the following changes at ROPP9.1:

  * A change in the damping of the signal below the Earth's surface, from a 1 km width Gaussian centred 1 km above the surface, to a 500 m Gaussian centred at the surface.  This allows the bending angle profiles to penetrate deeper in some cases.

  * The inclusion of an extra term in the complex exponential that is integrated over the final 'screen' to give the signal at the LEO.   This extra term, which can be as much as 10% of the basic expression, improves the comparison with the results of high resolution wave optics propagation codes and direct forward modelling of interpolated refractivities in some large bending angle cases.

  * The disregarding of points of low amplitude in the estimation of the Doppler offset in the FSI routine.  This allows occasional problematic cases to generate bending angles successfully.

These changes are being tested in https://trac.romsaf.org/ropp/browser/ropp_src/branches/dev/Share/ic_wopt.

"	enhancement	closed	normal	9.1	ropp_pp	9.0	fixed	WOPT