Theoretical analysis and numerical experiments of variational adjoint approach for refractivity estimation
Article first published online: 28 JAN 2011
Copyright 2011 by the American Geophysical Union.
Volume 46, Issue 1, February 2011
How to Cite
2011), Theoretical analysis and numerical experiments of variational adjoint approach for refractivity estimation, Radio Sci., 46, RS1006, doi:10.1029/2010RS004417., , and (
- Issue published online: 28 JAN 2011
- Article first published online: 28 JAN 2011
- Manuscript Accepted: 13 OCT 2010
- Manuscript Revised: 5 SEP 2010
- Manuscript Received: 20 APR 2010
- atmospheric refractivity estimation;
- parabolic wave equation;
- variational adjoint approach;
 This paper puts forward possibilities of refractive index profile retrieval using field measurements at an array of radio receivers in terms of variational adjoint approach. The derivation of the adjoint model begins with the parabolic wave equation for a smooth, perfectly conducting surface and horizontal polarization conditions. To deal with the ill-posed difficulties of the inversion, the regularization ideas are introduced into the establishment of the cost function. Based on steepest descent iterations, the optimal value of refractivity could be retrieved quickly at each point over height. Numerical experiments demonstrate that the method works well for low-distance signals, while it is not accurate enough for long-distance propagations. Through curve fitting processing, however, giving a good initial refractivity profile could generally improve the inversions.