Advances in Radio Science www.adv-radio-sci.net 1684-9965 1684-9973 2 Kleinheubacher Berichte 2003 2004 10.5194/ars-2-289-2004 http://www.adv-radio-sci.net/2/289/2004/ http://www.adv-radio-sci.net/2/289/2004/ars-2-289-2004.html http://www.adv-radio-sci.net/2/289/2004/ars-2-289-2004.pdf 289 291 2005-05-27 A wonderful laboratory and a great researcher N. M. Sheikh Faculty of Electrical Engineering, University of Engineering and Technology, Lahore, Pakistan It was great to be associated with Prof. Dr. Karl Rawer. He devoted his life to make use of the wonderful laboratory of Nature, the Ionosphere. Through acquisition of the experimental data from AEROS satellites and embedding it with data from ground stations, it was possible to achieve a better empirical model, the International Reference Ionosphere. Prof. Dr. Karl Rawer has been as dynamic as the Ionosphere. His vision about the ionospheric data is exceptional and has helped the scientific and engineering community to make use of his vision in advancing the dimensions of empirical modelling. As a human being, Prof. Dr. Karl Rawer has all the traits of an angel from Heaven. In short he developed a large team of researchers forming a blooming tree from the parent node. Ionosphere still plays an important role in over the horizon HF Radar and GPs satellite data reduction.