IEEE Geoscience and Remote Sensing Magazine - December 2020 - 142

[42]	D. Massonnet, K. L. Feigl, M. Rossi, and F. Adragna, " Radar interferometric mapping of deformation in the year after the Landers
earthquake, " Nature, vol. 369, no. 6477, pp. 227-230, 1994. doi:
10.1038/369227a0.
[43]	D. Massonnet, P. Briole, and A. Arnaud, " Deflation of Mount
Etna monitored by spaceborne radar interferometry, " Nature, vol.
375, no. 6532, pp. 567-570, 1995. doi: 10.1038/375567a0.
[44]	P. A. Rosen, S. Hensley, H. A. Zebker, F. H. Webb, and E. J. Fielding,
" Surface deformation and coherence measurements of Kilauea
Volcano, Hawaii from SIR-C radar interferometry, " J. Geophys.
Res., vol. 101, no. E10, pp. 109-123, 125, 1996. doi: 10.1029/
96JE01459.
[45]	G. E. Tucker and R. L. Bras, " Hillslope processes, drainage density, and landscape morphology, " Wat. Resour. Res., vol. 34, no.
10, pp. 2751-2764, 1998. doi: 10.1029/98WR01474.
[46]	S. Fujiwara, P. A. Rosen, M. Tobita, and M. Murakami, " Crustal
deformation measurements using JERS-1 SAR interferometry
near the Izu peninsula, Japan, " J. Geophys. Res., vol. 103, no. B2,
pp. 2411-2426, 1998. doi: 10.1029/97JB02382.
[47]	R. Burgmann, P. A. Rosen, and E. J. Fielding, " Synthetic aperture
radar interferometry to measure Earth's surface topography and
its deformation, " Ann. Rev. Earth Plan. Sci., vol. 28, no. 22, pp.
4291-4294, 2000.
[48]	S. Hensley, R. Munjy, and P. A. Rosen, " Interferometric synthetic
aperture radar, " in Digital Elevation Model Technologies and Applications: The DEM Users Manual, D. Maune, Ed. ASPRS, 2001,
142-206.
[49]	G. E. Tucker, F. Catani, A. Rinaldo, and R. L. Bras, " Statistical
analysis of drainage density from digital terrain data, " Geomor-

IN MEMORIAM 

(continued from p. 124)

- nder JPL's responsibility; he then served as the director
u
for astronomy, physics, and space technology and later as
the associate director for project formulation and strategy.
In that role, he helped to formulate a new vision for the
laboratory of the future. He was also the project manager
of GeoSAR, a three-year effort to develop a dual-frequency interferometric synthetic aperture radar system that
could penetrate vegetation to precisely map the Earth's
surface topography.
Born in Outjo, Namibia, on 24 February 1957, van Zyl
received his first degree in electrical engineering from the
University of Stellenbosch, South Africa, in 1979. He followed that with a master of science degree in electrical engineering in 1983 and a Ph.D. degree in electrical engineering
in 1986, both from the California Institute of Technology
142

phology, vol. 36, nos. 3-4, pp. 187-202, 2001. doi: 10.1016/S0169
-555X(00)00056-8.
[50]	B. S. D. Sagar and T. T. Lea, " Allometric relations of a Hortonian
fractal digital elevation model, " Geophys. Res. Lett., vol. 31, no. 6,
p. L06501, 2004. doi: 10.1029/2003GL019093.
[51]	J. T. Perron, J. W. Kirchner, and W. E. Dietrich, " Formation of
evenly spaced ridges and valleys, " Nature, vol. 460, no. 7254, pp.
502-505, 2009. doi: 10.1038/nature08174.
[52]	C. M. Tseng, C. W. Lin, C. P. Stark, J. K. Liu, L. Y. Fei, and Y. C.
Hsieh, " Application of a multi-temporal, LiDAR-derived, digital terrain model in a landslide-volume estimation, " Earth Surf.
Processes Landforms, vol. 38, no. 13, pp. 1587-1601, 2013. doi:
10.1002/esp.3454.
[53]	H. Mitasova, R. S. Harmon, K. J. Weaver, N. J. Lyons, and M. F.
Overton, " Scientific visualization of landscapes and landforms, "
Geomorphology, vol. 137, no. 1, pp. 122-137, 2012. doi: 10.1016/j.
geomorph.2010.09.033.
[54]	B. S. D. Sagar and S. L. Lim, " Morphing of grayscale DEMs via morphological interpolations, " IEEE J. Sel. Topics Appl. Earth Observ.
Remote Sens., vol. 8, no. 11, pp. 5190-5198, 2015. doi: 10.1109/
JSTARS.2015.2490098.
[55]	K. Nagajothi and B. S. Daya Sagar, " Classification of geophysical basins derived from SRTM and Cartosat DEMs via directional granulometries, " IEEE J. Sel. Topics Appl. Earth Observ. Remote Sens., vol. 12, no. 12, pp. 5259-5267, 2019. doi: 10.1109/
JSTARS.2019.2955986.
[56]	P. S. Dodds and J. S. Weitz, " Packing-limited growth of irregular
objects, " Phys. Rev. E, vol. 67, no. 1, p. 016117, 2003. doi: 10.1103/
GRS
PhysRevE.67.016117.

(Caltech). He taught at Caltech as a senior faculty associate in electrical engineering and aerospace over the last two
decades. He contributed in numerous ways to promote interactions between Caltech's Division of Engineering and
Applied Science and the JPL.
He holds two patents and 17 NASA certificates of recognition. The GRSS community is richer for his many technical and managerial contributions and for his unwavering
dedication, mentorship of young researchers, and engaging
personality. One colleague described van Zyl as something
of a rock star, always with something important to say at his
well-attended talks and with a crowd of young researchers
around him to learn.
He is survived by his wife, Kalfie, and two siblings.
GRS
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