IEEE Geoscience and Remote Sensing Magazine - September 2019 - 124

signals can keep coherence up to ~15° elevation angles.
This enables altimetric retrievals over the sea with a several-centimeter precision level at very short integration times
(20 ms). This performance, together with the dense spatiotemporal coverage of GNSS reflectometry, might complement monostatic radar altimeters, and it has potential for
new submesoscale ocean science.
What professional achievement are you the proudest of?
Cardellach: I am proud of having conceived a new measurement concept, GNSS polarimetric radio occultation,
and proving it from a spaceborne experiment. GNSS nonpolarimetric radio occultations are widely used for sounding the thermodynamic variables of the atmosphere. With
the dual-polarization capabilities, we have proven that it is
also possible to sense heavy precipitation events. The experiment, called ROHP-PAZ [i.e.,the Radio Occultation and
Heavy Precipitation experiment aboard the PAZ low Earth
orbiter], is orbiting aboard the PAZ satellite (which was
launched February 2018, with the experiment being activated in May 2018). Demonstrating sensitivity to hydrometeors has been quite straightforward, but the difficult job starts
now to find optimal ways to use the data, untangle ambiguous parameters, target user-required resolutions, and so on.
If we succeed in this second stage of the experiment, GNSS
polarimetric radio occultations will for the first time provide
both thermodynamic and heavy precipitation profiles of the
atmosphere. These data sets could then contribute to improving our knowledge of extreme precipitation events and,
thus, their modeling, forecast, and climate projections. All of
these aspects have a strong impact on our societies.
Why are you active in the GRSS?
Cardellach: I just got involved in GRSS activities gradually
and without planning it. Being active takes some of my time,
but it is generally worth the effort. Being an associated editor
of IEEE Journal of Selected Topics in Applied Earth Observations and
Remote Sensing keeps me up to date with other research groups.
Cochairing a working group of the IFT technical committee
helps me in connecting to this research community and working synergistically toward common goals. Giving an IGARSS

tutorial and organizing the first IFT-R3S is a good way to let
other communities know about our field of research and potentially involve them as researchers or users of our products.
If you could give one piece of advice to your younger
self, what would it be?
Cardellach: First, I would remind myself that there might be
some impossible or even unachievable goals, but you will only
know after you try, and you can certainly learn from failures.
Saying that, I would also advise myself to better gauge which
targets I should put my efforts into. (And so do not take the
first advice too seriously, and come down to Earth!)
What is on your horizon?
Cardellach: I would like to see the GNSS polarimetric radio occultation concept fully developed and giving useful
products to meteorologists and climate modelers. I would
also like to work on an altimetric spaceborne mission based
on GNSS reflectometry.
What led you to your current role or participation in
the organization of IFT-RS3?
Cardellach: I was asked to organize RS3. The former two
editions were on astrophysics and cosmology topics, so
it was time to tackle Earth observation techniques. The
background of my group is too focused on GNSS remote
sensing, and I thought this topic is too narrow for a oneweek summer school. I needed help from other remote
sensing researchers, so I asked the IFT-TC whether a summer school focusing on technologies under the IFT would
be interesting to the TC. The response was very enthusiastic, and we managed to put together a rather successful summer school (do I have a biased perception?). As
general chair of the summer school, it took a lot of work,
but I like to believe I managed to make it compatible with
my other duties.
What activities were you most excited about at the
IFT-R3S summer school that you helped to plan?
Cardellach: The IFT-R3S as a whole, from the idea to its
conclusion. It was exciting to see the positive response by
the technical committee and how we created this summer
school from scratch. I also put some effort on organizing social events to facilitate friendship and good communication

An afternoon social volleyball activity at the GRSS IFT-R3S in Barcelona, Spain. (Source: Matteo Alparone.)
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IEEE Geoscience and Remote Sensing Magazine - September 2019

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