The Topography of the Mediterranean Sea - GPS reflection measurements with the German Research Aircraft HALO

Measurements of GPS signals that are reflected off the sea surface allow the detection of sea surface height differences with centimetre precision. Scientists from the German Research Centre for Geosciences GFZ together with colleagues from the Leibniz University Hannover, the Technical University Dresden and the Institute for Space Sciences in Barcelona gathered these data with dedicated GPS receivers aboard the German research aircraft (HALO) and demonstrated for the first time that GPS reflection measurements can resolve anomalies of the sea surface topography.

Measurements of GPS signals that are reflected off the sea surface allow the detection of sea surface height differences with centimetre precision. Scientists from the German Research Centre for Geosciences GFZ together with colleagues from the Leibniz University Hannover, the Technical University Dresden and the Institute for Space Sciences in Barcelona gathered these data with dedicated GPS receivers aboard the German research aircraft (HALO) and demonstrated for the first time that GPS reflection measurements can resolve anomalies of the sea surface topography.

These measurements were part of the GEOHALO flight experiment that focused on the investigation of different geoscientific topics in the Mediterranean region. Using reflected GPS signals for ocean surface monitoring is a rather new field of geoscientific research. Compared to established radar or laser altimeter measurements, the use of GPS reflections offers a significantly higher ocean coverage. This is due to simultaneous observations along multiple reflection tracks that are provided by the different navigation satellites, whereas established sensors provide only one track.

The ambition of the GFZ researchers is even higher and is focused on the International Space Station ISS. The successful aircraft campaign is an important step towards the application of GPS reflectometry aboard satellites for global observations of the ocean surface. Possible applications hereby comprise, e.g., the potential early detection of tsunamis, that have only small amplitudes in the open ocean and can hardly be located with today's observation coverage. Even our understanding of climate change can profit from GPS reflectometry. Mesoscale oceanic currents (eddies) with extentions between 10 and 100 km are crucial for the climate relevant ocean's energy transport, and currently cannot be sufficiently explored. These global scale challenges are recently studied by the GFZ scientists to prepare the reflectometry experiment aboard the ISS in cooperation with the European Space Agency ESA.

Semmling, A. M.; Beckheinrich, J.; Wickert, J.; Beyerle, G.; Schön, S.; Fabra, F.; Pflug, H.; He, K.; Schwabe, J., and Scheinert, M. (2014): “Sea surface topography retrieved from GNSS reflectometry phase data of the GEOHALO flight mission”, Geophysical Research Letters, 2014, 41, doi:10.1002/2013GL058725

Figures related to GEOHALO in printable resolution can be found in:

www.gfz-potsdam.de/medien-kommunikation/bildarchiv/halo/

Additional News

DEUQUA Logo mit Mammut und Friedenstaube

DEUQUA 2022 Tagung am GFZ

PAW Logo

Postdoc Appreciation Week Germany

Building, photo taken in winter, Isaac Newton Institute

Simons Scholarship for Dr Monika Korte

Die Verteilung der seismischen Stationen auf einer Karte der Region.

How deeply does Eifel volcanism sleep?

Geomagnetic Field. Space with stars, Earth with animation around

GFZ film among the finalists of the Earth Futures Festival 2022

Earth's radiation belt: High-energy particles modelled around the Earth. The particles are ring-shaped

A new population of particles in the Earth’s radiation belts

[Translate to English:] Die teilnehmenden GFZ Mitarbeiter als Gruppenfoto

2nd proWissen run in Potsdam with successful participation by GFZ employees

The group on the first day of work.

New faces at the GFZ - start of the training year 2022/2023

Forest vs no forest on two sides of a road

Agriculture drives more than 90% of tropical deforestation

Group photo: people on the roof terrace of a house

2nd International Symposium of International Association of Geodesy’s Commission 4…

[Translate to English:] Foto eines Bergs mit darüber gelegter Skizze des geologischen Profils.

How thick should clay be as a host rock for a repository?

White dots of different thicknesses in a hexagonal pattern on a black ground.

Synthesis of hexagonal SiGe semiconductor using high pressure and temperature

Landslide on a slope directly adjacent to a settlement with small houses.

Landslides increasingly threaten the world's urban poor cities

Different coloured liquids mix in an aquarium. A child watches.

Catching up after Corona: "GEOtogether" brings joy for pupils in collaborative…

A woman and a man stand on a stage holding a picture with a coloured map of Türkiye..

Four decades of joint Turkish-German earthquake research

Egon Althaus sitting around a table with colleagues outside on a project

We mourn the death of Egon Althaus (1933-2022)

A dry dam near Capetown, South Africa.

The challenge of unprecedented floods and droughts in risk management

Drawing of a fictional historical submersible.

Eleven short research stays with GFZ participation funded

Drilling platform on Lake Junin with several people on it

Tropical glaciers followed the rhythm of the ice sheet expansion in the northern…

Schematic representation of the VECTOR project: A large arrow with different levels - from the earth's surface to underground.

Improving the exploration efficiency in Europe

Hoby Razafindrakoto

Project from Dr. Razafindrakoto to create a seismological lab in Madagascar wins ARISE…

3D digital Earth at night

Open-Earth-Monitor getting started

The dam of the Steinbach Dam in the Eifel region, cut by flooding but not destroyed.

Flood risk management after the Eifel flood in July 2021

Group picture of the Cermak7 Conference in front of the Museum Barberini in Potsdam

International heat flow conference and workshop in Potsdam

Castor platform in the ocean. The sea is still.

Filling geological gas reservoirs: Causal research in the most important event of induced…

People sit on chairs in a circle in a room.

GFZ PhD Days

Jeffrey Perez in front of the Logo of the meeting

Two GFZ Researchers participate in the 71st Lindau Nobel Laureate Meeting

Young woman standing with certificate in hand in a hall in front of the lettering EAGE

Best Paper Award for Evgeniia Martuganova

Four persons are holding a large golden key, standing in front of a house

Housing for visiting scientists

Diver

Favoring curiosity-driven research of the solid earth

back to top of main content