Plain English summary
Besides being a professor of planetary research at TU Delft, geophysicist Bert Vermeersen is head of the NIOZ Sea Level Center of Expertise. ‘The rise of the sea level is one of the hot potatoes in the current climate issue. However, the sea level is far more than just a water level. To start with, it is a relative number, because sea level is related to factors such as subsidence, rebound (rising ground level) and sediment transport. And not just people, but fauna and flora in coastal areas also immediately feel the sea level’s impact on the environment. These effects are also important research subject for our Sea Level Center.’
‘One important initial outcome of our Center’s work was the sea-level scenarios that we compiled for the Wadden Sea on behalf of the Wadden Academy in close collaboration with Deltares and TNO. A relative sea-level change can differ per place and region for various reasons. Besides vertical ground movements and sediment transport, sea-level rise can also be influenced by sea currents, wind direction, differences in the heating up of the seawater and even changes in gravity if an enormous mass of water is moved. We have incorporated all these effects into a single integrated study with scenarios for the Wadden Sea in the coming decades.’
‘At present, the eastern Wadden area is still silting up. Will that change this century with the result that the area becomes more submerged? There are still many uncertainties, such as whether the ice in West Antarctica will start to melt faster, for example. In any case, the scenarios provide a guideline for what could happen in the 21st-century.’
‘Unlike my research at TU Delft into the oceans on the icy moons that orbit Jupiter and Saturn, the research into sea levels is highly applied. We have seen that not only government ministries but also mayors of coastal municipalities were very happy with this independent and integrated research. They can use these scenarios to better support far-reaching interventions, such as dyke reinforcements and other coastal defence measures. In the future, we hope to further refine our research, for example by no longer working on a scale 100 by 100 km, but instead calculating scenarios with a far higher resolution at a scale of 10 by 10 km.’
The scenarios for the sea level of the Wadden Sea are described in the Netherlands Journal of Geosciences.Read more +
I have two main areas of interest at NIOZ: Sea level change & oceans inside icy moons.
Sea level change
Only recently it has been recognised that regional sea level change can deviate strongly from the global average. This recognition has important consequences for effects of sea level change at coastlines, ranging from coastal protection to biogeomorphological impacts and interactions. My main task at NIOZ is to establish a Center of Expertise on Sea Level Change in general and on these regional effects in particular, with special emphasis on Dutch coastal areas. This part of my research interests has close connections to my appointment in the Geoscience & Remote Sensing Department at the Faculty of Civil Engineering & Geosciences of TU Delft.
Example of regional sea level change due to a collapse of the West Antarctic Ice Sheet (after Bamber, Riva, Vermeersen & LeBroq, Science, 324, 901-903, 2009)
Oceans inside icy moons
Water oceans do not only occur on the Earth, but are also present in the interiors of some of the moons of Jupiter and Saturn. Although not directly belonging to the science agenda of NIOZ, the study of these planetary water oceans underneath the surface ice has close resemblances with areas of expertise of NIOZ, ranging from physical oceanography to deep sea habitats and possibly life. This part of my research interests has close connections to my work at the Faculty of Aerospace Engineering and to NWA Route 4 / Origins Center and is partly done at the OCS Department on Texel.
I studied astronomy at Utrecht University and did my PhD in geophysics at the same university. During my postdoc years in Italy (Bologna, Milan) and Germany (Stuttgart) I started to numerically model regional variations of sea level change due to postglacial rebound and other geophysical processes. These models were combined with earth-oriented space observations from gravity and altimetry satellites when I was appointed assistant professor at TU Delft in 1999 and associate professor in 2007. Around the time of the landing of the Huygens probe on Saturn moon Titan in 2005 I became interested in planetary exploration as well. This resulted in the establishment of the new TU Delft Chair on Planetary Exploration in 2014, of which I spend 0.7 fte at the Faculty of Aerospace Engineering and 0.1 fte at the Faculty of Civil Engineering & Geosciences. In the meantime, my expertise on sea level change led to the appointment as (then 0.3 fte, now 0.2 fte) Senior Scientist at NIOZ in 2011.