Photo of Prof Chris Hughes

Prof Chris Hughes

Professor of Sea Level Science Earth, Ocean and Ecological Sciences

    Research

    Research Overview

    "My research focuses on the relationship between ocean dynamics, sea level, ocean bottom pressure, and geodesy. Geodesy is the science of measuring the Earth's shape, orientation, and gravity field, all of which are closely related to sea level. In fact, the Global Geodetic Observing System "Grand Challenge" goals for accuracy and stability are determined by the requirements of sea level science.

    Sea level matters to people, not least because it can cause flooding - a good rule of thumb for the UK is that, for every 32 cm of sea level rise, the frequency of coastal floods would increase by a factor of 10, all other things being equal.

    Ocean currents are closel related to sea level via geostrophic balance, which means that any current that persists for more than a few days will have an associated slope in the sea surface. Counterintuitively, this slope is at right angles to the flow: the current flows with high sea level to its right in the northern hemisphere, and to its left in the southern hemisphere (water to the right of the Gulf Stream stands more than half a metre higher than that to the left). The currents associated with the global ocean conveyor - ocean's biggest contribution to the climate system which carries warm water to the north throughout the Atlantic and helps keep Europe warm - result in the Pacific ocean being on average about 40 cm higher than the Atlantic.

    This means two things:

    1) We can learn about the ocean currents from measurements of sea level. Satellite altimetry (measuring sea level from space) has completely revolutionlised our understanding of ocean dynamics because of this.

    2) If we understand ocean currents, we can make better predictions of how ocean dynamics can affect sea level.

    I am currently most interested in how effects of ocean dynamics are felt at the coast. There are some quite surprising differences between coastal sea level and nearby open ocean sea level, because the steep continental slope acts to filter out much of the variability from the open ocean and to smooth out and shift the spatial patterns. There are also local changes to sea level near the coast, because changing winds have a bigger effect on sea level where the water is shallower. Much of my present work is focused on disentangling these different causes of variability in coastal sea level."

    Research Group Membership

    Research Grants

    GOCE++ Dynamic Coastal Topography and TG Unification

    EUROPEAN SPACE AGENCY (FRANCE)

    December 2015 - December 2017