Dr Ed Pope, from our Department of Geography, has been appointed as a Natural Environment Research Council (NERC) Independent Research Fellow. Here, he explores his research, which will focus on understanding the offshore record of tropical cyclones.
Tropical cyclones and climate change
Over the past 50 years, tropical cyclones have killed more than 750,000 people and caused more than US$ 1400 billion in economic losses. However, during the 21st Century it is expected that the impacts of these extreme weather phenomena will increase.
This is thought to be a consequence of human-induced climate change driving an increase in the strongest tropical cyclones, coupled with increase exposure of coastal areas to the impacts of these events due to socio-economic development.
However, beyond their impacts on humans, tropical cyclones play a major role in global sediment and nutrient cycles, as well as atmospheric circulation. Understanding the frequency, intensity and wider impacts of tropical cyclones is therefore crucial to developing mitigation strategies aimed at reducing the impacts of these events, as well as understanding how our planet works.
Records of tropical cyclones
On land, it is easy to document the impacts of tropical cyclones, despite their effects being felts across 100s to 1000s of kilometres. For example, detailed satellite images can be used to map individual landslides that have been triggered by tropical cyclones.
But satellite records only go back as far as the 1970s. It is therefore challenging to compile reliable records of changes to tropical cyclone frequency, intensity and duration further back in time.
However, offshore records of tropical cyclones could extend much further back in time than terrestrial records, if we can decipher that offshore record correctly.
Tropical cyclones and turbidity currents
A known consequence of tropical cyclones is the triggering of seafloor flows called turbidity currents. Turbidity currents are best thought of as avalanches of sediment akin to snow avalanches seen in alpine environments. The principle aim of my Fellowship is to determine whether the deposits from seafloor turbidity currents, called turbidites, can be used to reconstruct histories of tropical cyclones in different regions of the world.
To achieve this, I will attempt to combine measurements of turbidity currents in action on the seabed, which have been triggered by tropical cyclones with sediment cores containing the deposits of past turbidity currents. Turbidity currents are notoriously challenging to measure in action, and the project will use some of the first such measurements.
By comparing these two unique datasets, this NERC Independent Fellowship project will determine whether long term records of tropical cyclones can be derived to understand and mitigate risk from tropical cyclones.
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Photo by NASA on Unsplash
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