Research project: Re-constructing Past Environmental Conditions Using Landscape Evolution Models

Reconstruction of palaeo-environmental conditions over long time periods is notoriously difficult, especially where there are limited or no proxy records from which to extract data. Application of landscape evolution models (LEMs) for palaeo-environmental reconstruction involves hindcast modeling, in which simulation scenarios are configured with specific model variables and parameters chosen to reflect a specific hypothesis of environmental change. In this form of modelling, the environmental time series utilized are considered credible when modelled and observed landscape metrics converge. In this research we account for the uncertainties involved in evaluating the degree to which the model simulations and observations converge using Monte Carlo analysis of reduced complexity `metamodels'. This approach allows many thousands of simulations (each representing a different hypothesis of environmental change) to be undertaken.

The technique is being applied at the terrestrial-marine interface, an environment that has hitherto received little focus due to the difficulties involved in simulating the interacting process regimes.

A recent case study focused on a set of gullies found on the southwest coast of the Isle of Wight, UK. A key factor controlling the Holocene evolution of these coastal gullies is the balance between rates of sea-cliff retreat (driven by sea-level rise) and headwards incision caused by knickpoint migration (driven by the rate of runoff). We simulate these processes using a version of the GOLEM model that has been modified to represent sea-cliff retreat.

Other current research seeks to use the CHILD LEM to simulate long-term rates of sediment delivery to the Mekong Delta in order to explore hypotheses of changing environmental conditions through the Pleistocene.