Glaciology and Modelling
A model is a simplification of a complex set of natural processes (which in our case result in the glaciation of a landscape) into a system where the processes have been separated and quantified. It is created by gathering information from observation which is then used to define relationships between different variables, e.g. how does temperature vary with elevation? How do ice flow rates vary with ice thickness and surface slope?
Once the model has been created it can be tested by simulating a known situation and comparing the simulation with reality, making sure that the comparison is against data that have not been used to create the model in the first place! The more thoroughly a model is constrained by actual measurements taken from nature, the more confidence we have in the output.
Once set up, the input data and model parameters can be changed to test different outcomes. This allows the investigation of significant cause and effect relationships and can provide insight into the most important processes driving a system. A good model is therefore a very powerful tool for purposes of understanding, experimentation and prediction. For example, a glacier model could be used to identify the most important climate variables that affect ice volume and extent. Or it could be used to identify the climate conditions needed for the glacier to reach moraines that were deposited in the last ice age. The impact of present and future climate change on glaciers can also be investigated. Glacier models can be driven by climate proxy information (such as ice core, speleothem or palaeoecological reconstructions), and/or can be coupled to broader models of atmospheric and/or oceanic circulation.
Models are becoming increasingly significant for planning for the future in many areas of social and economic life such as agriculture, medicine, insurance, energy generation and transport. In the Antarctic Research Centre, our glacier modelling programme is helping with investigations into the way Southern Hemisphere glaciers respond to past, present and future climatic changes . This work, the only of its kind in New Zealand fills a knowledge gap in the understanding of Southern Hemisphere mid latitude climate processes.