School of Physical and Chemical Sciences, Te Kura Matū Seminar Series

Working with the New Zealand Earth System Model to understand and improve our climate projections

Speaker

Shona Mackie, Research Fellow

Institute

Research Fellow Physics Dept., University of Otago

Time & Place

Fri, 11 Oct 2019 11:00:27 NZDT in West 701, Level 7

All are welcome

Abstract

Many physical processes that are represented in climate models like the New Zealand Earth System Model (NZESM) are heavily simplified, because computational resources are not infinite, and because a paucity of observations makes determining the most appropriate representation difficult. It is important that we understand the effect that such simplifications and omissions have on climate projections so that policy and decisions are based on appropriate interpretation of the evidence. One thing not accounted for in our current climate projections is the rate of Antarctic mass loss, which glaciology observations tell us is increasing, but which is assumed constant in model calculations. I will describe experiments carried out using the NZESM to look at possible effects of this on our calculated climate. As computers get bigger and we make more observations, our understanding of physical processes increases and we can include more processes in more detail in our model. In the current model, new sea ice is thinner than in reality, and forms more quickly, covering the ocean surface too soon, increasing the albedo and insulating the ocean from heat and CO2 exchange with the atmosphere. I will explain the more detailed representation that we are implementing in the NZESM to make our climate projections more reliable.

All Welcome