The New Zealand Earth System Model (NZESM)
This page gives you an overview of the NZ earth system modelling project, including updates on current and planned model simulations.
The basic make-up of the model
The New Zealand Earth System Model (NZESM) is a state-of-the-art modelling system that couples together representations of atmospheric physics (wind, temperature and water in the atmosphere and the processes that link them), ocean dynamics (oceanic temperatures, currents and salinity), sea ice (both sea ice coverage and sea ice thickness), and land physics (soil moisture, soil temperature and river run-off).
In addition, the model represents some chemical, biological and land-ice aspects of the “earth system”: chemistry of the lower and middle atmosphere (with a focus on ozone), ocean “biogeochemistry” (think plankton and dissolved carbon), and Antarctic ice shelves.
Relationship between the NZESM and the UK Earth System Model
In New Zealand, we don't have the resources to develop or even to maintain our own, fully independent earth system model.
We therefore develop the NZESM in partnership with the Unified Model Consortium, led by the UK Met Office. The NZESM is derived from and feeds back into the UK Earth System Model (UKESM).
Further, all the components that feed into the NZESM represent large, multi-institutional model development efforts.
The Deep South Challenge model development effort is geared towards advancing the model in several areas that are of key interest to New Zealand. Check out the range of projects we have in our earth system modelling and prediction programme here.
Producing useful climate simulations using a hierarchy of models
A global climate or earth system model is generally characterised by relatively low resolution, such as 1 to 2 degrees in latitude and longitude in the atmosphere (around 100 to 200 kilometres). This means a country like New Zealand is covered by a small number of grid points, which in turn means that the effects of local geography (for example, the Southern Alps), are not fully represented in these simulations.
A global model is generally used to assess large-scale features of climate change, such as the global-mean surface temperature. To assess local-scale questions (at around 10 to 15 kilometres), global climate model simulations need to be followed by regional climate modelling. In New Zealand, it looks something like this:
Current and planned simulations for the Deep South National Science Challenge
The NZESM will exercise some liberty when configuring the model for our own planned production simulations, in ways that may differ from UKESM.
We also will produce some simulations using the HadGEM3 climate model, which is the physical basis of UKESM, but which lacks atmospheric chemistry, biogeochemistry and ice shelves. We will be running some atmosphere-only and ocean-only simulations.
Have a look at this Gantt chart of our planned simulations with different model constellations:
How does our earth system modelling programme assist our other programmes conducting research into climate adaptation in New Zealand?
One of the unique aspects of the Deep South Challenge is the way we join together physical science, modelling, social science and political response.
By building strong relationships between our modelling, Vision Matauranga and Impacts & Implications programmes, we're helping communities, councils, property owners and businesses access reliable climate information in formats they can understand and apply:
Latest news and updates
We in the Deep South Challenge have established a critical new position, the "Climate Change Knowledge Broker". This person will play a critical role in the Deep South Challenge as a translator between disciplines, enabling connections between different research programmes for maximum impact. In particular, the Climate Change Knowledge Broker will focus on making the outputs from the New Zealand Earth System Model (NZESM) and associated climate models, accessible to research in other programmes within the Challenge as well as to external stakeholders. Applications close Monday 11 May.
New research released by the Deep South Challenge: Changing with our Climate supports decision-makers to map out how decisions can be made now for ongoing climate change impacts, by starting with the future we wish to avoid. The research report, Supporting decision making through adaptive tools: Practice Guidance on signals and triggers, has been a multi-disciplinary and multi-institute effort, with team members from Victoria University of Wellington, Manaaki Whenua Landcare Research, and NIWA.
Weather-related hazards have already cost the EQC $450 million in (inflation adjusted) payouts since the year 2000. New research by Jacob Pastor-Paz, Ilan Noy, Isabelle Sin, Abha Sood, David Fleming-Munoz and Sally Owen has found that climate change, and the expected increase in intensity and frequency of extreme weather-related events, is likely to translate into higher damages and thus an additional financial liability for the EQC.