Climate and hydrology projection data for researchers

For researchers who are interested in using climate or hydrology projections for their work, this is an update on what is currently available, what is being worked on, and who to talk to for data provision (as at September 2021)

The most readily available climate projections dataset for New Zealand is the downscaled CMIP5 (Coupled Model Intercomparison Project 5) suite, detailed here and in the MfE (2018) publication on updated climate projections for New Zealand. These projections (CMIP5-NZRCM) are the result of the outputs of six global models being fed into the New Zealand Regional Climate Model (NZRCM), which were subsequently further downscaled and bias corrected to a 5 km grid.

The global climate model inputs are driven by the four Representative Concentration Pathways (RCPs) of the IPCC’s 5^th Assessment Report (2014) (AR5). Further details on the bias correction procedure are available here. For simple visualisations of some of these datasets, visit NIWA’s Our Future Climate NZ website. 

These projections are available for research and you can contact Andrew Tait, NIWA Chief Scientist – Climate, Atmosphere and Hazards to discuss data provision.

How to access climate modelling data

• Data is provided at cost of provision to researchers under a data access agreement or sub-contracted as part of your project
• Deep South Challenge project researchers will be able to access this projection data under these same conditions (please liaise with our Climate Change Knowledge Broker in the first instance)
• If you are planning to use these climate (CMIP5-NZRCM) projections in your research, please engage with NIWA prior to applying for funding to ensure the data is appropriate for the intended use and that any necessary post-processing and analysis is built into the resourcing of your project
• Uncalibrated hydrological (surface river flow) projections are also available based on the downscaled CMIP5 data. Please contact our Climate Change Knowledge Broker if you are interested in working with this dataset

Future climate modelling data

NIWA is currently working on assessing and subsequently downscaling a suite of CMIP6 projections, the next generation of global models which have been presented in the IPCC’s 6^th Assessment Report (2021). These projections are based on Shared Socioeconomic Pathways, an evolution from the Representative Concentration Pathways of AR5.

The CMIP6 global model assessment and downscaling work is ongoing and NIWA will make test data available as soon as possible for research purposes, with the goal of publishing a fully documented updated climate projections dataset by 2024. With this in mind, we reiterate that the CMIP5 dataset is still very much fit for purpose.

New Zealand Earth System Model (including high-resolution ocean around New Zealand) and downscaled New Zealand Earth System Model runs now exist for three Shared Socioeconomic Pathways, although this data has not yet been properly analysed.

Regarding regional atmospheric projections, the full suite of downscaled CMIP5 projections remains the most robust dataset for use and is the current release dataset. For global NZESM projections (atmosphere, ocean, etc.) please contact our Climate Change Knowledge Broker to discuss possible use and collaboration.