Dataset
Climate model simulations of decadal-scale South Pacific Convergence Zone (SPCZ) rainfall using the Intermediate General Circulation Model version 4 (IGCM4)
Abstract
This dataset contains outputs from modelling experiments using the Intermediate Global Circulation Model version 4 (IGCM4). The experiments use plausible scenarios of climate variability to simulate the processes driving South Pacific Convergence Zone (SPCZ) rainfall, and the decadal-scale SPCZ changes likely under different past and future modes of climate variability.
Directory names refer to the different experiments, in which perturbations were added onto sea surface temperatures corresponding to the: Atlantic Multidecadal Variability (A); Interdecadal Pacific Oscillation (I); and Southern Ocean (S). The numbers preceding each letter encode the size of the perturbation (see Skinner et al. for full details). For example, the directory 0A0I0S contains variables from the pre-industrial control experiment onto which no perturbations were added, while the directory 0A-3I0S contains variables from the experiment in which a three standard deviation magnitude negative IPO event was added onto the prescribed sea surface temperatures.
Each experiment's directory contains the following daily data in netCDF format:
- clouds.nc - Low, mid and high levels clouds
- olr.nc - Outgoing longwave radiation
- ppt.nc - Precipitation
- tsfc.nc - Surface temperature
- zg_500.nc - Geopotential height at 500 hPa
- ta_250.nc - Air temperature at 250 hPa
- ta_850.nc - Air temperature at 850 hPa
- uwnd_250.nc - Zonal wind velocity at 250 hPa
- uwnd_850.nc - Zonal wind velocity at 850 hPa
- vwnd_250.nc - Meridional wind velocity at 250 hPa
- vwnd_850.nc - Meridional wind velocity at 850 hPa
This dataset has two related publications:
- Peaple et al. "Ocean variability drives a millennial-scale shift in South Pacific hydroclimate." Communications Earth & Environment 6.1 (2025): 679. DOI: https://doi.org/10.1038/s43247-025-02676-5 (linked in the documentation section below)
- Skinner et al. "Decadal-scale drivers of South Pacific hydroclimate variability." Quarterly Journal of the Royal Meteorological Society (2026)
This dataset was produced as part of the Natural Environment Research Council (NERC) project Pacific Rainfall over Millennial Scales (PROMS) (grant reference: NE/W005565/1).
Details
| Previous Info: |
No news update for this record
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| Previously used record identifiers: |
No related previous identifiers.
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| Access rules: |
Public data: access to these data is available to both registered and non-registered users.
Use of these data is covered by the following licence(s): http://www.nationalarchives.gov.uk/doc/open-government-licence/version/3/ When using these data you must cite them correctly using the citation given on the CEDA Data Catalogue record. |
| Data lineage: |
Data were generated using the Intermediate General Circulation Model version 4 (IGCM4), data were saved in netCDF format and then submitted to CEDA for archiving. |
| File Format: |
NetCDF
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Process overview
| Title | Intermediate General Circulation Model version 4 (IGCM4) |
| Abstract | The IGCM4 (Intermediate Global Circulation Model version 4) is a global spectral primitive equation climate model whose predecessors have extensively been used in areas such as climate research, process modelling and atmospheric dynamics. The IGCM4's niche and utility lies in its speed and flexibility allied with the complexity of a primitive equation climate model. Moist processes such as clouds, evaporation, atmospheric radiation and soil moisture are simulated in the model, though in a simplified manner compared to state-of-the-art global circulation models (GCMs). IGCM4 is a parallelised model, enabling both very long integrations to be conducted and the effects of higher resolutions to be explored. It has also undergone changes such as alterations to the cloud and surface processes and the addition of gravity wave drag. These changes have resulted in a significant improvement to the IGCM's representation of the mean climate as well as its representation of stratospheric processes such as sudden stratospheric warmings. The IGCM4's physical changes and climatology are described in the paper linked in the documentation section. |
| Input Description | None |
| Output Description | None |
| Software Reference | None |
- units: METRES
- long_name: GEOPOTENTIAL HEIGHT
- var_id: GEOPOT
- units: %
- long_name: HIGH CLOUD AMOUNT
- var_id: HIGCLD
- units: %
- long_name: LOW CLOUD AMOUNT
- var_id: LOWCLD
- var_id: V
- long_name: MERIDIONAL WIND
- units: M/S
- units: %
- var_id: MIDCLD
- long_name: MID LEVEL CLOUD AMOUNT
- units: K
- long_name: SURFACE TEMPERATURE
- var_id: ST
- var_id: TEMP
- units: DEG C
- long_name: TEMPERATURE
- var_id: TULW
- long_name: TOP UPWARD LONGWAVE FLUX
- units: W/M2
- long_name: TOTAL RAINFALL
- units: MM/DAY
- var_id: PTOT
- var_id: U
- units: M/S
- long_name: ZONAL WIND
- units: degrees_north
- var_id: latitude
- units: level
- var_id: level
- units: degrees_east
- var_id: longitude
- units: mbar
- var_id: pressure
- var_id: surface
- units: dummy variable
- var_id: time
- units: day
- var_id: zonal
- units: dummy variable
Co-ordinate Variables
Temporal Range
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Geographic Extent
90.0000° |
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-180.0000° |
180.0000° |
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-90.0000° |