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Chapter 3 of the Working Group I Contribution to the IPCC Sixth Assessment Report - data for Figure 3.14 (v20211001)

Update Frequency: Not Planned
Latest Data Update: 2021-12-03
Status: Completed
Online Status: ONLINE
Publication State: Citable
Publication Date: 2021-10-31
DOI Publication Date: 2023-02-08
Download Stats: last 12 months
Dataset Size: 6 Files | 108KB


Data for Figure 3.14 from Chapter 3 of the Working Group I (WGI) Contribution to the Intergovernmental Panel on Climate Change (IPCC) Sixth Assessment Report (AR6).

Figure 3.14 shows wet and dry region tropical mean (30°S-30°N) annual precipitation anomalies.

How to cite this dataset
When citing this dataset, please include both the data citation below (under 'Citable as') and the following citation for the report component from which the figure originates:
Eyring, V., N.P. Gillett, K.M. Achuta Rao, R. Barimalala, M. Barreiro Parrillo, N. Bellouin, C. Cassou, P.J. Durack, Y. Kosaka, S. McGregor, S. Min, O. Morgenstern, and Y. Sun, 2021: Human Influence on the Climate System. In Climate Change 2021: The Physical Science Basis. Contribution of Working Group I to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change [Masson-Delmotte, V., P. Zhai, A. Pirani, S.L. Connors, C. Péan, S. Berger, N. Caud, Y. Chen, L. Goldfarb, M.I. Gomis, M. Huang, K. Leitzell, E. Lonnoy, J.B.R. Matthews, T.K. Maycock, T. Waterfield, O. Yelekçi, R. Yu, and B. Zhou (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA, pp. 423–552, doi:10.1017/9781009157896.005.

Figure subpanels
The figure has four panels, with data provided for all panels in subdirectories named panel_a, panel_b, panel_c and panel_d.

List of data provided
The dataset contains timeseries (1988-2020) of annual precipitation anomalies from

- observation (GPCP)
- reanalysis (ERA5)
- multi-model mean (CMIP6)

GPCP is the Global Precipitation Climatology Project.
ERA5 is the fifth generation ECMWF (European Centre for Medium-Range Weather Forecasts) atmospheric reanalysis of the global climate.
CMIP6 is the sixth phase of the Coupled Model Intercomparison Project.

Data provided in relation to figure
- panel_a/AR6_WG1_Chap3_Figure3_14_panel_a_wetdry.csv (timeseries for wet regions)
- panel_b/AR6_WG1_Chap3_Figure3_14_panel_b_wetdry.csv (timeseries for dry regions)
- panel_c/AR6_WG1_Chap3_Figure3_14_panel_c_wetdry.csv (scaling factors for wet regions)
- panel_d/AR6_WG1_Chap3_Figure3_14_panel_d_wetdry.csv (scaling factors for dry regions)
Details on data provided in relation to each figure panel and its elements in the metadata associated to the corresponding files.

Sources of additional information
The following weblinks are provided in the Related Documents section of this catalogue record:
- Link to the report component containing the figure (Chapter 3)
- Link to the Supplementary Material for Chapter 3, which contains details on the input data used in Table 3.SM.1
- Link to the code for the figure, archived on Zenodo.

Citable as:  Kazeroni, R.; Schurer, A.; Bock, L. (2023): Chapter 3 of the Working Group I Contribution to the IPCC Sixth Assessment Report - data for Figure 3.14 (v20211001). NERC EDS Centre for Environmental Data Analysis, 08 February 2023. doi:10.5285/8c9c35e4c877440abcaa10b9aa173c33.
Abbreviation: Not defined
Keywords: IPCC-DDC, IPCC, AR6, WG1, WGI, Sixth Assessment Report, Working Group I, Physical Science Basis, Chapter 3, Human influence, large-scale indicators, Natural variability, anthropogenically-forced change, observed changes, Figure 3.14, Tropical precipitation, detection and attribution


Previous Info:
No news update for this record
Previously used record identifiers:
No related previous identifiers.
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: When using these data you must cite them correctly using the citation given on the CEDA Data Catalogue record.
Data lineage:

Data produced by Intergovernmental Panel on Climate Change (IPCC) authors and supplied for archiving at the Centre for Environmental Data Analysis (CEDA) by the Technical Support Unit (TSU) for IPCC Working Group I (WGI).
Data curated on behalf of the IPCC Data Distribution Centre (IPCC-DDC).

Data Quality:
Data as provided by the IPCC
File Format:
Data are netCDF formatted.

Process overview

This dataset was generated by the computation detailed below.

Caption for Figure 3.14 from Chapter 3 of the Working Group I (WGI) Contribution to the Intergovernmental Panel on Climate Change (IPCC) Sixth Assessment Report (AR6)


Wet (a) and dry (b) region tropical mean (30°S–30°N) annual precipitation anomalies. Observed data are shown with black lines (GPCP), ERA5 reanalysis in grey, single model simulations results are shown with light blue/red lines (CMIP6), and multi-model-mean results are shown with dark blue/red lines (CMIP6). Wet and dry region annual anomalies are calculated as the running mean over 12 months relative to a 1988–2020 based period. The regions are defined as the wettest third and driest third of the surface area, calculated for the observations and for each model separately for each season (following Polson and Hegerl, 2017). Scaling factors (c, d) are calculated for the combination of the wet and dry region mean, where the observations, reanalysis and all the model simulations are first standardized using the mean standard deviation of the pre-industrial control simulations. Two total least squares regression methods are used: noise in variables (following Polson and Hegerl, 2017) which estimates a best estimate and a 5–95% confidence interval using the pre-industrial controls (circle and thick green line) and the pre-industrial controls with double the variance (thin green line); and a bootstrap method (DelSole et al., 2019) (5–95% confidence interval shown with a purple line and best estimate with a purple circle). Panel (c) shows results for GPCP and panel (d) for ERA5. Figure is adapted from Schurer et al. (2020). Further details on data sources and processing are available in the chapter data table (Table 3.SM.1).

Input Description


Output Description


Software Reference


No variables found.

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