Sets of regions for regional synthesis#

Several alternative sets of regions are included to facilitate the regional synthesis of information:

  • IPCC AR6 WGI reference regions (land and mountain-range subregions are also defined using masks under reference-grids)

  • IPCC AR6 WGII continental regions

  • Monsoon regions

  • River basins

  • Small islands

  • Ocean biomes

These sets of regions can be displayed in an integrated viewer by clicking on the corresponding geojson files above.

AR6-WGI Reference Regions: IPCC-WGI Reference Regions version 4#

Different sets of climatic reference regions have been proposed for the regional synthesis of historical trends and future climate change projections, and have been subsequently used in the different Assessment Reports of the IPCC WGI (we refer to these sets as IPCC-WGI reference regions). The 23 rectangular reference regions originally proposed in [Giorgi and Francisco] (version 1) were used in the third (AR3) and fourth (AR4) IPCC Assessment reports. These regions were later modified using more flexible polygons in the IPCC SREX special report ([Seneviratne et al.], version 2) and then slightly modified and extended to 33 regions (by including island states, the Arctic and Antarctica) for the fifth Assessment Report (AR5, [Atlas of Global and Regional Climate Projections — IPCC], version 3).

This repository includes technical and supplementary information for a recent update of these regions presented in [Iturbide et al., 2020], referred to as version 4, which is used in AR6-WGI (AR6-WGI Reference Regions). The updated reference regions are provided as polygons in different formats (CSV with coordinates, R data, shapefile and geojson) together with R and Python notebooks illustrating the use of these regions with worked examples.

The CSV file contains the corner coordinates defining each region in [WGS 84: EPSG Projection – Spatial Reference] and it is used to build the spatial objects (the R data file and the shapefile), which contain coordinate information at a 0.44º resolution. This additional information is created via linear interpolation, while keeping the original vertices defined in the CSV file. Note that, in the CSV file, region acronyms followed by the * suffix define the part of the polygon of the same name that extends beyond the 180º meridian (i.e. RAR, NPO, EPO and SPO). This distinction is not needed in the spatial objects (the R data object, shapefile and geojson), as the regions separated by the 180° meridian are merged and considered as a single polygon.

Spatially averaged output from CMIP5 and CMIP6 global climate models (see data-sources) have been computed for the different reference regions and are available at the datasets-aggregated-regionally folder.

IPCC-WGII continental regions#

Comprises eight continental regions used in the WGII report (Africa, Antarctica, Asia, Australasia, Central and South America, Europe, North America, and Small Islands).

Monsoon regions#

Comprises the six land monsoon regions defined in WGI Chapter 8 (Section 8.3.2.4, Figure 8.11): North American monsoon (NAmerM, Jul-Sep), West African monsoon (WAfriM, Jun-Sep), South and Southeast Asian monsoon (SAsiaM, Jun-Sep), East Asian monsoon (EAsiaM, Jun-Aug), South American monsoon (SAmerM, Dec-Feb), Australian and Maritime Continent monsoon (AusMCM, Dec-Feb).

River basins#

Comprises 28 major river basins filtered from the world bank data catalogue ([Major River Basins of the World | Data Catalog]). This dataset was facilitated by Aristeidis Koutroulis (Technical University of Crete) and Richard Betts (Met Office Hadley Centre), as part of IPCC WGII activities.

Small islands#

Comprises nine small island regions used in the Atlas Chapter (Section Atlas.10; Figure Atlas.4): North Indian Ocean (ARB and BOB), West Indian Ocean, Midway-Hawaian Islands, Northwest tropics, Equatorial Pacific, Northwest SPCZ, Southwest SPCZ, Southern subtropics and the Caribbean.

Ocean biomes#

Ocean regions or biomes as defined by [Gregor et al.], clustering and expanding the open ocean biomes defined by [Fay and McKinley] on a 1° × 1° grid. The regions are:

  • Northern Hemisphere High Latitudes (NH-HL),

  • Northern Hemisphere Subtropics (NH-ST),

  • Equatorial (EQU)

  • Southern Hemisphere High Latitudes (SH-HL)

  • Southern Hemisphere Subtropics (SH-ST)

  • Eastern Boundaries (EastBound)

  • Amazon River (AmzOut)

  • Gulf of Mexico (GulfMex)

  • Arabian Sea (ArabSea)

  • Indonesian Flowthrough (IndoFlow)

References#

Atl

Atlas of Global and Regional Climate Projections — IPCC. https://www.ipcc.ch/report/ar5/wg1/atlas-of-global-and-regional-climate-projections/.

Maj

Major River Basins of the World | Data Catalog. https://datacatalog.worldbank.org/search/dataset/0041426.

WGS

WGS 84: EPSG Projection – Spatial Reference. https://spatialreference.org/ref/epsg/wgs-84/.

FM14

A. R. Fay and G. A. McKinley. Global open-ocean biomes: mean and temporal variability. Earth System Science Data, 6(2):273–284, August 2014. doi:10.5194/essd-6-273-2014.

GF

F. Giorgi and R Francisco. Uncertainties in regional climate change prediction: a regional analysis of ensemble simulations with the HADCM2 coupled AOGCM | SpringerLink. https://link.springer.com/article/10.1007/PL00013733.

GLKSM19

Luke Gregor, Alice D. Lebehot, Schalk Kok, and Pedro M. Scheel Monteiro. A comparative assessment of the uncertainties of global surface ocean CO\textsubscript 2 estimates using a machine-learning ensemble (CSIR-ML6 version 2019a) – have we hit the wall? Geoscientific Model Development, 12(12):5113–5136, December 2019. doi:10.5194/gmd-12-5113-2019.

IGutierrezA+20

Maialen Iturbide, José M. Gutiérrez, Lincoln M. Alves, Joaquín Bedia, Ruth Cerezo-Mota, Ezequiel Cimadevilla, Antonio S. Cofiño, Alejandro Di Luca, Sergio Henrique Faria, Irina V. Gorodetskaya, Mathias Hauser, Sixto Herrera, Kevin Hennessy, Helene T. Hewitt, Richard G. Jones, Svitlana Krakovska, Rodrigo Manzanas, Daniel Martínez-Castro, Gemma T. Narisma, Intan S. Nurhati, Izidine Pinto, Sonia I. Seneviratne, Bart van den Hurk, and Carolina S. Vera. An update of IPCC climate reference regions for subcontinental analysis of climate model data: definition and aggregated datasets. Earth System Science Data, 12(4):2959–2970, November 2020. doi:10.5194/essd-12-2959-2020.

SNE+12

Sonia I. Seneviratne, Neville Nicholls, David Easterling, Clare M. Goodess, Shinjiro Kanae, James Kossin, Yali Luo, Jose Marengo, Kathleen McInnes, Mohammad Rahimi, Markus Reichstein, Asgeir Sorteberg, Carolina Vera, Xuebin Zhang, Matilde Rusticucci, Vladimir Semenov, Lisa V. Alexander, Simon Allen, Gerardo Benito, Tereza Cavazos, John Clague, Declan Conway, Paul M. Della-Marta, Markus Gerber, Sunling Gong, B. N. Goswami, Mark Hemer, Christian Huggel, Bart van den Hurk, Viatcheslav V. Kharin, Akio Kitoh, Albert M.G. Klein Tank, Guilong Li, Simon Mason, William McGuire, Geert Jan van Oldenborgh, Boris Orlowsky, Sharon Smith, Wassila Thiaw, Adonis Velegrakis, Pascal Yiou, Tingjun Zhang, Tianjun Zhou, and Francis W. Zwiers. Changes in Climate Extremes and their Impacts on the Natural Physical Environment. In Christopher B. Field, Vicente Barros, Thomas F. Stocker, and Qin Dahe, editors, Managing the Risks of Extreme Events and Disasters to Advance Climate Change Adaptation, pages 109–230. Cambridge University Press, first edition, May 2012. doi:10.1017/CBO9781139177245.006.