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Chapter 2 of the Working Group I Contribution to the IPCC Sixth Assessment Report - data for Figure 2.22 (v20211109)

Update Frequency: Not Planned
Latest Data Update: 2022-11-18
Status: Ongoing
Online Status: ONLINE
Publication State: Citable
Publication Date: 2023-05-16
DOI Publication Date: 2023-07-03
Download Stats: last 12 months
Dataset Size: 3 Files | 9KB


Data for Figure 2.22 from Chapter 2 of the Working Group I (WGI) Contribution to the Intergovernmental Panel on Climate Change (IPCC) Sixth Assessment Report (AR6).

Figure 2.22 shows the April snow cover extent (SCE) for the Northern Hemisphere over the 1922-2018 period.

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:
Gulev, S.K., P.W. Thorne, J. Ahn, F.J. Dentener, C.M. Domingues, S. Gerland, D. Gong, D.S. Kaufman, H.C. Nnamchi, J. Quaas, J.A. Rivera, S. Sathyendranath, S.L. Smith, B. Trewin, K. von Schuckmann, and R.S. Vose, 2021: Changing State of 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. 287–422, doi:10.1017/9781009157896.004.

List of data provided
This dataset contains Northern Hemisphere April snow cover extent (SCE) time series from 1922-2018 for:

- Observed SCE (1922-1991) from Brown (2000)
- Blended Multi-observation SCE dataset (1967-2018) from Mudryk et al. (2020)
- Upper and lower boundary for uncertainty range for each time series

Data provided in relation to figure
Data provided in relation to Figure 2.22
Data file: Apr_snow_cover_extent_SCE.csv; (yearly data) relates to data for blue line (Brown 2000) and red line (Multi-obs Mudryk et al. 2020) and the upper and lower boundaries for uncertainty range (shaded area) for each time series

Sources of additional information
The following weblinks are provided in the Related Documents section of this catalogue record:
- Link to the figure on the IPCC AR6 website
- Link to the report component containing the figure (Chapter 2)
- Link to the Supplementary Material for Chapter 2, which contains details on the input data used in Table 2.SM.1

Citable as:  Smith, S.; Mudryk, L. (2023): Chapter 2 of the Working Group I Contribution to the IPCC Sixth Assessment Report - data for Figure 2.22 (v20211109). NERC EDS Centre for Environmental Data Analysis, 03 July 2023. doi:10.5285/8bbebd486eed4b7392dd306462e3f724.
Abbreviation: Not defined
Keywords: IPCC-DDC, IPCC, Intergovernmental Panel on Climate Change, AR6, WG1, WGI, Sixth Assessment Report, Working Group I, Physical Science Basis, Chapter 2, Changing state, Multi-millennial context, pre-industrial, Natural forcing, anthropogenic forcing, Radiative forcing, Large-scale indicators, observed changes, Modes of variability, Figure 2.22, Snow cover extent, Northern Hemisphere


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:

Process overview

This dataset was generated by the computation detailed below.

Caption for Figure 2.22 from Chapter 2 of the Working Group I (WGI) Contribution to the Intergovernmental Panel on Climate Change (IPCC) Sixth Assessment Report (AR6)


April snow cover extent (SCE) for the Northern Hemisphere (1922–2018). Shading shows very likely range. The trend over the entire 1922–2018 period (black line) is –0.29 (± 0.07) million km2 per decade. Further details on data sources and processing are available in the chapter data table (Table 2.SM.1)

Input Description


Output Description


Software Reference


  • var_id: 2
  • long_name: April SCE from Brown
  • units: million square km
  • var_id: 5
  • units: million square km
  • long_name: Blended April SCE
  • units: 1
  • var_id: 6
  • long_name: Lower boundary uncertainty range
  • units: 1
  • var_id: 7
  • long_name: Upper boundary uncertainty range
  • long_name: Year
  • var_id: 1
  • units: Year

Co-ordinate Variables

Temporal Range
Start time:
End time:
Geographic Extent