Data for Figure 3.16 from Chapter 3 of the Working Group I (WGI) Contribution to the Intergovernmental Panel on Climate Change (IPCC) Sixth Assessment Report (AR6).

Figure 3.16 shows observed and simulated changes in Hadley cell extent and Walker circulation strength.

---------------------------------------------------

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 six panels, with data provided for all panels in subdirectories named panel_a, panel_b, panel_c, panel_d, panel_e and panel_f.

---------------------------------------------------

List of data provided

---------------------------------------------------

This dataset contains:

- Modelled and observed trends of the Northern Hemisphere annual-mean subtropical edge latitude of the Hadley cell for 1980-2014

- Modelled and observed trends of the Southern Hemisphere annual-mean subtropical edge latitude of the Hadley cell for 1980-2014

- Modelled and observed trends of the Southern Hemisphere December-January-February subtropical edge latitude of the Hadley cell for 1981-2000

- Modelled and observed trends of the annual-mean Walker circulation strength for 1901-2010

- Modelled and observed trends of the annual-mean Walker circulation strength for 1951-2010

- Modelled and observed trends of the annual-mean Walker circulation strength for 1980-2014

---------------------------------------------------

Data provided in relation to figure

---------------------------------------------------

Panel a:

- lat in panel_a/NHedge_ANN_1980-2014_ERA-Interim.nc; black dotted line

- lat in panel_a/NHedge_ANN_1980-2014_ERA5.nc; black solid line

- lat in panel_a/NHedge_ANN_1980-2014_JRA-55.nc; black dash-dotted line

- lat in panel_a/NHedge_ANN_1980-2014_MERRA2.nc; black dashed line

- lat in panel_a/NHedge_ANN_1980-2014_cmip5hist.nc; multimodel ensemble mean and percentiles for red open box-whisker

- lat in panel_a/NHedge_ANN_1980-2014_cmip6GHG.nc; multimodel ensemble mean and confidence interval for brown filled box, with ensemble means of individual models for black dots

- lat in panel_a/NHedge_ANN_1980-2014_cmip6aer.nc; multimodel ensemble mean and confidence interval for light blue filled box, with ensemble means of individual models for black dots

- lat in panel_a/NHedge_ANN_1980-2014_cmip6amip.nc; multimodel ensemble mean and percentiles for orange open box-whisker

- lat in panel_a/NHedge_ANN_1980-2014_cmip6hist.nc; multimodel ensemble mean and percentiles for red open box-whisker, and multimodel ensemble mean and confidence interval for red filled box, with ensemble means of individual models for black dots

- lat in panel_a/NHedge_ANN_1980-2014_cmip6nat.nc; multimodel ensemble mean and confidence interval for green filled box, with ensemble means of individual models for black dots

- lat in panel_a/NHedge_ANN_1980-2014_cmip6stratO3.nc; multimodel ensemble mean and confidence interval for purple filled box, with ensemble means of individual models for black dots

- lat in panel_a/NHedge_ANN_35yrs_cmip6pi.nc; multimodel ensemble mean and percentiles for blue open box-whisker

Panel b: As Panel a, but with

- lat in panel_b/SHedge_ANN_1980-2014_ERA-Interim.nc

- lat in panel_b/SHedge_ANN_1980-2014_ERA5.nc

- lat in panel_b/SHedge_ANN_1980-2014_JRA-55.nc

- lat in panel_b/SHedge_ANN_1980-2014_MERRA2.nc

- lat in panel_b/SHedge_ANN_1980-2014_cmip5hist.nc

- lat in panel_b/SHedge_ANN_1980-2014_cmip6GHG.nc

- lat in panel_b/SHedge_ANN_1980-2014_cmip6aer.nc

- lat in panel_b/SHedge_ANN_1980-2014_cmip6amip.nc

- lat in panel_b/SHedge_ANN_1980-2014_cmip6hist.nc

- lat in panel_b/SHedge_ANN_1980-2014_cmip6nat.nc

- lat in panel_b/SHedge_ANN_1980-2014_cmip6stratO3.nc

- lat in panel_b/SHedge_ANN_35yrs_cmip6pi.nc

Panel c: As Panel a, but with

- lat in panel_c/SHedge_DJF_1981-2000_ERA-Interim.nc; ERA-Interim

- lat in panel_c/SHedge_DJF_1981-2000_ERA5.nc; ERA5

- lat in panel_c/SHedge_DJF_1981-2000_JRA-55.nc; JRA-55

- lat in panel_c/SHedge_DJF_1981-2000_MERRA2.ncl MERRA2

- lat in panel_c/SHedge_DJF_1981-2000_cmip5hist.nc; CMIP5 historical-RCP4.5

- lat in panel_c/SHedge_DJF_1981-2000_cmip6GHG.nc; CMIP6 hist-GHG

- lat in panel_c/SHedge_DJF_1981-2000_cmip6aer.nc; CMIP6 hist-aer

- lat in panel_c/SHedge_DJF_1981-2000_cmip6amip.nc; CMIP6 AMIP

- lat in panel_c/SHedge_DJF_1981-2000_cmip6hist.nc; CMIP6 historical

- lat in panel_c/SHedge_DJF_1981-2000_cmip6nat.nc; CMIP6 hist-nat

- lat in panel_c/SHedge_DJF_1981-2000_cmip6stratO3.nc; CMIP6 hist-stratO3

- lat in panel_c/SHedge_DJF_20yrs_cmip6pi.nc; CMIP6 piControl

Panel d:

- dslp in panel_d/WalkerStrength_ANN_1901-2010_20CRv3.nc; max-min range for grey diagonal hatching

- dslp in panel_d/WalkerStrength_ANN_1901-2010_CERA-20C.nc; max-min range for grey vertical hatching

- dslp in panel_d/WalkerStrength_ANN_1901-2010_ERA-20C.nc; grey dashed line

- dslp in panel_d/WalkerStrength_ANN_1901-2010_HadSLP2.nc; grey solid line

- dslp in panel_d/WalkerStrength_ANN_1901-2010_cmip5hist.nc; multimodel ensemble mean and percentiles for red open box-whisker

- dslp in panel_d/WalkerStrength_ANN_1901-2010_cmip6GHG.nc; multimodel ensemble mean and confidence interval for brown filled box, with ensemble means of individual models for black dots

- dslp in panel_d/WalkerStrength_ANN_1901-2010_cmip6aer.nc; multimodel ensemble mean and confidence interval for light blue filled box, with ensemble means of individual models for black dots

- dslp in panel_d/WalkerStrength_ANN_1901-2010_cmip6amip-hist.nc; multimodel ensemble mean and percentiles for orange open box-whisker

- dslp in panel_d/WalkerStrength_ANN_1901-2010_cmip6hist.nc; multimodel ensemble mean and percentiles for red open box-whisker, and multimodel ensemble mean and confidence interval for red filled box, with ensemble means of individual models for black dots

- dslp in panel_d/WalkerStrength_ANN_1901-2010_cmip6nat.nc; multimodel ensemble mean and confidence interval for green filled box, with ensemble means of individual models for black dots

- dslp in panel_d/WalkerStrength_ANN_1901-2010_cmip6stratO3.nc; multimodel ensemble mean and confidence interval for purple filled box, with ensemble means of individual models for black dots

- dslp in panel_d/WalkerStrength_ANN_110yrs_cmip6pi.nc; multimodel ensemble mean and percentiles for blue open box-whisker

Panel e: As Panel d, but with

- dslp in panel_e/WalkerStrength_ANN_1951-2010_20CRv3.nc

- dslp in panel_e/WalkerStrength_ANN_1951-2010_CERA-20C.nc

- dslp in panel_e/WalkerStrength_ANN_1951-2010_ERA-20C.nc

- dslp in panel_e/WalkerStrength_ANN_1951-2010_HadSLP2.nc

- dslp in panel_e/WalkerStrength_ANN_1951-2010_cmip5hist.nc

- dslp in panel_e/WalkerStrength_ANN_1951-2010_cmip6GHG.nc

- dslp in panel_e/WalkerStrength_ANN_1951-2010_cmip6aer.nc

- dslp in panel_e/WalkerStrength_ANN_1951-2010_cmip6amip-hist.nc

- dslp in panel_e/WalkerStrength_ANN_1951-2010_cmip6hist.nc

- dslp in panel_e/WalkerStrength_ANN_1951-2010_cmip6nat.nc

- dslp in panel_e/WalkerStrength_ANN_1951-2010_cmip6stratO3.nc

- dslp in panel_e/WalkerStrength_ANN_60yrs_cmip6pi.nc

Panel f: As Panel d, but with

- dslp in panel_f/WalkerStrength_ANN_1980-2014_20CRv3.nc

- dslp in panel_f/WalkerStrength_ANN_1980-2014_ERA-Interim.nc; black dotted line

- dslp in panel_f/WalkerStrength_ANN_1980-2014_ERA5.nc; black solid line

- dslp in panel_f/WalkerStrength_ANN_1980-2014_JRA-55.nc; black dashed-dotted line

- dslp in panel_f/WalkerStrength_ANN_1980-2014_MERRA2.nc; black dashed line

- dslp in panel_f/WalkerStrength_ANN_1980-2014_cmip5hist.nc

- dslp in panel_f/WalkerStrength_ANN_1980-2014_cmip6GHG.nc

- dslp in panel_f/WalkerStrength_ANN_1980-2014_cmip6aer.nc

- dslp in panel_f/WalkerStrength_ANN_1980-2014_cmip6amip-hist.nc

- dslp in panel_f/WalkerStrength_ANN_1980-2014_cmip6hist.nc

- dslp in panel_f/WalkerStrength_ANN_1980-2014_cmip6nat.nc

- dslp in panel_f/WalkerStrength_ANN_1980-2014_cmip6stratO3.nc

- dslp in panel_f/WalkerStrength_ANN_35yrs_cmip6pi.nc

Acroynms:

Ann - Annual GHG - Greenhouse gas, aer - aerosol, CMIP - Coupled Model Intercomparison Project, 20CRv3 - NOAA-CIRES-DOE Twentieth Century Reanalysis (V3), CERA-20C - Coupled climate reanalyses of the 20th century, HadSLP2 - Hadley Centre Sea Level Pressure dataset (HadSLP2), AMIP - Atmospheric Model Intercomparison Project (AMIP), JRA - The Japanese 55-year Reanalysis (JRA-55), MERRA-2 - Global Modeling and Assimilation Office - NASA.

---------------------------------------------------

Notes on reproducing the figure from the provided data

---------------------------------------------------

Ensemble mean, interquartile ranges and 5th and 95th percentiles are calculated after weighting individual members with the inverse of the ensemble size of the same model, i.e. the inverse of the numbers given as the esize attribute in each variable.

Suppose X(i) is the array of lat, and w(i) is the corresponding weight.

- Mean should be suｍ_i(X(i) * w(i)) / sum_i(w(i))

- For percentile values,

1. Sort X and w so that X is in the ascending order

2. Accumulate w until i = j so that accumulated(w)/sum_i(w(i)) equals or exceeds the specified percentile level (e.g. 0.05)

3. Use X(j) or (X(j) + X(j - 1))/2 as the percentile value

- Finally, multiply by 10 all numbers for unit conversion.

Filled boxes and black dots are evaluated based on the models with minimum 3 ensemble members. Model ID of each ensemble member is given as the model_id attribute in each variable. For the confidence interval, first the ensemble average of individual models (with minimum 3 ensemble members) are calculated and then the confidence interval is evaluated based on t statistic.

---------------------------------------------------

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