Auxiliary Material for –
Impact of soil moisture-climate feedbacks on CMIP5 projections: First results from
the GLACE-CMIP5 experiment
Sonia I. Seneviratne1*, Micah Wilhelm1, Tanja Stanelle1, Bart van den Hurk2, Stefan
Hagemann3, Alexis Berg4,5, Frederique Cheruy6, Matthew E. Higgins7, Arndt Meier8,
Victor Brovkin3, Martin Claussen3, Agnès Ducharne9, Jean-Louis Dufresne6, Kirsten L.
Findell4, Joséfine Ghattas9, David M. Lawrence7, Sergey Malyshev10, Markku
Rummukainen8, and Ben Smith8
1
Institute for Atmospheric and Climate Science, ETH Zurich, 8092 Zurich, Switzerland
2
KNMI, PO Box 201, NL-3730 AE De Bilt, Netherlands
3
Max Planck Institute for Meteorology, 20146 Hamburg, Germany
4
GFDL, NOAA, PO Box 308, Princeton, NJ 08542-0308, USA
5
The State University of New Jersey, Rutgers, New Brunswick, NJ 08901-855, USA
6
LMD/IPSL, Université Pierre et Marie Curie, 75252 Paris Cedex 05, France
7
NCAR, PO Box 3000, Boulder, CO 80307, USA
8
Lund University, Centre for Environmental and Climate Research, 22362 Lund, Sweden
9
Laboratoire Sisyphe/IPSL, Université Pierre et Marie Curie, 75252 Paris Cedex 05,
France
10
Princeton University, Princeton, NJ 08544-2016, USA
*corresponding author: sonia.seneviratne@env.ethz.ch
Submitted to Geophysical Research Letters, 5 September 2013 (revised)
Supplementary Discussion 1. GLACE-CMIP5 set-up
We provide here some additional information on the GLACE-CMIP5 set-up (see also
main text).
Soil moisture climatology used in experiments A and B
The computation of the soil moisture climatologies are based on 30 years of data for both
experiments (1971-2000 for expA and transient climatology for exp B; see main text for
more details). The exact computation was not prescribed in the GLACE-CMIP5 protocol,
and thus the modeling groups used slightly different approaches (e.g. 30-year averages
for single julian days, 30-year averages for 5 days around every single julian day, or 30year monthly averages linearly interpolated between middle of each month to derive daily
values)
Prescribed soil moisture in the experiments
Only soil moisture is prescribed in the experiments. Soil moisture is prescribed at each
time step and for each model level.
Supplementary Discussion 2. Computation of extreme statistics.
The 95th percentile values for maximum temperature and precipitation (Tmax95 and P95,
respectively) are computed from daily values for the respective seasons (June-JulyAugust, and December-January-February) over the respective 30-year periods (20712100 for Figures 3 and 4, as well as 1971-2000 for Figure 4b). For temperature, they are
thus based on 2700 to 2760 values depending on the considered season and model
(calendars with or without leap years). For precipitation extremes, the statistics are only
computed for wet days (>0.1 mm/d).
Supplementary Discussion 3. Statistical significance of differences in Figure 3.
The hatching in Figure 3 indicates regions in which at least 4 out of 5 models agree on
the sign of change (see also Supplementary Figures 1-8). In addition, we provide in
Supplementary Figure 9 an analysis indicating the number of models with significant
changes for each respective differences. For the differences in mean values (Tmean, Tmax,
Pmean), the statistical significance was tested with the non-parametric Wilcoxon rank sum
test. For the temperature and precipitation extremes (Tmax95, P95) we use an adapted
version of this test assessing the presence of significance differences in estimates of
Tmax95 and P95 derived from 30-year averages of respective yearly statistics.
Supplementary Discussion 4. Computation of regression in Figure 4a.
The analysis in Figure 4a (regression of temperature signals for Tmean, Tmax and Tmax95
with latent heat flux signal) is based on data from the JJA multi-model averages (i.e. JJA
multi-model averages of temperature and latent heat flux at each grid points). The data is
binned according to given changes in latent heat flux (with a bin size of 2.5 Wm2). The
analyses are only provided for grid cells with negative changes in latent heat flux
between expA and expB (i.e. less latent heat flux in expB). Results for bins < -22.5 Wm2
are not provided because they cover a too little number of grid cells.