- Recommended Use
- The World Climate Research Programme (WCRP)
Coordinated Regional Climate Downscaling Experiment (CORDEX)
dataset for South Asia region is provided to assist the
science community in conducting studies of climate change
impacts at regional scales, and to enhance public
understanding of possible future climate patterns at the
spatial scale of homogenous regions. This dataset is intended
for use in scientific research only, and use of this dataset
for other purposes, such as commercial applications, and
engineering or design studies is not recommended without
consultation with a qualified expert. User feedback to improve
and validate the dataset for modeling usage is appreciated.
- Email comments to email@example.com,
- Dataset and Methods
- The WCRP CORDEX foster international partnership in
order to produce an ensemble of high-resolution past and
future climate projections at regional scale. This CORDEX
dataset is comprised of downscaled climate scenarios for the
South Asia region that are derived from the Atmosphere-Ocean
coupled General Circulation Model (AOGCM) runs conducted under
the Coupled Model Intercomparison Project Phase 5 (CMIP5)
[Taylor et al. 2012] and using three of the four greenhouse
gas emissions scenarios known as Representative Concentration
Pathways (RCPs) [Meinshausen et al. 2011]. The CMIP5 AOGCM
runs were developed in support of the Fifth Assessment Report
of the Intergovernmental Panel on Climate Change (IPCC AR5).
The coarser spatial resolution ranging from 1.0° to 3.8°, and
systematic error (called bias) of these AOGCMs limits the
examination of possible impacts of climate change and
adaptation strategies on a smaller scale. The CORDEX South
Asia dataset includes dynamically downscaled projections from
the 10 models and scenarios for which daily scenarios were
produced and distributed under CMIP5. The purpose of these
datasets is to provide a set of high resolution (50 km)
regional climate change projections that can be used to
evaluate climate change impacts on processes that are
sensitive to finer-scale climate gradients and the effects of
local topography on climate conditions.
The dynamical downscaling method using high resolution limited area regional
climate models (RCMs) utilizes the outputs provided by AOGCMs
as lateral boundary condition to provide physically consistent
spatiotemporal variations of climatic parameters at spatial
scales much smaller than the AOGCMs’ grid. The RCMs by
resolving the topographical details, coastlines, and
land-surface heterogeneities allow the reproduction of
small-scale processes and information that are most useful for
impact assessment and in decision making for adaptation (Flato
et al. 2013). An initial assessment of the ability of the
CORDEX RCMs to simulate the general characteristics of the
Indian climate indicated that the geographical distribution of
surface air temperature and seasonal precipitation in the
present climate for land areas in South Asia is strongly
affected by the choice of the RCM and boundary conditions
(i.e. driving AOGCMs), and the downscaled seasonal averages
are not always improved (Sanjay et al. 2017).
- File Format and Data Access
- The CORDEX Archive Design document (Cordex Archive Specifications) specifies
technical aspects of CORDEX archive file and data formats, as
well as archive content. The data is published on the Earth
System Grid Federation (ESGF) data nodes by the contributing
CORDEX modeling centers after checking for their compliance
with the specifications outlined in the archive design
document using the tools available for automated quality
assurance. The ESGF maintains a global system of federated
data centers that allow access to the largest archive of
climate data world-wide. Data files comply with the NetCDF
format, version 4 compressed with zlib deflation, using the
NetCDF 4 classic data model. The CF convention 1.4 is
CCCR-IITM is the nodal agency for coordinating the CORDEX modeling activity in South Asia
The CCCR-IITM and several international partner institutions
have contributed towards generation and evaluation of regional
climate simulations for CORDEX South Asia. Table 1 lists the
details of the 17 CORDEX South Asia RCM outputs available on
ESGF. This dataset includes the ensemble of high resolution
(50 km) downscaled projections of regional climate and monsoon
over South Asia until 2100 generated by CCCR-IITM using the
RegCM4 RCM developed and maintained by ICTP (Giorgi et al.
2012). The CORDEX South Asia output from this IITM-RegCM4 RCM
are archived and published on the CCCR-IITM ESGF data node
dissemination to users. The list of CORDEX South Asia (domain
WAS-44, WAS-44i) multi-model output variables available for
download from ESGF and the details for data access are
provided on the webpage: (http://cccr.tropmet.res.in/home/esgf_data.jsp)
Additionally, the raw CORDEX South Asia RCM outputs shared by
the modeling partners, which do not strictly conform to the
CORDEX archive design specifications, are archived and
published on the CCCR-IITM climate data portal designed to
facilitate the dissemination of climate information using a
publicly accessible FTP and web-based interface (http://cccr.tropmet.res.in/home/old_portals.jsp).
Table 2 lists the details of the RCM outputs available on this CORDEX
South Asia regional data bank. The details of the few selected
CORDEX South Asia multi-model output variables available for
download are provided on the webpage: (http://cccr.tropmet.res.in/home/ftp_data.jsp)
- For publications that use the CORDEX South Asia model
data providers by an acknowledgement similar to the following:
“The World Climate Research Programme's Working Group on
Regional Climate, and the Working Group on Coupled Modelling,
former coordinating body of CORDEX and responsible panel for
CMIP5 are gratefully acknowledged. The climate modeling groups
(listed in Table 1 and Table 2) are sincerely thanked for
producing and making available their model output. The authors
thank the Earth System Grid Federation (ESGF) infrastructure
and the Climate Data Portal hosted at the Centre for Climate
Change Research (CCCR), Indian Institute of Tropical
Meteorology (IITM) for providing CORDEX South Asia data.”
- Dobler, A., and B. Ahrens (2008)
Precipitation by a regional climate model and bias correction
in Europe and South Asia, Meteorol. Z., 17, 499–509.
- Flato, G., J. and Coauthors, 2013:
Evaluation of Climate Models. In: Climate Change 2013:
The Physical Science Basis. Contribution of Working Group I to
the Fifth Assessment Report of the Intergovernmental Panel on
Climate Change [Stocker, T.F., D. Qin, G.-K. Plattner, M.
Tignor, S.K. Allen, J. Boschung, A. Nauels, Y. Xia, V. Bex and
P.M. Midgley (eds.)]. Cambridge University Press, Cambridge,
United Kingdom and New York, NY, USA.
- Giorgi, F. and Coauthors (2012)
model description and preliminary tests over multiple CORDEX
domains. Clim Res 52:7–29.
- McGregor, J. L., and M. R. Dix (2001)
CSIRO Conformal-Cubic Atmospheric GCM. IUTAM Symposium on
Advances in Mathematical Modelling of Atmosphere and Ocean
Dynamics, P. F. Hodnett, Ed., Kluwer: Dordrecht, 197–202.
- Meinshausen M., S.J. Smith, K. Calvin, J.S.
Daniel, M.L.T. Kainuma, and et al., 2011:
greenhouse gas concentrations and their extensions from 1765
to 2300. Climatic Change, 109, 213-241.
- Sabin, T. P. and Coauthors (2013)
resolution simulation of the South Asian monsoon using a
variable resolution global climate model. Clim Dyn 41:173–194.
- Samuelsson, P. and Coauthors (2011)
Rossby Centre regional climate model RCA3: Model description
and performance. Tellus, 63A, 4–23.
- Sanjay J., M.V.S. Ramarao, M. Mujumdar and
R. Krishnan, 2017:
Regional climate change scenarios.
Chapter of book: Observed Climate Variability and Change over
the Indian Region. Editors: M. N. Rajeevan and Shailesh Nayak,
Springer Geology, pp. 285-304, doi: 10.1007/978-981-10-2531-0.
- Taylor K. E., R. J. Stouffer, G. A. Meehl,
An Overview of CMIP5 and the Experiment Design.
Bull. Amer. Meteor. Soc., 93, 485–498.
- Teichmann C, Eggert B, Elizalde A, Haensler
A, Jacob D, Kumar P, Moseley C, Pfeifer S, Rechid D, Remedio
A, Ries H, Petersen J, Preuschmann S, Raub T, Saeed F, Sieck
K, Weber T (2013)
How does a regional climate model modify
the projected climate change signal of the driving GCM: A
study over different CORDEX regions using REMO, Atmosphere,