- 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 firstname.lastname@example.org,
- 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
node after checking for their compliance with the
specifications outlined in this document using the tools
available for automated quality assurance.
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 followed.
The CORDEX South Asia RCM outputs shared by the
modeling partners 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. The details of the few selected CORDEX
South Asia multi-model output variables available for download
are provided on the webpage: FTP Datasets
The quality checked CCCR-IITM climate model datasets
(CORDEX-South Asia and CMIP6) are being published on the
CCCR-IITM Earth System Grid Federation (ESGF) Data Node. The
ESGF maintains a global system of federated data centers that
allow access to the largest archive of climate data
world-wide. 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
CORDEX-South Asia Datasets
- For publications that use the CORDEX South Asia model
outputs, an appropriate credit as mentioned in the CORDEX
must be given to the 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) 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.”
- Flato, G., J. and Coauthors, 2013: Evaluation of
Climate Models. In: Climate Change 2013:
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.
- Meinshausen M., S.J. Smith, K. Calvin, J.S. Daniel,
M.L.T. Kainuma, and et al., 2011:
The RCP greenhouse
gas concentrations and their extensions from 1765 to 2300.
Climatic Change, 109, 213-241.
- Sanjay J., M.V.S. Ramarao, M. Mujumdar and R.
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, 2012:
An Overview of CMIP5 and the Experiment Design. Bull. Amer.
Meteor. Soc., 93, 485–498.