Eos, Vol. 94, No. 22, 28 May 2013
VOLUME 94
NUMBER 22
28 MAY 2013 EOS, TRANSACTIONS, AMERICAN GEOPHYSICAL UNION
PAGES 197–204
An Interactive Web Application for Visualizing Climate Data
model’s simulation of historical (1980–2004) and future climatologies. The histograms provide an intuitive way of summarizing the distribution of climate change simulated by all the models for a selected country and month of the year. The application also provides a detailed interactive summary table that includes annual root-mean-square error (a measure of how well the model simulates the seasonal cycle), bias relative to the observations, and future change anomalies. The interactive table offers insight into biases of all models for a selected country. In addition, the GCCV application provides more than 20,000 downloadable time series figures of temperature and precipitation from 1850 to 2100 that include tables in which present and future changes are summarized in quantiles. Finally,
PAGES 197–198 Massive volumes of data are being created as modeling centers from around the world finalize their submission of climate simulations for the Coupled Model Intercomparison Project, phase 5 (CMIP5), in preparation for the forthcoming Intergovernmental Panel on Climate Change (IPCC) Fifth Assessment Report (AR5). Scientists, resource managers, and other potential users of climate data are faced with the daunting task of analyzing, distilling, and summarizing this unprecedented wealth of climate information. To aid in this task, in late 2012 the U.S. Geological Survey, in collaboration with Lawrence Livermore National Laboratory, created the Global Climate Change Viewer (GCCV, http://regclim.coas.oregonstate.edu/ gccv) Web application to provide basic visualization of the CMIP5 data sets. The GCCV application is a user-friendly, interactive interface that summarizes simulated future changes in temperature and precipitation for each country (Figure 1). Users can visualize global and country- specific spatial patterns of change, compare present- day simulations with observations, and display the distribution of climate change for a given country. The application Web page includes documentation for describing in detail the methods and data sets used to create the data displayed by the GCCV. Through the GCCV application, users have access to some of the 1.8 petabytes of climate model data from a variety of CMIP5 experiments [Taylor et al., 2012] that the Earth System Grid Federation (ESGF) is currently hosting. ESGF is a multiagency, international collaboration that is developing, deploying, and maintaining software infrastructure for the management of model output and observational data. For CMIP5, the ESGF is expected to archive more than 3 petabytes of data.
GCCV Application Components The GCCV application comprises three main components: global maps of temperaBY J. ALDER, S. HOSTETLER, AND D. WILLIAMS
ture and precipitation anomalies (future minus present), climographs of monthly data (graphical representations of the seasonal cycle) for a selected country, and histograms detailing the distribution of anomalies from the available models (Figure 1). More than 5000 possible combinations of maps are available for monthly and annual temperature and precipitation for all models, emission scenarios, and months. The climographs enable users to interactively compare observed data (Climatic Research Unit time series 3.10 [Mitchell and Jones, 2005]) to a
Fig. 1. (top) The Global Climate Change Viewer (GCCV), showing the representative concentration pathway RCP8.5 ensemble mean annual temperature change for 2050–2074. The RCP8.5 scenario is the highest emission scenario used in the Intergovernmental Panel on Climate Change Fifth Assessment Report. (bottom left) The observed (1980–2004), simulated 1980–2004, and simulated 2050–2074 climatologies for the United States. (bottom right) The annual mean temperature changes for the United States from 26 models.
This paper is not subject to U.S. copyright. Published in 2013 by the American Geophysical Union.
Eos, Vol. 94, No. 22, 28 May 2013 GCCV includes Web links to the ESGF portal, where the primary model data sets can be downloaded for additional analysis.
The Models The GCCV application includes data from all CMIP5 models available on the ESGF without current use restrictions for all four representative concentration pathways (RCP) emission scenarios that will be used by the IPCC for AR5. Each RCP scenario represents a range of radiative forcing—the difference between incoming energy from the Sun and energy radiated back into space—in the year 2100. For instance, RCP2.6 is a scenario with an increased radiative forcing of 2.6 watts per square meter in 2100. Data from each simulation are averaged into 25-year climatology periods that span the 21st century. The emission scenarios (number of models contributing to each scenario) are RCP2.6 (19 models), RCP4.5 (23 models), RCP6.0 (15 models), and RCP8.5 (26 models). The GCCV application also includes the unrestricted models participating in the Paleoclimate Modelling Intercomparison Project, phase 3 [Braconnot et al., 2011] for the mid-Holocene (6000 years ago, with seven models) and Last Glacial Maximum (21,000 years ago, with four models). A detailed table is provided on the GCCV Web page documenting which ensemble number and physics version was used for each model.
The countrywide averages used in the GCCV application are derived from global models, which use relativity coarse model grids. Small countries may thus contain only a few model grid cells, giving a very generalized average temperature and precipitation. As such, GCCV is not intended as a replacement for downscaling global climate simulations.
Use for Outreach and Education
CMIP5 data sets were downloaded and summarized, and the summaries are made available, but the raw data are not. Future versions of the GCCV will map and summarize the model simulations in real time by streaming data directly from the ESGF. Better integration with ESGF will allow users easy access into other model intercomparison projects, observation data, and reanalysis products associated with CMIP5.
The GCCV’s Web-based application is well suited for public outreach and education. Frequently, global climate change information is conveyed to the public as a single number or range of how many degrees the Earth will warm. The GCCV application provides a way to display to nonscientists the spatial and seasonal expression of climate change, as opposed to one global annually averaged number derived from an ensemble of climate models. The histogram, for example, illustrates the distribution of model simulations for a country of interest and allows a user to explore how different emission scenarios translate into climate change. For more advanced users, the climographs and summary tables can be used to begin a conversation about model bias and their implications on model interpretation.
References
Looking Forward
—J. Alder, U.S. Geological Survey (USGS), Corvallis, Oreg.; E-mail:
[email protected]; S. Hostetler, USGS, Corvallis, Oreg.; and D. Williams, Lawrence Livermore National Laboratory, Livermore, Calif.
The initial release of the GCCV application employs an offline analysis approach. The
This paper is not subject to U.S. copyright. Published in 2013 by the American Geophysical Union.
Braconnot, P., S. P. Harrison, B. Otto- Bliesner, A. Abe- Ouchi, J. Jungclaus, and J.-Y. Peterschmitt (2011), The Paleoclimate Modeling Intercomparison Project contribution to CMIP5, CLIVAR Exch. 56, pp. 15–19, Int. CLIVAR Proj. Off., Southampton, U. K. Mitchell, T. D., and P. D. Jones (2005), An improved method of constructing a database of monthly climate observations and associated highresolution grids, Int. J. Climatol., 25, 693–712, doi:10.1002/joc.1181. Taylor, K. E., R. J. Stouffer, and G. A. Meehl (2012), An overview of CMIP5 and the experiment design, Bull. Am. Meteorol. Soc., 93, 485–498, doi:10.1175/BAMS-D-11-00094.1.
