Abstract
The present study aims at comparing total cloud cover (TCC) as simulated by regional climate models (RCM) from CORDEX project with the same variable as simulated by the driving global climate models (GCM), which are part of the fifth phase of the Climate Model Intercomparison Project ensemble. The comparison is performed for the Mediterranean region, and for the 1971–2005 period, when results from the “historical” scenario can also be compared with two data sets of ground-based cloud observations. We work with 14 modeling results (resolution, 0.11° × 0.11°), which are a combination of five GCMs and five RCMs. In general, RCMs improve only very slightly the climatic estimation of TCC when compared with observations. Indeed, not all RCMs behave the same, and some indicators (monthly evolution of the relative bias) show an enhancement, while other indices (overall mean bias and annual range difference) improve only very slightly with respect to GCMs. Changes in the estimate of TCC in summer might be the most relevant value added by RCMs, as these should describe in a more proper way several mesoscale processes, which play a more relevant role in summer. Noticeably, RCMs are unable to capture the observed decadal trend in TCC. Thus, TCC simulated by RCMs is almost stable, in contradiction with observations and GCMs, which both show statistically significant decreasing trends in the Mediterranean area. This result is somewhat unsatisfactory, as if RCMs cannot reproduce past trends in TCC, their skill in projecting TCC into the future may be questioned.
| Original language | English |
|---|---|
| Pages (from-to) | 11,664-11,677 |
| Journal | Journal of Geophysical Research: Atmospheres |
| Volume | 122 |
| Issue number | 21 |
| DOIs | |
| Publication status | Published - 16 Nov 2017 |
Bibliographical note
Publisher Copyright:©2017. American Geophysical Union. All Rights Reserved.
Funding
This research was supported by the Spanish Ministry of Science and Innovation (currently Ministry of Economy and Competitiveness) Project CGL2014-55976-R. The third author was supported by the postdoctoral fellowship JCI-2012-12508. The authors acknowledge the World Climate Research Programme's Working Groups on Regional Climate and on Coupled Modeling, which is the former coordinating body of CORDEX and the responsible panel for CMIP5, and we also thank the climate modeling groups for producing and making available their model outputs. No new data have been generated in this research. Data from climate models are available at the CMIP5 and CORDEX data servers, as well as in other secondary servers (https://cmip.llnl.gov/cmip5/data_portal.html; http://euro-cordex.net/060378/index.php.en). Urs Beyerle from the Institute for Atmospheric and Climate Science, ETH Zurich, helped us in accessing model results, in particular for EC-Earth (http://iacweb.ethz.ch/staff/beyerleu/welcome/). EECRA gridded data were generated by Joel Norris from Scripps Institution of Oceanography and can be accessed through https://climatedataguide.ucar.edu/climate-data/extended-edited-synoptic-cloud-reports-archive-eecra-ships-and-land-stations-over-globe. Most cloudiness observations are readily available at the European Climate Assessment and Dataset site (ECA&D, www.ecad.eu). Additional cloudiness data were obtained upon request from the Spanish Meteorological Agency (Aemet, www.aemet.es) and the Turkish State Meteorological Service (https://mgm.gov.tr/eng/forecast-cities.aspx). The three referees, and in particular Sonia Jerez, constructively contributed to improve this paper. This research was supported by the Spanish Ministry of Science and Innovation (currently Ministry of Economy and Competitiveness) Project CGL2014-55976-R. The third author was supported by the postdoctoral fellowship JCI-2012-12508. The authors acknowledge the World Climate Research Programme’s Working Groups on Regional Climate and on Coupled Modeling, which is the former coordinating body of CORDEX and the responsible panel for CMIP5, and we also thank the climate modeling groups for producing and making available their model outputs. No new data have been generated in this research. Data from climate models are available at the CMIP5 and CORDEX data servers, as well as in other secondary servers (https:// cmip.llnl.gov/cmip5/data_portal.html; http://euro-cordex.net/060378/index. php.en). Urs Beyerle from the Institute for Atmospheric and Climate Science, ETH Zurich, helped us in accessing model results, in particular for EC-Earth (http://iacweb.ethz.ch/staff/beyerleu/ welcome/). EECRA gridded data were generated by Joel Norris from Scripps Institution of Oceanography and can be accessed through https://climatedata-guide.ucar.edu/climate-data/extended-edited-synoptic-cloud-reports-archive-eecra-ships-and-land-stations-over-globe. Most cloudiness observations are readily available at the European Climate Assessment and Dataset site (ECA&D, www.ecad.eu). Additional cloudiness data were obtained upon request from the Spanish Meteorological Agency (Aemet, www. aemet.es) and the Turkish State Meteorological Service (https://mgm. gov.tr/eng/forecast-cities.aspx). The three referees, and in particular Sonia Jerez, constructively contributed to improve this paper.
| Funders | Funder number |
|---|---|
| Intelligence Community Postdoctoral Research Fellowship Program | |
| Ministerio de Economía y Competitividad | CGL2014-55976-R, JCI-2012-12508 |
| Ministerio de Ciencia e Innovación |
Keywords
- Mediterranean region
- global climate models
- regional climate models
- total cloud cover
- trends