12.12.2012 Views

chapter - Atmospheric and Oceanic Science

chapter - Atmospheric and Oceanic Science

chapter - Atmospheric and Oceanic Science

SHOW MORE
SHOW LESS

Create successful ePaper yourself

Turn your PDF publications into a flip-book with our unique Google optimized e-Paper software.

Climate scenarios<br />

The reliability of future climate scenarios obtained from GCMs is based on their<br />

ability to represent current climate <strong>and</strong> its variability. Gates et al. (1999) presents<br />

results of some simulations on current climate made in the context of the <strong>Atmospheric</strong><br />

Model Intercomparison Project (AMIP). The largest errors correspond to cloud cover<br />

<strong>and</strong> temperature at 200 hPa, while the lowest ones are in the surface temperature. The<br />

outputs related to the global hydrological processes within the AMIP project were<br />

analyzed by Lau et al. (1996) from the analysis of 29 GCMs. Although it is observed<br />

a great variability among the different models, when considering an ensemble of<br />

them, the result is very close to the observations showing an overestimation in the<br />

tropical precipitation <strong>and</strong> an underestimation in the extra-tropics.<br />

Results of GCMs developed by a group of institutes with high scientific <strong>and</strong><br />

computer capability are available through the web page of the Data Distribution<br />

Centre (DDC) of the IPCC (www.dkrz.de/ipcc/ddc/html/SRES/SRES_all.html).<br />

Table 12.1 shows a list of models <strong>and</strong> the institutions that developed them. Their validation<br />

for the climate of Southeastern South America is presented in Chapter 13.<br />

Table 12.1. GCM with information available through the DDC.<br />

Model Institution Current period Future period<br />

HADCM3<br />

Hadley Centre for Climate Prediction<br />

<strong>and</strong> Research (Reino Unido)<br />

12.6. Climate change scenarios from GCMs<br />

In the previous section, the difficulties of the GCMs to represent current climate<br />

were mentioned. This imposes limitations on the reliability of the scenarios of<br />

future climate. Likewise, it is necessary to validate the GCMs outputs at a regional<br />

level before using them in the preparation of scenarios. A way to elaborate climate<br />

change scenarios based on GCMs despite of errors that they show in the representation<br />

of current climate consists of preparing scenarios of differences between<br />

what is foreseen by GCMs for the future <strong>and</strong> its representation for the current baseline<br />

climate. This way, it is obtained a spatial distribution of the change in climate<br />

variables based exclusively on one GCM results.<br />

158<br />

1950-1999 2000-2100<br />

Australia's Commonwealth Scientific<br />

CSIRO-mk2 <strong>and</strong> Industrial Research Organization 1961-1999 2000-2100<br />

(Australia)<br />

ECHAM4/ Max Planck Institute<br />

OPYC3 für Meteorologie (Alemania)<br />

GFDL-R30<br />

NCAR-PCM<br />

CCCma<br />

Geophysical Fluid Dynamics<br />

Laboratory (Estados Unidos)<br />

National Centre for <strong>Atmospheric</strong><br />

Research (Estados Unidos)<br />

Canadian Center for Climate<br />

Modeling <strong>and</strong> Analysis (Canadá)<br />

1990-1999 2000-2100<br />

1961-1999 2000-2100<br />

1981-1999 2000-2100<br />

1950-1999 2000-2100

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!