Wednesday, February 13, 2008

Global Climate Models

This interesting article addresses some of the key issues regarding Global Climate Models. A careful reading of this material could make a big difference in how you think about Global Climate Models.

If you base what you do on inaccurate information, you might be unpleasantly surprised by the consequences. Make sure you get the whole Global Climate Models story from informed sources.

The class of computer-driven models known as General Circulation Models or simply GCMs used for weather forecasting, understanding climate and projecting climate change are commonly called Global Climate Models. Syukuro Manabe and Kirk Bryan at the Geophysical Fluid Dynamics Laboratory in Princeton, New Jersey created the versions calculating decade to century time scale climate applications. These Global Climate Models are computer intensive numerical models based on the integration of a variety of dynamic, chemical, and biological equations.

Global Climate Models are differential equations based on the basic laws of physics, fluid motion, and chemistry. To implement a model, researchers divided the earth into a 3-dimensional grid, applying the basic equations, and evaluated the results. The atmospheric climate models are used to calculate the speed of winds, heat transfer, radiation, relative humidity, and surface hydrology within each grid and estimate relations with neighboring points. A major focus of Global Climate Models is to study the possibilities for humans to impact the climate and the impact of a changing climate on society and the environment. Climate Models developmental research aims on the formations of clouds and moist convection, ground hydrology, and the interaction between ocean atmosphere and ice, and also investigates more accurate numerical methods to determine climate change and its impact on society and environment. The program also focuses on developing techniques to deduce the properties of global cloud from measurements of satellite radiance of the International Satellite Cloud Climatology Project. Ongoing field and laboratory programs in palynology, paleoclimate reconstruction, and other geophysical sciences offer essential data on climate for evaluating and validating model predictions.

The use of the Global Climate Models is primarily emphasized on investigation of climate sensitivity, including the climate system's response to such force like solar variability, anthropogenic and natural emissions of greenhouse gases and aerosols, etc. The Global Climate Models also focuses on the global ocean circulation. Paleoclimatic evidence proposes that past climate shifts such as the glacial-interglacial cycles were connected with changes in the formation of the North Atlantic deep-water. This circulation inflicted transportation of strong northward heat, making the northern North Atlantic about 4°C warmer than corresponding latitudes in the Pacific. Climate variations in ocean circulation can cause significant climate change.

Various studies on Global Climate Models indicate that meltwater of dying continental ice masses might have led to the end of the formation of North Atlantic deep water, slowed down circulation, and cooled northern hemisphere climate. paleoclimatic records show that melted water from glacier has entered the Atlantic Ocean during a warm period preceding the Younger Dryas. a recent scenario supported by paleoceanographic data have resolved this absurdity and model simulations that water crossing the Greenland-Scotland Ridge inhibited a breakdown of the ocean circulation. This helped Europe to maintain the mild climatic condition during the Bolling warm period, despite the massive influx of meltwater.

A recent trend in GCMs is to extend them to become Earth system models which include sub-models for atmospheric chemistry or a carbon cycle model to predict changes in the levels of carbon dioxide due to changes in emissions.

As your knowledge about Global Climate Models continues to grow, you will begin to see how Global Climate Models fits into the overall scheme of things. Knowing how something relates to the rest of the world is important too.

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