The quizzes have been postponed!

• New dates for Quiz #2 and Quiz #3 are now set respectively at the 12th of November, and the 5th of December.

• There will be some homework assignments starting from next class.

Climate modeling: Successes and Challenges

• A little history about climate modeling

• Some basic concepts in the numerical modeling of climate

• Successes

• Challenges

• The future of climate modeling

A little history about climate modeling

• Swedish scientist Svante Arrhenius

(Year:1896)

A little history about climate modeling

• Manabe’s 3D GCM • Syukuro Manabe

Geophysical Fluid Dynamics Laboratory (GFDL)

Some basic concepts

• The Newton’s law applied to the atmosphere and ocean; the conservation of mass, heat, water, etc….

• Represent the atmosphere, the ocean, and other components in the climate system by a set of boxes--the concept of grid and the issue of spatial resolution

• The time step for integration• Numerical instability--constraints on the time step

from the spatial resolution• Parameterization of sub-grid scale phenomena

Successes and challenges

• Simulation of the surface air temperature

Successes and challenges

• Simulation of the precipitation

Successes and challenges

Simulation of the ocean temperature

Successes and challenges

• Simulation of the sea-ice

Successes and challenges

• Simulation of the snow extent

Successes and challenges

• Variability--power spectrum

Successes and challenges

• Vertical structure of temperature

Successes and challenges

• Simulation of El Nino warming

Successes and challenges

Forecast of the 1997-98 El Nino

The future of climate modeling

• High spatial and temporal resolution• A better parameterization of sub-scale processes• Better observations--improved spatial and

temporal coverage of the observational network• Improved understanding of the

interactions/feedback loops among the components of the climate system

• A better understanding of the model world-model diagnostics

Model Diagnostics: Evaluating Key Climate Feedbacks

Model Diagnostics: Evaluating Key Climate Feedbacks

• Water vapor feedback• Cloud feedbacks• Atmospheric circulation feedbacks• Ocean feedbacks• Land surface feedbacks• Biosphere feedbacks• Societal feedbacks

Model Diagnostics: Evaluating cloud feedbacks

Model Diagnostics: Evaluating Cloud Feedbacks