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Research projects
Here is a brief summary of a few CCSM projects

Marine Life

How will future climate affect marine life and fisheries?

Using CCSM, oceanographers at NCAR, the Woods Hole Oceanographic Institution, and several universities across the country and abroad are finding evidence that predicted ocean changes (including warmer surface temperatures and an increase in freshwater from increased rainfall and melting ice) will have important impacts on the algae that form the base of the entire marine food chain. With more warm freshwater forming a cap on the surface, the saltier, colder, and nutrient-rich water below has less ability to mix into layers closer to the surface, the region the algae inhabit. In the subtropics, a type of algae known as Trichodesmium is likely to become more prevalent because it produces its own nutrients from dissolved nitrogen gas instead of relying on nutrients rising from below. "That’s going to shift how the entire ecosystem works," says Woods Hole’s Scott Doney.

Doney and his colleagues are using CCSM to ask other vital questions about the interplay of ocean physics and marine life. Researchers want to know, for example, if the cycling of material by living organisms will partially offset or perhaps exacerbate human-caused carbon dioxide emissions.

Dirty skies and climate

Field observations over the Indian subcontinent and Southeast Asia, as well as over the Indian Ocean, indicate that these regions are highly polluted due, in part, to the burning of wood and other biomass materials for fuel and cooking. This pollution absorbs a significant amount of sunlight, thus heating the atmosphere and cooling the surface of both land and ocean.

Researchers at the Scripps Institution of Oceanography, led by V. Ramanathan, are using a version of CCSM to explore the climatic effects of pollution in the region. They find that the presence of aerosols from biomass burning indeed cools the surface and that the predicted cooling in the model correlates closely with observations in this region. Perhaps more importantly, the model predicts a significant decrease in monsoon-driven rainfall, which again is supported by observations. Human-produced pollution has altered the availability of rain on the Indian subcontinent—rain that is essential for food production in this densely populated region.

Helping farmers predict the rainy season

Brazil and other South American countries have emerged as major U.S. trading partners, thanks in part to the ability of their farmers to supply consumers with fresh fruits and vegetables yearround. But the farmers are heavily dependent on the rainy season that begins any time between late September and late December—making it difficult for them to know when to start planting their crops.

At the Georgia Institute of Technology, Rong Fu is using CCSM to investigate an important trigger for the rainy season: sea-surface temperatures in the Pacific and Atlantic Oceans. By raising surface temperatures in the Pacific in model experiments, for example, she has found that the rainy season tends to be delayed because rain that would normally reach the Amazon basin instead falls far away in the eastern Pacific Ocean.

Fu believes that weather reports may be issued three to six months before the rainy season if satellite readings of temperature are combined with information about local conditions in the Amazon, such as whether the soil is unusually moist or dry. Forecasters could anticipate both the approximate timing of the rainy season as well as its intensity. “If we are able to predict this,” she says, “it will be very helpful for agriculture.”

     
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