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posted online with permission "Acid Rain and the Greenhouse Effect" (Fluid Earth, Unit 4, Topic 6)

Aerosols Altered Asian Monsoons Summer monsoons provide much of the water for farming on the Indian subcontinent, but the pattern of rain shifted dramatically during the last half of the 20th century. In a study appearing online 29 September in Science, researchers pin the blame on soot and other aerosols from human activities. From 1951 to 1999, central-northern India became drier while Pakistan, northwestern India, and southern India got wetter. To determine whether these changes were due to natural variability or human interference (greenhouse gases or aerosols), climate scientists Massimo Bollasina, Yi Ming, and V. Ramaswamy of the Geophysical Fluid Dynamics Laboratory/NOAA in Princeton, New Jersey, compared the history of rainfall with simulations that singled out each climate "forcing" factor to observe its impact. Although greenhouse gases would have increased rainfall over north-central India, the aerosols, they found, caused the "very pronounced drying trend," Ming says. Here's why: Under normal conditions, the northern hemisphere receives more energy from the sun from June to September; that imbalance drives the ocean-atmosphere circulation that powers the monsoons. But atmospheric aerosols shaded the northern hemisphere relative to the southern hemisphere, altering the energy balance between the two-weakening the circulation and altering where the rain falls.

Information Science Bounds and Vision Atlas of Science Visualizing What We Know by Katy Börner MIT Press, Cambridge, MA, 2010. 266 pp. $$29.95, £22.95. ISBN 9780262014458. 1. Mason A. Porter + Author Affiliations 1. The reviewer is at the Oxford Centre for Industrial and Applied Mathematics, Mathematical Institute, University of Oxford, Oxford OX1 3LB, UK, and at the CABDyN Complexity Centre and Somerville College, University of Oxford. 1. E-mail: porterm@maths.ox.ac.uk Visualization is a crucial but underappreciated part of science. As venues like the American Physical Society's Gallery of Fluid Motion and Gallery of Nonlinear Images illustrate every year, good visuals can make science more beautiful, more artistic, more tangible, and often more discernible. Katy Börner's continuing exhibition Places & Spaces: Mapping Science (1) and her book Atlas of Science: Visualizing What We Know arise from a similar spirit but are much more ambitious. Visualization is one of the most compelling aspects of science. Breathtaking visuals from sources like fractals and Disneyland's long-dead "Adventure Thru Inner Space" ride are what originally inspired me toward my personal scientific path, so I welcome any resource that promises to bring the visual joys of discovery to a wide audience. Importantly, Börner's exhibition and book are not mere artistic manifestations, although they would be impressive accomplishments even if that were her only goal. Some scientists have occasionally had great success in the visual arts; for example, physicist Eric Heller has long exhibited the gorgeous fruits of his research on quantum chaos and other topics (2). To fully appreciate Börner's efforts, however, one must be conscious that she is deeply concerned not just with visualization itself but with the science of visualization. Accordingly, her book discusses the history of the science of visualization, where it is now, and where she thinks it can go. Atlas of Scie