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Thursday, 6 January 2011

AGU10 Robert P. Sharp lecture - Doug Jerolmack

Click the image to link to the video of the lecture
One of the highlights of the AGU Fall Meeting in San Francisco on 17th December this year was the inaugural Robert P. Sharp lecture, given by Doug Jerolmack from the University of Pennsylvania. The Earth and Planetary Surface Processes section gave two new awards this year, Bill Dietrich being the other awardee. Doug gave a very entertaining talk titled "Noise is the new signal: Moving beyond zeroth-order geomorphology".
Doug's lecture aimed to 'celebrate variability' in every aspect of geomorphology, rather than just averaging it out to look for a primary signal. He discussed the importance of timescale in measuring rates of surface processes, and how what we call a transient feature of a landscape changes its behaviour depending on the timescale over which we observe it. This can even be seen in totally uniform grains, as sediment transport will alter the organisation of their bed structures and so change the threshold for entrainment, as seen in work by Charru et al., (2004). We had a whistle-stop tour of the behaviour of rice grains flowing downslope, avulsion timescales, how the inactive proportion of an alluvial fan decays with a harmonic function over time (Cazanacli et al., 2002) and finished up with the noise-induced stability of turbulence. All in, a great round-up of the state of play in studies of sediment transport, and the future of geomorphology. The video is available at the AGU website for those who missed it.