Mark Flanner's Homepage

Research

My research interests encompass a broad range of physical and biogeochemical interactions within Earth's climate system.

Topics I am currently exploring include:

» Snow darkening from absorbing particles (more, 2007 JGR paper ©AGU, 2007 Science paper ©AAAS)
» Snow-albedo feedback (article in ACP-Discussions)
» Snowpack microphysics (2006 JGR paper ©AGU)
» Aerosol influence on carbon uptake in the Amazon (poster presented at Fall 2007 AGU meeting)
» Anthropogenic heat flux (more)
» Climate forcing of fires (2006 Science paper ©AAAS)

Peer-reviewed publications (reverse chronological order)

9) Flanner, M. G., C. S. Zender, P. G. Hess, N. M. Mahowald, T. H. Painter, V. Ramanathan, and P. J. Rasch (2009), Springtime warming and reduced snow cover from carbonaceous particles, Atmos. Chem. Phys., 9, 2481-2497. (pdf © 2009 by the authors).

8) Flanner, M. G. (2009), Integrating anthropogenic heat flux with global climate models, Geophysical Research Letters, 36, L02801, doi:10.1029/2008GL036465 (pdf © 2009 by AGU).

7) Quinn, P. K., T. S. Bates, E. Baum, N. Doubleday, A. M. Fiore, M. Flanner, A. Fridlind, T. J. Garrett, D. Koch, S. Menon, D. Shindell, A. Stohl, and S. G. Warren (2008), Short-lived pollutants in the Arctic: Their climate impact and possible mitigation strategies, Atmos. Chem. Phys., 8, 1723-1735 (pdf © 2008 by the authors).

6) McConnell, J. R., R. Edwards, G. L. Kok, M. G. Flanner, C. S. Zender, E. S. Saltzman, J. R. Banta, D. R. Pasteris, M. M. Carter, and J. D. W. Kahl (2007), 20th Century industrial black carbon emissions altered Arctic climate forcing, Science, 317, 1381-1384 (pdf © 2007 by AAAS).

5) Flanner, M. G., C. S. Zender, J. T. Randerson, and P. J. Rasch (2007), Present day climate forcing and response from black carbon in snow, J. Geophys. Res., 112, D11202, doi:10.1029/2006JD008003 (pdf © 2007 by AGU).

4) Painter, T. H., N. P. Molotch, M. Cassidy, M. Flanner, and K. Steffen (2007), Contact spectroscopy for determination of stratigraphy of snow grain size, J. Glaciol., 53, 180, 121-127 (pdf © 2007 by IGS).

3) Randerson, J. T., H. Liu, M. G. Flanner, S. D. Chambers, Y. Jin, P. G. Hess, G. Pfister, M. C. Mack, K. K. Treseder, L. R. Welp, F. S. Chapin, J. W. Harden, M. L. Goulden, E. Lyons, J. C. Neff, E. A. G. Schuur and C. S. Zender (2006), The impact of boreal forest fire on climate warming, Science, 314, 1132-1134 (pdf © 2006 by AAAS).

2) Flanner, M. G., and C. S. Zender (2006), Linking snowpack microphysics and albedo evolution, J. Geophys. Res., 111, D12208, doi:10.1029/2005JD006834 (pdf © 2006 by AGU).

1) Flanner, M. G., and C. S. Zender (2005), Snowpack radiative heating: Influence on Tibetan Plateau climate, Geophys. Res. Lett., 32, L06501, doi:10.1029/2004GL022076 (pdf © 2005 by AGU), Erratum: Figure 3 caption reverses top and bottom panel descriptions.

Snow darkening from atmospheric particles

Small concentrations of particles that absorb solar radiation (e.g., black carbon, mineral dust, and volcanic ash) can significantly darken snow surfaces (see below). The resulting increase in absorbed energy can induce early melt and trigger snow albedo feedback, arguably the most powerful positive feedback mechanism currently operating in Earth's climate system. Changes in melt timing and magnitude also have important consequences for the 1+ billion people who rely on seasonal snow and glacier melt for potable water.

An important snowpack property that controls the magnitude of albedo reduction from impurities, and the albedo of the snow itself, is the effective grain size (essentially the surface area of the ice crystals divided by their mass). My research also examines factors which govern the time-evolution of this quantity. To study these processes, I develop and apply numerical models of radiative transfer and snow microphysics, and adapt them for suitable use in climate models. These tools help us identify global-scale cryospheric feedback mechanisms and strengths.

Below is the influence of 1 gram (about the mass of a paper clip) of black carbon dispersed on a square meter of snow at Niwot Ridge, Colorado:

5 days later... the height of the snow surface was reduced 15 cm.
(Photo courtesy of Mark Losleben, Niwot Ridge LTER)