Department of Earth Sciences
Newton Horace Winchell School of Earth Sciences


Katsumi Matsumoto

Office: 

385-12 Tate Hall

Phone: 
612-624-0275
Email: 
katsumi@umn.edu

Professor
PhD, 2000, Columbia University

Biogeochemical Cycles Research Group

 

Research Interests

With training in oceanography and geochemistry, I conduct research on carbon cycle and climate change. In recent years, my focus has been on the global ocean and Lake Superior, which both comprise a complex natural network involving mechanisms of fluid interaction, biogeochemistry, and chemical exchange. Upper circulation is strongly influenced by winds. Deep circulation is driven in part by density gradients that arise from variations of water temperature and salt content. Both are influenced on large scales by Coriolis forces. Vertical mixing can bring nutrients from the deep to the near surface where plant and animal life can flourish. Cold surface waters at the two poles soak up more CO2 from the atmosphere than warm waters elsewhere. These processes are represented in numerical models of the earth system, global ocean, and Lake Superior. My research group tries to characterize the biogeochemical controls of air-sea CO2 exchange and carbon distribution within the ocean both at the present time and times of ice age climate. We also study Lake Superior, the largest lake in the world by surface area. It is undergoing significant change, with ice out days coming earlier and summertime surface waters becoming warmer.  My group is focused on the lake-wide carbon cycle and distribution of phytoplankton. We are also interested in documenting and understanding the formation and migration of the Lake Superior thermal bar (progressive seasonal warming from the shores to open waters) using satellite imagery and numerical modeling.

 

Courses Taught

  • Oceanography
  • Earth Surface Dynamics
  • Introductory Geology Field Camp
  • Science and Politics of Global Warming
  • Biogeochemical Cycles in the Ocean
  • Graduate seminars

 

Selected Publications

  • Matsumoto, K., K. Tokos, and *C. Gregory, Ventilation and dissolved oxygen cycle in Lake Superior: Insights from a numerical model, Geochemistry, Geophysics, Geosystems, 16, doi:10.1002/2015GC005916, 2015.
  • Matsumoto, K., Z. Chase, and K. Kohfeld, Different mechanisms of silicic acid leakage and their biogeochemical consequences, Paleoceanography, 29, doi:10.1002/2013PA002588, 2014.
  • Matsumoto, K. and Y. Yokoyama, Atmospheric Δ14C reduction in simulations of Atlantic overturning circulation shutdown, Global Biogeochemical Cycles, 27, 1-9, doi:10.1002/gbc.20035, 2013.
  • *McKinney, P., B. Holt, and K. Matsumoto, Small eddies observed in Lake Superior using SAR and sea surface temperature data, J. Great Lakes Research, 38, 786-797, 2012.
  • *White, B. and K. Matsumoto, Causal mechanisms of the deep chlorophyll maximum in Lake Superior: A numerical modeling investigation, J. Great Lakes Research, 38, 504-513, 2012.
  • Lee, S., J. H. Chiang, K. Matsumoto, and K. Tokos, Southern Ocean wind response to North Atlantic cooling and the rise in atmospheric CO2: Modeling perspective and paleoceanographic implications, Paleoceanography, 26, PA1214, doi:10.1029/2010PA002004, 2011.
  • Matsumoto, K., K. Tokos, M. O. Chikamoto, and A. Ridgwell, Characterizing postindustrial changes in the oean carbon cycle in an Earth system model, Tellus, 62B, 296-313, 2010.
  • Matsumoto, K., Biology-mediated temperature control on atmospheric pCO2 and ocean biogeochemistry, Geophysical Research Letters, 34, L20605, doi:10.1029/2007GL031301, 2007.
  • Matsumoto, K., Radiocarbon-based circulation age of the world oceans, J. Geophysical Research, 112, C09004, doi:10.1029/2007JC004095, 2007.
  • Contributing author to Jansen, E., J. Overpeck, and others, Paleoclimate, Chapter 6 inClimate Change 2007: The Physical Science Basis. Contribution of WG1 to the Fourth Assessment Report of the IPCC, edited by S. Solomon and others. Cambridge University Press, 2007.
  • Matsumoto, K. and N. Gruber, How accurate is the estimation of anthropogenic carbon in the ocean? An evaluation of the DC* method, Global Biogeochemical Cycles, 19, GB3014, doi:10.1029/2004GB002397, 2005.
  • Matsumoto, K. and 35 others, Evaluation of ocean carbon cycle models with data-based metrics, Geophysical Research Letters, 31, L07303, doi:10.1029/2003GL018970, 2004.
  • Matsumoto, K., J.L. Sarmiento, and M.A. Brzezinski, Silicic acid "leakage" from the Southern Ocean: A possible explanation for glacial atmospheric pCO2Global Biogeochemical Cycles, 16(3), 10.1029/2001GB001442, 2002. 

 

Recent Research Support

  • NSF: Collaborative research: Exploring hypotheses of southern hemisphere westerly wind changes on Southern Ocean circulation and
    biogeochemistry
  • NASA: Seasonal evolution of the coastal thermal front and small eddies in the Great Lakes as characterized by satellite SST and SAR imagery and numerical modeling
  • NSF: REU: Fluids in the earth from surface to the core
  • NSF: Collaborative research: The role of ice in the response of large lakes to a changing climate
  • DOE: Changes in the natural ocean carbon cycle during the Industrial period

 

Recent Honors and Awards

  • Elsevier Best Paper by a Student (White, PhD advisee), Journal of Great Lakes Research, 2013
  • AGU Editor's Citation for Excellence in Refereeing - Global Biogeochemical Cycles, 2012
  • University of New South Wales Visiting Fellow, 2012
  • University of Tasmania Visiting Scholar, 2012
  • University of Tokyo Visiting Professor, 2011-2012
  • University of Minnesota McKnight Land-Grant Professorship, 2008
  • Swiss National Science Foundation Visiting Researcher Fellowship, 2005
  • Geochemical Society of Japan Young Scientist Award, 2004