Natalie M. Mahowald

General Information

Contact Information:
PO Box 3000, Boulder, CO 80307-3000
Office: ML-202c
Currently on leave at Cornell University
Telephone: 303-497-1719 | Cornell: 607-255-5166
Email: mahowald@ucar.edu | mahowald@cornell.edu
CGD Home Page | Cornell Home Page
Vita

Research Focus FY08:

Absolute RMS variability (in ppmv) from 1997 to 2004 of best-case total CO2. (a) Seasonal, (b) interannual (note different color bar scale). Portional contribution to RMS seasonal variability: (c) best-case WHOI ocean, (e) GFED land, (g) fossil fuel. Portional contribution to RMS interannual variability (d) best-case WHOI ocean, (f) GFED land, (h) fossil fuel. Note that portional RMS variabilities of ocean, land, and fossil fuel add up to >1 when cancellation among component tracers occurs in the summing of total CO2.
High resolution figure

My research group is focused understanding on global and regional scale atmospheric transport of biogeochemically important species such as desert dust. We are interested in how humans are perturbing the natural environment, especially through perturbations to aerosols. We look at these issues through a combination of 3-dimensional global transport and climate models, as well as analysis of satellite and in situ data.

Abstract from one of my publications this year:
J. Geophy. Res., Contribution of ocean, fossil fuel, land biosphere, and biomass burning carbon fluxes to seasonal and interannual variability in atmospheric CO2.

Seasonal and interannual variability in atmospheric carbon dioxide (CO2) concentrations was simulated using fluxes from fossil fuel, ocean and terrestrial biogeochemical models, and a tracer transport model with time-varying winds. The atmospheric CO2 variability resulting from these surface fluxes was compared to observations from 89 GLOBALVIEW monitoring stations. At northern hemisphere stations, the model simulations captured most of the observed seasonal cycle in atmospheric CO2, with the land tracer accounting for the majority of the signal. The ocean tracer was 3-6 months out of phase with the observed cycle at these stations and had a seasonal amplitude only ~10% on average of observed. Model and observed interannual CO2 growth anomalies were only moderately well correlated in the northern hemisphere (R ~ 0.4-0.8), and more poorly correlated in the southern hemisphere (R < 0.6). Land dominated the interannual variability (IAV) in the northern hemisphere, and biomass burning in particular accounted for much of the strong positive CO2 growth anomaly observed during the 1997-1998 El Niño event. The signals in atmospheric CO2 from the terrestrial biosphere extended throughout the southern hemisphere, but oceanic fluxes also exerted a strong influence there, accounting for roughly half of the IAV at many extratropical stations. However, the modeled ocean tracer was generally uncorrelated with observations in either hemisphere from 1979-2004, except during the weak El Niño/post-Pinatubo period of the early 1990s. During that time, model results suggested that the ocean may have accounted for 20-25% of the observed slowdown in the atmospheric CO2 growth rate.

Publications FY08 (abstracts):

Thornton, P. E., J.-F. Lamarque, N. A. Rosenbloom, N. M. Mahowald, 2007: Influence of carbon-nitrogen cycle coupling on land model response to CO2 fertilization and climate variability. Global Biogeochemical Cycles, 21, GB4018, doi: 10.1029/2006GB002868.

Winckler, G., R. F. Anderson, M. Q. Fleisher, D. McGee, and N. Mahowald, 2008: Covariant Glacial-Interglacial Dust Fluxes in the Equatorial Pacific and Antarctica. Science, 320, 93-96, doi: 10.1126/science.1150595.

Wagener, T., C. Guieu, R. Losno, S. Bonnet, and N. Mahowald, 2008: Revisiting atmospheric dust export to the Southern Hemisphere ocean: Biogeochemical implications. Global Biogeochem. Cycles, 22, GB2006, doi:10.1029/2007GB002984.

Wong, S., A. E. Dessler, N. M. Mahowald, P. R. Colarco, and A. da Silva, 2008: Long-term variability in Saharan dust transport and its link to North Atlantic sea surface temperature. Geophys. Res. Lett., 35, L07812, doi:10.1029/2007GL032297.

Nevison, C. D., N. M. Mahowald, S. C. Doney, I. D. Lima, G. R. van der Werf, J. T. Randerson, D. F. Baker, P. Kasibhatla, and G. A. McKinley, 2008: Contribution of ocean, fossil fuel, land biosphere, and biomass burning carbon fluxes to seasonal and interannual variability in atmospheric CO2. J. Geophys. Res., 113, G01010, doi:10.1029/2007JG000408.

Luo, C., N. Mahowald, T. Bond, P. Y. Chuang, P. Artaxo, R. Siefert, Y. Chen, and J. Schauer, 2008: Combustion iron distribution and deposition, Global Biogeochem. Cycles, 22, GB1012, doi:10.1029/2007GB002964.

Winckler, G., R. F. Anderson, M. Q. Fleisher, D. McGee, and N. Mahowald, 2008: Half a million years of coherent dust flux variations in the tropical Pacific and Antarctica. Geochimica et Cosmochimica Acta, 72, A1026-A1026.

Nevison, C. D., N. M. Mahowald, S. C. Doney, I. D. Lima, and N. Cassar, 2008: Impact of variable air-sea O-2 and CO2 fluxes on atmospheric potential oxygen (APO) and land-ocean carbon sink partitioning. Biogeosciences, 5, 875-889.

Neff, J. C., A. P. Ballantyne, G. L. Farmer, N. M. Mahowald, J. L. Conroy, C. C. Landry, J. T. Overpeck, T. H. Painter, C. R. Lawrence, and R. L. Reynolds, 2008: Increasing eolian dust deposition in the western United States linked to human activity. Nature Geoscience, 3, 189-195.

Evan, A. T., A. K. Heidinger, R. Bennartz, V. Bennington, N. M. Mahowald, H. Corrada-Bravo, c. S. Velden, G. Myhre, and J. P. Kossin, 2008: Ocean temperature forcing by aerosols across the Atlantic tropical cyclone development region. Geochemistry Geophysics Geosystems, 9, Q05V04, doi:10.1029/2007GC001774.

Natalie M. Mahowald Research Catalog