image of seawinds near South 
Georgei Isl.  NASA PIA02457 NASA image of quikSCAT 
winds associated with hurricane Katrina.  Source: 
http://visibleearth.nasa.gov/view_rec.php?id=20206 an orbimage picture of ocean 
Chla from oceancolor.gsfc.nasa.gov/cgi/image_archive.cgi?c=CHLOROPHYLL SST and rainfall in the tropical 
Atlantic from Grodsky and Carton (2004) Earth photographed during 
Apollo 17 (I've altered the background a bit) NASA/Orbimage picture of seasonal Chl-a 
in the tropical Pacific.
 

James Carton, Professor

address/contact

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The Arctic Ocean is warmed and salinified by 8 million metric tons per second of Atlantic Water inflow into the Nordic Seas. Variations in this flow both cause and reflect changes in Arctic climate. In Carton et al. (2011) we examine the historical record of temperature and salinity variations in the Nordic Seas and their connections to North Atlantic climate.

The main system for tracking ocean surface currents are the drifters maintained by the Global Drifter Program. An examination of the historical data which extends back to the 1970s reveals a remarkable, spurious, acceleration. For example, in the westerly wind region of the Southern Ocean the ocean currents are apparently increasing at a rate of 5 cm/s per decade. Grodsky et al. (2011) explores possible causes of this error including the likely contribution of major changes in the design of the drifters and their drogues.

The oceans play a crucial role in regulating our climate. However, key aspects of this role remain uncertain because of the limited number of historical observations and their uneven distribution. Carton and Giese (2008) address this uncertainty by combining numerical simulation and observations through data assimilation to produce the SODA ocean reanalysis -- essentially a gridded reconstruction of the history of ocean circulation, temperature, salinity, etc. Shown: # temperature observations with depth (vertical) and time (horizontal) since 1950. The increase in the late-1960s follows the introduction of the XBT.

The oceanic mixed layer is the nearsurface layer of the ocean that interacts directly with the atmosphere, exchanging heat, freshwater, and gases such as O2 and CO2. In Carton et al (2008) we explore year-to-year changes in the winter mixed layer. Here we see a basin-scale pattern of variability of the depth of the mixed layer which is related to the Pacific Decadal Oscillation.

Ocean reanalyses are gradually improving our ability to track longterm changes in ocean properties such as heat content. Carton and Santorelli (2008) compare nine recent global estimates and find a general convergence toward an average rise of 0.77x108 Jm-2/10yr or 0.24Wm-2. This paper points out areas of descrepency as well as the influence of changing observing systems.

Earth's Climate: The Ocean-Atmosphere Interaction,2004, Wang, Xie, and Carton, ed.s. Satellite-based and in situ monitoring systems and numerical models have greatly increased our understanding of climate variations in the Pacific, Atlantic, and Indian sectors as well as interactions cross-basin and between the tropics and extratropics. This new volume is the first attempt to provide a global treatment of this important subject. Shown: Book cover.

The subtropical oceans are biological deserts due to the presence of deep thermoclines, low mixing, and thus low food supply. A recent study by Babin, Carton, Dickey, and Wiggert (2004) shows that hurricanes play an important role in the biology of this region by mixing up deep nutrient-rich waters, resulting in a green wake of plant growth. This study recieved a publication award from the JHU Applied Physics Laboratory. Shown: Hurricane Bonnie.

Learn more about these and other projects here