Over the past decade it has become apparent that the atmosphere is a significant pathway for the transport of many natural and pollutant materials from the continents to the ocean. The atmospheric input of many of these species can have an impact (either positive or negative) on biological processes in the sea and on marine chemical cycling. For example, there is now evidence that the atmosphere may be an important transport path for such essential nutrients as iron and nitrogen in some regions. In this report we assess current data in this area, develop global scale estimates of the atmospheric fluxes of trace elements, mineral aerosol, nitrogen species, and synthetic organic compounds to the ocean; and compare the atmospheric input rates of these substances to their input via rivers. Trace elements considered were Pb, Cd, Zn, Cu, Ni, As, Hg, Sn, Al, Fe, Si, and P. Oxidized and reduced forms of nitrogen were considered, including nitrate and ammonium ions and the gaseous species NO, NO2, HNO3, and NH3. Synthetic organic compounds considered included polychlorinated biphenyls (PCBs), hexachlorocyclohexanes (HCHs), DDTs, chlordane, dieldrin, and hexachlorobenzenes (HCBs). Making this assessment was difficult because there are very few actual measurements of deposition rates of these substances to the ocean. However, there are considerably more data on the atmospheric concentrations of these species in aerosol and gaseous form. Mean concentration data for 10° × 10° ocean areas were determined from the available concentration data or from extrapolation of these data into other regions. These concentration distributions were then combined with appropriate exchange coefficients and precipitation fields to obtain the global wet and dry deposition fluxes. Careful consideration was given to atmospheric transport processes as well as to removal mechanisms and the physical and physicochemical properties of aerosols and gases. Only annual values were calculated. On a global scale atmospheric inputs are generally equal to or greater than riverine inputs, and for most species atmospheric input to the ocean is significantly greater in the northern hemisphere than in the southern hemisphere. For dissolved trace metals in seawater, global atmospheric input dominates riverine input for Pb, Cd, and Zn, and the two transport paths are roughly equal for Cu, Ni, As, and Fe. Fluxes and basin‐wide deposition of trace metals are generally a factor of 5‐10 higher in the North Atlantic and North Pacific regions than in the South Atlantic and South Pacific. Global input of oxidized and reduced nitrogen species are roughly equal to each other, although the major fraction of oxidized nitrogen enters the ocean in the northern hemisphere, primarily as a result of pollution sources. Reduced nitrogen species are much more uniformly distributed, suggesting that the ocean itself may be a significant source. The global atmospheric input of such synthetic organic species as HCH,PCBs, DDT, and HCB completely dominates their input via rivers.
SLMMARYAn analysis is made of the Monin-Obukhov function @.*I in the familiar wind profile equation, using data from two recent expeditions to Gurley (New South Wales) and Hay (New South Wales). In one, the friction velocity u1 is determined directly by the eddy correlation method, and in the other, conducted during mid-winter when small heat-fluxes were experienced, by the use of a friction coefficient applied to a low-!eve1 wind.By collating with a similar earlier analysis for heat and water vapour transfer, the variations of @.u, and @w with stability are presented in tabular torm in the z / L range --0.01 to -1.0. Within this range thc empirical relationships @JI = (1 -16 z/L)-i and @ H , IV -( 1 -16 z/L)-f, and the implied equality between Ri and z/L, are found to approximate the data to within a few per-cent. 1067 1% 1970 KEFERENCES ' Transfer of momentum and heat in the planetary boundary layer,' Proceedings of the Symposium on Arctic Heat Budget and Atmospheric Circulation (The Rand Chporation), pp. 305-332. ' Wind profiles and the shearing stressan anomaly resolved,' Quart. J. R. Met. Soc., 83, pp. 537-540. ' T h e turbulent transport of heat and water vapour in an unstable atmosphere,' Ibid., 93, pp. 501-5OX. The Fluxatron -A revised approach to the measurement of eddy fluxes in the lower atmosphere,' J. Appl. Met., 6, pp. 408-113.' The measurement of atmospheric fluxes near the surface :A generalized approach,' Ibid., (in press).' The eddy-correlation technique of evaporation measurement using a sensitized quartz-crystal hygrometer.'Submitted to J. Appl. Met. ' The structure of atmospheric turbulence,' Interscience Monographs and Texts in I'hysics and Astronomy, Vol.
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