Physical Sciences and Mathematics Commons^™

Seasonal And Inter-Annual Patterns Of Sediment-Water Nutrient And Oxygen Fluxes In Mobile Bay, Alabama (Usa): Regulating Factors And Ecological Significance., Jean L. Cowan, Jonathan Pennock, Walter R. Boynton

School of Marine Science and Ocean Engineering

Sediment oxygen and nutrient fluxes were measured monthly for 2 yr in Mobile Bay, Alabama, USA. Rates of sediment oxygen consumption (0.1 to 1.25 gO₂ m^-2 d^-1), ammonium flux (-22 to 181 µmol m^-2 h^-1), nitrate flux (-14 to 67 µmol m^-2 h^-1), phosphate flux (-2 to 20.4 µmol m^-2 h^-1), and dissolved silicate flux (-15 to 342 µmol m^-2 h^-1) were moderate to high compared to values for other estuaries. A step-wise regression analysis revealed that dissolved oxygen concentration and temperature in bottom-waters …

In-Situ Far-Field Calibration Of Multibeam Sonar Arrays For Precise Backscatter Imagery, Larry Fusillo, Christian De Moustier, John H. Satriano, Stanley Zietz

Center for Coastal and Ocean Mapping

Calibration of large hull-mounted sonar transducer arrays is usually done by measuring the performance of individual components in a test tank. Multiple transducer element beam patterns are superimposed and combined with window attenuation and other partial measurements to give an approximation of the total beam pattern. This process often ignores or fails to accurately model factors such as mounting hardware, array misalignment, reflections from the hull structure and other real world absorbers, reflectors and attenuators which can have significant effect on the actual beam pattern. This paper describes an application of a novel technique for in-situ measurement of the far-field …

Swath Mapping On The Continental Shelf And Slope: The Eel River Basin, Northern California, John A. Goff, Larry A. Mayer, John E. Hughes Clarke, Lincoln F. Pratson

Affiliate Scholarship

First Paragraph

The STRATAFORM program sponsored by the Office of Naval Research (Nittrouer and Kravitz, 1996, this issue) seeks to understand how sedimentary processes lead to the formation of the stratigraphic sequences on continental margins. A central challenge facing this effort is to understand the transport of sediments in shore-parallel as well as shore-perpendicular directions• Multidimensionality is necessary to describe, for example, the accumulation of sediments from river inputs, the distribution of gullies and canyons on the slope, the meandering of channels, and the structure of slumps and slides.

Modeling Of The Processing And Removal Of Trace Gas And Aerosol Species By Arctic Radiation Fogs And Comparison With Measurements, M H. Bergin, S N. Pandis, C Davidson, J L. Jaffrezo, Jack E. Dibb, A G. Russell, H D. Kuhns

Earth Sciences

A Lagrangian radiation fog model is applied to a fog event at Summit, Greenland. The model simulates the formation and dissipation of fog. Included in the model are detailed gas and aqueous phase chemistry, and deposition of chemical species with fog droplets. Model predictions of the gas phase concentrations of H₂O₂, HCOOH, SO₂, and HNO₃ as well as the fog fluxes of S(VI), N(V), H₂O₂, and water are compared with measurements. The predicted fluxes of S(VI), N(V), H₂O₂, and fog water generally agree with measured …

Recent Climate Anomalies And Their Impact On Snow Chemistry At South Pole, 1987 - 1994, Jack E. Dibb, Sallie I. Whitlow

Earth Sciences

Three 2-m deep snowpits sampled at South Pole in 1994 provide detailed (2-cm resolution) profiles of the concentrations of soluble ionic species for the period 1987 - 1994. The most prominent feature is a large concentration spike of SO4 = in snow deposited in 1992 reflecting fallout from the eruptions of Pinatubo and Hudson in 1991. Concentrations of MSA and values of the MSA/(non-sea-salt SO4 =) ratio are elevated for about three years centered on the prominent volcanic signal. These changes appear to be due to the extended 1991 - 1993 El Nino. The overlapping effects of the volcanic eruptions …

Asian Influence Over The Western North Pacific During The Fall Season: Inferences From Lead 210, Soluble Ionic Species And Ozone, Jack E. Dibb, R. Talbot, Anthony Klemm, G L. Gregory, H B. Singh, J D. Bradshaw, S T. Sandholm

Earth Sciences

Aerosol samples collected over the western Pacific during the NASA/Global Tropospheric Experiment Pacific Exploratory Mission (PEM-West A) expedition (September–October 1991) revealed mean ²¹⁰Pb concentrations in the free troposphere in the 5–10 fCi m⁻³ STP range. Most soluble ionic aerosol-associated species were near detection limits [≪40 parts per trillion by volume (pptv)] in these same samples. The altitude distribution of O₃ near Asia closely resembled that of ²¹⁰Pb, while no relationship was found between the concentrations of O₃ and ⁷Be. Free tropospheric air over the western Pacific was depleted in soluble aerosol-associated species but enriched …

Chemical Characteristics Of Continental Outflow From Asia To The Troposphere Over The Western Pacific Ocean During September-October 1991: Results From Pem-West A, R. Talbot, Jack E. Dibb, K I. Klemm, J D. Bradshaw, S T. Sandholm, D R. Blake, G W. Sachse, J E. Collins Jr, B J. Heikes, G L. Gregory, B E. Anderson, H B. Singh, D C. Thornton, J T. Merrill

Earth Sciences

An important objective of the Pacific Exploratory Mission-West A (PEM-West A) was the chemical characterization of the outflow of tropospheric trace gases and aerosol particles from the Asian continent over the western Pacific Ocean. This paper summarizes the chemistry of this outflow during the period September – October 1991. The vertical distributions of CO, C₂H₆, and NO_xshowed regions of outflow at altitudes below 2 km and from 8 to 12 km. Mixing ratios of CO were ≈130 parts per billion by volume (ppbv), ≈1000 parts per trillion by volume (pptv) for C₂H …

Atmospheric Sampling Of Supertyphoon Mireille With Nasa Dc-8 Aircraft On September 27,1991, During Pem-West A, G W. Sachse, R E. Newall, W Hu, Z X. Wu, H Akimoto, B E. Anderson, E V. Browell, G L. Gregory, G W. Sachse, M C. Shipman, A S. Bachmeier, A R. Bandy, D C. Thornton, D R. Blake, F Sherwood Rowland, J D. Bradshaw, J H. Crawford, D D. Davis, S T. Sandholm, W Brockett, L Degreef, D Lewis, D Mccormick, E Monitz, J E. Collins Jr, B J. Heikes, J T. Merrill, K K. Kelly, S C. Liu, Y Kondo, M Koike, C M. Liu, F Sakama, H B. Singh, Jack E. Dibb, R. Talbot

Earth Sciences

The DC-8 mission of September 27, 1991, was designed to sample air flowing into Typhoon Mireille in the boundary layer, air in the upper tropospheric eye region, and air emerging from the typhoon and ahead of the system, also in the upper troposphere. The objective was to find how a typhoon redistributes trace constituents in the West Pacific region and whether any such redistribution is important on the global scale. The boundary layer air (300 m), in a region to the SE of the eye, contained low mixing ratios of the tracer species O3, CO, C2H6, C2H2, C3H8, C6H6and CS2 …