Physical Sciences and Mathematics Commons^™

Phytoplankton Production In The Delaware Estuary: Temporal And Spatial Variation., Jonathan Pennock

School of Marine Science and Ocean Engineering

ABSTRACT:

Phytoplankton production in the Delaware Estuary (USA) was measured over several seasonal cycles (1980-1985). Seasonal variability in daily area1 production (JP; g C m-2 d-l) was dlrectly related to chlorophyll concentrations in the upper estuary, ranging from a maximum of 1.1 g C m-' d-' In summer to a minlmum of d-l) dunng summer in the presence of low phytoplankton biomass (2 to 10 kg Chl I-'), and in mid-estuary [2.6 g C d-l) during the spring diatom bloom (50 to 60 yg Chll-l). Desplte the occurrence of maximum nutnent concentrations in the freshwater region, highest JP and 90 …

The Average Magnetic Field Draping And Consistent Plasma Properties Of The Venus Magnetotail, David J. Mccomas, Harlan E. Spence, C. T. Russell, M. A. Saunders

Physics & Astronomy

A new technique has been developed to determine the average structure of the Venus magnetotail (in the range from −8 R_v to −12 R_v) from the Pioneer Venus magnetometer observations. The spacecraft position with respect to the cross-tail current sheet is determined from an observed relationship between the field-draping angle and the magnitude of the field referenced to its value in the nearby magnetosheath. This allows us statistically to remove the effects of tail flapping and variability of draping for the first time and thus to map the average field configuration in the Venus tail. From this …

Bathymetric Artifacts In Sea Beam Data: How To Recognize Them And What Causes Them, Christian De Moustier, Martin C. Kleinrock

Center for Coastal and Ocean Mapping

Sea Beam multibeam bathymetric data have greatly advanced understanding of the deep seafloor. However, several types of bathymetric artifacts have been identified in Sea Beam's contoured output. Surveys with many overlapping swaths and digital recording on magnetic tape of Sea Beam's 16 acoustic returns made it possible to evaluate actual system performance. The artifacts are not due to the contouring algorithm used. Rather, they result from errors in echo detection and processing. These errors are due to internal factors such as side lobe interference, bottom-tracking gate malfunctions, or external interference from other sound sources (e.g., 3.5 kHz echo sounders or …

Beyond Bathymetry: Mapping Acoustic Backscattering From The Deep Seafloor With Sea Beam, Christian De Moustier

Center for Coastal and Ocean Mapping

In its standard mode of operation, the multibeam echosounder Sea Beam produces high resolution bathymetric contour charts of the seafloor surveyed. However, additional information about the nature of the seafloor can be extracted from the structure of the echo signals received by the system. Such signals have been recorded digitally over a variety of seafloor environments for which independent observations from bottom photographs or sidescan sonars were available. An attempt is made to relate the statistical properties of the bottom‐backscattered sound field to the independently observed geologicalcharacteristics of the seafloor surveyed. Acoustic boundary mapping over flat areas is achieved by …