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Bradford Butman

Publications and source records attributed to Bradford Butman.

At least 73 records · Page 4Linked to original sources
USGS1995

Comparison of BASS and VACM current measurements during STRESS

Current measurements from a vector-averaging current meter (VACM) on a subsurface mooring and a benthic acoustic stress sensor (BASS) on a bottom tripod are compared to assess their relative accuracy. The instruments were deployed off northern California at a midshelf site (water depth approximately 90 m) as part of the STRESS (Sediment Transport Events on Shelves and Slopes) field program. The subsurface mooring and bottom tripod were within a few hundred meters of each other, with the BASS 5.0 m and the VACM 6.7 m above the bottom, during two tripod deployments of 49 and 32 days in the winter of 1988/89. Speed differences between the VACM and BASS current observations have a mean of 0.2 cm s −1 and a standard deviation of 1.2 cm s −1 . If the mean speed profile is logarithmic, the expected mean speed difference due to the vertical separation is about 0.4 cm s −1 . The average speed difference between the VACM and BASS increases as near-bottom wave orbital velocities get large relative to hourly averaged currents, consistent with laboratory studies of VACMs in oscillating flows. Direction differences have a mean of 1° and standard deviations of about 5° for speeds greater than 10 cm s −1 . The relative accuracy of the corresponding velocity measurements is ±2 cm s −1 (mean differences less than 0.6 cm s −1 and standard deviations of about 1 cm s −1 ). The equations used to convert VACM rotor rotation rates to current speed we based on a calibration study by Woodward and Appell rather than one based on a study by Cherriman that is routinely used at the Woods Hole Oceanographic Institution. The former yields closer agreement between the BASS and VACM speed measurements during STRESS (mean speed difference 0.2 cm s −1 versus 1.4 cm s −1 ).

Journal of Atmospheric and Oceanic Technology↗
USGS1992

Contaminant transport in Massachusetts Bay

Construction of a new treatment plant and outfall to clean up Boston Harbor is currently one of the world's largest public works projects, costing about $4 billion. There is concern about the long-term impact of contaminants on Massachusetts Bay and adjacent Gulf of Maine because these areas are used extensively for transportation, recreation, fishing, and tourism, as well as waste disposal. Public concern also focuses on Stellwagen Bank, located on the eastern side of Massachusetts Bay, which is an important habitat for endangered whales. Contaminants reach Massachusetts Bay not only from Boston Harbor, but from other coastal communities on the Gulf of Maine, as well as from the atmosphere. Knowledge of the pathways, mechanisms, and rates at which pollutants are transported throughout these coastal environments is needed to address a wide range of management questions.

Massachusetts↗
USGS1992

Contaminant transport and accumulation in Massachusetts Bay and Boston Harbor: A summary of U.S. Geological Survey studies

The U.S. Geological Survey (USGS) is conducting studies in Boston Harbor, Massachusetts Bay, and Cape Cod Bay designed to define the geologic framework of the region and to understand the transport and accumulation of contaminated sediments. The region is being studied because of environmental problems caused by the introduction of wastes for a long time, because a new ocean outfall (to begin operation in 1995) will change the location for disposal of treated Boston sewage from Boston Harbor into Massachusetts Bay, and because of the need to understand the transport of sediments and associated contaminants in order to address a wide range of management questions. The USGS effort complements and is closely coordinated with the research and monitoring studies supported by the Massachusetts Environmental Trust, the Massachusetts Bays Program, and by the Massachusetts Water Resources Authority. The USGS study includes (1) geologic mapping, (2) circulation studies, (3) long-term current and sediment transport observations, (4) measurements of contaminant inventories and rates of sediment mixing and accumulation, (5) circulation modeling, (6) development of a contaminated sediments data base, and (7) information exchange. A long-term objective of the program is to develop a predictive capability for sediment transport and accumulation.

Massachusetts↗
USGS1992

Physical oceanographic investigation of Massachusetts and Cape Cod Bays

This physical oceanographic study of the Massachusetts Bays (fig. 1) was designed to provide for the first time a bay-wide description of the circulation and mixing processes on a seasonal basis. Most of the measurements were conducted between April 1990 and June 1991 and consisted of moored observations to study the current flow patterns (fig. 2), hydrographic surveys to document the changes in water properties (fig. 3), high-resolution surveys of velocity and water properties to provide information on the spatial variability of the flow, drifter deployments to measure the currents, and acquisition of satellite images to provide a bay-wide picture of the surface temperature and its spatial variability. A longterm objective of the Massachusetts Bays program is to develop an understanding of the transport of water, dissolved substances and particles throughout the bays. Because horizontal and vertical transport is important to biological, chemical, and geological processes in Massachusetts and Cape Cod Bays, this physical oceanographic study will have broad application and will improve the ability to manage and monitor the water and sediment quality of the Bays. Key results are: There is a marked seasonal variation in stratification in the bays, from well mixed conditions during the winter to strong stratification in the summertime. The stratification acts as a partial barrier to exchange between the surface waters and the deeper waters and causes the motion of the surface waters to be decoupled from the more sluggish flow of the deep waters. During much of the year, there is weak but persistent counterclockwise flow around the bays, made up of southwesterly flow past Cape Ann, southward flow along the western shore, and outflow north of Race Point. The data suggest that this residual flow pattern reverses in fall. Fluctuations caused by wind and density variations are typically larger than the long-term mean. With the exception of western Massachusetts Bay, flushing of the Bays is largely the result of the mean throughflow. Residence time estimates of the surface waters range from 20-45 days. The deeper water has a longer residence time, but its value is difficult to estimate. There is evidence that the deep waters in Stellwagen Basin are not renewed between the onset of stratification and the fall cooling period. Current measurements made near the new outfall site in western Massachusetts Bay suggest that water and material discharged there are not swept away in a consistent direction by a well-defined steady current but are mixed and transported by a variety of processes, including the action of tides, winds, and river inflow. One-day particle excursions are typically less than 10 km. The outfall is apparently located in a region to the west of the basin-wide residual flow pattern. Observations in western Massachusetts Bay, near the location of the future Boston sewage outfall, show that the surficial sediments are episodically resuspended from the seafloor during storms. The observations suggest onshore transport of suspended material during tranquil periods and episodic offshore and southerly alongshore transport of resuspended sediments during storms. The spatial complexity of the flow in the Massachusetts Bays is typical of nearshore areas that have irregular coastal shorelines and topography and currents that are forced locally by wind and river runoff as well as by the flow in adjacent regions. Numerical models are providing a mechanism to interpret the complex spatial flow patterns that cannot be completely resolved by field observations and to investigate key physical processes that control the physics of water and particle transport.

Massachussetts↗
USGS1990

Hydrography of the Gulf of Maine and Massachusetts Bay, data report for R/V OCEANUS cruise 181, 5-15 February 1987

This report presents hydrographic data obtained on R/V OCEANUS Cruise 181 from February 5-15, 1987. The hydrographic measurements (pressure, temperature, salinity, oxygen, beam attenuation, phosphate, silicate and nitrate/nitrite) were obtained in Georges, Jordan, and Wilkinson Basin in the Gulf of Maine and directly east of Boston across Massachusetts Bay as part of a study of currents and sediment transport in this region (figure 1). During Cruise 181, a total of 95 hydrographic profiles were obtained by means of a conductivity-temperature-depth (CTD) profiler. Stations are numbered sequentially and station information is tabulated in table 1. The stations were arranged in ten transects (figure 1). Section 1 was across the Great South Channel and section 7 was across the Northeast Channel--the two main oceanic entrances and exits of the Gulf of Maine. Section 2 was along a saddle (Rodgers Pass) separating Wilkinson Basin from Georges Basin. Sections 3,5, and 10 were across different regions of Wilkinson Basin and all intersected at the longterm mooring site W1 in the center of Wilkinson Basin; section 8 was a dog-leg section through the southern portion of Jordan Basin; and sections 6 (east-west) and 9 (north-south) were within Georges Basin. A severe winter storm (see table 2 and 3) occurred between February 9 and 10 and work was stopped while the OCEANUS rode out the storm in Cape Cod Bay and repaired storm damage. Section 4 across Massachusetts Bay and section 5 across Wilkinson Basin, were repeated twice, once before the storm (sections 4a and 5a) and once after the storm (sections 4b and 5b).

Maine, Massachusetts↗