Geoffrey P. Allsup

An autonomous aerosol sampler/elemental analyzer designed for ocean buoys and remote land sites

An autonomous aerosol sampler/elemental analyzer, that employs energy dispersive X-ray fluorescence spectrometry to determine the elemental (Fe, Si, S, Ca and K) concentrations of aerosols in near real time, has been designed, built and successfully tested on a roof. The ultimate technical goal is to deploy a buoy-mounted aerosol sampler/analyzer in order to make the long-term measurements necessary to quantify the deposition of mineral dust to the oceans. A major scientific goal is to address the question of enhanced biological production due to the release of dissolved iron from the deposition of mineral dust. Design and operating features are discussed and illustrated. This instrument has the sensitivity to measure the concentrations of mineral dust and Fe over the oceans with a time resolution of a few days during periods of moderate to high dust deposition.

Aerosol sampling from ocean buoys shows promise

Tests of a new sampler for collecting aerosols from ocean buoys are showing promising results. The idea of using buoys as platforms for more precise sampling of continental dust falling on the oceans sprang from seeing large quantities of reddish brown Saharan dust adhering to buoy-mounted meteorological sensors in the ocean off northwest Africa. Deploying meteorological and physical oceanographic instruments from moored buoys is a well-established and an important tool in studying marine meteorology, atmosphere-ocean interactions, and upper ocean physics [Rudnick et al., 1997; Weller et al., 1990]. An emerging field of research in oceanography is centered on developing analytical instruments for the chemical, biological, and optical measurements of seawater under moored buoys [Dickey et al., 1997]. Research on aerosols, in particular, and atmospheric chemistry, in general, has not been previously attempted from buoys.

Vector Measuring Current Meter (VMCM) upgrade

The Vector Measuring Current Meter (VMCM), developed by Drs. Robert Weller and Russ Davis and commercially produced by EG&G Sealink Systems, has proven itself over many years as the instrument of choice for accurate velocity measurements in the upper ocean, especially when used on a surface mooring. The Upper Ocean Processes (UOP) group at the Woods Hole Oceanographic Institution (WHOI) is presently in the process of upgrading the existing inventory of VMCMs. This project was undertaken because the VMCM and most of its electronic components are no longer commercially available and because replacement for the Sea Data Corp., data reader and 4-track cassette reader are no longer available. The firmware control of the VMCM makes it virtually impossible to add additional sensors to the existing instruments. By upgrading the VMCM with a flexible data logger/controller, they will continue to be a viable instrument.

King Abdullah University of Science and Technology (KAUST) mooring deployment cruise and fieldwork report, fall 2008 R/V Oceanus voyage 449-5, October 9, 2008–October 14, 2008

Funding for this report was provided by the King Abdullah University of Science and Technology (KAUST) under a cooperative research agreement with Woods Hole Oceanographic Institution.

A self-contained wind speed, direction and location system for buoys and ships in the World Ocean Circulation Experiment

Abstract : Knowledge of the absolute wind velocity near the surface of the ocean is a requirement of the World Ocean Circulation Experiment (WOCE) and other large programs directed towards understanding air-sea interactions and how ocean circulation and climate are interrelated. The measurement is made possible using IMET (Improved METeorology) modules, a next generation meteorological data acquisition system developed as part of the WOCE program. An IMET system consists of a set of intelligent modules for each measurement variable, with data being recorded on a computer, typically PC-based. The IMET wind module includes a propeller for wind speed, a vane and optical encoder for wind direction, a flux gate compass for the north reference, and microprocessor-based electronics for control and data formatting. The IMET Global Positioning System (GPS) module includes a five channel GPS receiver and microprocessor based electronics for control and data formatting. These modules, as part of the complete measurement suite, result in a self-contained system that can make accurate measurements from research ships, drifting and moored buoys, and volunteer observing ships (VOS). (MM)