Biomass in the upwelling areas along the northwest coast of Africa as viewed with ERTS-1
Biomass determination in upwelling water of northwestern coast of Africa from ERTS-1 imagery
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Biomass determination in upwelling water of northwestern coast of Africa from ERTS-1 imagery
The author has identified the following significant results. During the period 1 May to 30 June 1973 material was processed and interpreted for use in analyzing the three ocean seasons along the California coast. ERTS imagery from the first season of the year, called the Davidson Current period, was mosaiced and analyzed. The second season of the year, the Upwelling period, was mosaiced and interpretation was initiated. Imagery for the third ocean season, the Oceanic period, is being collected for future study.
ERTS-1 imagery has proven very useful in studies of the distribution of suspended sediment in the Gulf of Mexico off the Texas coast. Moreover, by using suspended matter concentrations as tags on water masses, much information on water movement can be obtained. The utility of suspended sediment as a tracer is dependent on the sediment remaining in suspension long enough to travel an appreciable distance or to be visible on successive images. Although the evidence is not conclusive, it seems likely that much of the suspended sediment in Gulf of Mexico nearshore waters during normal seastate conditions has remained in suspension since the time of its entry into the Gulf of Mexico through rivers and tidal inlets.
Light penetration in water is affected by plankton, algae, and dissolved and suspended matter. As a consequence, the composition of backscattered light from below the air-sea interface is determined by the nature of the constituents in the water column. In contrast to the absorption spectrum of chemically pure chlorophyll in solution, algae suspensions absorb and scatter light more uniformly throughout the visible part of the electromagnetic spectrum. Because of their spectral absorption and scattering properties plankton concentration can be estimated by measuring the spectral backscattered radiance over water. Experiments using this approach were performed in upwelling regions along the northwest coast of Africa.
The author has identified the following significant results. This project is currently involved in making visits to state and county agencies to obtain their reactions and opinions to the Mississippi Gulf Coast ERTS-1 data. The data products being used in these interviews are produced by NASA/MTF-ERL and consist of computer plotted maps with eight classifications and a statistical summary in booklet form. Reaction by potential users has been very favorable, but cost will be the largely determining factor in their ability to utilize ERTS-1 data in a recurring manner.
The author has identified the following significant results. Large scale sediment plumes from intermittent streams and rivers form detectable seasonal patterns on ERTS-1 imagery. The ocean current systems, as plotted from three California coast ERTS mosaics, were identified. Offshore patterns of sediment in areas such as the Santa Barbara Channel are traceable. These patterns extend offshore to heretofore unanticipated ranges as shown on the ERTS-1 imagery. Flying spot scanner enhancements of NASA tapes resulted in details of subtle and often invisible (to the eye) nearshore features. The suspended sediments off San Francisco and in Monterey Bay are emphasized in detail. These are areas of extremely changeable offshore sediment transport patterns. Computer generated contouring of radiance levels resulted in maps that can be used in determining surface and nearsurface suspended sediment distribution. Tentative calibrations of ERTS-1 spectral brightness against sediment load have been made using shipboard measurements. Information from the combined enhancement and interpretation techniques is applicable to operational coastal engineering programs.
The upwelling off the NW coast of Africa in the vicinity of Cape Blanc was studied in February - March 1974 from aircraft and in September 1973 from Skylab. The aircraft study was designed to determine the effectiveness of a differential radiometer in quantifying surface chlorophyll concentrations. Photographic images of the S190A Multispectral Camera and the S190B Earth Terrain Camera from Skylab were used to study distributional patterns of suspended material and to locate ocean color boundaries. The thermal channel of the S192 Multispectral Scanner was used to map sea-surface temperature distributions offshore of Cape Blanc. Correlating ocean color changes with temperature gradients is an effective method of qualitatively estimating biological productivity in the upwelling region off Africa.
The author has identified the following significant results. On the basis of analysis of late winter 1973, 1974, and 1975 LANDSAT imagery of the Beaufort Sea coast of Alaska, the following conclusions regarding near-shore ice conditions were made: (1) by March, the seaward limit of contiguous ice is often beyond the 10 fathom contour. (2) During March, shearing can and does take place along a line roughly coincident with the 10 fathom contour. (3) Ice motions during these shearing events are not extremely great, generally on the order of 10 km. (4) Many large ice features have already been formed by late February. (5) Based on look-ahead at later LANDSAT imagery, it seems apparent that Beaufort Seas shore-fast ice was already formed by late February and may well be safe for exploratory activities from this data forward until the melt season.
The U.S. Coast Guard Fire-fighting Module developed for the purpose of fighting fires in harbors and on ships is described. The module can be lifted by a dockside crane or helicopter and placed on the deck of a patrol boat or cutter for transportation to the scene of the fire. At the fire the module can be set up and put in operation by a crew of two in approximately fifteen minutes. Once in operation the module will deliver water to two fire nozzles at a pressure of 150 psi and a flow rate of 2000 gpm. Sufficient fuel is carried in the module for three hours of continuous operation. A record of the development of the fire fighting module is also presented.
During the West Coast Experiment in March 1977, a test was conducted to ascertain the effectiveness of using remote sensing techniques to estimate sea surface temperature (SST) from infrared (IR) emissions of the sea surface. Aircraft flights were made over three buoys moored in southern California coastal waters, and data was collected of sea surface emissions at thermal IR wavelengths (7.95-13.5 micrometers). SST obtained from the remote sensing measurements were compared with in situ SST measured with thermistors mounted on the buoys. The remotely determined SST were from 1.4-2.9 C lower than the in situ measurements. Several factors are discussed that could account for the differences.
The joint air sea interaction (JASIN) experiment took place off the Northwest coast of Scotland. Sea surface and boundary layer parameters were measured. The JASIN data was used as ground truth for various sensors on the SEASAT satellite.
Dynamometer performance of a South Coast Technology electric conversion of a Volkswagen (VW) Rabbit designated SCT-8 was tested. The SCT-8 vehicle was fitted with a transistorized chopper in the motor armature circuit to supplement the standard motor speed control via field weakening. The armature chopper allowed speed control below the motor base speed. This low speed control was intended to reduce energy loss at idle during stop-and-go traffic; to eliminate the need for using the clutch below base motor speed; and to improve the drivability. Test results indicate an improvement of about 3.5% in battery energy economy for the SAE J227a-D driving cycle and 6% for the C-cycle with only a minor reduction in acceleration performance. A further reduction of about 6% would be possible if provision were made for shutting down field power during the idle phases of the driving cycles. Drivability of the vehicle equipped with the armature chopper was significantly improved compared with the standard SCT Electric Rabbit.
Satellite infrared temperature images illustrate several effects of the 1982-1983 El Nino: warm sea-surface temperatures with the greatest anomalies near the coast, weakened coastal upwelling, and changes in surface circulation patterns. Phytoplankton pigment images from the Coastal Zone Color Scanner indicate reduced productivity during El Nino, apparently related to the weakened coastal upwelling. The satellite images provide direct evidence of mesosale changes associated with the oceanwide El Nino event.
Mesoscale numerical forecasts utilizing the Mesoscale Atmospheric Simulation System (MASS) are documented for two East Coast severe weather events. The two events are the thunderstorm and heavy snow bursts in the Washington, D.C. - Baltimore, MD region on 8 March 1984 and the devastating tornado outbreak across North and South Carolina on 28 March 1984. The forecasts are presented to demonstrate the ability of the model to simulate dynamical interactions and diabatic processes and to note some of the problems encountered when using mesoscale models for day-to-day forecasting.
Aerospatiale Helicopter Corporation (AHC) was awarded a contract by the United States Coast Guard for a new Short Range Recovery (SRR) Helicopter on 14 June 1979. The award was based upon an overall evaluation of performance, cost, and technical suitability. In this last respect, the SRR helicopter was required to meet a wide variety of mission needs for which the integrated avionics system has a high importance. This paper illustrates the rationale for the avionics system requirements, the system architecture, its capabilities and reliability and its adaptability to a wide variety of military and commercial purposes.
Snowfall, surface and upper air charts, and available satellite images are presented for eighteen major East Coast snowstorms that occurred between 1960 and 1983. The charts and descriptions of key fields are provided so that students, weather forecasters, and researchers alike can visualize how a large sample of major winter cyclones form and intensify. Although there are noted similarities in certain aspects of the surface and upper tropospheric development of the storms, significant case-to-case variability precludes the ability to effectively composite these weather systems.
A comment is presented on a recent paper by Pagnotti and Bosart (1984) which contrasted different forcing mechanisms for weak and strong cyclones along the east coast of the U.S., and Bosart replies. The comment argues that the paper did not give a clear definition of 'weak' upper-level forcing and did not provide sufficient evidence to support its claim that the return branch of transverse circulations may be coupled to the middle as opposed to the lower troposphere.
The surface and upper-level characteristics in selected wind, pressure, and temperature fields of some significant east coast cyclones are studied. The surface, 200, 300, 500, 700, and 850 mb charts of 18 case studies of storms are analyzed. The surface patterns are described in terms of the type of cyclone, the variation in rate of motion, the effect of coastal frontogenesis on the storms, sea level pressures, and the deepening rate of pressure. The influence of upper-level troughs, ridges, jet streaks, location of wind amplification, and time on cyclogenesis is examined.