GLERL Publications Abstracts: FY 1979

Publications List Key
Capitalized names represent GLERL authors.
* = Not available from GLERL.
** = Available in GLERL Library only.
+ = Available electronically via GLERL web site.

Allender, J.H., and J.H. SAYLOR. Model and observed circulation throughout the annual temperature cycle of Lake Michigan. Journal of Physical Oceanography 9:573-579 (1979). https://www.glerl.noaa.gov/pubs/fulltext/1979/19790001.pdf

Monthly average currents and temperatures predicted by a three-dimensional, numerical model of Lake Michigan are compared with observations made in that lake during June-October 1976. The observed data are from 17 current meters with integral temperature recorders that were concentrated on a transverse section of the southern basin of the lake. A brief interpretation of the overall aspects of these data is given and the evolution of a deep temperature anomaly in the west-central basin is discussed. Model results are evaluated in terms of their comparability with the dominant features of the observed data. Lakewide-average temperatures in the model are reasonable and the signs of the computed and observed currents show some agreement. However, the model exaggerates upwelling along the upwind (western) shore, leading to temperature predictions that worsen progressively throughout the stratified season. The present study and other recent work suggest the need for improved mixed-layer physics in lake models.

ASSEL, R.A., and F.H. QUINN. A historical perspective of the 1976-77 Lake Michigan ice cover. Monthly Weather Review 107(3):336-341 (1979). https://www.glerl.noaa.gov/pubs/fulltext/1979/19790002.pdf

The formation of ice cover on the Great Lakes during the 1976-77 winter was unusual because of the early onset and continuation of below normal air temperatures. The severe winter produced a particularly extensive ice cover in the southern half of Lake Michigan. During the height of the winter, in early February 1977, the lake was almost entirely frozen over. To put the winter in its proper perspective, temperature records starting in 1897 and ice-cover record beginning in the 1962-63 winter were analyzed to classify winter severity and to examine the relationship between winter severity and maximum ice extent on Lake Michigan. The winters were classified by freezing degree-days into five categories: severe, severer than normal, normal, milder than normal and mild. The classification indicates that the winter of 1976-77 was one of the four coldest in the past 80 years. The analysis also shows that the past 15-20 winters have been colder than the normal established by the 80-year data base. As well-documented ice-cover records of Lake Michigan have only been collected during the past 15 years, existing ice-cover normals based on these records are probably biased toward the severe condition. The analysis also shows that extensive ice cover (in excess of 50% of the total lake's surface area) develops on Lake Michigan only when the southern subregion of the lake experiences a severe winter.

AUBERT, E.J. Testimony before the Committee on Science and Technology, Subcommittee on Natural Resources and the Environment. Hearings on coordinating of federal research and monitoring programs for toxic and hazardous substances in the Great Lakes region. Great Lakes Environmental Research Laboratory, Ann Arbor, MI, 17 pp. (1979).

No abstract.

BELL, G.L. Characteristics of the Oswego River plume and its influence on the nearshore environment. NOAA Technical Memorandum ERL GLERL-22, Great Lakes Environmental Research Laboratory, Ann Arbor, MI (PB-293-648/3GA) 74 pp. (1978). https://www.glerl.noaa.gov/pubs/tech_reports/glerl-022/

Ion and suspended material concentrations were relatively high in the Oswego River as compared to Lake Ontario background levels and generally decreased rapidly through Oswego Harbor. Most of the variables mix conservatively, with gradients similar to those of specific conductance. There were indications of loading of nutrients, chloride, chemical oxygen demand, and volatiles other than from the river. However, oxygen depletion was not a problem in any area. Specific conductance shows that 90 percent of the dilution occurs within 3 km to the northeast and 2 km to the west of the harbor entrance. Transmissometer profiles were used to supplement the chemical and temperature data. They conveniently detail the plume structure. The prevailing nearshore current direction is northeastward; however, periods of northward and westward flows were observed. Plume configurations varied in response to stream flow, prevailing longshore currents, and current variations related to changes in wind direction and velocity. During late spring and summer the relatively warmer plume tends to spread over the cooler lake water with accompanying lake water intrusion over the harbor bottom, which complicates sedimentation patterns. In late summer and fall the relatively cooler river water tends to plunge beneath the lake surface at or near the harbor entrance. Suspended materials varied with the river flow. During low flow periods these materials are deposited in the harbor on either side of the channel and in the plume area adjacent to the harbor. Materials with high concentrations of oil and grease and other organics exert a deleterious effect on the local environment, primarily through oxidation. Dredging operations resuspend some materials, which are then redistributed. Dredged spoil deposited offshore produces an additional impact on the deeper portion of the lake. Sediments overlying bedrock outside the harbor were often less than 2.5 cm in thickness. The combined effects of longshore and wave generated currents tend to keep the materials moving. Particulates deposited below the wave base prior to stratification are essentially separated from the epilimnion by the development of a thermocline. Movement of fine particulates over a thermocline surface provides a mechanism by which these materials are kept in suspension and widely distributed.

BENNETT, J.R., and B.A. Magnell. A dynamical analysis of currents near the New Jersey coast. Journal of Geophysical Research 84(C3):1165-1175 (1979).

A numerical model is used to analyze currents measured on the continental shelf near the shore of New Jersey. The model neglects longshore variations of current and all variations of density, but includes inertial accelerations and a nonlinear eddy viscosity. Local wind stress, sea level changes, and a constant longshore pressure gradient are the forcing terms. The model successfully reproduces most of the current variance; however, the predicted currents do not exhibit the dominant 4-hour response time of the observed currents, and the model sometimes misses energetic current events. These differences are ascribed to three-dimensional setup effects elsewhere in the New York Bight.

BOLSENGA, S.J. Solar altitude effects on ice albedo. NOAA Technical Memorandum ERL GLERL-25, Great Lakes Environmental Research Laboratory, Ann Arbor, MI (PB-301-252/3GA) 43 pp. (1979). https://www.glerl.noaa.gov/pubs/tech_reports/glerl-025/

No abstract.

BOYD, J.D. A surface spill model for the Great Lakes. GLERL Open File Report , Great Lakes Environmental Research Laboratory, Ann Arbor, MI 48 pp. (1979).

No abstract.

CHAMBERS, R.L., and S.B. Upchurch. Multivariate analysis of sedimentary environments using grain-size frequency distributions. Mathematical Geology 11:27-43 (1979).

Multivariate statistics were used to characterize and test the effectiveness of grain-size frequencies as environmental discriminators. Sediment from the following two depositional systems along eastern lake Michigan were studied: (10 a closed system with respect to available grain sizes (Little Sable Point), and (2) an open system (Sleeping Bear Point-Manitou Passage). Principal components analysis shows that grain-size distributions are composed of two or more subgroups that reflect surface creep bedload, mixed suspension bedload, and uniform suspension. Discriminant function and principal latent vector analyses of the Little Sable Point environments show that, when available sediment is limited with respect to grain size (0.5F to 3.0F), similar size distributions can occur in environments supposedly characterized by different energy conditions. Sediment in the Sleeping Bear Point-Manitou Passage system is not restricted to available grain sizes and the environments discriminated very well (a<0.001). The grain-size distributions are such that they reflect differences in energy conditions within the environments. It is apparent that the grain sizes available to a depositional system control to a great extent the effectiveness of environmental discrimination.

CHAPRA, S.C. Applying phosphorus loading models to embayments. Limnology and Oceanography 24(1):163-168 (1979). https://www.glerl.noaa.gov/pubs/fulltext/1979/19790010.pdf

An explicit turbulent mass transport term is added to a phosphorus budget model to make it applicable to completely mixed water bodies with open boundaries; an application to Saginaw Bay demonstrates the importance of this modification. A method is devised to incorporate turbulent diffusion into loading plots by adjusting the loading term to include the flux of phosphorus from the main lake into the bay and including the effect of turbulent flow in the residence time.

CHAPRA, S.C. Total phosphorus model for the Great Lakes. Journal of Environmental Engineering, Division ASCE EE6:1309-1310 (1978).

No abstract.

DERECKI, J.A. Evaporation from Lake St. Clair. NOAA Technical Memorandum ERL GLERL-23, Great Lakes Environmental Research Laboratory, Ann Arbor, MI (PB-295-686/0GA) 34 pp. (1978). https://www.glerl.noaa.gov/pubs/tech_reports/glerl-023/

Available land-based data adjusted to overwater conditions were used to determine monthly evaporation from Lake St. Clair for individual years of a 26-year period, 1950-75, by the mass transfer method. Because of extensive ice cover on the lake, the overwater mass transfer results were adjusted for the ice cover during winter. The ice-cover adjustment reduced the average annual evaporation by 100 mm, with a resultant average annual evaporation of 750 mm. The mass transfer method is the only technique that permits operational evaporation estimates from this lake with presently available data; it is also most amenable for future improvements.

*DERECKI, J.A., and A.J. POTOK. Hydrometeorological data system for the Great Lakes, Appendix D: Evaluation of runoff simulation for southeast Michigan with SSARR watershed model. U.S. Army Corps of Engineers, North Central District, Chicago, IL, (1978).

No abstract.

DOUGHTY, B.C., T.A. KESSENICH, and P.C. LIU. Surface wave data recorded in Lake Michigan during 1973 and 1975-77. NOAA Technical Memorandum ERL GLERL-19, Great Lakes Environmental Research Laboratory, Ann Arbor, MI (PB-297-296/6GA) 3 pp. (1978). https://www.glerl.noaa.gov/pubs/tech_reports/glerl-019/

This report presents surface wave data recorded by Wave-rider Buoys deployed in Lake Michigan during 1973, 1975, 1976, and 1977.

GREAT LAKES ENVIRONMENTAL RESEARCH LABORATORY. Annual Report for the Great Lakes Environmental Research Laboratory, FY 1979. Great Lakes Environmental Research Laboratory, Ann Arbor, MI, 34 pp. (1979).

No abstract.

GREAT LAKES ENVIRONMENTAL RESEARCH LABORATORY. Detailed technical plan for the Great Lakes Environmental Research Laboratory. Great Lakes Environmental Research Laboratory, Ann Arbor, MI, 214 pp. (1979).

No abstract.

GREAT LAKES ENVIRONMENTAL RESEARCH LABORATORY. Technical plan for the Great Lakes Environmental Research Laboratory. Great Lakes Environmental Research Laboratory, Ann Arbor, MI, 57 pp. (1979).

No abstract.

HUANG, J.C.K. Numerical case studies for oceanic thermal anomalies with a dynamic model. Journal of Geophysical Research 84(C9):5717-5726 (1979).

Numerical investigations to identify the physical processes responsible for the generation, evolution, and dissipation of oceanic thermal anomalies (OTA) were carried out using the numerical dynamic model of the North Pacific Experiment (Norpax). The Norpax model is based on time-integrations of the finite-difference forms of the primitive equations. It possesses an actual coastal configuration and 10 vertical layers, with a constant maximum depth of 4 km. The horizontal grid spacing, both longitudinal and latitudinal, is 2.5o. The seasonally varying model climatology is generated by integrating the model over 80 years of simulations under the climatological atmospheric forcing, of which the first 60 years are the long-term annual mean conditions and the last 20 years vary with the seasonal cycle. Large-scale features of the model ocean climatology compare favorably with observed large-scale motions and structure in the North Pacific Ocean. The model is used for oceanic thermal anomaly studies. Two simulated cases are presented: one demonstrates the generation and evolution of OTA's under anomalous atmospheric wind forcing of winter 1949-1950, and the other portrays the evolution and dissipation of the OTA's under climatological atmospheric conditions in winter 1971-1972. The resulting model simulations are compared with observational data to examine to what extent change of the oceanic thermal structure is accounted for by the anomalous wind forcing and how much by the internal adjustments in the ocean. The model indicates that OTA's are generated by anomalous atmospheric winds and that thermal advection, both horizontal and vertical, plays the most important role in the generation. During winter, anomalous wind-induced upwelling has more influence on a cold anomaly in the tropic and subtropic regions than anomalous downwelling has on a warm anomaly in the subarctic region under a weak stable state. The behavior of an initial anomaly under climatological conditions is closely related to large-scale features, such as the circulation pattern and the thermal gradient in the ocean, and is also subject to modifications due to the presence of OTA'S. Aside from limitations of the present course-grid model, most discrepancies found between the simulated and observed anomalies can generally be attributed to the lack of reliable and accurate meteorological and subsurface data. As better oceanic and atmospheric data become available, further studies of anomaly dynamics through numerical experiments will lead to understanding anomalous heat distributions in the upper layers of the ocean and hence to better ocean predictions.

HUANG, J.C.K. Numerical simulation studies for oceanic anomalies in the north Pacific Basin. II: Seasonally varying motions and structures. Journal of Physical Oceanography 9(1):37-56 (1979). https://www.glerl.noaa.gov/pubs/fulltext/1979/19790003.pdf

Seasonally varying currents and structures in the North Pacific Ocean are simulated by a baroclinic ocean model. The model has satisfactorily reproduced the gross nature of current systems and density fields as well as their seasonal variations in the North Pacific Ocean. The simulated fluctuations of oceanic transport have been found to be closely related to the imposed meridional movement of the atmospheric system. The vertically integrated transport is strong in late winter and early spring, with a maximum in the Kuroshio region of 63 x 106 m3 s-1, and weak in summer, with a minimum of about 33 x 106 m3 s-1. All three major circulation gyres, namely, the subtropic anticyclonic gyre, the subarctic and the tropic cyclonic gyres are intense in winter and broad and weak in summer. The subarctic gyre almost disappears from the North Pacific basin in July. The simulated equatorial undercurrent and countercurrent demonstrate significant seasonal changes. Both currents are strong but shallow in fall and winter, and weak but deep in spring and summer. The simulated surface temperature agrees with observations in midlatitudes, especially in summer, but it is higher than that observed in high latitudes during winter. In the tropics, westward propagating baroclinic long waves having wavelengths of about 11,000 km are also shown in the simulation. Most of the poleward flow of heat energy is transported in the upper layers, especially the surface layer. The maximum heat transport occurs near 17oN in winter and near 25oN in summer. The seasonal cycle of energetic shows that variations of the total barotropic energy follow the variations of the imposed winds with a lag of about one month and that the maximum baroclinic energy follows closely the maximum of the overall horizontal thermal gradient in the cooling cycle. This also confirms that the large-scale baroclinic current is generally in geostrophic balance.
Simulated results are compared with observational data whenever appropriate. General agreement is satisfactory. Discrepancies in comparisons are pointed out and improvements needed for the model are discussed.

HUANG, J.C.K. Response of the NCAR general circulation model to north Pacific sea surface temperature anomalies. Journal of Atmospheric Science 35:1164-1179 (1978).

The general circulation model (GCM) of the National Center for Atmospheric Research was used to investigate the effects of anomalous sea surface temperature (SST) patterns in the mid-latitudes of the North Pacific Ocean on atmospheric circulations. One of the most frequently observed SST anomaly (SSTA) patterns, a "cold pool" of water in the west and a "warm pool" in the east (from 35 to 55oN) with magnitudes +/-4oC of the temperature of the surrounding water, was superimposed on the seasonally varying oceanic temperature as the thermal boundary condition in the North Pacific of the atmospheric GCM for the anomaly experiment. Three similar experiments, one the control, two the noise and three an exaggerated SSTA, were run simultaneously. Time integrations for all cases were carried out for 120 days, beginning on 15 January. Preliminary results indicate that cyclonic activities are strengthened above the warm SSTA and suppressed above the cold SSTA. A direct thermal circulation is induced in the vertical section: warm air rises and a warm-core low forms above the warm SSTA; cold air sinks and a cold-core high forms above the cold SSTA. The Aleutian low is elongated, shifted northeast and deepened. The planetary wave in midlatitudes shows ridging above the cold SSTA and troughing above the warm SSTA in the lower troposphere. A westward tilting of the trough with increasing altitude above the warm SSTA is also discerned. The westerlies north of the warm SSTA are much strengthened. The westerlies are also stronger in the western as well as eastern North Pacific region, but are much weaker in the central North Pacific region. Some effects on the equatorial circulation due to the existence of midlatitude SSTA's are discussed and a transocean teleconnection is indicated. Certain general features of the experimental results support the hypothesis of Namias (1972). However, they did not conclusively demonstrate the significance of downstream oceanic influences on the weather pattern over a time period longer than one season.

LIU, P.C., and A.W. Green. Higher order wave spectra. Proceedings, 16th Coastal Engineering Conference, American Society of Civil Engineers, New York, 360-371 (1979).

No abstract.

NALEPA, T.F. Freshwater macroinvertebrates. Journal of Water Pollution Control Federation 51:1694-1708 (1979).

No abstract.

Ou, H.W., and J.R. BENNETT. A theory of the mean flow driven by long internal waves in a rotating basin, with application to Lake Kinneret. Journal of Physical Oceanography 9:1112-1125 (1979). https://www.glerl.noaa.gov/pubs/fulltext/1979/19790004.pdf

The rectified flow induced by wind-driven internal seiches in a rotating lake is studied. Friction and nonlinearity combine to generate a secondary mean flow which is calculated analytically for the case of a uniform depth lake and numerically for variable depth. The theory is applied to Lake Kinneret, the former Sea of Galilee, where the diurnal wind forcing produces a large internal Kelvin wave and which has a strong cyclonic mean flow. The uniform depth model reproduces the diurnal response adequately, but variable depth is required to reproduce the mean flow.

PICKETT, R.L. Preliminary tests of GLERL circulation models. GLERL Open File Report, Great Lakes Environmental Research Laboratory, Ann Arbor, MI (1979).

No abstract.

PICKETT, R.L., and D.A. DOSSETT. Mirex and the circulation of Lake Ontario. Journal of Physical Oceanography 9(2):441-445 (1979). https://www.glerl.noaa.gov/pubs/fulltext/1979/19790005.pdf

The observed pattern of mirex in Lake Ontario's sediments is consistent with what is known about the Lake's long-term circulation. A reasonable simulation of the mirex pattern was obtained using a steady-state circulation model coupled to a simple water quality model. The equivalent 10-year mirex accumulation on the lake bottom from these numerical models is similar to the observed mirex pattern.

POTOK, A.J. Upper St. Lawrence River hydraulic transient model. NOAA Technical Memorandum ERL GLERL-24, Great Lakes Environmental Research Laboratory, Ann Arbor, MI (PB-297-490/5GA) 96 pp. (1978). https://www.glerl.noaa.gov/pubs/tech_reports/glerl-024/

The Great Lakes Environmental research Laboratory (GLERL) has developed hydrologic response models for simulation studies on precipitation augmentation, ice retardation, system diversions, and connecting channel changes. For example, hydraulic transient models developed for use on the Detroit and St. Clair Rivers have been used to compute channel flow. The most recent addition to this series of models, a hydraulic transient model of the upper St. Lawrence River, is designed to simulate river profiles and flows on the St. Lawrence River from Lake Ontario to the Moses-Saunders powerhouse near Massena, N.Y. It is capable of simulation on varying time increments and includes flow under ice-covered, as well as open-water conditions. This paper describes the mathematical model, its development, calibration, verification, and typical applications.

QUINN, F.H. Derivation and calibration of stage-fall-discharge equations for the Great Lakes connecting channels. GLERL Open File Report, Great Lakes Environmental Research Laboratory, Ann Arbor, MI (1979). https://www.glerl.noaa.gov/pubs/fulltext/1979/19790011.pdf

No abstract.

QUINN, F.H. Lake Superior regulation effects. Water Resources Bulletin 14(5):1129-1142 (1978).

The outflows of Lake Superior through the St. Marys River have been modified from natural conditions, initially by the construction of engineering works, such as bridges, and later by the construction of control works and the regulation of the lake. For all practical purposes, the period form 1860 to 1887 represents the natural river conditions. During the period 1888-1900 the regimen was modified by the construction of the International Railroad Bridge and the Chandler-Dunbar Power Canal. In 1901 construction began on the compensating works. Following the completion of the compensating works in August 1921, the Lake Superior outflows were regulated in accordance with the Orders of Approval, 26 and 27 May 1914. A hydrologic response model was developed to simulate natural Lake Superior regime. The model was run for the 1860-1975 period to simulate natural Lake Superior levels and outflows. The simulated levels were compared with the recorded levels to determine the effect of regulation. It was found that regulation has resulted in a rise in Lake Superior water levels. The simulated natural outflows for the period from 1937 to 1975 were run through the Great Lakes hydrologic response model to analyze the regulation effects on Lakes Michigan-Huron, St. Clair, and Eire. The results show no long-term bias due to regulation.

QUINN, F.H. Relative accuracy of connecting channel discharge data with application to Great Lakes studies. Journal of Great Lakes Research 5(1):73-77 (1979). https://www.glerl.noaa.gov/pubs/fulltext/1979/19790007.pdf

The flows in the Great Lakes connecting channels are a major component in the water balance of the Great Lakes Basin. The increased emphasis on Great Lakes water quality and quantity requires an assessment of the accuracy of both measured and computed connecting channel discharge data. In this study, the standard error of typical discharge measurements was found to be approximately 3 to 5 percent, depending upon the number of panels used in the cross section. Measurement sets were found to have a practical limit of about 25 measurements. The standard error of a set of measurements was found to be on the order of 1 percent. The procedure used to compute the published flows of the Niagara River was found to have an apparent bias of about 2 percent on the high side. It is recommended that the published Niagara River flows be adjusted prior to use in detailed water balance studies.

QUINN, F.H., R.A. ASSEL, D.E. Boyce, G.A. LESHKEVICH, C.R. Snider, and D. Weisnet. Summary of Great Lakes weather and ice conditions, winter 1976-77. NOAA Technical Memorandum ERL GLERL-20, Great Lakes Environmental Research Laboratory, Ann Arbor, MI (PB-292-613/7GA) 141 pp. (1978). https://www.glerl.noaa.gov/pubs/tech_reports/glerl-020/

The winter of 1976-77 was the fifth coldest in the past 200 years. Record-breaking low temperatures from mid-October to mid-February, associated with an upper air pressure pattern consisting of a strong ridge in the westerly flow over North America, resulted in extraordinary ice cover on the Great Lakes. Ice was produced almost simultaneously in various shallow protected areas of the Great Lakes in early December. The progression of early winter, mid-winter, and maximum ice extent was from 4 to 5 weeks earlier than normal. At the time of maximum ice extent in early February, Lake Superior was approximately 83 percent ice covered, Lake Michigan over 90 percent, Lake Huron approximately 89 percent, Lake Erie 100 percent, and Lake Ontario approximately 38 percent. Spring breakup started in late February in the southern part of the Great Lakes region and in early March in the northern part. The bulk of the ice cover was gone by the fourth week of April. Shipping was severely hampered by the abnormally large amount and duration of the ice cover. Direct icebreaker assistance by the U.S. Coast Guard was up about 55 percent over the previous winter season.

QUINN, F.H., J.A. DERECKI, and R.N. KELLEY. Great Lakes beginning-of-month water levels and monthly rates of change of storage. Journal of Great Lakes Research 5(1):11-17 (1979). https://www.glerl.noaa.gov/pubs/fulltext/1979/19790006.pdf

Time series of beginning-of-month water levels and rates of change of lake storage were determined for each of the Great Lakes and Lake St. Clair for 1941-1975 period. The Thiessen polygon procedure was used to compute the beginning-of-month levels because it provides more representative overall lake levels than straight averaging and requires minimum subjectivity. The effect of crustal movement on the rate of change of lake storage was investigated and found to be negligible. A gage density analysis shoed good agreement between various size gage networks with the maximum deviation between networks decreasing with increasing gage density. Thiessen polygon weighting factors are presented for the current gage networks to enable future extension of the time series.

RAO, D.B. Lake Erie dynamics experiment planned. Coastal Oceanography and Climatology News 1:25 (1979).

No abstract.

RAO, D.B. Lake Superior heat storage study continued. Coastal Oceanography and Climatology News 1:21 (1979).

No abstract.

ROBERTSON, A., and D. SCAVIA. The examination of ecosystem properties of Lake Ontario through the use of an ecological model. In Perspectives on Lake Ecosystem Modeling, D. Scavia and A. Robertson (eds.). Ann Arbor Science, Ann Arbor, MI, 281-292 (1979).

No abstract.

SAYLOR, J.H., and G.S. MILLER. Lake Huron winter circulation. Journal of Geophysical Research 84(C6):3237-3252 (1979).

Twenty-one current meter moorints were deployed in Lake Huron during winter 1974-1975. The moorings were set in November 1974 and retrieved approximately 6 months later. The stations were configured on a coarse grid to measure the lake-scale circulation during winter. Water temperature was also recorded in nearly all of the 65 current meters deployed. Results reveal a strong cyclonic flow pattern in the Lake Huron Basin persisting throughout the winter. The observed winter circulation was in essence very similar to what is now believed to be the summer circulation of epilimnion water, although the winter currents penetrated to deeper levels in the water column and were more intense. Winter cyclonic flow persisted in a nearly homogeneous water mass, while summer currents have been shown to exhibit an almost geostrophic balance with observed water density distributions. This suggests that the current field driven by prevailing wind stresses across the lake's water surface may be largely responsible for maintaining the horizontal gradients of water density observed in the lake during summer. Analyses of energetic wind stress impulses reveal the prevailing wind directions that drive the dominant circulations. When combined with results of summer surveys, the winter studies permit a description of the annual cycle of horizontal current speed variation with depth in Lake Huron.

SCAVIA, D. The use of ecological models of lakes in synthesizing available information and identifying research needs. In Perspectives on Lake Ecosystem Modeling, D. Scavia and A. Robertson (eds.). Ann Arbor Science, Ann Arbor, MI, 109-168 (1979).

No abstract.

SCAVIA, D., and A. ROBERTSON. Perspectives on lake ecosystem modeling. Ann Arbor Science, Ann Arbor, 168 pp. (1979).

No abstract.

SCHWAB, D.J. Analytical and empirical response functions for storm surges on Lake Erie. Proceedings, Symposium on Long Waves in the Ocean, Manuscript Report Series No. 53, Marine Sciences Directorate, Ottawa, ON, 140-144 (1979).

A comparison between unit impulse response functions for water level displacement generated by several numerical models of Lake Erie and response functions derived empirically from water level and wind records indicates some significant differences. Numerical models include a channel model, a two-dimensional finite difference model, and a two-dimensional finite element model. The response of the finite difference model is calculated on 5- and 10km grids and with two different parameterizations of bottom friction. Response functions can also be derived empirically from time series of winds and water levels. this has been done for a series of storm surge cases on Lake Erie by using wind data from seven weather stations around the lake. Both empirical and analytical response functions are then used to simulate storm cases. The empirical functions tend to show a more rapid response to wind stress than the model results.

SCHWAB, D.J. Simulation and forecasting of Lake Erie storm surges. Monthly Weather Review 106(10):1476-1487 (1978). https://www.glerl.noaa.gov/pubs/fulltext/1978/19780003.pdf

A numerical model based on the impulse response function method is used to hindcast and forecast storm surges on Lake Erie. The impulse response function method is more efficient than numerical integration of the dynamic equations when results are required at only a few grid points. Hindcasts use wind observations from seven weather stations around Lake Erie. The surge phenomenon depends on the two-dimensional structure of the wind field and on the stability of the atmospheric boundary layer over the lake. The overall correlation coefficient between computed and observed water level deviations for 15 five-day hindcast cases is 0.83 at eight water level recording stations. Operational Great Lakes wind forecasts are used to drive the model for water level forecasts at Buffalo, NY, and Toledo, OH. The accuracy of the water level forecasts is currently limited by the accuracy of the forecast winds.

SCHWAB, D.J. Storm surge studies on the Great Lakes. American Society of Cvil Engineers Convention and Exposition, Chicago, IL, October 16-20, 1978. ASCE, Chicago, IL, 12 (1978).

No abstract.

VANDERPLOEG, H.A. Dynamics of zinc-65 specific activity and total zinc in benthic fishes on the outer continental shelf off central Oregon. Marine Biology 52:259-272 (1979).

The dynamics of 65zn specific activity and total zinc in benthic fishes on the outer continental shelf off central Oregon (USA) were examined. A differential equation that relates specific activity of 65zn in fish to that in fish food was used to estimate a's (zinc uptake-rate coefficients) for 3 different size classes of the flounder Lyopsetta exilis, a small predator of pelagic Crustacea, and for 1 size class of the flounder Microstromus pacificus, a large predator of infauna. The a's obtained for L. exilis were very close to the a obtained in the laboratory for the flounder Pleuronectes platessa. The a estimated for m. pacificus was very much smaller than the a's estimated for the other two species. A model that related a to predicted weight-specific feeding rates suggested that the smaller a of M. pacificus was caused by a low absorption efficiency of zinc from its prey. Sensitivity studies indicated that time histories of specific activity in the fishes are not sensitive to moderate changes in a. The negative correlation between specific activity in the diet and in the weight of L. exilis was the major cause of the negative correlative between specific activity and weight in this species. In M. pacificus, where composition of diet does not vary with size, specific activity was independent of weight. The time history of specific activity in M. pacificus was very much lower than those in the different size classes of L. exilis, a result caused mainly by the much lower specific activity of the prey of M. pacificus. Differences in specific activity among other benthic fishes were also correlated with differences in specific activity of their prey. The food-web dynamics responsible for these patterns are discussed. Variation in total zinc concentrations among species was small. Within species of flounder, zinc concentration varied only slightly or not at all with weight.

VANDERPLOEG, H.A., and D. SCAVIA. Calculation and use of selectivity coefficients of feeding: Zooplankton grazing. Ecological Modeling 7:135-149 (1979).

A straightforward method of calculating selectivity coefficients (Wij) of predation from raw data, mortality rates of prey, filtering rates, feeding rates and electivity indices is derived. results from a comparison of selectivity coefficients for the copepod Diaptomus oregonensis grazing under a number of experimental conditions suggested that Wij's for size-selective feeding are invariant, a conclusion also supported by the leaky-sieve model. Recommendations are made on how to use Wij's in linear and nonlinear feeding constructs for zooplankton and other animals.

VANDERPLOEG, H.A., and D. SCAVIA. Two electivity indices for feeding with special reference to zooplankton grazing. Journal Fisheries Research Board Canada 36(4):362-365 (1979).

The electivity indices Ei and Ei' of predator--prey interaction are currently used to quantify particle-size selection by grazers. Under conditions of passive, mechanical particle-size selection predicted by the leaky-sieve model, these indices yield electivity vs. particle-size curves that vary with the shape of the particle-size spectrum of food offered to the zooplankton. In addition to this bias, poor estimates of electivity will be obtained unless only a small fraction of the food is eaten in such experiments. The selectivity coefficient (Wi) used by modelers in feeding constructs and the electivity index Ei*, derived here, are recommended instead because they do not suffer from the shortcomings described for Ei and Ei'. Moreover, use of Wi's and Ei*'s is recommended for quantifying selection for many other cases of predator--prey interactions.

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