A nomogram method for predicting the movement of oil slicks

In order to obtain quick initial guidance on a first estimation of motion of the spilled oil, a simple manual procedure incorporating advection and spreading processes has been devised. This procedure involves the utilization of a nomogram based on simplified equations. Spill displacements throughout a given forecast period can be easily read from the nomogram. The technique is demonstrated with a real spill case.     

Winter ice experiment Beaufort Sea (Wiebs)—data collection

Abstract

Under a joint government/industry program called the Winter Ice Experiment Beaufort Sea (WIEBS), during November and December 1979 and April 1981, two data sets were acquired in the southeastern Beaufort Sea, for the purpose of developing and testing a dynamical/thermodynamical sea ice model. The data sets included meteorological, oceanographic, and sea ice parameters. Also, on a limited scale, ground truthing data were obtained. This paper deals with the data collection aspects of the experiment and their archival.     

On the impossibility of the co-existence of monsoons and severe storm surges in the Bay of Bengal

The problem of storm surges is introduced briefly. The utility of passive microwave observations to study this phenomenon is pointed out. The reasons for the nonoccurrence of severe surges in the Bay of Bengal, during monsoon regimes, is discussed in this paper. It was demonstrated that the predominant reason for lack of severe surges over the Bay of Bengal coast is due to the absence of weak wind shear during monsoon seasons.Atmospheric Environment Service, Ice Center, Environment Canada, 373 Sussex Drive, Ottawa, Ontario, Canada K1A OH3.     

The oil spill behaviour model of the canadian atmospheric environment service. Part II: Evaluation of model guidance for emergency response

Abstract

In a companion paper the theoretical basis for the Canadian Atmospheric Environment Service oil spill behaviour model was discussed along with its evaluation, in non‐real time, using data collected from field experiments and a real spill. This paper deals with the use of the model in real time to provide guidance in support of the emergency created by an oil spill in the Canadian Beaufort Sea. The spill of about 2440 barrels of diesel oil occurred in September 1985, the result of storm damage to an artificial island used for hydrocarbon exploration.

Model simulations were carried out for two time periods while the spill was being tracked. These simulations identified the marked shifts in the direction of movement of the spill. While the predictive skills for the two time periods varied, with re‐initialization the final observed slick location was predicted to within 2 km. This model prediction was used by the regulatory authorities as guidance information in locating the slick when it could not be easily spotted from the air. The prediction of the size of the slick 27 h after initial time was in very good agreement with observations. A qualitative evaluation of the model‐simulated weathering of the oil was also carried out.     

The solar cycle and Indian rainfall

Summary The objective of this study is to examine critically the relationship between solar cycles and Indian monsoon rainfall, for the period 1871–1984, and to search for significant periodicities, by utilizing the maximum entropy spectral technique (MEST). The results of this study using MEST show clearly a significant 11-year cycle in solar activity and rainfall. Also present is a significant 7.33-year cycle in rainfall. The double (Hale) sunspot cycle is not discernible here either in sunspot number or in rainfall. The cross-spectral analysis between the sunspot number and rainfall confirms the existence of a reasonable correlation over an 11-year cycle with a relative phase lag of 0.16 year (sun lead).

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Zusammenfassung Zweck dieser Studie ist die kritische Überprüfung des Zusammenhangs zwischen Sonnenzyklus und dem indischen Monsunregen im Zeitraum 1871–1984 und die Festlegung spezifischer Periodizitäten mittels der Maximal-Entropie-Analyse (MEST). Die Resultate zeigen einen signifikanten 7,33-jährigen Niederschlagszyklus. Der doppelte (Hale) Sonnenfleckenzyklus ist hierbei nicht ausnehmbar, weder bei der Anzahl der Sonnenflecken, noch beim Niederschlag. Die Kreuz-Spektralanalyse zwischen Sonnenfleckenzyklus und Niederschlag bestätigt die Existenz einer Korrelation über einen 11jährigen Zyklus mit einer relativen Phasenverzögerung von 0,16 Jahren.

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On leave from the Indian Institute of Tropical Meteorology, Pune, India.

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With 3 Figures     

Real-time application of an oil spill movement prediction system

This paper deals with the prediction, in real time, of the motion of experimental oil slicks. The experiments were conducted during September 1983 offshore near Halifax on the east coast of Canada. The objectives of the experiments were (i) to determine the suitability of oil spill dispersants as countermeasures and (ii) the testing and verification of oil spill trajectory models and systems.The Atmospheric Environment Service (AES) participated in the experiments to test the capability of its oil spill motion prediction system in providing real-time trajectory forecasts. The experiment consisted of three sets of spills. Each set had a control slick and a test slick. Sixteen barrels of crude oil were used in each spill. The test slicks were used to test the effectiveness of various dispersants, the control slicks were used to verify trajectory forecasts.The spill trajectories and oil weathering information obtained from the system during the experiments demonstrated the relative ease with which the system could handle the required input and provide timely forecasts. The accuracy of these forecast trajectories was confirmed by observations, and their utility was demonstrated by their application in the operational decision-making process.     

On the recurvature of tropical cyclones and the storm surge problem in Bangladesh

The disproportionality of the large frequency of occurrence of severe storm surges on the coast of Bangladesh is highlighted. The reasons for the recurvature of these storms towards the Bangladesh coast and the associated severe surges are discussed in this paper.Atmospheric Environment Service, Ice Center, Environment Canada, 373 Sussex Drive, Ottawa, Ontario, Canada K1A 0H3.