Introduction

Generally, oil spillage is categorized into four groups: minor, medium, major and disaster. Minor spill neither takes place when oil discharge is less than 25 barrels in inland waters nor less than 250 barrels on land, the offshore or coastal waters that does nor pose a threat to the public health or welfare. In case of the medium spill the spill must be 250 barrels or less in the inland water or from 250 to 2 500 barrels on land, offshore and coastal water while for the major spill, the discharge to the inland waters is in excess of 250 barrels on land, offshore or coastal waters. The disaster refers to any uncontrolled well blowout, pipeline rupture or storage tank failure which poses an immediate threat to public health or welfare.

Satellite-based remote sensing equipment installed in the satellite is used for monitoring, detecting and identifying sources of accidental oil spills. Remote sensing devices include the use of infrared, video and photography from airborne platforms. In the mean time presently a number of systems like airborne radar, laser fluorescence, microwave radiometer, SAR, ERS 1, ERS 2, ENVISAT and LANDSAT satellite systems are applied for the same purposes. Currently more than a dozen satellites are in the orbit producing petabytes of data daily. Detailed description of these satellites, major characteristics of sensors can be summarized as follows:

• Spatial resolution of sensors ranges from 1 meter (e.g. IKONOS) to several kilometers (e.g. GEOS);

• Satellite sensors commonly use visible to near-infrared, infrared and microwave portions of electromagnetic spectrum;

• Spectral resolution of satellite data ranges from single band (Radarsat) to multibands (e.g. MODIS with 36 bands);

• Temporal resolution (repeat time) varies from several times a day (e.g. Meteosat);

• The majority of satellites are sun synchronous and polar orbiting, crossing the equator at around 10 a.m. local time during their descending pass;

• Digital data are available in both panchromatic (black and white) and multi-spectral modes.

Using the recent advanced space technology, the following methodology can be applied for the oil spills detections:

• Development of oil spill detection methods for the purpose of practical oil spill surveillance related to the space imagery with application of any weather conditions;

• Adaptation of the observation to other systems to predict the oil spill spread direction and flow rate characteristics, determination the pollutant contaminations;

• Development of appropriate data and user interface.

There is a need for effectively direct spill countermeasures such as mechanical containment and recovery, dispersant application and burning, protection of sites along threatened coastlines and the preparation of resources for the shoreline clean-up.

As it is mentioned in the beginning, the remote sensing is one of the main methods for an effective response to the oil spills environmental monitoring. Timely response to an oil spill requires rapid investigation of the spill site to determine its exact location, extent of oil contamination, oil spill thickness, in particular.

Policy makers, managers, scientists and the public can view the changing environment using the satellite images. Remote sensing is the discipline of observing the Earth's surface without direct contact with the objects located at the surface. It allows obtaining information about the planet and human activities from a distance which can reveal interesting features that may not be possible or affordable from the ground level. One of the applications of remote sensing is water and coastal resources. It is essential to undertake the following aspects while using the remote sensing method:

• Determination of surface water areas;

• Monitoring the environmental effects of human activities;

• Mapping floods and flood plains;

• Determination of the extent of snow and ice;

• Measuring glacial features;

• Mapping shoreline changes;

• Tracing oil and pollutions.

The fact that remote sensing allows multi-temporal analysis is also very important. This means that an area of interest can be monitored over time so that changes can be detected. It allows analyzing phenomena like vegetation growth during different seasons, the extent of annual floods, the retreat of glaciers or the spread of forest fires or oil spills (Vhenenye Okoro, 2004).

Remote sensing is a useful method in several modes of oil spill control, including a large scale area of surveillance ability, specific site monitoring and advantages of technical and technological assistance in emergency cases. There is a significant capacity of providing essential information to enhance strategic and tactical decision-making, decreasing response costs by facilitating rapid oil recovery and ultimately minimizing impacts.

Observation can be undertaken visually or by using remote sensing systems. In remote sensing, a sensor other than human vision or conventional photography is used to detect or map oil spills.

Oil Spill Detection

Oil production and transportation is started on the offshore "Azeri - Chiraq -Guneshli" oilfield, located at the Azerbaijani sector of the Caspian Sea. Therefore development and implementation of onshore and offshore oil spill monitoring and detection are highly important for the Caspian Sea basin countries. Figure 1 shows the overall map of the Caspian Sea region countries.

Oil statistics of the major Caspian Sea oil producing countries are presented in Table 1.

For visual observations of oil spill from the air using the video photography are the simplest, most common and convenient method of determining the location and extent (scale and size) of an oil spill. There are a number of sensors on surveillance of the sea surface:

• Microwave radiometers which allow the determination of the oil thickness;

• Ultraviolet and infrared scanners which allow to detect respectively very thin and very thick oil films;

• Laser fluorescence sensors which allow the determination of oil type.

Caspian Sea Extent
Fig. 1 Overall map of the Caspian Sea region countries
Table 1 Statistical information of oil producing countries

Azerbaijan

Kazakhstan

It is assumed that the Guneshli oilfield

Currently the country meets its domestic

will meet the domestic needs and the

needs. Below are presented only the

export volumes will be as fellows:

export volumes from the Tengiz oil

Was this article helpful?

0 0

Post a comment