ZABAVNIKOV V.B., LISOVSKY A.S. Polar Research Institute of Marine Fisheries and Oceanography

In recent ten years PINRO have been conducting comprehensive annual aerial surveys during the third ten-day period of August - the first five-day period of September in the eastern and southeastern Barents Sea.

Used as a surveillance platform is a twin-engine aircraft AN-26 "Arktika" equipped as laboratory and having the following main specifications.

Specifications a twin-engine aircraft AN-26 "Arktika"
maximal flight distance - 1500 nautical miles
maximal flight duration - 9 hours
average speed during aerial survey - (altitude - 150-200 m) 170 knots
maximal take-off mass - 25 tons
minimal allowable length of the runway with a maximal take-off mass - 1300 m

Comprehensive survey means that the input data on oceanographic state on the sea surface and in the surface layers, distribution and abundance of marine mammals, birds and other biological objects, which are collected with the use of the distance system of aerial sounding, operating in different electrical and magnetic wave length ranges, as well as during visual observations, are obtained simultaneously, in real position and time. One of the elements of these research applied aerial works is a control over the contamination of different origin (plastic, wooden and other wastes, oil patches, overflow, films and etc. al and ecological situation in the sea surface layers.

All the comprehensive aerial surveys are conducted by the grid of tacks oriented across the streams of the main currents in the Barents Sea. The distance between primary survey tacks does not exceed 45 m miles and 20 m miles in the sites of maximal variability of hydrographic parameters.

Aerial surveys are carried out if the following meteorological parameters are registered in 60 % of the area:

- wind speed - to 7 in/s

- lack of haze, fog, any kind of intensive precipitation.

- the lower cloudiness border of not less than 150 m.

During the comprehensive surveys involving ecological monitoring, aboard the airborne laboratory "Arktika", the following systems of aerial sounding and auxiliary technical equipment are used:

1. The unit for sounding within the infrared (IR) range of electromagnetic waves including AIR-2 IR radiometer and "Malakhit" ER scanner.
• AIR-2 makes it possible to measure ocean surface temperature (OST) along the flight route of the airborne laboratory, in practice, uninterruptedly and with the accuracy of not worse than 0.1. Using the data obtained OST spatial structure is reconstructed based on the standard methods of interpolation and extrapolation with the allowance for the knowledge of thermal and dynamical features of aerial survey area.
• "Malakhit" allows us to derive information on temperature in the local pails of the sea surface, along the survey track with the width of not less than 90 m (depending on the altitude) based on IR image analysis that permits position and structure of thermal heterogeneity at the sea surface (fronts, eddies, meanders and etc.), as well as organic contamination such as patches, slicks and films to be identified. IR seamier sensitivity is 0.1°C.

2. The system of high frequency aerial sounding (HF-system) is represented by radar with synthesized aperture (radiation wave length - 4 cm. RSA-4) and passive HF radiometer ("FISH") with 5.6 cm received length of wave radiated from the sea surface.
• The main characteristic of system consists in the ability of effective, reliable and qualitative usage in any weather conditions (all-weather). The system allows us to obtain data on the position and structure of hydrodynamic heterogeneity and borders of different origin water masses at sea surface and on the organic contamination in the form of patches, slicks and films.
• RSA-4 gives us the possibility to derive data as radio location images (RLI) within the view band of not less than 2 km depending from the altitude of airborne laboratory flight and HF radiometer - to obtain digital values of radio brightness temperature along the track of the aerial survey, the analysis and interpretation of which permit us to determine the position of the borders between water masses of different origin and to identify organic contamination.

3. Aboard "Arktika" the system of laser location is represented by polarization PAL-1 aerial lidar making aerial sounding of the sea subsurface layers in the optical range of electromagnetic wavelength. The depth of sounding beam penetration to water column depends on their natural transparency and amounts to 55 m for oceanic waters and to 30-40 m, on the average.
• Applying PAL-1 one can obtain not only the data on values of oceanographic parameters at the sea surface and in the subsurface layers (transparency, pycnocline depth, the areas of primary biological production higher concentration), but register organic contamination at sea surface.

4. Besides using mentioned instrumental system, visual board observations by specialists from both aircraft "Arktika" sides are made. Each observer executes visual survey under the aircraft and within the vision band equaled to the flight altitude (45° angle of view). Abundance and species of marine mammals, birds and other biological objects are determined; as well as any kind of contamination at sea surface is registered. In addition to, board observers make photo and video surveys of the most interesting phenomena, effects and objects at sea surface with the purpose of their documenting.

Photo and video survey is executed by digital photo cameras (NIKON D1X), analogous and digital video cameras TK-880 and PANASONIC NV-MX7D, respectively, or PANASONIC NV-GX7.

For the accurate correspondence of all the data complex collected during the survey process in the real geographical position and time satellite navigation GPS-system of GARMIN II PLUS-type is used.

All the information derived by aerial sounding instrumental system and board observers goes to the aircraft board automatized system of the collection, filtration, primary processing, presentation, accumulation and storage of data (BAS) with simultaneous recording of the full volume of voice information by observers in the mode of dictaphone.

At the aircraft, the local Ethernet including all the board personal computers (PC) is arranged that allows all the PCs to exchange data, obtain navigation data, synchronize time of all the systems through BAS set in the central computer.

Aboard "Arktika", there is a possibility of operative transmission and data exchange with the vessels and the coastal centers that is provided by standard radio communication facilities and modem "Inmarsat" system.

After the completion of each comprehensive aerial survey and/or their series (research works in the adjacent areas), processing, analysis and interpretation, all the materials and data are presented as maps adopted to the geographical information system (GIS), in the form of isolines, legends and symbols, not later, than after three hours. There's a possibility to present this resultant information to any consumer both at sea and land quickly.

Thus, airborne laboratory "Arktika" with the equipment installed and exploited may be efficiently used during the observations over contamination and ecological monitoring of the Barents Sea that is quite important in connection with expected industrial exploitation of gas and oil deposits on this sea shelf.

ARCTIC SHELF OIL AND GAS CONFERENCE 2004