Aerial Observation of Oil Pollution at Sea Aerialaerialoperational Guide OBSERVATIONOBSERVATION OFOF OILOIL POLLUTIONPOLLUTION
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Aerial Observation of Oil Pollution at Sea AERIALAERIALOperational Guide OBSERVATIONOBSERVATION OFOF OILOIL POLLUTIONPOLLUTION ATAT SEASEA OPERATIONAL GUIDE Cover photo: Aerial reconnaissance during the Exxon Valdez oil spill (Alaska, 1989) Source: Cedre AERIAL OBSERVATION OF OIL POLLUTION AT SEA OPERATIONAL GUIDE This guide was written and produced by Cedre, the Centre of Documentation, Research and Experimentation on Accidental Water Pollution, as part of its technical program, with financial support from the French Navy, Total and the Ministry of Ecology and Sustainable Development. The information contained in this guide is the result of Cedre’s research and experience. Cedre cannot be held responsible for the consequences resulting from the use of information contained in this publication. Published: July 2004 (French version) October 2006 (English translation) Translated by Sally Ferguson. 3 Aerial Observation of Oil Pollution at Sea Operational Guide Purpose of this Guide An important component of Cedre’s work of these experienced observers. They will involves designing operational guides which recognise their contributions, for which we present the results of studies, of experimental are extremely grateful. work and experience feedback from accidents A number of important new points have which have occurred. been added to this edition, in particular the The original operational guide dedicated to modelling of drift prediction (MOTHY model), aerial observation, published only in French, the use of satellite-tracked drifting buoys and dated back to 1993. It therefore seemed the Drift Prediction Committee, set up a few necessary both to our experts and our days after the shipwreck of the Prestige by the partners (the French Navy, French Customs French General Secretariat for the Sea. and Total) to update this guide, in light of The first vocation of this operational guide is the advances made in terms of practices and to be present onboard all aircraft likely to be knowledge in this field. involved in aerial observation of oil pollution The French Navy Air Force and French at sea. However it is also a useful tool in Customs (Aero-Maritime Surveillance Brigade) pollution response centres and as a technical share their knowledge at bi-annual training support for public relations personnel. courses organised by Cedre. Much of what is presented in this guide is a result of the work 4 Aerial Observation of Oil Pollution at Sea Operational Guide Operational Organisation The mission A A Different types of hydrocarbons B Before the Evolution of oil at sea C mission A B Appearance of oil D C slicks E Drift of oil slicks E Oil spill observation Pollution During F report the mission H Guiding response D G operations F G Pollution D H I observation report Other products and I natural phenomena 5 Aerial Observation of Oil Pollution at Sea Operational Guide PURPOSE OF THE GUIDE 4 OPERATIONAL ORGANISATION 5 CONTENTS 6 A THE MISSION 7 A.1 - The aims of reconnaissance flights 8 A.2 - Preparing the mission 9 A.3 - Flight profile 10 BI DIFFERENT TYPES OF HYDROCARBONS 12 B.1 - Oil and oil products 13 B.2 - Basic physical characteristics 14 C EVOLUTION OF OIL AT SEA 16 C.1 - The first few days 17 C.2 - Photographic imagery of the evolution of oil at sea 18 D APPEARANCE OF OIL SLICKS 19 D.1 - General overview 20 D.2 - Special cases 21 D.3 - Topography of oils slicks at sea 22 D.4 - Arrival of oil on the coast 24 E DRIFT OF OIL SLICKS 25 E.1 - Calculation of drift 26 E.2 - Information and data transmission 27 E.3 - Slick drift model 28 E.4 - Use of drifting buoys 30 F OIL SPILL OBSERVATION 32 F.1 - Observation criteria 33 F.2 - Bonn Agreement Oil Appearance Code 34 F.3 - Appearance at sea 36 F.4 - Observation on the coast 38 F.5 - Photographic and video imagery 39 F.6 - Remote sensing 41 G GUIDING RESPONSE OPERATIONS 43 G.1 - Guiding a pollution response vessel 44 G.2 - An example of guidance during the Prestige response 45 H RECONNAISSANCE REPORT 46 H.1 - Mapping pollution 47 H.2 - Estimating the quantity of pollutant 50 H.3 - Degree of coverage: reference plates 52 H.4 - POLREP 53 I OTHER PRODUCTS AND NATURAL PHENOMENA 54 GLOSSARY 58 BIBLIOGRAPHY AND USEFUL WEBSITES 60 6 Aerial Observation of Oil Pollution at Sea Operational Guide THE MISSION The aims of reconnaissance flights A1 Preparing the mission A2 Flight profile A3 7 Aerial Observation of Oil Pollution at Sea Operational Guide The Aims of Reconnaissance Flights A1 Aerial observation can be used for two distinct purposes. First, it can be carried out routinely, to look for Secondly, aerial observation is used in the and suppress operational pollution by ships. In event of an accident, to assist in recovery and this case the aims are to: dispersion operations at sea. The aims of the • detect the pollution observation missions are to: • accurately locate and describe the pollu- •locate the slicks tion •accurately describe the slicks • where possible, identify the polluter •map the pollution in order to: in order to: • assess the pollution (quantity and quality) •monitor the pollution • anticipate the evolution of the situation •adjust drift models • prosecute the polluter via a pollution obser- •guide response operations that day vation report •prepare the response operations for the following days In the event of an accident, aerial observation is the only means of obtaining a clear, realis- tic picture. It is the first link in a chain of important decisions. The Prestige, an example of a GIS prediction map providing the details of a pollution observation 8 Aerial Observation of Oil Pollution at Sea Operational Guide Preparing the Mission All missions must be prepared. The aim here is to try to predict what is A2 likely to be encountered, including the appearance, extent and location of the slicks. In all cases: In the absence of specific instructions from a coordination centre, estimate the most pro- Prepare basic maps of the zone, on which the bable location of the slick, by calculating its pollution can be mapped and observations probable drift (see E1), either from the place of noted during the flight. Clearly indicate on spillage or the last observed position. these maps the orientation, coastline, geogra- phical co-ordinates, scale... Investigate the possibility that other areas, so far unobserved, may be polluted. This should be carried out taking the prevailing local cir- In the case of an accident: cumstances into consideration, for example the Gather as much information on the slick as shipping route before the accident, a new leak possible: in the wreck, other pollutant contributions due • nature of the pollutant: crude, refined, light to slicks, previously having reached the shore, or heavy oil (its density, viscosity, pour point, breaking away and drifting... (see example at etc.). In the case of crude or light refined oil, foot of page). beware of the risk of explosion (see A3) and Identify the zone to be covered by the mission make sure an explosimeter is available. and establish a flight profile for maximum cove- • type of accident (sinking, grounding, explo- rage (see A3). sion during operations ...). Forecast slick evolution according to the cha- • type of spillage (isolated event, continuous racteristics of the pollutant (estimate viscosity flow, on surface, below surface). at ambient temperatures, assess tendency to • last slick observation (date, appearance, form a reverse emulsion), or according to the location). available observation data, and anticipate any Gather all the necessary data on the local con- potential identification difficulties (e.g. low floa- ditions (weather since last observation, sea cur- tability of the pollutant, fragmented slicks…) rents, sea state etc.). Prepare and take onboard buoys which can be detected by satellite. The example of the Erika Before breaking in two, the Erika had already been leaking for many hours and the lost fuel oil arrived onshore without being observed at sea. This occurred due to a lack of specific research aimed at locating this loss, as it had not been reported by the ship’s master. 9 Aerial Observation of Oil Pollution at Sea Operational Guide Flight Profile A3 As hydrocarbons tend to spread in bands First of all, look for the most polluted zones parallel to the wind (see D3), the zone to be (thick patches or slicks, accumulation zones). investigated should be covered flying cross Out at sea, follow thin patches or stripes wind, to increases the chances of detecting (rainbow, sheen or metallic appearance) with any slicks (“staggered sighting”). the wind, in order to detect any possible thick patches leeward of the contaminated zone - Mist and dazzle reflected from the sea (see D3). surface often hamper visibility. Sometimes the best way to fly will be governed by the If a new band of pollution or recent stripes position of the sun. are sighted, follow them in order to deter- mine the source of pollution. This source will - Flying altitude is determined by the size of usually be located upwind, particularly if the the slicks to be located, the visibility and spillage point is fixed, but also upcurrent (see the sea state. It is important to ensure D3). maximum sweep while conserving a good vision of all the details. - The use of polarised sunglasses facilitates observation. - As far as possible, observations made using non-specialised planes (e.g. maritime patrol) should be confi rmed by helicopter reconnaissance (which allows more precise observation), or by a plane fi tted with specialised remote sensing equipment (IR, SLAR, FLIR, UV or possibly microwave). Wind direction A Estimated slick drift B 0 10 20 NM A: Last known slick position B: Probable current position of slick NM: nautical miles 10 Aerial Observation of Oil Pollution at Sea Operational Guide In the event of a significant spill of light toxic vapours in the air.