Operational Ice Charting with Remote Sensing
Ice Charting services we provide are mainly targeted to raise efficiency of fleet usage in ice covered waters and increase safety of marine transits. The general set-up of seasonal office assumes close cooperation with a numerous number of Stakeholders in the ice charting production cycle, such as Marine Logistics, Ice Observers, Remote Sensing Data providers, Client’s Vessel Masters. The Basic scheme of data flows and interactions is outlined below. the systems built in house allow fast and efficient data exchange between all Stakeholders. Accumulating comlex database of numerous weather and ice parameters on the go enhances complex desision making with forecasting both favourable and hazardous ice events for marine operaitons in the region.
To the current date we have reached the level of automation, when only two persons can do the job that can cope with huge data flow at site supporting 20-30 vessels in transit.
Satellite Acquisition Plan – as all the projects involving Remote Sensing acquisition plan for satellite images is the most important part to optimize costs and ensure timely provision of data to support operations. Considering the cost involved with obtaining SAR data that is the major source of information we have focused on synergy of commercial platforms with free Sentinel data. This significantly reduces the cost of all operations. Significant effort was put with Mission planners and Copernicus Support team distributing the data to ensure all opportunities to downlink data from all Sentinel satellites passing over the Caspian Sea.
Current situation is more than satisfying when both S1A and S1B downlink data with high resolution and vast coverage on both ascending and descending orbits. As illustrated below coverage and revisit time for Saddle in the Northern part of the Caspian Sea has significantly improved in 2017 allowing to cut costs on other commercial platforms.
The following list of products were developed based on experience of more than 15 years of operations in the Caspian Sea Kashagan operations and have proven their efficiency there.
Daily Nowcast Product – a summary ice chart with enhanced WMO ice eggs with the best available information for the areas of operations and transit routes between supply base and operation sites. It provides data based on regional ice analysis of satellite images of the day, real observations from the field and, if not available, from interpolations of recent data. For each of the areas and transit route segments the region is divided to: estimated ice thickness (based on reports and aged using calculated ice growth data from observed air temperatures), ice cover as a percent, stability of the ice for the area or segment (ability to withstand movement due to wind or water level change stress), mean & max ice thickness, ice pressure as reported from vessels or expected based on statistics, ice displacement (based on manual ice drift calculations from successive imagery) , and reported ease-of-passage (from vessels). The transit route is examined on a segment by segment basis with average speed per segment and transit time is calculated. All this data day by day is compiled into single analyzable statistically geospatial database. The underlying database is used for derivative products discussed below and can be used for future reference for design and long-term forecasting.
In addition to GIS database daily description of ice conditions development over the region with major indicators like total ice coverage of the AOI, FDD, drift parameters and alike. This information generates a knowledge database to be used in future years for forecasting of ice events and generally understand ice behaviour over the seasons.
Daily Ice Outlook, Transit Route Summary and Forecast – one-page reports targeted to update wide audience on vessels in transit and the ice conditions they experience at the moment and may expect to see along the way as well as in the whole region. They include a summary of ice and weather conditions and forecast for the next 24 hours, a warnings note; a comments section in textual format and tables with simple trend graphs describing what is happening along the transit route and in the whole region based on recent reports and the forecast weather conditions; a graphic/textual section providing a segment by segment summary of track stability, ice pressure, and ease-of-passage as reported from vessels in transit (Latest Reported Conditions) accompanied by a forecast for track stability and ice pressure for the next 24 hours and again for the next 3-5 days and an auto-filled textual summary of calculated transit times and speeds.
A key feature of this report is an ice chart showing the ice cover concentrations and clearly showing leads, the ice edge with recent vessel tracks overlaid as dots color-coded by the vessel speed occurring at the time of their vessel reports issued; the 5-day trend for recent transit times in graphical format overlaid on the chart; and the most recent waypoint list in use for optimal transit route or stable pre-broken channel. Time for transit at current conditions is specifically essential for planning purposes.
Annotated Quicklooks are issued based on the latest imagery, whether radar-based such as Sentinel-1, RadarSat-2, TerraSAR or optical, such as MODIS, Sentinel-2 and Sentinel-3 (if not cloudy). The image is annotated with the latest ice edge position, floeberg locations, Ice concentration and ice types and drift parameters. The chart is a full-format coverage of the Northern Caspian Sea including all AOI specified by Client. The outcome format of the chart is georeferenced pdf file which allows to visualize the layers of data necessary for each.
Disseminated products containing only image and annotations for delineated areas is the most comprehensive tool for end-users to receive ice information and perform their own planning or analysis.
Transit Charts – vessels normally complete ice transit report on the go. We have developed custom made software to ensure quality of input data reducing chance of typos and misinterpretation. These reports when summarized and overlaid on the latest image provide generate a chart of transit. It is issued to all vessels thereby aiding subsequent voyages by other vessels. These data also feed into the daily issue of the Transit Route Summary & Forecast and verify modeled data for the region.
Waypoint Advisories – Often developed from the vessel reports and transit charts, these waypoint lists are provided as either a separate text e-mail, a list associated with the chart on the Transit Route Analysis & Forecast or at briefings provided directly to marine vessel management.
Major purpose of the advisories is to provide the most efficient transit routes with the easiest ice conditions. These can be either opening leads, less ridged areas or stable channels
TIPs – the Tactical Ice Product provides micro-scale (typically 5-20nm in range) ice advice to vessels underway on a transit through ice. Several TIPs may be issued to assist a single vessel to complete a voyage with the frequency of issue tied to new data arrival which could be from satellite, other vessels in transit, ice reconnaissance, changing conditions, changing forecast conditions or direct requests for assistance. It is issued in the form of a chart heavily annotated with description of ice conditions based on available data in the area.
Marine Mammals Population Chart – Depending on local regulations and necessity, marine mammals’ distribution over the region can be documented and monitored through the season in order to increase awareness of large accumulations and implement wild nature conservation measures with avoiding the areas. The charts normally show observed seal colony positions colour coded by age of sightings using icons to differentiate by species. The color coding uses age of sighting grouping for the past 24 hours (yellow), 1-3 days old (green) and 4-7 days old. The seal position data is overlaid on whatever the most recent imagery available. Note: the next step of forecasting combined with drift forecast and/or observations allows tracking large colonies attracted to specific ice features traversing AOI.
Ice Drift Charts – a chart product based on the latest received image or images that use different ice positions from subsequent images to determine drift displacement and direction. These data feed directly into the daily Nowcast dataset and support both the Daily Ice Outlook and Transit Route Summary & Forecast products. This product is not usually issued as a stand-alone product but used to turn a local or regional QuickLook into an annotated Local or Regional QuickLook.
As example by comparing set of the images same ice floe, once identified, is being vectorized, assigned with attributes (Floe ID, detected date, source of detection) and saved into geo-spatial database. The data can be used for operational ice drift chart and statistical analysis.
Drift chart evolves into similar forecast product where more focus on significant ice features and floes drift forecast. It includes the chart and text messages with the description of ice conditions, list of floes in the area within the AOI area (geo position, rel position to rig) and the potential development and movement of ice for the next 24,48,72 hours based on ECMWF or GFS forecast. The information regarding big floes can be processed with the software for estimation of its volume, size and other parameters and stored in the database. By tracking and forecasting floes with known hazardous for operations ice features (excess raftedness or ridging) or with high population of seals we can give early warning to operations to prepare for impact and take preventive measures.
Stamukhi and Ridges – Considering the water level decreasing significantly during the last years and most of the long-term expectations being its further reduction it is most likely the ACVs will start playing bigger role in the logistical chain for offshore operations in the Caspian sea. As most of the products above are mainly targeted for Ice Breaking Vessels support where degree of ice surface roughness has little value it is essential for maintenance of ACV skirts. In anticipation of growing ACV operations, we have developed specific set of monitoring applications to assist longevity of skirts ensuring continuity of operations with higher efficiency and safety. Read more about ACV support program and scientific research on ice rubble features recoggnition with remote sensing on separate pages.
GeoPDF – product contains an assembly of satellite image and layers from other ice charting products such as annotations with ice information, ice report labels, vessel tracks, wind speed and direction grid from forecasts, other relevant information.
The major advantages of this product are selectable information layers that can be switched off and that the file has spatial reference information, so one can use as an electronic chart for navigation extracting coordinates and measuring distances without installation of specific software and training. The intention is to provide this product directly to the ships/rig for use on their bridge while navigating through ice or analyzing current ice conditions.
WebPortals – Although our major focus is operations at sea where Internet connection is normally limited the design of our Database allows fast implementation of web solutions for dissemination of information.