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1 2020

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Sharing ships’ weather data via AIS

Tetreault B., Johnson G. W.

TransNav : International Journal on Marine Navigation and Safety of Sea Transportation

2020

Vol. 14, no. 1

143--150

In the aftermath of the sinking of the US-flagged containership El Faro in October 2015, one of the U.S. National Transportation Safety Board’s (NTSB) recommendations was for the National Oceanic and Atmospheric Administration (NOAA) to explore increasing the collection of weather data from ships in order to improve the weather forecast products that they distribute. Currently NOAA runs the Voluntary Observing Ship (VOS) program, where ships voluntarily submit weather observations to NOAA. However, only a small fraction of the thousands of vessels sailing worldwide participate in this program, and VOS weather observations are submitted infrequently, typically four times per day via a mainly manual process. One method being explored to automate and increase the frequency of data submittal is by using the existing Automatic identification System (AIS) equipment installed aboard vessels. Most commercial ships (in particular those subject to the International Maritime Organization's (IMO) Safety of Life and Sea (SOLAS) convention) have a Class A AIS transceiver installed to comply with mandatory carriage requirements. Many vessels not required to carry AIS equipment voluntarily install AIS transceivers (either Class A or B). All of these AIS transceivers (except for the Class B “CS”) can be used to transmit an AIS message 8 (broadcast binary message) by sending the transceiver an appropriately formatted NMEA sentence (BBM). Weather data can be embedded in an AIS application-specific message (ASM) carried by the AIS message 8 and automatically transmitted by the ship. This transmission can be received by terrestrial AIS stations (when in range) or by satellite AIS receivers. The AIS weather data can then be converted into the appropriate format and forwarded to the weather forecasting offices for use in models and weather predictions. This data may also be of use to other researchers monitoring climate change or other environmental factors. By leveraging this existing base of AIS transmitters, the volume of weather data being sent to weather forecast offices and others could be greatly increased. The U.S. Army Corps of Engineers (USACE) and U.S. Maritime Administration (MARAD) have been exploring the feasibility of this concept. Following a simple bench test performed by Alion Science in September 2018, an initial proof-of-concept was tested aboard the MARAD vessel Cape Wrath while moored in Baltimore in October 2018. After this successful demonstration, a prototype was installed on the Massachusetts Maritime Academy training ship TS Kennedy during her training cruise Jan-Feb 2019. During this cruise, the AIS equipment aboard the ship transmitted weather data at 3-minute intervals. Several different ASM formats were tested, including two developed specifically for this test to improve satellite reception. This report will discuss the concept, the demonstrations, and the results to date including the efficacy of the various ASM formats.