Sea condition information providing device, sea condition information providing system, sea condition information providing program, and sea condition information providing method

A non-transitory computer-readable recording medium storing a sea condition information providing program, the sea condition information providing program causing a computer to function as:

• a first layer tidal current data acquirer to acquire first layer tidal current data that represent an in-plane distribution in a first layer of the sea of a first layer vector quantity representing a direction and a speed of a tidal current in the first layer and that include the in-plane distribution of the first layer vector quantity as a future predicted value;
• a second layer tidal current data acquirer to acquire second layer tidal current data that represent an in-plane distribution in a second layer of a second layer vector quantity representing a direction and a speed of a tidal current in the second layer having a deeper water depth than the first layer and that include the in-plane distribution of the second layer vector quantity as a future predicted value;
• an inter-layer tidal current difference calculator to calculate, by using the first layer tidal current data and the second layer tidal current data, inter-layer tidal current difference data that represent an in-plane distribution of a difference vector quantity being a difference between the first layer vector quantity and the second layer vector quantity, the in-plane distribution being parallel to the first layer and the second layer;
• a display controller to perform inter-layer tidal current difference display control for displaying, over a map, an inter-layer tidal current difference distribution map that visualizes the in-plane distribution of the difference vector quantity represented by the inter-layer tidal current difference data;
• and
• a local region designation acceptor to accept, from a user, designation of a local region in the sea on the map displayed by the display controller, wherein,
• when designation of the local region is accepted by the local region designation acceptor,
• (i) the inter-layer tidal current difference calculator calculates, by using the first layer tidal current data and the second layer tidal current data, the inter-layer tidal current difference data about the local region for future n (note that n is a natural number equal to or more than two) unit periods, and
• (ii) the display controller performs local tidal current difference image display control for creating, by the unit period, a local tidal current difference image in which the inter-layer tidal current difference distribution map of the local region overlaps the map of the local region, by using the inter-layer tidal current difference data about the local region for future n unit periods, and displaying the created local tidal current difference image for future n unit periods.

A sea condition information providing method comprising steps of:

• (A) storing, in a storage device of a computer in advance before departure of a ship from port, first layer tidal current data that represent an in-plane distribution in a first layer of the sea of a first layer vector quantity representing a direction and a speed of a tidal current in the first layer, the first layer tidal current data including the in-plane distribution of the first layer vector quantity as a future predicted value;
• (B) storing, in the storage device in advance before departure of the ship from port, second layer tidal current data that represent an in-plane distribution in a second layer of a second layer vector quantity representing a direction and a speed of a tidal current in the second layer having a deeper water depth than the first layer, the second layer tidal current data including the in-plane distribution of the second layer vector quantity as a future predicted value;
• (C) by the computer in the ship after departure from port, calculating, by using the first layer tidal current data and the second layer tidal current data stored in the storage device, inter-layer tidal current difference data that represent an in-plane distribution of a difference vector quantity being a difference between the first layer vector quantity and the second layer vector quantity, the in-plane distribution being parallel to the first layer and the second layer, and displaying, over a map, an inter-layer tidal current difference distribution map that visualizes the calculated in-plane distribution of the difference vector quantity;
• (D) by the computer, accepting designation of a local region on the map displayed in the step (C) from a crew;
• and
• (E) by the computer, calculating, by using the first layer tidal current data and the second layer tidal current data stored in the storage device, the inter-layer tidal current difference data for future n (note that n is a natural number equal to or more than two) unit periods in the local region designated in the step (D), creating, by the unit period, a local tidal current difference image in which the inter-layer tidal current difference distribution map of the local region overlaps the map of the local region, by using the calculated inter-layer tidal current difference data for future n unit periods, and displaying the created local tidal current difference image for future n unit periods.