KAIRAKU

KAIRAKU is an interactive app for learning how the ocean works, with animated visuals and simple controls. Why is the sea layered? Where does deep water come from? Why does a tsunami cross the ocean as fast as a jet? Why do corals turn white? Change the conditions yourself and see. Developer: Fuji Bit Inc. The oceanography edition of the RAKU science series, from school earth science and biology to introductory oceanography, with real numbers and examples. 12 simulations in 3 categories: Seawater and currents: - Ocean layers: temperature, salinity and density (sigma-t) for the tropics, mid-latitude summer and winter, and the Arctic, from World Ocean Atlas values, with the mixed layer, thermocline, deep water and a T-S diagram. - Global conveyor belt: cold, salty water sinks near Greenland and Antarctica and circles the world's oceans over a thousand years or more. Add Greenland meltwater and watch the Atlantic overturning (AMOC) weaken, then shut down and stay off (Stommel's two-box model). - Ekman spiral: wind-driven surface water turns 45 degrees to the right in the Northern Hemisphere and keeps turning and weakening with depth. Change the wind speed, latitude and direction and see the spiral and the Ekman transport at right angles to the wind. - Sea ice: seawater freezes at about -1.9 °C. See how air temperature and snow set the growth rate, how brine is pushed out, and how ice and snow reflect sunlight. Waves and tides: - Tides: the Moon's and Sun's pull makes two tidal bulges, seen from above the North Pole. Spring and neap tides, high tide about 50 minutes later each day, and the diurnal inequality on a tide graph. - Wave refraction and breaking: waves slow down, shorten and grow in the shallows, and turn to face the beach. Change the period, height, angle and slope and see where and how they break. - Tsunami (new): a tsunami's speed depends only on depth, about 700 km/h over 4,000 m of water. Watch it slow and grow toward the coast, and follow the 1960 Chile tsunami across the Pacific to Japan. - Sound in the sea (new): sound speed depends on temperature, salinity and pressure, so a sound channel (SOFAR) forms near 1,000 m at mid-latitudes. Change the region, source depth and angles and watch the rays bend and travel far. Life in the sea: - Marine food web: only about 10% of the energy passes up each level, from phytoplankton to top predators. Change the efficiency, region and fishing and see the energy pyramid and biomagnification. - Plankton bloom: an NPZ model of nutrients, phytoplankton and zooplankton shows the spring bloom when the mixed layer gets shallower than the critical depth, the nutrient-poor summer and the small autumn bloom. - Coral bleaching: long marine heatwaves make corals lose their algae and turn white. See NOAA's Degree Heating Weeks and alert levels, and how ocean acidification weakens calcification. - Hydrothermal vents: deep-sea pressure keeps 350 °C water from boiling as it billows black smoke, and life gathers around chemosynthesis instead of sunlight. Change the depth, temperature and flow and see the boiling point and plume height. Features: - Clean, modern design (switch between dark and light themes) - Home screen organized by category, plus an "All modes" list - Tips and a play button in the control panel - Results change in real time as you move sliders and choices - An explanation sheet with formulas, terms and real examples for every simulation - Canvas and controls side by side in landscape and on large screens - Supports larger text sizes - 73 languages including English and Japanese (follows your device language) - No sign-in; start exploring right away - An educational simulator: it does not show real tide levels, tsunami warnings or sea conditions Price and purchases: - Price: Free - In-app purchases: none - Subscriptions: none - Ads: a Pangle banner ad at the bottom of the screen