HYOURAKU — Cryosphere

HYOURAKU is a visual education app for learning the science of Earth's ice — glaciology, sea ice, and paleoclimate — by watching and interacting with beautiful simulations. As the cryosphere module of the "Raku" series, it sits next to KAIRAKU (oceanography) and connects naturally through sea ice, thermohaline circulation, and sea-level rise. It covers six topics from high-school earth science up to introductory glaciology and climatology. [Six Modules] - Glacier Dynamics See how a glacier "flows even though it is solid," drawn as a valley cross-section. Move the temperature and accumulation (snowfall) sliders to shift the equilibrium-line altitude (ELA); the ratio of accumulation to ablation zones sets the mass balance. A positive balance advances the terminus, a negative one retreats it — a hands-on way to understand why so many mountain glaciers are retreating under warming. - Ice-Albedo Feedback White sea ice reflects most incoming sunlight, while dark ocean absorbs it. Seen from above the Arctic, experience the positive feedback "less ice -> lower albedo -> more absorbed heat -> even less ice." Push the external forcing past a threshold and the runaway collapses the ice abruptly (tipping); restoring the forcing does not easily bring it back (hysteresis). - Ice Core / Paleoclimate Each layer of an ice core traps the air of its time as bubbles. Drag the core up and down to travel into the past and read each layer's bubble CO₂ and the temperature reconstructed from isotopes. Glacials had low CO₂ and were cold; interglacials had high CO₂ and were warm — explore hundreds of thousands of years of climate paced by Milankovitch cycles. - Permafrost As it warms, the active layer deepens and thawing permafrost releases CO₂ and methane via microbes — a positive carbon feedback that drives further warming, shown in a soil cross-section. - Snow Crystals (Nakaya diagram) A snow crystal's shape is set by the cloud's temperature and supersaturation. Following Ukichiro Nakaya's diagram, plates, columns, needles, and dendrites are drawn in beautiful six-fold symmetry. - Sea Level Rise Melt sliders for Greenland, Antarctica, and mountain glaciers raise the sea and flood a coastal city in cross-section. The theme connects to thermohaline circulation and sea-level rise in KAIRAKU. [Features] - Principle / explanation sheet in every module - A timely theme tied directly to climate change - 9 languages (Japanese, English, Chinese Simplified/Traditional, Spanish, Portuguese (BR), Korean, German, French) - A one-line "how to try" guide on every simulation screen - Play / pause button with a clear label - Sea Level Rise: a zoomed tide gauge (cm scale) makes even the small contribution of mountain glaciers (about 0.4 m at most) visible - Supports landscape, large text sizes, and VoiceOver - About screen with links to the privacy policy and support - Simulations run at the same speed on any display refresh rate - Free to use with every feature unlocked (banner ads only; no in-app purchases or subscriptions) - Polar, realistic visuals on a dark theme - Intuitive, beautiful UI [Great for] - Students of earth science, glaciology, or climatology - Anyone who wants an intuitive grasp of glaciers, sea ice, and paleoclimate - Teachers looking for classroom material - Anyone who wants to properly understand the news on climate change, glacier retreat, and shrinking Arctic sea ice