氷楽

Hyouraku is a visual education app that lets you learn about the science of ice covering the Earth by "seeing" and "interacting." You can experience the fundamentals of glaciology, glaciology, and paleoclimatology through beautiful simulations and interactions.

As part of the Raku series' cryosphere module, it's positioned next to "Kairaku," which deals with marine science, and naturally connects to the landmass through sea ice, thermohaline circulation, and sea-level rise. It includes six areas covering topics from high school earth science to introductory university-level glaciology and climatology.

【Six Modules】

■ Glacier Dynamics
Visualize the phenomenon of glaciers "flowing despite being solid" using a longitudinal section of a valley. The equilibrium line (ELA) moves with temperature and recharge sliders, and the mass balance is calculated from the area ratio of the recharge zone to the atriate zone. A positive balance indicates terminal advancement, while a negative balance indicates retreat. You can understand, through hands-on experience, why mountain glaciers retreat due to global warming.

■ Ice Albedo Feedback
White sea ice reflects sunlight, while the dark ocean surface absorbs it. Experience the positive feedback loop of "ice reduction → albedo decrease → increased heat absorption → further reduction" on a disk viewed from directly above the Arctic. You can also observe hysteresis, where increasing external forcing beyond a threshold causes critical disappearance (tipping), and recovery is difficult even after reducing the threshold.

■ Ice Core and Paleoclimate
Each layer of the ice core contains the atmosphere trapped at that time. Drag the core up and down to trace back in time and read the CO₂ concentration and isotopic temperature of each layer. Glacial periods are cold with low CO₂, while interglacial periods are warm with high CO₂—experience hundreds of thousands of years of climate history synchronized with the Milankovitch cycle.

■ Permafrost
As temperatures rise, the active layer beneath the surface deepens, and microorganisms release CO₂ and methane from the thawed permafrost. This positive feedback loop (carbon feedback) that leads to further warming can be experienced in a cross-section of the earth's surface.

■ Snow Crystals (Nakaya Diagram)
The shape of snow crystals is largely determined by the cloud temperature and the degree of water vapor supersaturation. Following the Nakaya Diagram, revealed by Ukichiro Nakaya, plate-like, prismatic, needle-like, and dendritic (six-petal) crystals are beautifully depicted with six-fold symmetry.

■ Sea Level Rise
The melting amount sliders for Greenland, Antarctica, and mountain glaciers visualize the rising sea levels and the resulting flooding of coastal cities in a cross-sectional view. This is a continuous theme with the thermohaline circulation and sea level rise in the Ocean Fun project.

【Features】
• Each module includes a principle/explanation sheet
• Directly linked to the current context of climate change
• Supports 9 languages ​​(Japanese, English, Simplified/Traditional Chinese, Spanish, Portuguese (Brazil), Korean, German, French)
• Each simulation screen includes a one-line "How to Try" guide
• Labeled play/pause button
• For sea-level rise, the tide gauge is displayed in enlargement (cm scale), allowing even small contributions from mountain glaciers (maximum approximately 0.4m) to be read
• Supports landscape display, large font size, and TalkBack
• "About this app" screen with links to privacy policy and support
• Simulation proceeds at the same speed regardless of the display refresh rate
• All features are available for free (banner ads only. No in-app purchases or subscriptions)
• Dark mode-based polar realism visuals
• Intuitive and beautiful UI

【Recommended for:】
• High school earth science students and university students studying glaciology/climatology
• Those who want to intuitively understand the mechanisms of glaciers, sea ice, and paleoclimate
• Teachers who want to use it as teaching material
• Anyone who wants to properly understand news about climate change, glacier retreat, and the shrinking of Arctic sea ice