地球风场

Preprocess a global wind dataset into a regular latitude-longitude grid of u and v components. Use a D3 orthographic projection to draw land outlines, and build a screen-space vector field by inverse-projecting each pixel block and bilinearly interpolating the grid, accounting for projection distortion. Seed a few thousand particles at random visible points, move them along the interpolated vector each frame, give them a random max age, and respawn them when they expire. Fade the canvas each frame with a translucent fill so particles leave trails, and colour them by wind speed.