[omega3]

3) Data are highly spatially correlated. If the temperature is rising in one "grid-cell", it is rising in the neighbouring grid cells as well. Simply subtract the time-series from one grid-cell to the next grid-cell. Especially this yielded a large boost.

Can you expand on this?

[meteo-jeff]

Sure. I bundle a small rectangle of neighbouring locations like 5x5 (= 25 locations). The actual weather model may have a grid like 2878x1441 cells (4 million).

Inside the 5x5 chunk, I subtract all grid-cells from the center grid-cell. The borders will then contain only the difference to the center grid-cell.

Because the values of neighbouring grid-cells are similar, the resulting deltas are very small and better compressible.