By Sid Perkins
Scientists have added modern weather data to a century-old classification of the world’s climates to provide more accurate comparisons between the results of computer simulations and terrestrial reality.
The Köppen-Geiger system of climate classification—named after the researcher who formulated the scheme and another who later enhanced it—was developed in the late 1800s. It assigns the climate at any site to one of five general categories—tropical, arid, temperate, cold, or polar—and adds finer subdivisions according to annual variations in temperature and precipitation.