identifies the parts of Earth’s surface that are land-covered for data analysis purposes. This allows other Earth science parameters, such as snow and cloud cover, to be averaged separately for land vs water areas. Typically, a resolution and land percentage are chosen based on the intended data use. For example, a 1 degree resolution gridbox area that contains greater than 90 percent land may be considered as land and analyzed as land even though water may be present in the form of rivers and lakes. Often, the number 1 is used for a land gridbox (white in the figure) and the number 0 is used for a water gridbox (blue in the figure). Coastal areas may be noted using the number 2 (black in the figure). These identify gridbox areas that are partially land, for example between 10 and 90 percent land. Note the areas of permanent sea ice around Antarctica that are denoted as land image of land mask data