A desert is a landscape or region that receives almost no precipitation. Deserts are defined as areas with an average annual precipitation of less than 250 millimetres (10 in) per year, or as areas where more water is lost by evapotranspiration than falls as precipitation.deserts of China picturesdeserts of China picturesdeserts of China picturesdeserts of China picturesdeserts of China picturesdeserts of China picturesdeserts of China picturesdeserts of China pictures