The Blue Marble: Next Generation is a series of images that show the color of the Earth’s surface for each month of 2004 at moderate resolution (500 meters/pixel) at a global scale. These monthly images reveal seasonal changes to the land surface: the green-up and dying-back of vegetation in temperate regions such as North America and Europe, dry and wet seasons in the tropics, and advancing and retreating Northern Hemisphere snow cover. In 2004, the generation of the Blue Marble: Next Generation imagery utilized new techniques allowing the computer to automatically recognize and remove cloud-contaminated or otherwise bad data—a process that was previously done manually. The quality of the Blue Marble imagery was notable for its time. So much so that Steve Jobs and team selected it for the default wallpaper for the Apple iPhone.
GIBS has selected the August monthly imagery for the three static layers available for use. August was selected based on the lower concentration of snow that exposes more land features. The Blue Marble: Next Generation imagery includes the a base image along with bathymetry and topography visual enhancements. These enhancements are described below:
Bathymetry
Bathymetry is a digital image of the undersea land surface and water depth. Bathymetry is the underwater equivalent of land topography. In the maps provided here, shading indicates changes in slope or depth. Much of the data on ocean bathymetry come from "soundings." To collect a sounding, scientists use sonar devices to emit a sound wave that passes into the water. By measuring how long it takes the sound wave to bounce off the ocean floor and return to the sonar, scientists can estimate the depth of the water. Other characteristics of the returned sound wave can help reveal the shape and size of features on the sea floor. These images represent ocean depths between -8000m and 0m (surface).
Topography
Land topography is a digital image of the three-dimensional structure of the Earth's surface. Shading indicates changes in slope or elevation. The relief shading in this topographic map comes mostly from elevation data collected by space-based radars. Topography not only gives a realistic picture of what the Earth's surface actually looks like, it also helps scientists determine things like how rivers and streams drain through the landscape, where lowlands are prone to flooding, how plate tectonics or erosion are building or wearing away mountains, where hills may be prone to landslides, or how a volcanic eruption changed the shape of a mountain. Topography is also one of the factors that influences where particular ecosystems exist. Therefore topography is one of the factors that scientists can use to predict where certain plants or animals, such as endangered species, might be found.
View more information about the Blue Marble: Next Generation imagery products.