Blue Marble: Next Generation

From Wikiteer

• offers a year's worth of monthly composites
• 500 meter resolution
• http://earthobservatory.nasa.gov/Newsroom/BlueMarble/BlueMarble_monthlies.html

Those who intend to use the Blue Marble: Next Generation in their own publications or projects should be aware of areas that still require improvement. Areas of open water still show some 'noise.' In tropical lowlands, cloud cover during the rainy season can be so extensive that obtaining a cloud-free view of every pixel of the area for a given month may not be possible. Deep oceans are not included in the source data; the creator of the Blue Marble uses a uniform blue color for deep ocean regions, and this value has not been completely blended with observations of shallow water in coastal areas. The lack of blending may, in some cases, make the transition between shallow coastal water and deep ocean appear unnatural. Finally, the data do not completely distinguish between snow and cloud cover in areas with short-term snow cover (less than three or four months). This problem may be resolved in the future through the use of a more sophisticated snow mask.

Source: http://www.nasa.gov/vision/earth/features/blue_marble.html