Sea Ice Observed from New AMSR Sensor
September 16, 2002
The Aqua satellite, a new component of NASA's Earth Observing System, was launched on May 4, 2002 and is dedicated to advancing our understanding of the Earth's water cycle. One of 6 key Earth-observing instruments on board Aqua, the Advanced Microwave Scanning Radiometer or (AMSR), was developed by the National Space Development Agency of Japan (NASDA). This sensor measures passive microwave radiation emanating from various surfaces, such as sea ice. The image pairs above compare sea ice conditions in the Arctic and Antarctic during the periods from June 2-4 and from July 21-22.
On these images, white indicates the area of sea ice cover and gray indicates land. Note that the ice sheets on Antarctica and Greenland have been masked-out. Because of the time period covered (late spring to summer in the Northern Hemisphere; late fall to winter in the Southern Hemisphere), the area of the ice cover in the Arctic region is decreasing while the area of ice cover in the Antarctic region is increasing. The presence of sea ice is extremely important to radiation balance in polar regions. Its presence restricts heat exchange between the ocean and atmosphere, and in addition, it reflects much of the solar radiation that would otherwise reach the seawater during the spring and summer months.