Earth Observing System AM1 mission to Earth

In 1998, NASA launches EOS-AM1, the first of a series of the Earth Observing System (EOS) satellites. EOS will monitor the evolution of the state of the earth for 18 years, starting with the morning observations of EOS-AM1 (10:30 a.m. equatorial crossing time). An integrated view of the earth, as planned by EOS, is needed to study the interchange of energy, moisture, and carbon between the lands, oceans, and atmosphere. The launch of EOS-AM1 and other international satellites marks a new phase of climate and global change research. Both natural and anthropogenic climate change have been studied for more than a century. It is now recognized that processes that vary rapidly in time and space—e.g., aerosol, clouds, land use, and exchanges of energy and moisture—must be considered to adequately explain the temperature record and predict future climate change. Frequent measurements with adequate resolution, as only possible from spacecraft, are key tools in such an effort. The versatile and highly accurate EOSAM1 data, together with previous satellite records, as well as data from the Advanced Earth Observing System (ADEOS) (I and II), Tropical Rainfall Measuring Mission (TRMM), Sea-viewing Wide Field-of-view Sensor (SeaWiFS), Along Track Scanning Radiometer (ATSR), Medium Resolution Imaging Spectrometer (MERIS), Environmental Satellite (ENVISAT), EOS-PM1, Land Remote-Sensing Satellite (Landsat), and ground-based networks is expected to revolutionize the way scientists look at climate change. This article introduces the EOS-AM1 mission and the special issue devoted to it. Following a brief historical perspective for an insight into the purpose and objectives of the mission, we shall summarize the characteristics of the five instruments onboard EOS-AM1. Specifically, we concentrate on the innovative elements of these five instruments and provide examples of the science issues that require this type of data. These examples show the importance of collecting data simultaneously from each of the five EOS-AM1 sensors for studying rapidly varying processes and parameters.