|Moran, Mary - Susan|
|Holifield Collins, Chandra|
Submitted to: IEEE Transactions on Geoscience and Remote Sensing
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/20/2003
Publication Date: 9/20/2003
Citation: Bryant, R.B., Moran, M.S., Mcelroy, S.A., Holifield, C.D., Thome, K.J., Miura, T., Biggar, S.F. 2003. Data continuity of earth observing-1 (eo-1) advanced land imager (ali) and landsat tm and etm+. IEEE Transactions on Geoscience and Remote Sensing. 41:1204-1214. Interpretive Summary: Satellites have been used to monitor the environment for decades. One NASA satellite program, Landsat, was started on 1972. The Landsat program was developed specifically for monitoring the earth's land masses. This is an extremely important program because it lets us know how the earth is changing over time. So far, the Landsat program has launched six satellites and the seventh is in the development stages. Due to technological advances, the specifications of the sensors have changed over time. It is very important that the information that researchers are gleaning from the sensors is not biased due to sensor differences. This research looked at the two most recent Landsat sensors and one experimental sensor that is expected to be very similar to the next Landsat sensor. We were able to determine that, for these three sensors, the information acquired from them is not influenced by sensor differences. Therefore these sensors are very good sources of data for studying the earth over time
Technical Abstract: The NASA Landsat program has been dedicated to sustaining data continuity over the twenty-year period during which Landsat Thematic Mapper (TM) and Enhanced TM Plus (ETM+) sensors have been acquiring images of the Earth's surface. In year 2000, NASA launched the Earth Observing-1 (EO-1) Advanced Land Imager (ALI) to test new technology that could improve the TM/ETM+ sensor series, yet ensure Landsat data continuity. The study reported here quantified the continuity of satellite-retrieved surface reflectance (D) for the three most recent Landsat sensors (Landsat 4 TM, Landsat 5 TM and Landsat 7 ETM+) and the EO-1 ALI sensor. The study was based on ground-data verification and, in the case of the ETM+ to ALI comparison, coincident image analysis. Reflectance retrieved from all four sensors showed good correlation with ground-measured reflectance, and the sensor-to-sensor data continuity was excellent for all sensors and all bands. A qualitative analysis of the new ALI spectral bands (4p:0.845-0.890 um and 5p:1.20-1.30 um) showed that ALI band 5p provided information that was different from that provided by the ETM+/ALI SWIR bands 5 and 7 for agricultural targets; and ALI band 4p has the advantage over the existing ETM+ near infrared (NIR) band 4 and ALI NIR band 4 of being relatively insensitive to water vapor absorption. The basic conclusion of this study is that the four sensors can provide excellent data continuity for temporal studies of natural resources. Furthermore, the new technologies put forward by the EO-1 ALI sensor have had no apparent effect on data continuity and should be considered for the upcoming Landsat 8 sensor payload.