How does Landsat 8 differ from previous Landsat satellites?
Landsat 8 carries two push-broom instruments: the Operational Land Imager (OLI), and the Thermal Infrared Sensor (TIRS).
The spectral bands of the OLI sensor, while similar to Landsat 7’s ETM+ sensor, provides enhancement from prior Landsat instruments, with the addition of two new spectral bands: a deep blue visible channel (band 1) specifically designed for water resources and coastal zone investigation, and a new infrared channel (band 9) for the detection of cirrus clouds. A new Quality Assurance band is also included with each data product. This provides information on the presence of features such as clouds, water, and snow.
The TIRS instrument collects two spectral bands for the wavelength covered by a single band on the previous TM and ETM+ sensors. This page describes the band designations for all Landsat sensors: http://landsat.usgs.gov/band_designations_landsat_satellites.php.
The data quality (signal to noise ratio) and radiometric quantization (12-bits) of the OLI and TIRS is higher than previous Landsat instruments (8-bit for TM and ETM+), providing significant improvement in the ability to detect changes on the Earth’s surface.
At least 400 scenes are collected daily, and placed into the USGS archive to become available for download within 24 hours after acquisition.
Details about Landsat 8 data can be found at http://landsat.usgs.gov/landsat8.php.