新一代Landsat系列卫星：Landsat8遥感影像新增特征及其生态环境意义

Abstract

The successful launch of Landsat 8 on February 11,2013 has made it possible for the continuity of Landsat earth observation mission once stopped due to the failure of the aged Landsat 5 in late 2011.The satellite has two sensors,the Operational Land Imager(OLI) and the Thermal Infrared Sensor(TIRS),which collect remotely-sensed data over a 185 km swath.Landsat 8 has several new characteristics as well as those of Landsat 7.These include adding two spectral bands(deep blue and cirrus bands),refining spectral range of some bands of Landsat 7 ETM+,splitting one thermal band to two bands,and improving radiometric resolution from 8 bits to 16 bits.This paper aims to examine the new characteristics of the satellite′s image.Image processing and analysis have been carried out on the satellite′s first image acquired on March 18,2013.The results show that(1) the addition of the cirrus band can be useful for the separation of cloud from bright ground objects;(2) the band is also helpful for the distinguishing soil from building materials because the spectral range of the cirrus band is designed within a strong water vapor absorbing zone of the clay minerals;(3) the addition of the deep blue band can be useful for monitoring suspended materials in open waters;(4) the narrowing of spectral range of the panchromatic band can help the differentiation of vegetated and non-vegetated area in the panchromatic image;and(5) the enhancement of radiometric resolution from 8 bits to 16 bits would avoid spectral saturation of the data in extremely dark/light regions.In general,Landsat 8 has technical advantages over Landsat 7 except a lower spatial resolution in thermal data.Its launch and operation can undoubtedly make significant contributions to the morning of global ecosystem and environmental changes.