The Spectral Response of the Landsat-8 Operational Land Imager

Abstract

This paper discusses the pre-launch spectral characterization of the Operational Land Imager (OLI) at the component, assembly and instrument levels and relates results of those measurements to artifacts observed in the on-orbit imagery. It concludes that the types of artifacts observed and their magnitudes are consistent with the results of the pre-launch characterizations. The OLI in-band response was characterized both at the integrated instrument level for a sampling of detectors and by an analytical stack-up of component measurements. The out-of-band response was characterized using a combination of Focal Plane Module (FPM) level measurements and optical component level measurements due to better sensitivity. One of the challenges of a pushbroom design is to match the spectral responses for all detectors so that images can be flat-fielded regardless of the spectral nature of the targets in the imagery. Spectral variability can induce striping (detector-to-detector variation), banding (FPM-to-FPM variation) and other artifacts in the final data products. Analyses of the measured spectral response showed that the maximum discontinuity between FPMs due to spectral filter differences is 0.35% for selected targets for all bands except for Cirrus, where there is almost no signal. The average discontinuity between FPMs is 0.12% for the same targets. These results were expected and are in accordance with the OLI requirements. Pre-launch testing identified OPEN ACCESSRemote Sens. 2014, 6 10233 low levels (within requirements) of spectral crosstalk amongst the three HgCdTe (Cirrus, SWIR1 and SWIR2) bands of the OLI and on-orbit data confirms this crosstalk in the imagery. Further post-launch analyses and simulations revealed that the strongest crosstalk effect is from the SWIR1 band to the Cirrus band; about 0.2% of SWIR1 signal leaks into the Cirrus. Though the total crosstalk signal is only a few counts, it is evident in some scenes when the in-band cirrus signal is very weak. In moist cirrus-free atmospheres and over typical land surfaces, at least 30% of the cirrus signal was due to the SWIR1 band. In the SWIR1 and SWIR2 bands, crosstalk accounts for no more than 0.15% of the total signal.

Remote sensing of the chlorophyll-a based on OLI/Landsat-8 and MSI/Sentinel-2A (Barra Bonita reservoir, Brazil)

“…Bands of those sensors were simulated from in situ data and used to calibrate and validate models for Chl-a estimation. The simulation of bands was carried out from in situ R rs measurements and the spectral response function of each sensor (Barsi et al 2014, ESA 2015, using Equation 2 (Van der Meer 1999).…”

In-Season Mapping of Crop Type with Optical and X-Band SAR Data: A Classification Tree Approach Using Synoptic Seasonal Features

“…Landsat 8 OLI data [63] were converted to surface reflectance through atmospheric correction, performed with Atmospheric/Topographic CORrection for Satellite Imagery (ATCOR) [64]. Multitemporal SIs have already demonstrated their efficacy in capturing cropland characteristics [54,65].…”

Landsat-8 Thermal Infrared Sensor (TIRS) Vicarious Radiometric Calibration

“…Though the instruments are different, Landsat-8 maintains the swath width, scene framing, radiometric and geometric accuracy and precision and general spectral bandwidths of prior Landsat missions. Details of the OLI are covered in other papers [1][2][3]; this paper will focus only on TIRS and the vicarious calibration of the sensor.…”