The Atmospheric Compensation Component of a Landsat Land Surface Temperature (LST) Product: Assessment of Errors Expected for a North American Test Product

The Landsat archive of thermal data (Landsats 4, 5 and 7) has gone through a rigorous calibration assessment and update. However, in order to be useful to most users the calibrated sensor reaching radiance must be corrected to surface temperatures by first compensating for atmospheric effects and then emissivity variations. The USGS is exploring the possibility of producing a LST product through a joint program with RIT (the atmospheric compensation component) and JPL (the emissivity compensation component). This paper addresses the atmospheric compensation component for an initial North American pilot study. In particular, the results of a comparison of retrieved water surface temperature (where emissivity is well known) and truth temperatures for over 800 sites are presented. The errors are broken down by cloud conditions with extremely good results for cloud-free conditions (errors less than 1 K). The results of the error assessment for North America by cloud class are presented along with a discussion of potential quality data for a LST product. An initial assessment of the LST errors observed for Landsat 8 bands 10 and 11 are also presented. The next steps on this effort include testing of a global atmospheric compensation approach and full integration of the atmospheric and emissivity compensation tools into an operational LST product.

Temperature Estimation and Precision Control of RTP Systems by Multi-Zone Lamp Interference and Wafer Emissivity Compensation I: Model Identification

ABSTRACTRTP temperature measurement using conventional pyrometric technique has serious limitations such as uncertainty of emissivity, lamp interference, and window/chamber heating effect. In this paper, we propose to compensate for these effects using a real-time computational algorithm based on physical model of pyrometric detectors and wafer temperature dynamics. We consider an RTP system for processing 200 mm wafers with five circular zones of heating lamps and ten pyrometric sensors, five of which measure the radiation from five optically isolated dummy lamps and the rest measure the radiation of the wafer back side at different radial positions. Thermocouple measurements are also used to identify the model parameters. Part I of the paper is concerned with modeling and parameter identification.