Document Type

Thesis - University Access Only

Award Date

2011

Degree Name

Master of Science (MS)

Department / School

Electrical Engineering and Computer Science

Abstract

To effectively monitor land surface processes over a wide range of temporal and spatial scales, it is necessary to have coordinated observations of the Earth's surface using imagery acquired from multiple spaceborne imaging sensors. However, an integrated global observation framework requires an understanding of how land surface processes are seen differently by various sensors. This is particularly true for sensors acquiring data in spectral bands whose relative spectral responses (RSRs) are not similar and thus may produce similar, or may produce significantly different results, while observing the same target. The intrinsic offsets between two sensors caused by RSR mismatches can be adjusted by using a spectral band adjustment factor (SBAF), which takes into account the spectral profile of the target and the RSRs of the two sensors. The primary objective of the work presented in this thesis is to use Earth Observer (EO-1) Hyperion data to calculate and apply SBAF between Landsat 7 (L 7) Enhanced Thematic Mapper Plus (ETM+) and the Terra Moderate Resolution Imaging Spectroradiometer (MOD IS) for pseudo invariant test sites The motivation of the work comes from the need to adjust the spectral response differences of multispectral sensors to provide more accurate cross-calibration between the sensors. The study is done for all the Committee on Earth Observation Satellites (CEOS) reference standard pseudo-invariant test sites (Libya 4, Mauritania 1/2, Algeria 3, Libya 1, and Algeria 5). Overall results are presented and extensive details for the Libya 4 test site are provided. The name Libya 4 was referenced in Cosnefroy (1996), and considered by Centre National d'Etudes Spatiales (CNES) to be one of the best sites, based on long term trending of North African and Arabian sites. For the Libya 4 site, before SBAF adjustment, ETM+ top of atmosphere {TOA) reflectance was up to 16% different than the TOA reflectance reported by MODIS for all the bands. After spectral band adjustment, ETM+ TOA reflectance (ETM+*) measurements agree with MODIS to within 6% for all the bands. Similar results were obtained for each of the other test sites. It should be noted that the spectral resolution of Hyperion is 10 nm and therefore may not sample all the atmospheric absorption features. To reinforce this point, a comparative study was done to check if this resolution samples every absorption feature in the atmosphere by comparing the Hyperion profile with the high resolution (1nm) top of atmosphere hyperspectral profile from the SCIAMACHY instrument on board ENVISAT. SBAF derived from SCIAMACHY 1nm spectra over Libya 4 is compared to the one derived from EO-1 Hyperion to analyze the effect of coarser Hyperion spectral resolution on SBAF. Sciamachy spectra was then resampled to 10 nm to match the Hyperion resolution and SBAF was performed to check if the coarser spectral resolution was adding the uncertainties in Hyperion derived results. Finally, a set of steps is recommended to improve the adjustments for these two sensors to provide more accurate cross comparisons.

Library of Congress Subject Headings

Landsat satellites -- Calibration

Earth resources technology satellites

Format

application/pdf

Number of Pages

120

Publisher

South Dakota State University

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