I: Remote Spectroscopic Measurements of Atmospheric HDO/H₂O and Column CO₂. II: Interannual Variations of the Earth’s Reflectance

• Main Author: Kuang, Zhiming
• Format: Thesis
• Language: English
• Published: 2003
• Subjects: Sea ice
• Online Access: https://thesis.library.caltech.edu/2377/; https://thesis.library.caltech.edu/2377/1/thesis_kuang.pdf; https://resolver.caltech.edu/CaltechETD:etd-06022003-114148

The theme of this thesis is to apply remote sensing data on problems concerning the climate system. It is grouped into two parts. Part I (Chapters 1, 2) is devoted to spectroscopic measurements of HDO, H₂O and column CO₂, and Part II (Chapters 3-5) is devoted to variations in the Earth's reflectance. In Chapter 1, we derive the first simultaneous measurements of HDO and H₂O in the tropical upper troposphere and lower stratosphere. This is made possible by extending the retrievals of the Atlas-3 Atmospheric Trace Molecule Spectroscopy (ATMOS) data deeper into the troposphere. The derived HDO/H₂O ratio demonstrates that convection has a major influence on the moisture budget and the dehydration processes in this region. The objective of Chapter 2 is to determine the precision to which column averaged CO₂ volume mixing ratio (VMR) can be measured by near-infrared (NIR) spectrometry of reflected sun light. The key idea in this study is the simultaneous use of the CO₂ (1.58-µm and 2.06-µm) and O₂ (0.76-µm) bands. This approach allows small changes in the spectrum arising from variations of column CO₂ VMR to be distinguished from those arising from variations of other atmospheric/surface parameters. Using prototype retrieval simulations based on a practical satellite instrument design, we show that the 3-band, high-resolution, spectrometric approach using NIR reflected sunlight has the potential for highly accurate column CO₂ VMR measurements. In Chapters 3-5, we examine the interannual variations in the Earth's reflectance. Chapter 3 introduces the Nimbus-7 TOMS reflectance measurements and provides an overview on the interannual variability of the Earth's reflectance. Variations in the globally averaged reflectance are also used to examine a postulated cosmic ray-cloud-climate connection. In Chapter 4, we relate interannual reflectance variations over the summertime polar icy areas to variations in the microwave-derived sea ice concentration. The results provide independent confirmation on sea ice variations ...