Passive microwave remote sensing of rainfall in mountainous regions.

摘要

The hydrologic cycle in its broadest sense forms the theme which binds the three parts of this thesis. On long time scales erosion is an important component in the balance of forces which determine the topography of the earth's surface. Average erosion rates are a function of both average precipitation and it's temporal nature or ‘pulsiness’. While this thesis doesn't consider erosion directly, it does pursue an understanding of floods (Chapter 3) and rainfall (Chapter 1) at shorter, modern time scales. In the case of floods, Chapter 3 uses 40 years of daily average flows in the US to show that standard estimates of flood frequency may underestimate the frequency of the largest severe floods. In the case of rainfall, Chapter 1 extends previously developed techniques for estimating rainfall from satellite to remote, mountainous areas where orographic precipitation is the dominant erosive agent acting at the base of active mountain belts. Chapter 2 is an application of this technique to the water balance of a high plateau lake. While Lake Titicaca is gauged, validation of the technique has application in other, ungauged regions such as Tibet.