L. P. Flynn

An autonomous Earth observing sensorweb

We describe a network of sensors linked by software and the Internet to an autonomous satellite observation response capability. This sensor network is designed with a flexible, modular, architecture to facilitate expansion in sensors, customization of trigger conditions, and customization of responses. This system has been used to implement a global surveillance program of multiple science phenomena including: volcanoes, flooding, cryosphere events, and atmospheric phenomena. In this paper we describe the importance of the Earth observing sensorWeb application as well as overall architecture for the network

A comparison of the thermal characteristics of active lava flows and forest fires

Landsat TM data of active lava flows from Kilauea Volcano Hawaii (7/23/91) and forest fires within Yellowstone National Park (9/8/88) are compared to show the differences in the spectral and spatial distribution of radiance. At visible wavelengths, smoke from forest fires obscures terrain features, while active eruptions show little degassing at breakouts (ruptured lava tubes). Lava flows exhibit a gradual increase in infrared radiance (>2 µm) from the edge of an emplaced flow to the central breakout. The hottest parts of the forest fire (which radiate similar amounts of energy to flow breakouts) are located within 90 m of the edge of the burn scar with the interior portions exhibiting sharp decreases in infrared radiance. The radiance measured at 10.4–12.4 µm relative to that at near-infrared wavelengths (2.08–2.35 µm) suggests that the surface cracks exposing molten lava anneal proportionately with the progressive thickening of the flow crust, while burn scars, produced by forest fires, cool to pre-burn background temperatures rapidly with only small areas of high-temperature embers remaining. These differences will be important for the implementation of an automatic thermal-anomaly detection system using satellite data.

The effects of volcanic eruptions observed in satellite images: Examples from outside the North Pacific region

The effect of a volcanic eruption by liberating magma, gases, and energy is to modify the Earth’s surface and its atmosphere. Quite how these changes are produced depends on the nature of the eruption; for example, whether it is explosive or effusive, the period of time over which the eruption occurs, the mass of material erupted, and the geographic area over which the erupted products are distributed.