Evaluation of Effects of Forest-Fire Smoke/Haze on Basin-Wide Stream Temperatures

Objective/Intended Use

Remote sensing imagery during the time of the Megram Fire in Northwestern California during the summer of 1999 will be acquired. The effects of smoke and haze from the fire on stream temperatures in watersheds and basins underlying the Megram Fire smoke plume will be evaluated. It is hypothesized that elevated levels of particulate matter in smoke and haze from the fire may filter out longwave radiation, resulting in a decrease in stream temperatures in basins underlying the smoke plume.

Abstract

The effects of forest fires on ecological resources in the area experiencing the burn are well documented in the literature. What is not well known is the effect of smoke and haze generated from forest fires on ecological resources adjacent to or at great distances from the burn area. Increasing levels of particulate matter (PM) associated with haze and smoke are of concern from both a human and ecological health perspective. Very little documented evidence exists on the ecological effects of elevated levels of PM from fires and other sources on aquatic resources. A unique dataset is available to explore the influence of smoke/haze on stream temperatures in Northern California. Preliminary acquisition of satellite imagery showed that the smoke plume from the Megram Fire that occurred in the summer of 1999 passed over watersheds and basins where stream temperatures exhibited a marked decrease. Stream temperature fluctuations due to increased haze could have serious consequences to aquatic biota whose life histories rely on the temporal predictability of a stream's thermal regime.

Project Status

On-going. This study was initiated in the last quarter of FY02. A second one-year no-cost extension was authorized in March 2004. SeaWiFS satellite imagery which spans the period of the Megram Fire has been acquired. Atmospheric correction of imagery is completed. Stream temperature data from approximately 400 sites have been obtained. Stream temperature data have undergone quality assurance / quality control checks and spatial accuracy assessment. Meteorological data from the National Weather Service have been acquired to use in the interpretation of the stream temperature signal. This project is expected to be completed in FY05.

Project Start Date

09/01/2002