2000 Progress Report: Application of Remotely-sensed Data To Regional Analysis and Assessment of Stream Temperature in the Pacific NorthwestEPA Grant Number: R827675
Title: Application of Remotely-sensed Data To Regional Analysis and Assessment of Stream Temperature in the Pacific Northwest
Investigators: Burges, Stephen J. , Booth, Derek B.
Current Investigators: Burges, Stephen J. , Booth, Derek B. , Gillespie, Alan R.
Institution: University of Washington - Seattle
EPA Project Officer: Packard, Benjamin H
Project Period: April 1, 2000 through March 31, 2003 (Extended to March 31, 2004)
Project Period Covered by this Report: April 1, 2000 through March 31, 2001
Project Amount: $998,395
RFA: Regional Scale Analysis and Assessment (1999) RFA Text | Recipients Lists
Research Category: Ecosystems , Ecological Indicators/Assessment/Restoration
Objective:The aims and goals of this project have not changed. They are to: (1) develop efficient methods for regional assessments of stream temperature; and (2) demonstrate how these methods can be applied to assess effects of land use on stream temperature.
Progress Summary:The first year of the project proceeded as planned, with the acquisition of the preliminary remotely sensed imagery, the establishment of the field instrumentation, the collection of the first year of field data, and the development of infrastructure for subsequent field seasons.
Field Analyses. Temperature probes were deployed throughout the Soos Creek basin during summer 2000. Thirteen probes were placed in the main tributaries and the Green River to monitor water temperature. At three sites, probes were placed in the ground (~ 0.5 m deep) and in the air. The results from these initial temperature probes were then used to locate additional probes in the study area. Preliminary results from these probes have identified stream reaches with strong temperature gradients (Figure 1).
Other field requirements have been established, including finding a secure site to locate a weather station. Before spring leaf-out, a GPS survey was initiated to spatially locate the measurement sites, other ground-control points, and ground locations of a size suitable for radiometric calibration of the remotely sensed imagery.
Remotely Sensed Imagery. Preliminary TIR images were taken with the Forward Looking Infrared Device (FLIR) (Figure 2), which will be used during the 2001 summer to examine issues of multiple-scattering, and scaling between coarser resolution imagery [(e.g., MASTER (air-borne) and ASTER (satellite)]. The first images from ASTER have been obtained over the study area (Figure 3). These images are being used to refine the processing methodology, and to determine the best locations for field validation sites.
Figure 1. The distribution of stream temperatures and gradients in the study area.
Figure 2. Reclassifying TIR imagery to determine temperatures.
Figure 3. ASTER images over Puget Sound, June 28, 2000.
Future Activities:Extensive field data will be collected during summer 2001. As well as downloading and analyzing data from the temperature gauges in the study area, additional experiments will be conducted on more focused issues to:
? Refine the understanding of the distribution of water temperatures throughout the Soos Creek stream network, using the existing temperature gauges and analysis of the basin hydrology.
? Measure air temperatures at different heights of the canopy surrounding the stream.
? Examine variation in water and land surface temperatures at fine scales (< 5 m) by imaging water, land and vegetation surfaces, and combinations of different surfaces from above. This includes comparison with skin (top 100 micro-m) and kinetic (< 1 m) temperatures in shallow water.
? Measure radiation reflected from the stream surroundings (vegetation, rocks, etc.).
? Compare the effects of smooth and rough water in a stream reach of homogeneous kinetic temperature, using fine resolution imagery obtained from the FLIR.
? Study the effects of diurnal heating and cooling on the stream and surrounding vegetation, using the FLIR with simultaneous measurements of air temperature.
The results of these experiments will be used in the subsequent analysis of the fine-scale effects on the coarser remotely sensed imagery, and in the hydrological analysis of the area.
While the project proposal outlined flying the FLIR over the study area to obtain medium-resolution imagery, an opportunity to fly the NASA airborne MASTER sensor became available (50 bands with wavelengths from visible to TIR). The MASTER sensor was designed to under-fly the ASTER and MODIS sensors, and post-flight processing will deliver geometrically corrected images (level 1B at sensor). On August 11, 2001, the MASTER sensor will be flown over the Green River study site to obtain 5-m and 15-m resolution multi-spectral images. These flights will be oriented both at nadir to the streams, and as a mosaic across the study site. ASTER images (90 m TIR) have been scheduled for acquisition both on this date and for all over-flight, dates in July and August. During the MASTER over-flight, an extensive ground validation is planned, including launching a radiosonde to determine the atmospheric profile for post-image processing, using the FLIR to image fine resolution images, measuring the total column water in the atmosphere, and deploying additional temperature probes. On the same day as the MASTER over-flights, a synoptic temperature survey will be in progress across the Puget Sound area. Additional collaborators in the Cedar Basin (North of the Green River) and in central Oregon have been found to cover the high cost of flying this sensor.