Open-File Report 2006-1312
U.S. GEOLOGICAL SURVEY
Open-File Report 2006-1312
Micrometeorological and soil data were collected at each platform. The data include air temperature, dewpoint temperature, and vapor pressure (measured at two heights above land surface), average relative humidity, net radiation, soil temperature, 20-minute temperature change in soil, soil heat flux (sampled at 30-second intervals), and wind speed and direction (sampled at 10-second intervals) (see appendix A). These data were used to calculate ET using the Bowen ratio method over a 20-minute period. Examples of select maximum and minimum 20-minute averaged micrometeorological data for the brush site are shown in figure 4. Periodic gaps in the data set exist due to adverse weather conditions and instrument failure.
Heat-dissipation-probe (HDP; Campbell Scientific, Inc., 1998) and water-content-reflectometer (WCR; Campbell Scientific, Inc., 1996) instrumentation were used to collect matric water potential and volumetric soil-water content data, respectively (table 1). To collect these data, three shallow holes, approximately 0.30 m deep were dug at each site. Two HDP sensors were placed in each hole between 0.05 and 0.20 m below land surface. Additionally, one WCR sensor was placed in each of the holes with the HDP sensors and inserted into the soil at about a 30 degree angle to collect data from the top 0.15 m of soil. In July 2004, three additional holes, approximately 12.2 m deep, were excavated at each site using a pneumatic rock hammer. Two HDP sensors were placed in each of these holes at about 0.46 and 1.07 m below land surface. These sensors were installed at greater depths than the initial HDP sensors to gain a better understanding of how water moves through the soil. Figure 5 shows the setup of the soil-water sensors in the holes. An example of volumetric soil-water content and matric water potential data at the brush site is shown in figure 6.
During the period of record (2002–05) presented in this report, 20-minute averaged air-temperature data (from the upper temperature probe) ranged from 31.8 to ‑16.4oC. The recorded maximum 20-minute averaged wind-speed data was 20.7 m/s. The daily average matric water-potential data ranged from a maximum of -0.0001 bars to a minimum of ‑10,000 bars. The volumetric soil-water content data ranged from 99 to 6.5 percent. Annual precipitation on Rainier Mesa recorded by NOAA ranged from 85.8 to 436.0 mm (fig. 7).
U.S.
Department of the Interior | U.S. Geological
Survey
Persistent URL: http://pubs.water.usgs.gov/ofr20061312
Page Contact Information: Publications Team
Page Last Modified: Saturday, 12-Jan-2013 22:24:10 EST
