This file contains data collected from 1996-1999 at a Bowen ratio tower adjacent to the Deep Well Meteorological Station at Deep Well (Station 40). The Bowen ratio method employs a method of measuring the temperature and vapor pressure gradient over a vegetation canopy to quantify evapotranspiration from that canopy.
The data was collected to identify the daily patterns of evapotranspiration from the surrounding area.
The Bowen ratio method measures the gradient of temperature and moisture above a typical canopy. In conjunction with measuring incoming net radiation, this method can partition the energy into soil heating, atmospheric heating (specific heat) and evaporation as latent heat.
A Bowen ratio station includes a 3 m tower on which is mounted most of the following sampling equipment: an enclosure, which houses a datalogger, and a gas flow system which directs air from upper and lower arms of the station to the cooled mirror hygrometer. On the tripod are upper and lower arms with mountings for thin wire thermocouples and intakes for air samples. A set of 4 temperature probes are buried in the top 10 cm of the soil with readings taken at 2 and 8 cm. One pair of probes is located under a clump of grass while a second is in unvegetated soil. Two soil heat flux plates are buried at a depth of 10 cm, again one under vegetation and one in the open. A net radiometer is mounted on a pipe about 1 m above the soil surface. A wind sentry, which includes both an anemometer and wine vane, is mounted at a height of 3 m.
Manufacturer: Campbell Scientific Inc.
Components: 21X Data logger
Fine Wire Thermocouples
Soil Heat Flux plates
Averaging soil temperature thermocouple probe
Wind Sentry set
Model Number: na
Reference Manuals: na
Modifications and Adjustments: na
April 28 1997 Started Bowen Station
No data day 224 1340 to day 227 1240
No data day 245 1300 to day 252 1100
No data day 267 1240 to day 274 1120
Oct 17 1997 Bowen Station turned off
When the Samples/Data were Collected:
The data were collected spring, summer, and fall of each year when the instrument was operating properly. For 1996 the period of collection was Julian day 1 (Jan 1) through 183. For 1997 the period of collection was Julian day 118 (Apr 27) through 290 (Oct 17) with some missing periods due to equipment problems - see mainentance log. For 1998 the period of collection was Julian day 84 (Mar 25) through 274 (Oct 1). For 1999 the period of collection was Julian day 99 (Apr 9) through 123 (May 3) and day 147 (May 27) through day 315 (Nov 11). Data were measured over 20 minute periods and means, totals, and instantaneous readings were output at the hour, 20 min. and 40 min. past the hour for the preceeding 20 minutes.
Where the Data were Collected:
Sevilleta LTER Project Area Description
McKenzie Flats, Deep Well Meteorological Site
Latitude 34.3586 Longitude -106.6911
Study Area Description:
The study area is about halfway between Black Butte and Five Points. It is about 200 m west of the road site
The area around the station can be classified as desert grassland, dominated by black grama (Bouteloua eriopoda) and blue grama grass (B. gracilis), with lesser amonts of various drop seeds and sacatons (Sporobolus spp.), purple three-awn (Aristida purpurea), and Pleuraphis jamesii. The sub-shrub snakeweed (Gutierrezia sarothrae) is common during wet years and there are a few creosote bushes (Larrea tridentata) and four-wing salt bushes (Atriplex canescens) in the vicinity.
Berino Series: The soils in the Berino series are classified as fine-loamy, mixed, thermic Typic Haplargids. These form well drained, moderately permeable soils formed in alluvial and eolian material. They are on bajadas, plains, and broad fan terraces.
Slope/Aspect: Approximately 1-2%, westerly aspect.
Vegetation Community: Mixed-species desert grassland.
Terrain/Physiography: McKenzie Flats is a broad, nearly flat grassland plain between the Los Pinos Mountains and the breaks on the east side of the Rio Grande.
Geology/Lithology: Deep (20,000 ft) alluvial and eolian deposits. Caliche layer varies between 10 cm to 1 m in depth.
Hydrology - surface/groundwater: Surface water is present only during rainfall events (particularly summer thunderstorms). Area is considered a "run-on" plain for watersheds of the Los Pinos Mountains. No major arroyos are present on the study area, although Palo Duro Canyon borders the southern part of the study area.
Size: McKenzie Flats encompasses an area of approximately 50 square miles.
Elevation: 1600 m (5249 ft)
Climate (general): The McKenzie Flats area of the Sevilleta NWR has one of the LTER weather stations located in the central part of the flats. This is the Deep Well station. For climate details and data, consult the Sevilleta Meteorology databases.