Part II - Continuous Observations
|Turbulence and mean meteorological parameters |||Radiation 10 m tower |||Microbarometers-Sonic |||Scintillometers|
Turbulence and mean meteorological parameters
In the BLLAST experiment, 9 masts will be equipped with a total of 26 instruments measuring turbulence. Measured properties are: wind, temperature, CO2 concentration and water vapour concentration. The first aim of all the stations is to get a clearer picture of the fluxes in the diverse landscape that is the BLLAST experimental site and integrated in the airborne measurements. Beyond this purpose, most of the surface stations are implemented to also deal with other objectives.
- The southern Corn, moor and forest EC-stations will sample three contiguous large areas with relatively homogeneous vegetation . The moor site has some heterogeneity in the vegetation, but this is uniform throughout the field. These three sites are devoted to study the impact of surface heterogeneities on the late afternoon transition. The surface energy balance time-shift between the different vegetation cover and the secondary circulation between the fields during this phase of the day will be investigated. The EC-data here are complemented with tethered balloons and unmanned aircraft data. In addition, the forest site tower will be instrumented at two levels, just above the canopy and 5 meters above, to study the flow near the canopy.
- The Micro-site main focus is the small surface heterogeneities study. Over a 100m square flat surface, bare soil, small bushes, grass, and small puddles constitute a very heterogeneous surface whose soil characteristics (temperature, humidity) will be extensively mapped. Added to the Ec- station, the temperature vertical profile up to 1.5m will be measured.
- The 60m mast is equipped with quick (10Hz) sensors at three levels. With this mast, a vertical profile can be made in and above the surface layer. This mast is a permanent platform at the CRA and provides year-round flux-data.
- The Skinflow-mast is a 10m high mast equipped with a total of 6 sonic anemometers. The aim of this set-up is to investigate near-surface divergence of the sensible heat flux. The lowest sonics are at a height of less than one meter. Complimentary to the sonic anemometers is a set of fast thermocouples, close to the ground. A twin tower will be settled near the skinflow-mast to measure the radiative divergence.
- At the edge site, a set-up of three masts, all equipped with sonic anemometers and fast water vapour and CO2 sensors, is used to validate a flux-footprint model. Two stations will be set up in a grass and wheat field respectively and one station will be located at the edge. With a model that includes the land-uses in the surrounding area, representative fluxes can be reconstructed.
The following table presents the vegetation cover, the site latitude, longitude and height above the sea level and the properties measured at all EC-station.
|Site name||Land use||Latitude (N)|
|Height ASL [m]||Properties measured|
|Corn (Site 2)||Corn||43°05'24"|
|645±5||Temperature, wind, H2O, CO2, pressure, radiation, rain, soil temperature, soil humidity, soil heat flux|
|Moor (Site 2)||Mixed moor-like vegetation||43°05'24"|
|641±3||Temperature, wind, H2O, CO2, pressure, radiation, rain, soil temperature, soil humidity, soil heat flux|
|Forest (Site 2)||Douglas Spruce||620||Temperature, wind, H2O, CO2, pressure|
|60-m tower (Site 1)||Mixed||43°07'27.15"|
|602||Temperature, wind, H2O, CO2, pressure, radiation|
|Micro (Site 1)||Grass and shrubs||43°07'26"|
|601||Temperature, wind, H2O, CO2, pressure, radiation|
|Skinflow (Site 1)||Grass||43°07'39.2"|
|Edge (Site 1)||Wheat, rhye and peas||43°07'56.0"|
|582||Temperature,wind,H2O, CO2, pressure, wet-bulb-temperature, soil temperature, soil humidity, soil heat flux|
|581||Temperature,wind,H2O, CO2, pressure, wet-bulb-temperature, soil temperature, soil humidity, soil heat flux|
|581||Temperature, wind, H2O, CO2, pressure|