MICROFRONTS 1995

• ASTER was used as the base for the turbulence and radiation measurements, including those by the hot-wire anemometer.
• CLASS made soundings, mostly concentrated around frontal passages.

In addition, other organizations took data:

• Tethersonde data were taken several times during the program by Iowa State University/University of Kansas at the El Dorado Reservoir.
• Profiler and surface station data (including fluxes) were made by the Department of Energy ARM program in Kansas and Oklahoma.
• National Weather Service soundings from 8 sites North and West of the ASTER site.

The UCAR Office of Field Program Support (OFPS) has National Weather Service products, and will eventually have all of the above data, available through their CODIAC system.

(The following is paraphrased from the "MICROFRONTS EXPERIMENT Operations and Data Management Plans" by W. Blumen and L. Mahrt.)

This experiment was to study coherent structures in the atmospheric surface layer since they are responsible for most of the transport of momentum, heat, and other scalar quantities. Hotwire anemometer measurements were made at high temporal resolution to investigate the edges of these structures, known as microfronts. The specific scientific objectives were:

• Measure direct dissipation using the hotwire anemometers to test whether inertial subrange estimates of dissipation are correct in various atmospheric conditions (including synoptic frontal zones).
• Make dissipation measurements in frontal zones to determine the mechanisms which limit frontal contraction.
• Examine how thermals organize transport.
• Test bulk parameterizations of the surface heat flux using surface radiative temperatures.
• Study air modification by lakes. The ASTER measurements will provide an upwind state to compare with weather stations set up around the El Dorado Reservoir by Ray Arritt (Iowa State University).
• Check whether there is a relation between instability of the nocturnal boundary layer and gravity waves. A small network of five microbarographs were deployed by Carmen Nappo (NOAA/ORNL) to detect gravity waves.

Photos

South Tower Site (with North Towers in the background).	North Tower Site
Radiation Stand	Radiation Sensors
Shelter for Hotwire Electronics	ASTER and CLASS Trailers

Panoramic View near the South Site (taken during the site survey in October, 1994) with views (from top to bottom) to the SW-W, NW-N, NE-E, and SE-S.