EXPERIMENT
DESIGN
We
plan to use a variety of field observations collected from different
platforms along with numerical modeling to address the five scientific
questions listed earlier in the text. We will conduct
a field campaign to procure the required observations. The field
campaign will consist of a one year extended observation period and
two three-week periods of intensive observations. Surface energy measurement
instrumentation will be deployed on the two sides of the bunny fence
throughout the extended observation period. During this phase,
in addition to regular observations taken by the Australian Meteorological
Bureau (AMB), we will acquire temperature, humidity, pressure, soil
temperature, soil moisture and precipitation measurements from a network
of agricultural meteorology stations distributed through the study
region. The extended phase of the field campaign is expected
to start in December of 2005 and end in November of 2006. The
intensive field campaigns, during which coordinated observations will
be made using the mobile GLASS systems and the research aircraft, are
intended to be three-week periods, one during August-September of 2006
and another in December of 2005. During the summer month of December
the agricultural areas are bare after harvest, while winter months
of August-Spetember is the peak growing season for the agricultural
crops. The intensive field campaigns are thus designed to sample
the atmospheric thermodynamics and circulation patterns for extreme
conditions of contrast between surface vegetation on the either surface
of the bunny fence. However, note that even though the fractional
vegetation cover on the either sides of the fence is relatively similar
during the winter season, surface energy budgets are still expected
to be different, since agricultural crops and native vegetation have
varied transpirational characteristics. The use of the NCAR GLASS
systems is for the intensive phases of the field campaign.
The
observations from a pair of mobile GLASS systems will be used
to simultaneously sample thermodynamic and wind profiles on the
two sides of the bunny fence. The two potential sites for
deployment of the mobile GLASS systems (and other platforms) are
in the vicinity of the Lake King (33.01S, 119.176E) and Frank Hann
national park (33.2S, 120.2E) areas. The nearby Lake King
airstrip allows for convenient deployment of the aircraft in this
area. We will use the SERA Small Environmental Research Aircraft
(SERA) of Airborne Research Australia during the intensive phase
of the field campaigns for spatial sampling of atmosphere and surface
soil moisture. The aircraft has full instrumentation to measure
wind, temperature and turbulent fluxes, sampling at a rate of approximately
50Hz. In addition, instrumentation is available for remotely
sensing the soil moisture. The SERA platform will be used
to directly observe the structure of the mesoscale circulation. A
typical flight pattern used for this purpose will consist of vertical
ascents and descents from close to surface to well above cloud
tops over both land-use areas with connecting horizontal traverses
between two areas in a large 50 km box pattern and vertical stacks
of horizontal traverses covering the boundary layer within the
box to determine surface fluxes. Meteorological measurements
along with observations of turbulent energy fluxes will be used
examine the three-dimensional structure of the mesoscale circulations
in the vicinity of the bunny fence. |
