SOUZA, S. S.; http://lattes.cnpq.br/4079437093275721; SOUZA, Solange Silva de.
Abstract:
In this work, the possible implications of the substitution of the
Amazonia Forest cover by pasture in Rondonia State were analysed with
emphasis on the thermodynamics processes that command the Atmospheric
Boundary Layer (ABL). A few important parameters in the development of the
ABL were considered. The comparison was based on the results of two
experimental campaigns, both in the dry season, of the RBLE project ("Rondonia
Boundary Layer Experiment"): RBLE2 (July 1993) and RBLE3 (August 1994).
During theses campaigns, vertical profiles of temperature, pressure, moisture and
wind (a and V), using radiosonde, tethered balloon and surface monitoring
equipments were taken. The two experimental sites are: Forest (LAT. 1Q°()5'S;
LONG. 61°55'W; ALT. 120m) and Grassland (LAT. 10°45'S; LONG. 62°22'W;
ALT. 220m), with a distance of 100km from each other. Existing automatic
stations of the ABRACOS project ("Anglo-Brazilian Amazonian Climate
Observation Study") provided important data for establishing the lower boundary
conditions: surface radiation and energy balances. The results showed important
difference/exchange between ABLs over the two types of vegetation covers. In
the deforested area (grassland), at daytime, the ABL was 2.7K warmer and
3-Og.kg"1 drier, and its height was 1000m higher and turbulence stronger. At
night-time, the temperature difference remained practically constant (2.2K) and
the moisture difference was double compared to the daytime. On the other hand,
the Forest ABL was 30% thicker and more unstable, at night-time.