OLIVEIRA, G. M.; http://lattes.cnpq.br/1339247746532242; OLIVEIRA, Gertrudes Macario de.
Resumo:
This Dissertation deals with the effects of advection on water loss from peanut crop in
the semi-arid region of northeast Brazil. The experimental part of the study was
carried out during the period September 20 to december 23, 1996 in the irrigated
perimeter of the CODEVASF Experimental Station, in the city of Rodelas - Ba (lat. 08°
50'S; long. 38° 46'W; alt. 270m). Three micrometeorological towers equipped with
automatic data acquisition systems were installed along the cultivated area. Incident
and reflected solar radiation, net radiation, dry and wet bulb temperatures, wind
speed, soil heat flux and évapotranspiration were measured throughout the study
period. The micrometeorological parameters were measured each second while
évapotranspiration was measured once a day and twice a week hourly data was
collected during daytime. The peanut crop (Arachis hypogaea L.) was planted in an
area of 2 hectares with a spacing of 0.5 m between rows. The results showed that
until the phase of vegetative growth advection of humid air occurred in the first half
and advection of sensible heat in second half of the field. During the flowering phase
and maturation advection of sensible heat occurred in the entire field. Bare soil
surface between rows was a significant source for the prodution of sensible heat.
Radiation balance was affected by irrigation causing a decrease of up to 9% in hourly
albedo values and up to 6% in the daily mean value. In the phase of maturation
sensible heat advection caused évapotranspiration to exceed net radiation by about
50%. It is found that if the same time intervals are not considered for the
measurements of net radiation and évapotranspiration totals errors of up to 2.2
MJ/m2/day may occurr and this in turn may make it difficult to detect the presence of
advection.