MELLHO, C. C.; MELLO, Cléa Cardoso de.
Résumé:
The aim of the present investigation is to make a diagnostic study
of the synoptic fratures and circulation characteristics responsible
for marked anomalies i n precipitation in the drought prone region of
Northeast Brazil 1° - 18°S and 35° - 47°W. The years 1970 characterizing
dry, and 1977 characterizing wet have been selected after analysis of total annual precipitation, and specific periods (4- consecutive days)
in the typical and representative months of march, may and december, ha
ve been chosen for detailed study.
The daily pluviometric data for 41 stations, the upper air data
for 11 radiosonde stations of the Region and the tropospheric wind data
at grip points (5° x 5° intervals for Region 10°N-25°S and 2 5 ° - 50°W)
obtained from NCAR has been used. The surface synoptic charts and some
satellite imagery has also been obtained from INPE and used for asses
sing the position and intensity of south atlantic high, as also some
fronts.
The kinematic method has been used for computation of vertical ve
locity (to) at each level, and vertical velocity charts been prepared
and analysed for each standard level up t o 200 mb.
For areas of interest, vertical profiles have been prepared sho
wing mean divergence (V . V), vertical velocity (to) and relative humidi
ty (R H). These profiles are very useful in understanding some featu
res of precipitation in the Region.
Besides this, for better explanation of the nature and characteristics of observed precipitation, the effect of orography of the Regi
on has also been taken into consideration for computation of vertical
velocity (to. ) with the help of contour in the inferior.
