Estudo do desenvolvimento da camada limite convectiva no semiárido brasileiro

Abstract

The Objective of this thesis was to study experimentally the thermodynamic behavior of the Convective Boundary Layer (CBL) during the dry and rainy period in a semi-arid climate region of the Northeast of Brazil (NEB), with the use of radiosondes on days 16, 17 and 18 November 2013 (dry period) and from 03 to 08 April 2014 (rainy period) in the municipality of Apodi-RN and in the rainy period of 09 to 17 April 2011 in the municipalities of Mossoró-RN and Quixeramobim-CE. They were launched 15 balloons (dry period) and 32 in Apodi-RN and 35 in Mossoró-RN and 36 in Quixeramobim-CE (both in the rainy period). Through radiosondings were collected profile data of atmospheric pressure, air temperature, relative humidity, wind speed and direction and Low Level Jets. For surface data in Apodi-RN was used a portable surface weather station to collect data and were calculated the average, maximum and minimum every 10 minutes during 24 hours. It was applied the T-Student test and was found that some weather variables showed statistically significant differences at 5%. To determine the CBL height was applied the profiles method using the potential temperature and it was analyzed three informations from each profile: the average of layer, the value in the base and top. In Apodi-RN, the CBL height was higher in the dry season than in the rainy period, being lowest in the early morning (5:00 HL - Local Time) and highest in the late afternoon 17:00 HL. The potential temperature was slightly higher in the dry season than the in the rainy reaching maximum values at 17:00 HL. In Mossoró-RN and Quixeramobim-CE, the CBL height during the rainy season was shallower, colder and wetter in both sites. The T-Student test was applied both to evaluate the statistical differences between the data by period and by location.The results were shown in the Chapter 4.