PhD thesis: Characterization of the vertical structure of aerosols in the eastern subtropical region of the North Atlantic

On September 19, 2017, at 11:30 a.m. in the 4th-floor room of the Faculty of Physics and Mathematics of the University of La Laguna, the defense of the PhD thesis of Carmen Yballa Hernández Pérez was held, entitled “Characterization of the vertical structure of aerosols in the eastern subtropical region of the North Atlantic”. This work was developed in the Center of Atmospheric Research of Izaña of the State Agency of Meteorology and was supervised by Dr. Africa Barreto (Cimel Electronique, France) and Dr. Alberto Berjón (University of Valladolid) and Manuel Arbelo (University of La Laguna).

The thesis committee:

President: Dr. Francisco Javier Expósito González, University of La Laguna
Secretary: Dr. María José Granados Muñoz, Polytechnic University of Cataluña
Member: Dr. Rosa Delia García Cabrera, Air Liquide España, S.A.

PhD student Yballa Hernández during the defense of her thesis

The main objective of this thesis is the characterization of atmospheric aerosols in the eastern subtropical region of the North Atlantic, using the LIDAR technique and solar photometry. For the inversion of the LIDAR equation the investment methodology has been applied to one and two layers, the latter being novel within the study region, which is divided into two layers: the marine boundary layer and the free troposphere, separated by the thermal inversion associated to the Alisios winds.
For the accomplishment of the work a series of data of almost a decade has been used, which indicates the quality of the stations of measurement, the favorable atmospheric conditions, as well as the work done in the operation of the instruments.
In this work, a series of aerosol layers in the upper troposphere and low stratosphere were also detected and analyzed using LIDAR. The Transmittance and Inversion methodology of the LIDAR equation was combined with other tools such as retrotrajectories (to see the origin of the air masses), MODIS, NAAPS and CALIOP images. Four cases of study were distinguished: one of volcanic origin (Nabro volcano, Eritrea) and three fires (North America and Canada). It should be noted that the study of the eruption of the volcano Nabro carried out in the Thesis covers a time interval of approximately three months, which is the longest study performed up to the time of the event.
The thesis committee highlighted the great scientific interest of this thesis, not only for the strategic study area but also because of the nine-year LIDAR database.

From left to right: Africa Barreto (supervisor), Francisco Javier Expósito (president of the thesis committee), Rosa García (member of the thesis committee), Yballa Hernández (PhD student), Manuel Arbelo (supervisor), Alberto Berjón (supervisor) and María José Granados (secretary of the thesis committee).