As part of the project to specialize the Ourense campus as a Water Campus, in 2017 it launched its first academic product, the Doctoral Program in Water, Sustainability and Development. This Monday, Iago Algarra, a researcher from the Ephyslab Group at the Marine Research Center of the University of Vigo (CIM-UVigo), defended his first doctoral thesis online as part of this program. It advances knowledge of the main mechanisms of moisture transport on the planet and the link between them.
José Eugenio López, coordinator of this doctoral program, points out that the presentation of this thesis represents “a milestone that has been expected since it began”. Currently, he indicates, 51 students from 15 different degrees and from Spain, Brazil, Cameroon, Cuba, France, Portugal, Italy, Ecuador, Peru and Venezuela are enrolled in the Doctoral Program in Water, Sustainability and Development, in which, in addition to the University of Vigo, the Polytechnic Institute of Porto and the University of Trás-os-Montes and Alto Douro participate. Regarding this achievement, Iago Algarra highlights that “I hope that my thesis will be the first of many” since, he emphasizes, “the Ourense campus has enormous potential and its specialization through this Water Campus is a sample of it”.
Global moisture transport
The thesis presented this Monday was entitled Moisture transport associated with atmospheric rivers and low level tets at global scale, and was directed by Luís Gimeno and Raquel Olalla Nieto (Ephyslab, CIM-UVigo) and was made possible thanks to an FPI contract within the framework of the Evocar Project, focused on the study of moisture transport in the Arctic. According to Iago Algarra, the fundamental objective of his thesis was “to investigate the link between the main moisture transport mechanisms, specifically the so-called (low-level jets) and atmospheric rivers, and the global moisture transport, with the general assumption of strong water vapor advection by these two meteorological structures”. The work, he indicates, focused on the location and characterization of the main regions where these systems, responsible for most of the moisture transport on a global scale, take their moisture to be later transported. To analyze the behavior of the moisture, comments the researcher from the University of Vigo, he used the Flexpart particle dispersion model. “The use of this model allows us to track air parcels, either forward or backward in time, in order to locate those regions where they gain humidity (humidity sources) or where they lose it (humidity sinks),” explains Iago Algarra.
Low-level jets, says the Environmental Sciences graduate, “can be defined as wind corridors in which their maximum speed occurs within the first kilometer of the troposphere”. In recent years, adds the researcher, interest in these systems has been increasing due to the fact that “they are the main mechanism for transporting moisture in tropical and subtropical regions and it is precisely in these areas where the greatest amount of water vapor is concentrated in the lower troposphere”. Regarding atmospheric rivers, Iago Algarra details, they are “fundamental in extratropical regions” and “responsible for transporting large amounts of water along relatively narrow currents from the tropics to mid-latitudes”. In general, he describes, these atmospheric rivers “provide most of the long-distance moisture transport, which represents about 90% of the meridional water vapor flow”. Thus, points out the CIM-UVigo researcher, when “an atmospheric river reaches land it is often associated with extreme precipitation events and possible subsequent flooding”.
The conclusions
Among the conclusions drawn from the study, the researcher from the Ourense campus highlights how “the high sensitivity of the water vapor content in the atmosphere to temperature suggests a more humid atmosphere under future global warming scenarios. Greater evaporation and precipitation ratios are expected and therefore an intensification of the current hydrological cycle. A higher water vapor content will project a greater global moisture transport”. The analysis of the moisture source-sink relationship in the thesis, details Iago Algarra, “shows an important modulation of moisture transport by low-level jets”. With regard to atmospheric rivers, focusing on the case of the Arctic, the work concludes that it is the North Atlantic and North Pacific sectors that fundamentally constitute the gateways for atmospheric rivers that reach the Arctic domain.
In his doctoral thesis, the author also examines the link between atmospheric dynamics in South America and winter precipitation in South Africa. “It was found that a particular phase of the South American Low-Level Jet known as the No Chaco Jet Event transports moisture from the continental region of South America (particularly, from a region that includes the Paraná River basin and the southern Amazon River basin) towards the western and central South Atlantic ocean basin,” indicates the researcher. This moisture, he adds, “is subsequently collected and transported by atmospheric rivers that reach the west coast of South Africa.” “The two margins of the South Atlantic appear to be connected by the combination of two of the most important moisture transport structures,” finally emphasizes the researcher from the University of Vigo.
The research activity of Ephyslab (CIM-UVigo) has the support of the Xunta de Galicia and the European Union, through its co-financing under the FEDER/FSE Galicia 2014-2020 Operational Program.
Source: DUVI
