“Due to the threat of climate change, knowing the intensity of the hydrological cycle and its variations over time is one of the main challenges of this century”, says Marta Vázquez, researcher at the Ephyslab Group of the Marine Research Center of the University of Vigo. In this context, she details, “the Arctic represents one of the most vulnerable regions, with the changes experienced there being particularly drastic”. In her doctoral thesis, this physicist carried out a characterization of moisture transport in the Arctic and related this transport to the ice melt observed in the area.
Directed by Luis Gimeno and Raquel Olalla Nieto, the thesis was entitled Oceanic and terrestrial sources of precipitation in the Arctic: new goals and orientations from a Lagrangian approach and was presented at the Faculty of Sciences on the Ourense campus. Within the framework of the “current paradigm of global climate change”, Vázquez Domínguez points out that “it is especially important to know the processes that govern evaporation, the transport of moisture in the atmosphere and the effects of these processes on the hydrological cycle”. Despite the growing interest that the Arctic region has aroused in recent years, the researcher details, “the transport of moisture in the Arctic has not been fully analyzed to date and to this day there is still no complete understanding of its implication in the current and future climate”.
In his doctoral thesis, Vázquez Domínguez analyzed moisture transport in two directions: transport from the main sources of moisture to the Arctic, in order to study its influence on the region, and transport from the Arctic itself, to analyze the possible implications of the changes it has undergone in the last four decades. This analysis, he points out, was carried out through the Lagrangian Flexpart model, “through which the trajectory of atmospheric particles can be followed in order to locate those regions where moisture is taken up or lost.”
Towards the Arctic
As a result of the study carried out, Marta Vázquez points out that “it can be concluded that there are four main sources of moisture for the Arctic region: two oceanic sources (North Atlantic and North Pacific) and two continental (North America and Siberia)”. Oceanic sources, she details, “are present throughout the year, although their importance is greater in the winter, while continental sources only appear in the summer, when oceanic sources lose importance, becoming the main sources for this period”. In the summer, she adds, is when the greatest contribution of moisture to precipitation occurs taking into account all sources. The Pacific Ocean, she points out, contributes the most moisture to precipitation throughout the year while the Atlantic Ocean makes the least contribution, especially in the summer.
In the work carried out by the Ephyslab Group, the main sources of moisture for the Arctic system in the years 2007 and 2012 were also analyzed, those that show a smaller ice extent in recent decades, “finding some variation in the position, intensity and contribution of the same with respect to the climatological situation”. The relationship between the decrease in Arctic ice and moisture transport was also analyzed in this work based on previous publications in which Arctic melting is associated with a radiative process, referring to changes in cloudiness, and a hydrological process, referring to the discharge of rivers, and both associated with a greater transport of moisture towards the Arctic region.
“In this work we establish a relationship between changes in evaporation and melting that suggests an intricate chain of events related to an increase in evaporation over different sources, an intensification in the transport of moisture from them and an increase in the discharge of rivers or cloud cover in the Arctic region”, points out Marta Vázquez. “We found a relationship between the transport of moisture in summer and the decrease in sea ice. An increase in the contribution of moisture is observed over the regions that suffer a greater retreat of ice especially in the summer months”, details the researcher. Also, she points out, “the transport of moisture towards the main basins of the Arctic rivers is related to the decrease in sea ice in 2007”.
From the Arctic
In addition to studying the transport to the Arctic region, this work also analyzed the Arctic as a source of moisture, in order to analyze the implications that current changes in this region may have in other areas of the planet. “In general, most of the Arctic moisture affects the system itself, although some influence can also be observed on Eurasia and North America. With respect to seasonal variation, the maximum moisture contribution occurs in summer and autumn, coinciding with the minimum values in the ice extent”, summarizes the researcher.
The influence of moisture transport from the Arctic is also illustrated by the analysis of the role that ice melt has on snow precipitation in Eurasia. Through snow cover observations at 820 stations distributed throughout Russia, using Flexpart and with the help of various dynamic diagnostic parameters, the thesis studied the influence of ice melt over the Barents and Kara Seas on precipitation over Siberia in the months of October and November. “An intensification of these seas as moisture sources was found, also increasing their contribution over the southwestern region of Siberia for years of minimum ice extent,” the study notes.
Source: DUVI
