The scientific journal Nature Communications published this Thursday an article led by researchers from the Ephyslab Group of the Marine Research Center of the University of Vigo (CIM-UVigo), which indicates that the humidity of atmospheric rivers is increasing by 7% for each degree of increase in the global temperature of the planet. The text is the result of a study carried out over the period 1980-2017 and its results “reveal a very important and significant increase in the amount of humidity from the regions that provide the precipitable water that will be transported to the continents by the so-called atmospheric rivers”.
The article is entitled Significant increase of global anomalous moisture uptake feeding landfalling atmospheric rivers and is the result of a study carried out in the last year and a half directed by Luis Gimeno and Raquel Nieto and developed by Iago Algarra, all belonging to the CIM-UVigo Ephyslab Group. The article also features researchers Jorge Eiras-Barca, also from Ephyslab, and Alexandre M. Ramos and Ricardo M. Trigo, from the Dom Luiz Institute of the University of Lisbon (Portugal), the institute where Algarra did a research stay under the FPI contract of which he is a beneficiary.
The “essential” role of atmospheric rivers
As explained by the Ephyslab researchers, “one of the strongest signs of climate change is the incessant increase in the average global surface temperature, which is closely related to the atmosphere’s water vapor retention capacity, which is also increasing”. A more humid atmosphere, they explain, means a greater increase in moisture transport. In this context, atmospheric rivers, the authors of the work add in their analysis, “play an essential role since they are the main mechanisms for transporting moisture from subtropical regions to extratropical regions”.
The results of the research presented in the Nature Communications article, indicate its authors, “reveal a positive trend in the moisture captured by atmospheric rivers in the same magnitude (7%) as the trend observed in water vapor at a global level”. Furthermore, they add, the results show “that these increases in water vapor, which occur at a global level, also occur at a regional scale, with a greater supply of moisture from the Northern Hemisphere than from the Southern Hemisphere”. As the authors of the work explain, the article detects the sources of anomalous moisture absorption for these meteorological systems, the main input region being the Gulf of Mexico and the Caribbean Sea, which especially feed moisture to the atmospheric rivers that develop in the Atlantic Ocean.
The detection of these moisture sources associated with atmospheric rivers, they indicate, is carried out in the study by analyzing the changes in relative humidity in millions of air volumes (particles) that are followed in their movement in the atmosphere using a Lagrangian dispersion model, a technique that the authors have been working on in recent decades. “Once the moisture sources have been detected, and applying statistical techniques, it is observed that in the moisture source regions, during the study period, which was 1980-2017, the amount of moisture supplied from them to the atmospheric rivers is clearly increasing”, explain the researchers from CIM-UVigo. The importance of this increase, they point out, lies in the fact that the same trend is being observed in the global atmosphere, with an increase of 7% of water vapor for each degree of increase in surface atmospheric temperature. “Therefore, and under the current context of global warming in which we find ourselves, the intensification of atmospheric rivers due to this increase in the transport of moisture that feeds them will have an even more relevant role in the hydrological cycle, increasing their socioeconomic impact, since atmospheric rivers are responsible for many of the extreme precipitation events,” emphasize the authors of the work.
Contents of the first thesis of the Water Campus
The work presented in the article was part of the doctoral thesis presented by Iago Algarra and directed by Luís Gimeno and Raquel Olalla Nieto and focused on the study of the main mechanisms of atmospheric moisture transport. The thesis, which achieved the highest qualification and was entitled Moisture transport associated with atmospheric rivers and low level tets at global scale, was the first to be defended in the Water, Sustainability and Development Doctoral Program, launched at the Ourense campus as part of its specialization project as the Water Campus.
Furthermore, the article and the study that endorses it are part of and continue the line of work that the Ephyslab research group develops from its headquarters in the Campus da Auga building, on the Ourense campus. This line, explain its leaders, is focused “in recent years on determining the role of the atmosphere in moisture transport, analyzing in depth the role of this transport in the global and regional hydrological cycle”. Thus, they give as an example, they currently have in force the project, funded by the then Ministry of Science, Innovation and Universities, Lagrangian analysis of the impact on the global hydrological cycle of the major mechanisms of atmospheric moisture transport, in which the research now exposed in Nature Communications fits. They also have an active agreement with the European Space Agency for the validation of satellite water vapor products.
A actividade investigadora do grupo Ephyslab conta co apoio da Xunta de Galicia e a Unión Europea no marco do Programa Operativo FEDER/FSE Galicia 2014-2020.
Source: DUVI
