Moisture transport from the Arctic: a characterization from a Lagrangian perspective

Abstract

The Arctic Ocean has suffered extreme reductions in sea ice in recent decades, and these observed changes suggest implications in terms of moisture transport. The Arctic region is a net sink of moisture in terms of the total hydrological cycle, however, its role as a moisture source for specific regions has not been extensively studied. Our results show that 80% of the moisture supply from the Arctic contributes to precipitation over itself, representing about 8% of the global moisture supply to the Arctic, the remaining 20% is distributed in the surrounding. A reduction in the sea ice extent could make the Arctic Ocean a slightly higher source of moisture to itself or to the surrounding areas. The analysis of the areas affected by Arctic moisture transport is important for establishing those areas vulnerable to change in a framework of a growing sea ice decline. To this end, the Lagrangian model FLEXPART was used in this work to establish the main sinks for the Arctic Ocean, focusing on the moisture transport from this region. The results suggest that most of the moisture loss occurs locally over the Arctic Ocean itself, especially in summer. Some moisture contribution from the Arctic Ocean to continental areas in North America and Eurasia is also noted in autumn and winter especially from Central Arctic, the East Siberian Sea, the Laptev, Kara, Barents, East Greenland and Bering Seas, and the Sea of Okhotsk.

Characterization of Moisture Sources for Austral Seas and Relationship with Sea Ice Concentration

“…In other words, the moisture seems to make a negative contribution to the SIC over the blue area displayed in Figure 2. This result is similar to [34] for the Arctic region and the case study performed by [23,24] for the austral seas. Figure 5 further shows that the SIC in the Weddell Sea has stronger interannual variability (as shown by standard deviation bars) from January-June, and equally large variability is observed in the Amundsen Sea throughout the year.…”

“…In terms of the average, the moisture sink is higher and lower, respectively, in the Amundsen and Weddell seas. These annual cycle shapes of the moisture sink, with the maximum at the end-summer/autumn and the minimum in spring-begin/summer, are similar to those in the Arctic [34]. As moisture sinks over the target areas are mainly associated with precipitation, we can compare it with precipitation climatology over the Southern Ocean.…”

“…Among the multiple atmospheric and oceanic drivers controlling the sea ice variability, little attention has been paid to the moisture transport from the extratropics to the Southern Ocean [23,31,32], a mechanism proposed to have an important role in the Arctic atmospheric hydrological system e.g., [33,34], with implications for the Arctic Sea ice extension. Indeed, atmospheric moisture transport is a primary source of water in polar regions, and, according to [23], through the cloud radiative forcing, it directly or indirectly affects the snow, sea ice, and ice sheet.…”

Atmospheric moisture transport and the decline in Arctic Sea ice

“…For the Arctic as a whole, the findings of Vázquez et al () and Singh et al () reveal the importance of remote sources. Singh et al () estimated the contribution from local sources to the Arctic region at around 20%, with this being at a maximum from October to March, but the equivalent figure was only about 8% in another study by Vázquez, Nieto, Drumond, and Gimeno ().…”