North Atlantic Integrated Water Vapor Transport—From 850 to 2100 CE: Impacts on Western European Rainfall

Abstract

Moisture transport over the northeastern Atlantic Ocean is an important process governing precipitation distribution and variability over western Europe. To assess its long-term variability, the vertically integrated horizontal water vapor transport (IVT) from a long-term climate simulation spanning the period 850–2100 CE was used. Results show a steady increase in moisture transport toward western Europe since the late-nineteenth century that is projected to expand during the twenty-first century under the RCP8.5 scenario. The projected IVT for 2070–99 significantly exceeds the range given by interannual–interdecadal variability of the last millennium. Changes in IVT are in line with significant increases in tropospheric moisture content, driven by the concurrent rise in surface temperatures associated with the anthropogenic climate trend. On regional scales, recent and projected precipitation changes over the British Isles follow the global positive IVT trend, whereas a robust precipitation decrease over Iberia is identified in the twenty-first century, particularly during autumn. This indicates a possible extension of stable and dry summer conditions and a decoupling between moisture availability and dynamical forcing. The investigation of circulation features reveals a mean poleward shift of moisture corridors and associated atmospheric rivers. In particular, in Iberia, a significant increase in the frequency of dry weather types is observed, accompanied by a decrease in the frequency of wet types. An opposite response is observed over the British Isles. These changes imply a stronger meridional north–south dipole in terms of pressure and precipitation distributions, enhancing the transport toward central Europe rather than to Iberia.

Responses and impacts of atmospheric rivers to climate change

“…As discussed previously, dynamical changes are most discernible at lower latitudes, where the projected expansion of the subtropics and the poleward shift of the jet have the most influence. For example, in Mediterranean climate zones of the lower mid-latitudes, poleward shifts in the storm track are projected to also shift the distribution of AR landfalls, resulting in a decrease in both the amount and frequency of winter precipitation 66,114,115 . One exception is California, where many GCMs predict a southward migration of the mid-winter storm track caused by an El Niño-like shift in climatological sea-surface temperatures 108,110 .…”

A global climatological perspective on the importance of Rossby wave breaking and intense moisture transport for extreme precipitation events

“…Furthermore, recent studies employed IVT to improve the medium-range prediction of hydrometeorological extremes (Lavers et al, 2014(Lavers et al, , 2016 and to assess (thermo)dynamical changes of precipitation extremes in projected future climates Radic et. al., 2015;Espinoza et al, 2018;Benedict et al, 2019;Hsu and Chen, 2020;Sousa et al, 2020). For extensive reviews on the link between intense moisture transport and EPEs, the reader is referred to Gimeno et al (2016) and Liu et al (2020).…”

Meridional Heat Transport During Atmospheric Rivers in High‐Resolution CESM Climate Projections

“…Research has also been conducted on widely different climate regimes from paleoclimate (e.g., Last Glacial Maximum, Lora et al, 2017, andEocene, Kiehl et al, 2018) to future climates under global warming (Chang et al, 2012;Espinoza et al, 2018;Hagos et al, 2016;Mizuta, 2012;Payne & Magnusdottir, 2015;Shields & Kiehl, 2016a, 2016bWarner et al, 2015). However, other than quantifying the thermodynamical contributions of moisture transport under climate change Sousa et al, 2019) and investigating air temperature within the ARs themselves (Gonzales et al, 2019) Supporting Information:…”

“…Research has also been conducted on widely different climate regimes from paleoclimate (e.g., Last Glacial Maximum, Lora et al, , and Eocene, Kiehl et al, ) to future climates under global warming (Chang et al, ; Espinoza et al, ; Hagos et al, ; Lavers et al, ; Lavers et al, ; Mizuta, ; Payne & Magnusdottir, ; Shields & Kiehl, , ; Warner et al, ). However, other than quantifying the thermodynamical contributions of moisture transport under climate change (Gao et al, , ; Sousa et al, ) and investigating air temperature within the ARs themselves (Gonzales et al, ), little research has been devoted to investigating the energy transport explicitly by atmospheric rivers. Understanding energy changes within ARs is an important new direction identified by the scientific community (Ralph, Dettinger, et al, ).…”