Atmospheric moisture transport between mid‐latitudes and the Arctic: Regional, seasonal and vertical distributions

2019 ◽  
Vol 39 (6) ◽  
pp. 2862-2879 ◽  
Author(s):  
Tuomas Naakka ◽  
Tiina Nygård ◽  
Timo Vihma ◽  
Joseph Sedlar ◽  
Rune Graversen
Keyword(s):  
Moisture Transport ◽  
The Arctic ◽  
Atmospheric Moisture ◽  
Vertical Distributions ◽  
Atmospheric Moisture Transport

scholarly journals Atmospheric moisture transport: the bridge between ocean evaporation and Arctic ice melting

2015 ◽  
Vol 6 (2) ◽  
pp. 583-589 ◽  
Author(s):  
L. Gimeno ◽  
M. Vázquez ◽  
R. Nieto ◽  
R. M. Trigo
Keyword(s):  
Climate Change ◽  
Sea Ice ◽  
Moisture Transport ◽  
The Arctic ◽  
Atmospheric Moisture ◽  
Ice Melting ◽  
Moisture Sources ◽  
The North ◽  
Arctic Ice ◽  
Atmospheric Moisture Transport

Abstract. Changes in the atmospheric moisture transport have been proposed as a vehicle for interpreting some of the most significant changes in the Arctic region. The increasing moisture over the Arctic during the last decades is not strongly associated with the evaporation that takes place within the Arctic area itself, despite the fact that the sea ice cover is decreasing. Such an increment is consistent and is more dependent on the transport of moisture from the extratropical regions to the Arctic that has increased in recent decades and is expected to increase within a warming climate. This increase could be due either to changes in circulation patterns which have altered the moisture sources, or to changes in the intensity of the moisture sources because of enhanced evaporation, or a combination of these two mechanisms. In this short communication we focus on the more objective assessment of the strong link between ocean evaporation trends and Arctic Sea ice melting. We will critically analyse several recent results suggesting links between moisture transport and the extent of sea ice in the Arctic, this being one of the most distinct indicators of continuous climate change both in the Arctic and on a global scale. To do this we will use a sophisticated Lagrangian approach to develop a more robust framework on some of these previous disconnecting results, using new information and insights. Results reached in this study stress the connection between two climate change indicators, namely an increase in evaporation over source regions (mainly the Mediterranean Sea, the North Atlantic Ocean and the North Pacific Ocean in the paths of the global western boundary currents and their extensions) and Arctic ice melting precursors.

scholarly journals Relative Contributions of Synoptic and Low-Frequency Eddies to Time-Mean Atmospheric Moisture Transport, Including the Role of Atmospheric Rivers

2012 ◽  
Vol 25 (21) ◽  
pp. 7341-7361 ◽  
Author(s):  
Matthew Newman ◽  
George N. Kiladis ◽  
Klaus M. Weickmann ◽  
F. Martin Ralph ◽  
Prashant D. Sardeshmukh
Keyword(s):  
Moisture Transport ◽  
Low Frequency ◽  
The Arctic ◽  
Moisture Budget ◽  
Atmospheric Moisture ◽  
Atmospheric Rivers ◽  
Low Frequency Variability ◽  
The Mean ◽  
Mean Circulation ◽  
Atmospheric Moisture Transport

The relative contributions to mean global atmospheric moisture transport by both the time-mean circulation and by synoptic and low-frequency (periods greater than 10 days) anomalies are evaluated from the vertically integrated atmospheric moisture budget based on 40 yr of “chi corrected” NCEP–NCAR reanalysis data. In the extratropics, while the time-mean circulation primarily moves moisture zonally within ocean basins, low-frequency and synoptic anomalies drive much of the mean moisture transport both from ocean to land and toward the poles. In particular, during the cool-season low-frequency variability is the largest contributor to mean moisture transport into southwestern North America, Europe, and Australia. While some low-frequency transport originates in low latitudes, much is of extratropical origin due to large-scale atmospheric anomalies that extract moisture from the northeast Pacific and Atlantic Oceans. Low-frequency variability is also integral to the Arctic (latitudes > 70°N) mean moisture budget, especially during summer, when it drives mean poleward transport from relatively wet high-latitude continental regions. Synoptic variability drives about half of the mean poleward moisture transport in the midlatitudes of both hemispheres, consistent with simple “lateral mixing” arguments. Extratropical atmospheric transport is also particularly focused within “atmospheric rivers” (ARs), relatively narrow poleward-moving moisture plumes associated with frontal dynamics. AR moisture transport, defined by compositing fluxes over those locations and times where column-integrated water vapor and poleward low-level wind anomalies are both positive, represents most of the total extratropical meridional moisture transport. These results suggest that understanding potential anthropogenic changes in the earth ’s hydrological cycle may require understanding corresponding changes in atmospheric variability, especially on low-frequency time scales.

scholarly journals Short Communication: Atmospheric moisture transport, the bridge between ocean evaporation and Arctic ice melting

2015 ◽  
Vol 6 (1) ◽  
pp. 1033-1045
Author(s):  
L. Gimeno ◽  
M. Vázquez ◽  
R. Nieto ◽  
R. M. Trigo
Keyword(s):  
Sea Ice ◽  
Moisture Transport ◽  
Short Communication ◽  
Global Climate ◽  
Arctic Sea Ice ◽  
The Arctic ◽  
Atmospheric Moisture ◽  
Ice Melting ◽  
Moisture Sources ◽  
Atmospheric Moisture Transport

Abstract. If we could choose a region where the effects of global warming are likely to be pronounced and considerable, and at the same time one where the changes could affect the global climate in similarly asymmetric way with respect to other regions, this would unequivocally be the Arctic. The atmospheric branch of the hydrological cycle lies behind the linkages between the Arctic system and the global climate. Changes in the atmospheric moisture transport have been proposed as a vehicle for interpreting the most significant changes in the Arctic region. This is because the transport of moisture from the extratropical regions to the Arctic has increased in recent decades, and is expected to increase within a warming climate. This increase could be due either to changes in circulation patterns which have altered the moisture sources, or to changes in the intensity of the moisture sources because of enhanced evaporation, or a combination of these two mechanisms. In this short communication we focus on the assessing more objectively the strong link between ocean evaporation trends and Arctic Sea ice melting. We will critically analyze several recent results suggesting links between moisture transport and the extent of sea-ice in the Arctic, this being one of the most distinct indicators of continuous climate change both in the Arctic and on a global scale. To do this we will use a sophisticated Lagrangian approach to develop a more robust framework on some of these previous disconnect ng results, using new information and insights. Among the many mechanisms that could be involved are hydrological (increased Arctic river discharges), radiative (increase of cloud cover and water vapour) and meteorological (increase in summer storms crossing the Arctic, or increments in precipitation).

Atmospheric Moisture Transport Moderates Climatic Response to the Opening of Drake Passage

2009 ◽  
Vol 22 (9) ◽  
pp. 2483-2493 ◽  
Author(s):  
Willem P. Sijp ◽  
Matthew H. England
Keyword(s):  
Moisture Transport ◽  
Hydrological Cycle ◽  
Coupled Model ◽  
Drake Passage ◽  
Moisture Diffusivity ◽  
Atmospheric Moisture ◽  
Oceanic Circulation ◽  
Coupled Models ◽  
Storm Activity ◽  
Atmospheric Moisture Transport

Abstract The absence of the Drake Passage (DP) gateway in coupled models generally leads to vigorous Antarctic bottom water (AABW) formation, Antarctic warming, and the absence of North Atlantic deep-water (NADW) formation. Here the authors show that this result depends critically on atmospheric moisture transport by midlatitude storms. The authors use coupled model simulations employing geometries different only at the location of DP to show that oceanic circulation similar to that of the present day is possible when DP is closed and atmospheric moisture transport values enhanced by Southern Ocean storm activity are used. In this case, no Antarctic warming occurs in conjunction with DP closure. The authors also find that the changes in poleward heat transport in response to the establishment of the Antarctic Circumpolar Current (ACC) are small. This result arises from enhanced atmospheric moisture transport at the midlatitudes of the Southern Hemisphere (SH), although the values used remain within a range appropriate to the present day. In contrast, homogeneous or (near) symmetric moisture diffusivity leads to strong SH sinking and the absence of a stable Northern Hemisphere (NH) overturning state, a feature familiar from previous studies. The authors’ results show that the formation of NADW, or its precursor, may have been possible before the opening of the DP at the Eocene/Oligocene boundary, and that its presence depends on an interplay between the existence of the DP gap and the hydrological cycle across the midlatitude storm tracks.

scholarly journals Roles of the Rocky Mountains in the Atlantic and Pacific Meridional Overturning Circulations

2021 ◽  
pp. 1-41
Author(s):  
Rui Jiang ◽  
Haijun Yang
Keyword(s):  
North Atlantic ◽  
Rocky Mountains ◽  
North Pacific ◽  
Moisture Transport ◽  
Atmospheric Moisture ◽  
The North ◽  
Meridional Overturning ◽  
The North Atlantic ◽  
The North Pacific ◽  
Atmospheric Moisture Transport

AbstractThe effect of the Rocky Mountains (RM) on meridional overturning circulations (MOCs) is investigated using a fully coupled climate model. Located between the Atlantic and Pacific oceans, the RM is the major mountains in North America. It presence plays an important role in atmospheric moisture transport between the two oceans. Adding the RM to a flat global continent (OnlyRocky) leads to a weakening of the atmospheric moisture transport from the North Pacific to the North Atlantic, which is consistent with previous finding. However, the simulation also shows more atmospheric moisture is transported from the tropical Pacific and Atlantic to the North Atlantic. The net effect of moisture transport leads to a slight freshening of the North Atlantic. The Atlantic MOC (AMOC) is hardly changed, but the Pacific MOC (PMOC) declines by 40% due to more moisture retained in the North Pacific. The sensitivity experiment of removing the RM from a realistic global topography (NoRocky) gives roughly opposite atmospheric changes to the OnlyRocky experiment. The AMOC in NoRocky declines slightly and then recovers, while the PMOC is nearly unchanged. The paired experiments conducted in this study demonstrate that the presence of the RM plays a trivial role in Northern Hemisphere deep-water formation.

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