Forty-year climatology and variability of atmospheric rivers in the Arctic using MERRA-2 reanalysis from 1980 to 2020

Author(s):  
Carolina Viceto ◽  
Irina Gorodetskaya ◽  
Annette Rinke ◽  
Alfredo Rocha ◽  
Susanne Crewell

<p>A significant increase in the atmospheric moisture content over the Arctic region has been recently documented, that might be caused by the enhanced poleward moisture flux which is expected to continuously increase in the future. This change can be attributed to different causes, in which increasing moisture transport intensity is included. In this study we focus on events with anomalous moisture transport confined to long, narrow and transient corridors, known as atmospheric rivers (ARs), which are expected to have a strong influence on Arctic mass and energy budget.</p><p>This study is based on MERRA-2 reanalysis (Modern-Era Retrospective analysis for Research and Applications, Version 2) extending from an historical period until present (1980-2020). ARs are identified using the tracking algorithms by Gorodetskaya et al. (2020) and Guan et al. (2018). We explored the frequency of ARs focusing on annual, seasonal and monthly values. Spatial patterns were analysed for the Arctic latitudes, covering both Atlantic and Pacific moisture transport pathways, and showing the importance of the Siberian moisture pathway during summer. Furthermore, we include a more detailed analysis performed at different sites north of the Arctic circle. Specific attention is given to the ARs characteristics during the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) expedition from September 2019 to October 2020, as compared to the forty-year climatology and variability of the ARs in the Arctic.</p><p>Preliminary results show a higher frequency of ARs over the Norwegian and Barents Sea (Atlantic pathway), mainly during autumn and winter, although during May and June there is a high frequency of ARs over Western Siberia and Barents Sea. In contrast, the Canadian Artic has a lower frequency of ARs regardless the season, which is explained by a steep decrease of ARs frequency in the Gulf of Alaska and Bering Sea that block their progression to further north latitudes.</p><p> </p><p><strong>References: </strong></p><p>Gorodetskaya, I. V., Silva, T., Schmithüsen, H., and Hirasawa, N., 2020: Atmospheric River Signatures in Radiosonde Profiles and Reanalyses at the Dronning Maud Land Coast, East Antarctica. <em>Adv. Atmos. Sci.</em>, https://doi.org/10.1007/s00376-020-9221-8.</p><p>Guan, B., Waliser, D. E. and Ralph, F. M., 2018: An Intercomparison between Reanalysis and Dropsonde Observations of the Total Water Vapor Transport in Individual Atmospheric Rivers. <em>J. Hydrometeorol.</em>, 19, 321–337, https://doi.org/10.1175/JHM-D-17-0114.1.</p><p> </p><p><strong>Acknowledgments: </strong></p><p>This work is supported by FCT PhD Grant SFRH/BD/129154/2017 and developed in collaboration with Transregional Collaborative Research Centre (AC)<sup>3</sup>, AWI and U. Cologne.</p>

Water ◽  
2018 ◽  
Vol 11 (1) ◽  
pp. 41 ◽  
Author(s):  
Marta Vázquez ◽  
Iago Algarra ◽  
Jorge Eiras-Barca ◽  
Alexandre M. Ramos ◽  
Raquel Nieto ◽  
...  

In recent years, the Arctic has become a subject of special interest due to the drastic effect of climate change over the region. Despite that there are several mechanisms that influence the Arctic region; some recent studies have suggested significant influences of moisture transport over the observed loss of sea ice. Moisture transport can affect the region in different ways: direct precipitation over the region, radiative effect from the cloud cover and through the release of latent heat. Atmospheric rivers (ARs) represent one of the main events involved in moisture transport from the tropics to the mid-latitudes and despite having been shown especially relevant on the northward advection, their effect over the Arctic has not been deeply investigated. The aim of this work was to establish the groundwork for future studies about the effect of ARs linked to moisture transport over the Arctic region. For this purpose, an automated algorithm was used to identify regions of maximum AR occurrence over the Arctic. This was done by analysing the number of AR detections every month over a band of 10° of latitude centred on 60° N. The Lagrangian model FLEXPART was used to find the areas where the ARs take their moisture to the Arctic. Using this model, the anomalous moisture contribution to these baroclinic structures was analysed taking into account only the dates of AR occurrence. From the results, it appears that the main moisture sources for AR events extend over the North Atlantic and North Pacific oceans; moreover, the local input of moisture over the region of maximum AR occurrence seems to be especially relevant. In general terms, moisture comes from major evaporative areas over the western part of the oceanic regions in the band between 30° and 40° N for most months in the year, showing a continental origin in the summer months. This behaviour agrees with the climatological moisture transport into the Arctic determined in previous studies. However, in special association with AR events, an intensification of local moisture uptake is observed over the area of maximum AR activity and nearby. The study of the origin of this moisture and associated anomalies for Arctic ARs is an important step in the analysis of the effect of these structures on the Arctic environment.


2021 ◽  
Author(s):  
Hannah Zanowski ◽  
Alexandra Jahn ◽  
Marika Holland

<p>Recently, the Arctic has undergone substantial changes in sea ice cover and the hydrologic cycle, both of which strongly impact the freshwater storage in, and export from, the Arctic Ocean. Here we analyze Arctic freshwater storage and fluxes in 7 climate models from the Coupled Model Intercomparison Project phase 6 (CMIP6) and assess their agreement over the historical period (1980-2000) and in two future emissions scenarios, SSP1-2.6 and SSP5-8.5. In the historical simulation, few models agree closely with observations over 1980-2000. In both future scenarios the models show an increase in liquid (ocean) freshwater storage in conjunction with a reduction in solid storage and fluxes through the major Arctic gateways (Bering Strait, Fram Strait, Davis Strait, and the Barents Sea Opening) that is typically larger for SSP5-8.5 than SSP1-2.6. The liquid fluxes through the gateways exhibit a more complex pattern, with models exhibiting a change in sign of the freshwater flux through the Barents Sea Opening and little change in the flux through the Bering Strait in addition to increased export from the remaining straits by the end of the 21st century. A decomposition of the liquid fluxes into their salinity and volume contributions shows that the Barents Sea flux changes are driven by salinity changes, while the Bering Strait flux changes are driven by compensating salinity and volume changes. In the straits west of Greenland (Nares, Barrow, and Davis straits), the models disagree on whether there will be a decrease, increase, or steady liquid freshwater export in the early to mid 21st century, although they mostly show increased liquid freshwater export in the late 21st century. The underlying cause of this is a difference in the magnitude and timing of a simulated decrease in the volume flux through these straits. Although the models broadly agree on the sign of late 21st century storage and flux changes, substantial differences exist between the magnitude of these changes and the models’ Arctic mean states, which shows no fundamental improvement in the models compared to CMIP5.</p>


Author(s):  
Yuri Yegorov

Arctic region is an important resource for hydrocarbons (oil and gas). Their exploitation is not immediate but will develop fast as soon as oil prices approach $100 per barrel again. In the Arctic, fish stock is an important renewable resource. Contrary to hydrocarbons, it is already overexploited. Future simultaneous exploitation of both resources poses several problems, including externalities and common pool. The academic community still has some time for theoretical investigation of those future problems and working out the corresponding policy measures that are consistent with sustainable development of the region. The Barents Sea is especially important because it has a common pool both in hydrocarbons and fish.


2021 ◽  
pp. 370-398
Author(s):  
A.Yu. Lein ◽  
◽  
M.D. Kravchishina ◽  
G.A. Pavlova ◽  
A.L. Chultsova ◽  
...  

The data (Cl-, SO42-, Ca2+ Alk and biogenic elements) on the salt composition of pore water and the isotopic organic carbon composition of suspended particulate matter, fluffy layer and surface layers (0–30 cm) of bottom sediments in the Barents and Norwegian seas are discussed during the period of the supposed maximum warming in the Arctic region in the 21st century associated with the “atlantification” of the Arctic Ocean.


2010 ◽  
Vol 6 (5) ◽  
pp. 609-626 ◽  
Author(s):  
Q. Zhang ◽  
H. S. Sundqvist ◽  
A. Moberg ◽  
H. Körnich ◽  
J. Nilsson ◽  
...  

Abstract. The climate response over northern high latitudes to the mid-Holocene orbital forcing has been investigated in three types of PMIP (Paleoclimate Modelling Intercomparison Project) simulations with different complexity of the modelled climate system. By first undertaking model-data comparison, an objective selection method has been applied to evaluate the capability of the climate models to reproduce the spatial response pattern seen in proxy data. The possible feedback mechanisms behind the climate response have been explored based on the selected model simulations. Subsequent model-model comparisons indicate the importance of including the different physical feedbacks in the climate models. The comparisons between the proxy-based reconstructions and the best fit selected simulations show that over the northern high latitudes, summer temperature change follows closely the insolation change and shows a common feature with strong warming over land and relatively weak warming over ocean at 6 ka compared to 0 ka. Furthermore, the sea-ice-albedo positive feedback enhances this response. The reconstructions of temperature show a stronger response to enhanced insolation in the annual mean temperature than winter and summer temperature. This is verified in the model simulations and the behaviour is attributed to the larger contribution from the large response in autumn. Despite a smaller insolation during winter at 6 ka, a pronounced warming centre is found over Barents Sea in winter in the simulations, which is also supported by the nearby northern Eurasian continental and Fennoscandian reconstructions. This indicates that in the Arctic region, the response of the ocean and the sea ice to the enhanced summer insolation is more important for the winter temperature than the synchronous decrease of the insolation.


2019 ◽  
Vol 10 (1) ◽  
pp. 121-133 ◽  
Author(s):  
Luis Gimeno-Sotelo ◽  
Raquel Nieto ◽  
Marta Vázquez ◽  
Luis Gimeno

Abstract. By considering the moisture transport for precipitation (MTP) for a target region to be the moisture that arrives in this region from its major moisture sources and which then results in precipitation in that region, we explore (i) whether the MTP from the main moisture sources for the Arctic region is linked with inter-annual fluctuations in the extent of Arctic sea ice superimposed on its decline and (ii) the role of extreme MTP events in the inter-daily change in the Arctic sea ice extent (SIE) when extreme MTP simultaneously arrives from the four main moisture regions that supply it. The results suggest (1) that ice melting at the scale of inter-annual fluctuations against the trend is favoured by an increase in moisture transport in summer, autumn, and winter and a decrease in spring and, (2) on a daily basis, extreme humidity transport increases the formation of ice in winter and decreases it in spring, summer, and autumn; in these three seasons extreme humidity transport therefore contributes to Arctic sea ice melting. These patterns differ sharply from that linked to the decline on a long-range scale, especially in summer when the opposite trend applies, as ice melt is favoured by a decrease in moisture transport for this season at this scale.


2018 ◽  
Vol 9 (2) ◽  
pp. 611-625 ◽  
Author(s):  
Luis Gimeno-Sotelo ◽  
Raquel Nieto ◽  
Marta Vázquez ◽  
Luis Gimeno

Abstract. In this study we use the term moisture transport for precipitation for a target region as the moisture coming to this region from its major moisture sources resulting in precipitation over the target region (MTP). We have identified changes in the pattern of moisture transport for precipitation over the Arctic region, the Arctic Ocean, and its 13 main subdomains concurrent with the major sea ice decline that occurred in 2003. The pattern consists of a general decrease in moisture transport in summer and enhanced moisture transport in autumn and early winter, with different contributions depending on the moisture source and ocean subregion. The pattern is statistically significant and consistent with changes in the vertically integrated moisture fluxes and frequency of circulation types. The results of this paper also reveal that the assumed and partially documented enhanced poleward moisture transport from lower latitudes as a consequence of increased moisture from climate change seems to be less simple and constant than typically recognised in relation to enhanced Arctic precipitation throughout the year in the present climate.


2020 ◽  
Author(s):  
Richard Bintanja ◽  
Karin van der Wiel ◽  
Eveline van der Linden ◽  
Jesse Reusen ◽  
Linda Bogerd ◽  
...  

<p>The Arctic region is projected to experience amplified warming as well as strongly increasing precipitation rates. Equally important to trends in the mean climate are changes in interannual variability, but changes in precipitation fluctuations are highly uncertain and the associated processes unknown. Here we use various state-of-the-art global climate model simulations to show that interannual variability of Arctic precipitation will likely increase markedly (up to 40% over the 21<sup>st</sup> century), especially in summer. This can be attributed to increased poleward atmospheric moisture transport variability associated with enhanced moisture content, possibly modulated by atmospheric dynamics. Because both the means and variability of Arctic precipitation will increase, years/seasons with excessive precipitation will occur more often, as will the associated impacts.</p>


2021 ◽  
Vol 288 (1948) ◽  
Author(s):  
André Frainer ◽  
Raul Primicerio ◽  
Andrey Dolgov ◽  
Maria Fossheim ◽  
Edda Johannesen ◽  
...  

As temperatures rise, motile species start to redistribute to more suitable areas, potentially affecting the persistence of several resident species and altering biodiversity and ecosystem functions. In the Barents Sea, a hotspot for global warming, marine fish from boreal regions have been increasingly found in the more exclusive Arctic region. Here, we show that this shift in species distribution is increasing species richness and evenness, and even more so, the functional diversity of the Arctic. Higher diversity is often interpreted as being positive for ecosystem health and is a target for conservation. However, the increasing trend observed here may be transitory as the traits involved threaten Arctic species via predation and competition. If the pressure from global warming continues to rise, the ensuing loss of Arctic species will result in a reduction in functional diversity.


2021 ◽  
Author(s):  
Lukas Papritz ◽  
David Hauswirth ◽  
Katharina Hartmuth

Abstract. Poleward moisture transport occurs in episodic, high-amplitude events with strong impacts on the Arctic and its climate system components such as sea ice. This study focuses on the origin of such events and examines the moisture sources, moisture transport pathways, and their linkage to the large-scale circulation. For that purpose, 597 events of intense zonal mean poleward moisture transport at 70° N (exceeding the 90th anomaly percentile) are identified and kinematic backward trajectories from 70° N are computed to pinpoint the moisture sources and characterize the air-streams accomplishing the transport. The bulk of the moisture transported into the polar cap during these events originates in the eastern North Atlantic with an uptake maximum poleward of 50° N. This asymmetry between ocean basins is a direct consequence of the fact that most of the moisture transport into the polar cap occurs in this sector. As a result of the fairly high-latitude origin of the moisture, the median time moisture spends in the atmosphere prior to reaching 70° N amounts to about 2.5 days. Trajectories further reveal an inverse relationship between moisture uptake latitude and the level at which moisture is injected into the polar cap, consistent with ascent of poleward flowing air in a baroclinic atmosphere. Focusing on events for which 75 % of the zonal mean moisture transport takes place in the North Atlantic east of Greenland (424 events) reveals that lower tropospheric moisture transport results predominantly from two types of air-streams: (i) cold, polar air advected from the Canadian Arctic over the North Atlantic and around Greenland, whereby the air is warmed and moistened by surface fluxes, and (ii) air subsiding from the mid-troposphere into the boundary layer. Both air-streams contribute about 36 % each to the total transport. The former dominates the moisture transport during events associated with an anomalously high frequency of cyclones east of Greenland (218 events), whereas the latter is more important in the presence of atmospheric blocking over Scandinavia and the Ural (145 events). A substantial portion of the moisture sources associated with both types of air-streams are located between Iceland, the British Isles, and Norway. Long-range moisture transport, accounting for 17 % of the total transport, is the dominant type of air-stream during events with weak forcing by baroclinic weather systems (64 events). Finally, mid-tropospheric moisture transport is invariably associated with (diabatically) ascending air and moisture origin in the central and western North Atlantic, including the Gulf Stream front, accounting for roughly 10 % of the total transport. In summary, our study reveals that moisture injections into the polar atmosphere are not primarily caused by the poleward transport of warm and humid air from low latitudes – a conclusion that applies in particular to cases where the transport is driven by baroclinic weather systems such as extratropical cyclones. Instead, it results from a combination of air-streams with pre-dominantly high-latitude or high-altitude origin and their interplay with large-scale weather systems (e.g., cyclones, blocks).


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