scholarly journals Decadal changes of wintertime poleward heat and moisture transport associated with the amplified Arctic warming

2021 ◽  
Author(s):  
Xiaozhuo Sang ◽  
Xiu-Qun Yang ◽  
Lingfeng Tao ◽  
Jiabei Fang ◽  
Xuguang Sun
Keyword(s):  
Heat Transport ◽  
Moisture Transport ◽  
Stationary Wave ◽  
The Arctic ◽  
Stationary Waves ◽  
High Latitudes ◽  
Arctic Warming ◽  
Poleward Heat Transport ◽  
Heat And Moisture ◽  
Moisture Transports

Abstract The Arctic warming, especially during winter, has been almost twice as large as the global average since the late 1990s, which is known as the Arctic amplification. Yet linkage between the amplified Arctic warming and the midlatitude change is still under debate. This study examines the decadal changes of wintertime poleward heat and moisture transports between two 18-yr epochs (1999–2016 and 1981–1998) with five atmospheric reanalyses. It is found that the wintertime Arctic warming induces an amplification of the high latitude stationary wave component of zonal wavenumber one but a weakening of the wavenumber two. These stationary wave changes enhance poleward heat and moisture transports, which are conducive to further Arctic warming and moistening, acting as a positive feedback onto the Arctic warming. Meanwhile, the Arctic warming reduces atmospheric baroclinicity and thus weakens synoptic eddy activities in the high latitudes. The decreased transient eddy activities reduce poleward heat and moisture transports, which decrease the Arctic temperature and moisture, acting as a negative feedback onto the Arctic warming. The total poleward heat transport contributes little to the Arctic warming, since the increased poleward heat transport by stationary waves is nearly canceled by the decreased transport by transient eddies. However, the total poleward moisture transport increases over most areas of the high latitudes that is dominated by the increased transport by stationary waves, which provides a significant net positive feedback onto the Arctic warming and moistening. Such a poleward moisture transport feedback may be particularly crucial to the amplified Arctic warming during winter when the ice-albedo feedback vanishes.

A multimodel investigation of atmospheric mechanisms for driving Arctic amplification in warmer climates

2021 ◽  
pp. 1-55
Author(s):  
Deepashree Dutta ◽  
Steven C. Sherwood ◽  
Katrin J. Meissner ◽  
Alex Sen Gupta ◽  
Daniel J. Lunt ◽  
...  
Keyword(s):  
Heat Transport ◽  
General Circulation ◽  
Energy Transport ◽  
Longwave Radiation ◽  
General Circulation Models ◽  
The Arctic ◽  
Arctic Warming ◽  
Surface Warming ◽  
Poleward Heat Transport ◽  
Warm Climates

AbstractWhen simulating past warm climates, such as the early Cretaceous and Paleogene periods, general circulation models (GCMs) underestimate the magnitude of warming in the Arctic. Additionally, model intercomparisons show a large spread in the magnitude of Arctic warming for these warmer-than-modern climates. Several mechanisms have been proposed to explain these disagreements, including the unrealistic representation of polar clouds or underestimated poleward heat transport in the models. This study provides an intercomparison of Arctic cloud and atmospheric heat transport (AHT) responses to strong imposed polar-amplified surface ocean warming across four atmosphere-only GCMs. All models simulate an increase in high clouds throughout the year; the resulting reduction in longwave radiation loss to space acts to support the imposed Arctic warming. The response of low and mid-level clouds varies considerably across the models, with models responding differently to surface warming and sea ice removal. The AHT is consistently weaker in the imposed warming experiments due to a large reduction in dry static energy transport that offsets a smaller increase in latent heat transport, thereby opposing the imposed surface warming. Our idealised polar amplification experiments require very large increases in implied ocean heat transport (OHT) to maintain steady state. Increased CO2 or tropical temperatures that likely characterised past warm climates, reduces the need for such large OHT increases.

scholarly journals Impact of atmospheric heat and moisture transport on the Arctic warming

2019 ◽  
Vol 39 (8) ◽  
pp. 3582-3592 ◽  
Author(s):  
Genrikh Alekseev ◽  
Svetlana Kuzmina ◽  
Leonid Bobylev ◽  
Alexandra Urazgildeeva ◽  
Natalia Gnatiuk
Keyword(s):  
Moisture Transport ◽  
The Arctic ◽  
Arctic Warming ◽  
Heat And Moisture Transport ◽  
Atmospheric Heat ◽  
Heat And Moisture

Poleward Stationary Eddy Heat Transport by the Tibetan Plateau and Equatorward Shift of Westerlies during Northern Winter*

2013 ◽  
Vol 70 (10) ◽  
pp. 3288-3301 ◽  
Author(s):  
Hyo-Seok Park ◽  
Shang-Ping Xie ◽  
Seok-Woo Son
Keyword(s):  
Tibetan Plateau ◽  
Heat Transport ◽  
General Circulation ◽  
Hot Spot ◽  
Circulation Model ◽  
The Tibetan Plateau ◽  
Stationary Waves ◽  
Transient Eddy ◽  
Poleward Heat Transport ◽  
Eddy Heat Transport

Abstract The orographic effect of the Tibetan Plateau on atmospheric poleward heat transport is investigated using an atmospheric general circulation model. The linear interference between the Tibetan Plateau–induced winds and the eddy temperature field associated with the land–sea thermal contrast is a key factor for enhancing the poleward stationary eddy heat transport. Specifically, Tibetan Plateau–induced stationary waves produce northerlies over the cold eastern Eurasian continent, leading to a poleward heat transport. In another hot spot of stationary eddy heat transport over the eastern North Pacific, Tibetan Plateau–induced stationary waves transport relatively warm marine air northward. In an experiment where the Tibetan Plateau is removed, the poleward heat transport is mostly accomplished by transient eddies, similar to the Southern Hemisphere. In the presence of the Tibetan Plateau, the enhanced stationary eddy heat transport is offset by a comparable reduction in transient eddy heat transport. This compensation between stationary and transient eddy heat transport is seen in observed interannual variability. Both the model and observations indicate that an enhanced poleward heat transport by stationary waves weakens transient eddies by decreasing the meridional temperature gradient and the associated westerlies in midlatitudes.

Arctic warming revealed by multiple CMIP6 models: evaluation of historical simulations and quantification of future projection uncertainties

2021 ◽  
pp. 1-52
Author(s):  
Ziyi Cai ◽  
Qinglong You ◽  
Fangying Wu ◽  
Hans W. Chen ◽  
Deliang Chen ◽  
...  
Keyword(s):  
Barents Sea ◽  
Coupled Model ◽  
Internal Variability ◽  
The Arctic ◽  
Future Research ◽  
Total Uncertainty ◽  
Near Surface ◽  
Arctic Warming ◽  
Poleward Heat Transport ◽  
Warming Rate

AbstractThe Arctic has experienced a warming rate higher than the global mean in the past decades, but previous studies show that there are large uncertainties associated with future Arctic temperature projections. In this study, near-surface mean temperatures in the Arctic are analyzed from 22 models participating in the Coupled Model Intercomparison Project phase 6 (CMIP6). Compared with the ERA5 reanalysis, most CMIP6 models underestimate the observed mean temperature in the Arctic during 1979–2014. The largest cold biases are found over the Norwegian Sea, the Barents Sea, and the Kara Sea. Under the SSP1-2.6, SSP2-4.5 and SSP5-8.5 scenarios, the multi-model ensemble mean of 22 CMIP6 models exhibits significant Arctic warming in the future and the warming rate is more than twice higher than rates in the global/Northern Hemisphere. Model uncertainty is the largest contributor to the overall uncertainty in projections, which accounts for 55.4% of the total uncertainty at the start of projections in 2015 and remains at 32.9% at the end of projections in 2095. Internal variability uncertainty accounts for 39.3% of the total uncertainty at the start of projections but decreases to 6.5% at the end of the 21st century, while scenario uncertainty rapidly increases from 5.3% to 60.7% over the period from 2015-2095. It is found that the largest model uncertainties are consistent with the oceanic regions with cold biases in the models, which is connected with excessive sea ice area caused by the weak Atlantic poleward heat transport. These results suggest that the CMIP6 models’ simulation and projection of the Arctic near-surface temperature still exist large inter-model spread and uncertainties, and there are different behaviors over the ocean and land in the Arctic. Future research needs to pay more attention to the different characteristics and mechanisms of Arctic Ocean and land warming to reduce the spread.

Antarctic Peninsula warming and precipitation phase transition during atmospheric river events

2021 ◽  
Author(s):  
Irina Gorodetskaya ◽  
Penny Rowe ◽  
Xun Zou ◽  
Anastasia Chyhareva ◽  
Svitlana Krakovska ◽  
...  
Keyword(s):  
Phase Transition ◽  
Antarctic Peninsula ◽  
Moisture Transport ◽  
Large Scale ◽  
The Arctic ◽  
Polar Regions ◽  
Near Surface ◽  
Depth Analysis ◽  
Heat And Moisture ◽  
Precipitation Phase

<p><span lang="en-US">Polar amplification has been pronounced in the Arctic with near-surface air temperatures increasing at more than twice the global warming rate d</span>uring the last several decades<span lang="en-US">. At the same time, over Antarctica temperature trends have exhibited a large regional variability. In particular, the </span>Antarctic Peninsula (AP) <span lang="en-US">stands out as having a </span>warming<span lang="en-US"> rate much higher than</span> the rest of the Antarctic ice sheet and other land areas in the Southern Hemisphere (SH)<span lang="en-US">.</span> <span lang="en-US">F</span>uture projections indicate that <span lang="en-US">warming and ice loss will intensify in both polar regions with important impacts</span> globally. In addition to the warming amplification, there has been also an enhancement of the polar water cycle with increase<span lang="en-US">s</span> <span lang="en-US">in </span>poleward moisture transport and precipitation in both polar regions. An important process linking warming and precipitation enhancement is a shift towards more frequent rainfall compared to snowfall<span lang="en-US">. F</span>uture projections show that the rain fraction will significantly increase in coastal Antarctica, especially in the AP. Atmospheric rivers (ARs), long corridors of intense moisture transport from subtropical and mid-latitude regions poleward, are known for <span lang="en-US">their </span>prominent role in <span lang="en-US">both </span>heat and moisture transport with impacts ranging from intense precipitation to temperature records and major melt events in Antarctica.<span lang="en-US"> Limited observations have hampered process understanding and correct representation of these extreme events in models.</span> <span lang="en-US">This presentation will give an overview of the </span>enhanced observations targeting ARs in the A<span lang="en-US">P</span> (<span lang="en-US">including </span>surface meteorology, radiosonde, cloud and precipitation remote sensing, <span lang="en-US">and </span>radiative fluxes) as part of the <span lang="en-US">Year of Polar Prediction (</span>YOPP<span lang="en-US">)</span>-SH international collaborative effort<span lang="en-US">. </span>In-depth analysis of transport of heat and moisture, <span lang="en-US">atmospheric vertical structure, </span>cloud properties<span lang="en-US"> and precipitation phase transition from snowfall to rainfall </span>during selected <span lang="en-US">AR </span>case<span lang="en-US">s</span> will be<span lang="en-US"> presented and compared with ERA5 reanalysis and high-resolution Polar-WRF model simulations</span>.<span lang="en-US"> We will highlight three different local regimes around the AP: large-scale precipitation over the Southern Ocean north of the AP, orographic enhancement of precipitation in the western AP and the role of foehn, cloud/precipitation clearing and temperature increase in the northeastern AP. </span></p>

Relative Contributions of Atmospheric Energy Transport and Sea Ice Loss to the Recent Warm Arctic Winter

2017 ◽  
Vol 30 (18) ◽  
pp. 7441-7450 ◽  
Author(s):  
Hye-Mi Kim ◽  
Baek-Min Kim
Keyword(s):  
Sea Ice ◽  
Energy Transport ◽  
Open Water ◽  
The Arctic ◽  
Arctic Warming ◽  
Atmospheric Energy ◽  
Downward Longwave Radiation ◽  
Ice Retreat ◽  
Atmospheric Energy Transport ◽  
Heat And Moisture

Abstract The relative contributions of atmospheric energy transport (via heat and moisture advection) and sea ice decline to recent Arctic warming were investigated using high-resolution reanalysis data up to 2017. During the Arctic winter, a variation of downward longwave radiation (DLR) is fundamental in modulating Arctic surface temperature. In the warm Arctic winter, DLR and precipitable water (PW) are increasing over the entire Arctic; however, the major drivers for such increases differ regionally. In areas such as the northern Greenland Sea, increasing DLR and PW are caused mainly by convergence of atmospheric energy transport from lower latitudes. In regions of maximum sea ice retreat (e.g., northern Barents–Kara Seas), continued sea ice melting from previous seasons drive the DLR and PW increases, consistent with the positive ice–insulation feedback. Distinct local feedbacks between open water and ice-retreat regions were further compared. In open water regions, a reduced ocean–atmosphere temperature gradient caused by atmospheric warming suppresses surface turbulent heat flux (THF) release from the ocean to the atmosphere; thus, surface warming cannot accelerate. Conversely, in ice-retreat regions, sea ice reduction allows the relatively warm ocean to interact with the colder atmosphere via surface THF release. This increases temperature and humidity in the lower troposphere consistent with the positive ice–insulation feedback. The implication of this study is that Arctic warming will slow as the open water fraction increases. Therefore, given sustained greenhouse warming, the roles of atmospheric heat and moisture transport from lower latitudes are likely to become increasingly critical in the future Arctic climate.

scholarly journals An Identification of the Mechanisms that Lead to Arctic Warming During Planetary-Scale and Synoptic-Scale Wave Life Cycles

2017 ◽  
Vol 74 (6) ◽  
pp. 1859-1877 ◽  
Author(s):  
Cory Baggett ◽  
Sukyoung Lee
Keyword(s):  
Life Cycle ◽  
Life Cycles ◽  
Tropical Convection ◽  
The Arctic ◽  
Stationary Waves ◽  
Composite Analysis ◽  
Synoptic Scale ◽  
Arctic Warming ◽  
Planetary Scale ◽  
The Western Pacific

Abstract The dynamical mechanisms that lead to wintertime Arctic warming during the planetary-scale wave (PSW) and synoptic-scale wave (SSW) life cycles are identified by performing a composite analysis of ERA-Interim data. The PSW life cycle is preceded by localized tropical convection over the western Pacific. Upon reaching the midlatitudes, the PSWs amplify as they undergo baroclinic conversion and constructively interfere with the climatological stationary waves. The PSWs flux large quantities of sensible and latent heat into the Arctic, which produces a regionally enhanced greenhouse effect that increases downward IR and warms the Arctic 2-m temperature. The SSW life cycle is also capable of increasing downward IR and warming the Arctic 2-m temperature, but the greatest warming is accomplished in the subset of SSW events with the most amplified PSWs. Consequently, during both the PSW and SSW life cycles, wintertime Arctic warming arises from the amplification of the PSWs.

scholarly journals Influence of the atmospheric heat and moisture transport on summer warming in the Аrctic

2017 ◽  
pp. 67-77
Author(s):  
G. V. Alekseev ◽  
S. I. Kuzmina ◽  
L. P. Bobilev ◽  
A. V. Urazgildeeva ◽  
N. V. Gnatuk
Keyword(s):  
Moisture Transport ◽  
Atmospheric Transport ◽  
The Arctic ◽  
Wave Radiation ◽  
Annual Data ◽  
Summer Warming ◽  
Heat And Moisture Transport ◽  
Atmospheric Heat ◽  
Heat And Moisture

There are different points of view on the role of the atmospheric heat and moisture transport in increasing summer warming in the Arctic, which are often based on the analysis of average annual data. In this paper, the analysis of summer atmospheric transport, their influence on air temperature and water vapor content in the atmosphere, trends in multi-year transport changes are fulfilled. It is noted the important role of moisture inflows from the Arctic Ocean in the summer season and their influence on the growth of long-wave radiation and amplification of sea ice shrinking.

scholarly journals Source attribution of Arctic aerosols and associated Arctic warming trend during 1980–2018

2020 ◽  
Author(s):  
Lili Ren ◽  
Yang Yang ◽  
Hailong Wang ◽  
Rudong Zhang ◽  
Pinya Wang ◽  
...  
Keyword(s):  
Radiative Forcing ◽  
Climate Model ◽  
Warming Trend ◽  
The Arctic ◽  
Source Attribution ◽  
Surface Temperature Change ◽  
Arctic Warming ◽  
Surface Warming ◽  
Poleward Heat Transport ◽  
Arctic Surface

Abstract. Observations show that the concentrations of Arctic sulfate and black carbon (BC) aerosols have declined since the early 1980s, which potentially contributed to the recent rapid Arctic warming. In this study, a global aerosol-climate model equipped with an Explicit Aerosol Source Tagging (CAM5-EAST) is applied to quantify the source apportionment of aerosols in the Arctic from sixteen source regions and the role of aerosol variations in the Arctic surface temperature change over the past four decades (1980–2018). The CAM5-EAST simulated surface concentrations of sulfate and BC in the Arctic had a decrease of 43 % and 23 %, respectively, in 2014–2018 relative to 1980–1984, mainly due to the reduction of emissions from Europe, Russia and Arctic local sources. Increases in emissions from South and East Asia led to positive trends of Arctic sulfate and BC in the upper troposphere. Changes in radiative forcing of sulfate and BC through aerosol-radiation interactions are found to exert a +0.145 K Arctic surface warming during 2014–2018 with respect to 1980–1984, with the largest contribution (61 %) by sulfate decrease, especially originating from the mid-latitude regions. The changes in atmospheric BC outside the Arctic produced an Arctic warming of +0.062 K, partially offset by −0.005 K of cooling due to atmospheric BC within the Arctic and −0.041 K related to the weakened snow/ice albedo effect of BC. Through aerosol-cloud interactions, the sulfate reduction gave an Arctic warming of +0.193 K between the first and last five years of 1980–2018, the majority of which is due to the mid-latitude emission change. Our results suggest that changes in aerosols over the mid-latitudes of the Northern Hemisphere have a larger impact on Arctic temperature than other regions associated with enhanced poleward heat transport from the aerosol-induced stronger meridional temperature gradient. The combined aerosol effects of sulfate and BC together produce an Arctic surface warming of +0.297 K during 1980–2018, explaining approximately 20 % of the observed Arctic warming during the same time period.

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