Net air–sea surface heat flux during 1984–2004 over the North Pacific and North Atlantic oceans (10°N–50°N): annual mean climatology and trend

2010 ◽  
Vol 104 (3-4) ◽  
pp. 387-401 ◽  
Author(s):  
Gen Li ◽  
Baohua Ren ◽  
Jianqiu Zheng ◽  
Chengyun Yang
Keyword(s):  
Heat Flux ◽  
North Atlantic ◽  
North Pacific ◽  
Surface Heat Flux ◽  
Surface Heat ◽  
Sea Surface ◽  
The North ◽  
The North Pacific

Global Pattern Formation of Net Ocean Surface Heat Flux Response to Greenhouse Warming

2020 ◽  
Vol 33 (17) ◽  
pp. 7503-7522 ◽  
Author(s):  
Shineng Hu ◽  
Shang-Ping Xie ◽  
Wei Liu
Keyword(s):  
Heat Flux ◽  
North Atlantic ◽  
Surface Heat Flux ◽  
Surface Heat ◽  
Greenhouse Warming ◽  
Global Pattern ◽  
Passive Advection ◽  
The North ◽  
The North Atlantic ◽  
Circulation Changes

AbstractThis study examines global patterns of net ocean surface heat flux changes (ΔQnet) under greenhouse warming in an ocean–atmosphere coupled model based on a heat budget decomposition. The regional structure of ΔQnet is primarily shaped by ocean heat divergence changes (ΔOHD): excessive heat is absorbed by higher-latitude oceans (mainly over the North Atlantic and the Southern Ocean), transported equatorward, and stored in lower-latitude oceans with the rest being released to the tropical atmosphere. The overall global pattern of ΔOHD is primarily due to the circulation change and partially compensated by the passive advection effect, except for the Southern Ocean, which requires further investigations for a more definitive attribution. The mechanisms of North Atlantic surface heat uptake are further explored. In another set of global warming simulations, a perturbation of freshwater removal is imposed over the subpolar North Atlantic to largely offset the CO2-induced changes in the local ocean vertical stratification, barotropic gyre, and the Atlantic meridional overturning circulation (AMOC). Results from the freshwater perturbation experiments suggest that a significant portion of the positive ΔQnet over the North Atlantic under greenhouse warming is caused by the Atlantic circulation changes, perhaps mainly by the slowdown of AMOC, while the passive advection effect can contribute to the regional variations of ΔQnet. Our results imply that ocean circulation changes are critical for shaping global warming pattern and thus hydrological cycle changes.

scholarly journals Impacts of Sea Surface Temperature and Atmospheric Teleconnection Patterns in the Northern Mid-Latitudes on Winter Extremely Cold Events in North China

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Liping Li ◽  
Wenjie Ni ◽  
Yige Li ◽  
Dong Guo ◽  
Hui Gao
Keyword(s):  
North Atlantic ◽  
North Pacific ◽  
North China ◽  
Wave Train ◽  
Sea Surface ◽  
Atmospheric Teleconnection ◽  
Teleconnection Patterns ◽  
The North ◽  
Cold Events ◽  
The North Pacific

The frequency distribution of winter extreme cold events (ECEs) in North China and the influences of mid-latitude sea surface temperature anomalies (SSTAs) in the Northern Hemisphere are studied. The results show that (1) the frequency of single station ECEs (SSECEs) in winter increases from southeast to northwest, with a decrease before 2008 and then a significant increase. This trend abrupt change occurs in late winter. (2) When the SST in the North Pacific shows an “El-Niño-like” anomaly in winter, it triggers the negative Arctic Oscillation (−AO), positive Pacific North America (+PNA), and positive Eurasia Pacific (+EUP) atmospheric teleconnection patterns in the mid-lower troposphere. As a result, the ridge to south of Lake Baikal becomes stronger. Meanwhile, SST in the North Atlantic shows a “reversed C” negative anomaly with North Atlantic Oscillation (+NAO), (+PNA)-like and (+EUP)-like patterns, and the ridge to southwest of Lake Baikal becomes stronger. Furthermore, both cause the Siberian High to become weaker in the north and stronger in the south. With the weaker East Asia subtropical jet and stronger East Asia winter monsoon, these factors lead to a significant increase of SSECE frequency in North China. (3) When the SSTA shows an “El Niño-like” developing pattern from summer to autumn in the North Pacific, the winter SSECE frequency will be higher. (4) The purported mechanism between the mid-latitude SSTA and the winter SSECE frequency in North China is the following: the SSTA in the North Pacific in summer and autumn excites atmospheric teleconnection wave trains, and the Atlantic stores these anomaly signals. In winter, the interaction between the SSTAs in the North Pacific and the North Atlantic enhances the Eurasian teleconnection wave train. With the upstream fluctuation energy dispersing downstream, the wave train centers move eastward with the season, resulting in an increase in the frequency of the SSECEs.

scholarly journals Extratropical cyclone induced sea surface temperature anomalies in the 2013/14 winter

2019 ◽  
Author(s):  
Helen F. Dacre ◽  
Simon A. Josey ◽  
Alan L. M. Grant
Keyword(s):  
Heat Flux ◽  
North Atlantic ◽  
Surface Heat Flux ◽  
Cold Front ◽  
Winter Season ◽  
Surface Heat ◽  
Heat Fluxes ◽  
Sea Surface ◽  
Extratropical Cyclones ◽  
Sst Cooling

Abstract. The 2013/14 winter averaged sea surface temperature (SST) was anomalously cool in the mid-North Atlantic region. This season was also unusually stormy with extratropical cyclones passing over the mid-North Atlantic every 3 days. However, the processes by which cyclones contribute towards seasonal SST anomalies are not fully understood. In this paper a cyclone identification and tracking method is combined with ECMWF atmosphere and ocean reanalysis fields to calculate cyclone-relative net surface heat flux anomalies and resulting SST changes. Anomalously large negative heat fluxes are located behind the cyclones cold front resulting in anomalous cooling up to 0.2 K/day when the cyclones are at maximum intensity. This extratropical cyclone induced cold wake extends along the cyclones cold front but is small compared to climatological variability. To investigate the potential cumulative effect of the passage of multiple cyclone induced SST cooling in the same location we calculate Earth-relative net surface heat flux anomalies and resulting SST changes for the 2013/2014 winter period. Anomalously large winter averaged negative heat fluxes occur in a zonally orientated band extending across the North Atlantic between 40–60° N. The anomaly associated with cyclones is estimated using a cyclone masking technique which encompasses each cyclone centre and its trailing cold front. North Atlantic extratropical cyclones in the 2013/14 winter season account for 78 % of the observed net surface heat flux in the mid- North Atlantic and net surface heat fluxes in the 2013/14 winter season account for 70 % of the observed cooling in the mid-North Atlantic. Thus extratropical cyclones play a major role in determining the extreme 2013/2014 winter season SST cooling.

scholarly journals A Hemispheric Mechanism for the Atlantic Multidecadal Oscillation

2007 ◽  
Vol 20 (11) ◽  
pp. 2706-2719 ◽  
Author(s):  
Mihai Dima ◽  
Gerrit Lohmann
Keyword(s):  
Sea Ice ◽  
North Atlantic ◽  
North Pacific ◽  
Thermohaline Circulation ◽  
Atlantic Multidecadal Oscillation ◽  
Sea Surface ◽  
The North ◽  
Sea Surface Temperature Anomalies ◽  
The North Atlantic ◽  
The North Pacific

Abstract The physical processes associated with the ∼70-yr period climate mode, known as the Atlantic multidecadal oscillation (AMO), are examined. Based on analyses of observational data, a deterministic mechanism relying on atmosphere–ocean–sea ice interactions is proposed for the AMO. Variations in the thermohaline circulation are reflected as uniform sea surface temperature anomalies in the North Atlantic. These anomalies are associated with a hemispheric wavenumber-1 sea level pressure (SLP) structure in the atmosphere that is amplified through atmosphere–ocean interactions in the North Pacific. The SLP pattern and its associated wind field affect the sea ice export through Fram Strait, the freshwater balance in the northern North Atlantic, and consequently the strength of the large-scale ocean circulation. It generates sea surface temperature anomalies with opposite signs in the North Atlantic and completes a negative feedback. The authors find that the time scale of the cycle is associated with the thermohaline circulation adjustment to freshwater forcing, the SST response to it, the oceanic adjustment in the North Pacific, and the sea ice response to the wind forcing. Finally, it is argued that the Great Salinity Anomaly in the late 1960s and 1970s is part of AMO.

scholarly journals Extratropical-cyclone-induced sea surface temperature anomalies in the 2013–2014 winter

2020 ◽  
Vol 1 (1) ◽  
pp. 27-44 ◽  
Author(s):  
Helen F. Dacre ◽  
Simon A. Josey ◽  
Alan L. M. Grant
Keyword(s):  
Heat Flux ◽  
North Atlantic ◽  
Cold Front ◽  
Environmental Flow ◽  
Surface Heat ◽  
Sea Surface ◽  
The North ◽  
Sst Cooling ◽  
The North Atlantic ◽  
Anomalous Heat

Abstract. The 2013–2014 winter averaged sea surface temperature (SST) was anomalously cool in the mid-North Atlantic region. This season was also unusually stormy, with extratropical cyclones passing over the mid-North Atlantic every 3 d. However, the processes by which cyclones contribute towards seasonal SST anomalies are not fully quantified. In this paper a cyclone identification and tracking method is combined with European Centre for Medium-Range Weather Forecasts (ECMWF) atmosphere and ocean reanalysis fields to calculate cyclone-relative net surface heat flux anomalies and resulting SST changes. Anomalously large negative heat flux is located behind the cyclones' cold front, resulting in anomalous cooling up to 0.2 K d−1 when the cyclones are at maximum intensity. This extratropical-cyclone-induced “cold wake” extends along the cyclones' cold front but is small compared to climatological variability in the SSTs. To investigate the potential cumulative effect of the passage of multiple cyclone-induced SST cooling in the same location, we calculate Earth-relative net surface heat flux anomalies and resulting SST changes for the 2013–2014 winter period. Anomalously large winter averaged negative heat flux occurs in a zonally orientated band extending across the North Atlantic between 40 and 60∘ N. The 2013–2014 winter SST cooling anomaly associated with air–sea interactions (ASIs; anomalous heat flux, mixed layer depth and entrainment at the base of the ocean mixed layer) is estimated to be −0.67 K in the mid-North Atlantic (68 % of the total cooling anomaly). The role of cyclones is estimated using a cyclone-masking technique which encompasses each cyclone centre and its cold wake. The environmental flow anomaly in 2013–2014 sets the overall tripole pattern of heat flux anomalies over the North Atlantic. However, the presence of cyclones doubles the magnitude of the negative heat flux anomaly in the mid-North Atlantic. Similarly, the environmental flow anomaly determines the location of the SST cooling anomaly, but the presence of cyclones enhances the SST cooling anomaly. Thus air–sea interactions play a major part in determining the extreme 2013–2014 winter season SST cooling anomaly. The environmental flow anomaly determines where anomalous heat flux and associated SST changes occur, and the presence of cyclones influences the magnitude of those anomalies.

scholarly journals Extratropical cyclone induced sea surface temperature anomalies in the 2013/14 winter

2020 ◽  
Author(s):  
Helen Dacre ◽  
Simon Josey ◽  
Alan Grant
Keyword(s):  
Heat Flux ◽  
North Atlantic ◽  
Cold Front ◽  
Environmental Flow ◽  
Surface Heat ◽  
Sea Surface ◽  
The North ◽  
Sst Cooling ◽  
The North Atlantic ◽  
Anomalous Heat

<p>The 2013/14 winter averaged sea surface temperature (SST) was anomalously cool in the mid-North Atlantic region.  This season was also unusually stormy with extratropical cyclones passing over the mid-North Atlantic every 3 days.  However, the processes by which cyclones contribute towards seasonal SST anomalies are not fully quantified. In this paper a cyclone identification and tracking method is combined with ECMWF atmosphere and ocean reanalysis fields to calculate cyclone-relative net surface heat flux anomalies and resulting SST changes.  Anomalously large negative heat flux is located behind the cyclones cold front resulting in anomalous cooling up to 0.2K/day when the cyclones are at maximum intensity.  This extratropical cyclone induced 'cold wake' extends along the cyclones cold front but is small compared to climatological variability in the SST's.  To investigate the potential cumulative effect of the passage of multiple cyclone induced SST cooling in the same location we calculate Earth-relative net surface heat flux anomalies and resulting SST changes for the 2013/2014 winter period.  Anomalously large winter averaged negative heat flux occurs in a zonally orientated band extending across the North Atlantic between 40-60 <sup>o</sup>N. The 2013/2014 winter SST cooling anomaly associated with air-sea interactions (anomalous heat flux, mixed layer depth and entrainment at the base of the ocean mixed layer) is estimated to be -0.67 K in the mid-North Atlantic (68% of the total cooling anomaly).  The role of cyclones is estimated using a cyclone masking technique which encompasses each cyclone centre and its trailing cold front. The environmental flow anomaly in 2013/2014 sets the overall tripole pattern of heat flux anomalies over the North Atlantic.  However, the presence of cyclones doubles the magnitude of the negative heat flux anomaly in the mid-North Atlantic.  Similarly, the environmental flow anomaly determines the location of the SST cooling anomaly but the presence of cyclones enhances the SST cooling anomaly.  Thus air-sea interactions play a major part in determining the extreme 2013/2014 winter season SST cooling anomaly. The environmental flow anomaly determines where anomalous heat flux and associated SST changes occur and the presence of cyclones influences the magnitude of those anomalies.</p>

Winter-to-Winter Recurrence of Sea Surface Temperature Anomalies in the Northern Hemisphere

2010 ◽  
Vol 23 (14) ◽  
pp. 3835-3854 ◽  
Author(s):  
Xia Zhao ◽  
Jianping Li
Keyword(s):  
Atmospheric Circulation ◽  
North Atlantic ◽  
North Pacific ◽  
Sea Surface ◽  
The North ◽  
Sea Surface Temperature Anomalies ◽  
Circulation Anomalies ◽  
Atmospheric Circulation Anomalies ◽  
The North Pacific ◽  
Central North Pacific

Abstract The spatiotemporal characteristics of the winter-to-winter recurrence (WWR) of sea surface temperature anomalies (SSTA) in the Northern Hemisphere (NH) are comprehensively studied through lag correlation analysis. On this basis the relationships between the SSTA WWR and the WWR of the atmospheric circulation anomalies, El Niño–Southern Oscillation (ENSO), and SSTA interdecadal variability are also investigated. Results show that the SSTA WWR occurs over most parts of the North Pacific and Atlantic Oceans, but the spatiotemporal distributions of the SSTA WWR are distinctly different in these two oceans. Analyses indicate that the spatiotemporal distribution of the SSTA WWR in the North Atlantic Ocean is consistent with the spatial distribution of the seasonal cycle of its mixed layer depth (MLD), whereas that in the North Pacific Ocean, particularly the recurrence timing, cannot be fully explained by the change in the MLD between winter and summer in some regions. In addition, the atmospheric circulation anomalies also exhibit the WWR at the mid–high latitude of the NH, which is mainly located in eastern Asia, the central North Pacific, and the North Atlantic. The sea level pressure anomalies (SLPA) in the central North Pacific are essential for the occurrence of the SSTA WWR in this region. Moreover, the strongest positive correlation occurs when the SLPA lead SSTA in the central North Pacific by 1 month, which suggests that the atmospheric forcing on the ocean may play a dominant role in this region. Therefore, the “reemergence mechanism” is not the only process influencing the SSTA WWR, and the WWR of the atmospheric circulation anomalies may be one of the causes of the SSTA WWR in the central North Pacific. Finally, the occurrence of the SSTA WWR in the NH is closely related to SSTA interdecadal variability in the NH, but it is linearly independent of ENSO.

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