The Role of Clouds and Surface Heat Fluxes in the Maintenance of the 2013–2016 Northeast Pacific Marine Heatwave

Abstract This study examines the role of surface heat fluxes, particularly in relation to the wind-induced surface heat exchange (WISHE) mechanism, in the rapid intensification (RI) of tropical cyclones (TCs). Sensitivity experiments with capped surface fluxes and thus reduced WISHE exhibit delayed RI and weaker peak intensity, while WISHE could affect the evolutions of TCs both before and after the onset of RI. Before RI, more WISHE leads to faster increase of equivalent potential temperature in the lower levels, resulting in more active and stronger convection. In addition, TCs in experiments with more WISHE reach a certain strength earlier, before the onset of RI. During the RI period, more surface heat fluxes could provide convective instability in the lower levels, and cause a consequent development in the convective activity. More efficient intensification in a TC is found with higher surface heat fluxes and larger inertial stability, leading to a stronger peak intensity, more significant and deeper warm core in TC center, and the axisymmetrization of convection in the higher levels. In both stages, different levels of WISHE alter the thermodynamic environment and convective-scale processes. In all, this study supports the crucial role of WISHE in affecting TC intensification rate for TCs with RI.

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Role of surface heat fluxes underneath cold pools

Geophysical Research Letters ◽

10.1002/2015gl067262 ◽

2016 ◽

Vol 43 (2) ◽

pp. 874-883 ◽

Cited By ~ 30

Author(s):

Pierre Gentine ◽

Alix Garelli ◽

Seung‐Bu Park ◽

Ji Nie ◽

Giuseppe Torri ◽

...

Keyword(s):

Surface Heat ◽

Heat Fluxes ◽

Surface Heat Fluxes ◽

Cold Pools

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Observational Analysis of Extratropical Cyclone Interactions with Northeast Pacific Sea Surface Temperature Anomalies

Journal of Climate ◽

10.1175/jcli-d-19-0853.1 ◽

2020 ◽

Vol 33 (15) ◽

pp. 6745-6763

Author(s):

Briana Phillips ◽

Larry O’Neill

Keyword(s):

Thermal Anomaly ◽

Surface Heat ◽

Heat Fluxes ◽

Sea Surface ◽

Storm Events ◽

Storm Activity ◽

Surface Heat Fluxes ◽

Northeast Pacific ◽

Early Fall ◽

Sst Anomaly

AbstractThis study examines the interaction between a northeast Pacific upper-ocean thermal anomaly and individual fall storm events between 2013 and 2016. In 2013, a large upper-ocean thermal anomaly formed in the Gulf of Alaska (GOA) with sea surface temperatures (SST) warmer than 4°C above the climatological norm. Formation of the anomaly was associated with a persistent atmospheric ridge in the GOA that produced a lull in storm activity in the boreal winter of 2013/14. While reduced storm activity was the apparent cause of this SST anomaly, we present cases where extratropical cyclones significantly eroded its mixed layer heat content on synoptic time scales. Case studies during the 4-yr period 2013–16 using satellite and Argo hydrographic observations show that early fall storms produced the largest surface heat fluxes and the greatest cooling of SST. The magnitude of thermal energy transfer from the ocean to the atmosphere during individual storm events was then determined using vertically integrated heat budgets based on Argo temperature profiles and reanalysis surface heat fluxes. Storm-induced surface heat flux anomalies accounted for approximately 50% of the warm anomaly cooling observed by Argo profiles. This rapid heat loss occurred over time scales of approximately 3–5 days. The decay of the warm SST anomaly (SSTa) occurred much more quickly than expected from classic thermal damping by SST-induced turbulent heat fluxes, which may be attributed here at least partly to much shallower mixed layers during early fall. Analysis of the individual surface flux terms indicated that the latent heat flux was the dominant contributor to storm-induced heat exchange across the air–sea interface.

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Numerical Study of the Role of Microphysical Latent Heating and Surface Heat Fluxes in a Severe Precipitation Event in the Warm Sector over Southern China

Asia-Pacific Journal of Atmospheric Sciences ◽

10.1007/s13143-017-0061-0 ◽

2018 ◽

Vol 54 (1) ◽

pp. 77-90 ◽

Cited By ~ 4

Author(s):

Jin-Fang Yin ◽

Dong-Hai Wang ◽

Zhao-Ming Liang ◽

Chong-Jian Liu ◽

Guo-Qing Zhai ◽

...

Keyword(s):

Numerical Study ◽

Southern China ◽

Surface Heat ◽

Heat Fluxes ◽

Precipitation Event ◽

Latent Heating ◽

Surface Heat Fluxes ◽

Warm Sector

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The role of surface heat fluxes in tropical intraseasonal oscillations

Nature Geoscience ◽

10.1038/ngeo312 ◽

2008 ◽

Vol 1 (10) ◽

pp. 653-657 ◽

Cited By ~ 80

Author(s):

Adam H. Sobel ◽

Eric D. Maloney ◽

Gilles Bellon ◽

Dargan M. Frierson

Keyword(s):

Surface Heat ◽

Heat Fluxes ◽

Surface Heat Fluxes ◽

Intraseasonal Oscillations ◽

Tropical Intraseasonal Oscillations

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The Role of WISHE in Secondary Eyewall Formation

Journal of the Atmospheric Sciences ◽

10.1175/jas-d-17-0236.1 ◽

2018 ◽

Vol 75 (11) ◽

pp. 3823-3841 ◽

Cited By ~ 6

Author(s):

Chieh-Jen Cheng ◽

Chun-Chieh Wu

Keyword(s):

Control Experiment ◽

Inner Core ◽

Surface Wind ◽

Surface Heat ◽

Heat Fluxes ◽

Surface Heat Fluxes ◽

Secondary Eyewall Formation ◽

Tangential Wind ◽

The Impact

Abstract Numerical simulations are conducted to examine the role of the wind-induced surface heat exchange (WISHE) mechanism in secondary eyewall formation (SEF). The control experiment exhibits a coherent secondary eyewall structure as quantified by various parameters (e.g., the azimuthal-mean tangential wind and vertical velocity). Prior to SEF, an area characterized by increasing diabatic heating, enhanced inertial stability, and increasing supergradient winds at the top of the boundary layer is observed outside the eyewall. While these characteristics offer the possibility of both balanced and unbalanced dynamical pathways to SEF, the focus of this study is to evaluate the impact of WISHE. To examine the sensitivity of SEF to WISHE, the surface wind used for the calculation of surface heat fluxes is capped at several designated values and at different radial intervals. When the heat fluxes are moderately suppressed around and outside the SEF region observed in the control experiment, sensitivity experiments show that the formation of the outer eyewall is delayed, and the intensity of both eyewalls is weaker. When the heat fluxes are strongly suppressed in the same region, SEF does not occur. In contrast, suppressing the surface heat fluxes in the storm’s inner-core region has limited effect on the evolution of the outer eyewall. This study provides important physical insight into SEF, indicating that WISHE plays a crucial role in SEF and tropical cyclone evolution.

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