scholarly journals A Coupled Atmosphere–Wave–Ocean Modeling System: Simulation of the Intensity of an Idealized Tropical Cyclone

2011 ◽  
Vol 139 (1) ◽  
pp. 132-152 ◽  
Author(s):  
Bin Liu ◽  
Huiqing Liu ◽  
Lian Xie ◽  
Changlong Guan ◽  
Dongliang Zhao
Keyword(s):  
Tropical Cyclone ◽  
Negative Feedback ◽  
Heat Fluxes ◽  
Ocean Modeling ◽  
Sea Surface ◽  
Sea Spray ◽  
Wave Coupling ◽  
Sst Cooling ◽  
Ocean Coupling ◽  
The Impact

Abstract A coupled atmosphere–wave–ocean modeling system (CAWOMS) based on the integration of atmosphere–wave, atmosphere–ocean, and wave–current interaction processes is developed. The component models consist of the Weather Research and Forecasting (WRF) model, the Simulating Waves Nearshore (SWAN) model, and the Princeton Ocean Model (POM). The coupling between the model components is implemented by using the Model Coupling Toolkit. The CAWOMS takes into account various wave-related effects, including wave state and sea-spray-affected sea surface roughness, sea spray heat fluxes, and dissipative heating in atmosphere–wave coupling. It also considers oceanic effects such as the feedback of sea surface temperature (SST) cooling and the impact of sea surface current on wind stress in atmosphere–ocean coupling. In addition, wave–current interactions, including radiation stress and wave-induced bottom stress, are also taken into account. The CAWOMS is applied to the simulation of an idealized tropical cyclone (TC) to investigate the effects of atmosphere–wave–ocean coupling on TC intensity. Results show that atmosphere–wave coupling strengthens the TC system, while the thermodynamic coupling between the atmosphere and ocean weakens the TC as a result of the negative feedback of TC-induced SST cooling. The overall effects of atmosphere–wave–ocean coupling on TC intensity are determined by the balance between wave-related positive feedback and the negative feedback attributable to TC-induced SST cooling.

scholarly journals The Effect of Atmosphere–Ocean Coupling on the Structure and Intensity of Tropical Cyclone Bejisa in the Southwest Indian Ocean

Atmosphere ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 688
Author(s):  
Soline Bielli ◽  
Christelle Barthe ◽  
Olivier Bousquet ◽  
Pierre Tulet ◽  
Joris Pianezze
Keyword(s):  
Tropical Cyclone ◽  
Mixed Layer ◽  
Heat Fluxes ◽  
Sea Surface ◽  
Ocean Mixed Layer ◽  
Surface Cooling ◽  
Southwest Indian Ocean ◽  
Left Hand ◽  
Sea Surface Cooling ◽  
The Impact

A set of numerical simulations is relied upon to evaluate the impact of air-sea interactions on the behaviour of tropical cyclone (TC) Bejisa (2014), using various configurations of the coupled ocean-atmosphere numerical system Meso-NH-NEMO. Uncoupled (SST constant) as well as 1D (use of a 1D ocean mixed layer) and 3D (full 3D ocean) coupled experiments are conducted to evaluate the impact of the oceanic response and dynamic processes, with emphasis on the simulated structure and intensity of TC Bejisa. Although the three experiments are shown to properly capture the track of the tropical cyclone, the intensity and the spatial distribution of the sea surface cooling show strong differences from one coupled experiment to another. In the 1D experiment, sea surface cooling (∼1 ∘C) is reduced by a factor 2 with respect to observations and appears restricted to the depth of the ocean mixed layer. Cooling is maximized along the right-hand side of the TC track, in apparent disagreement with satellite-derived sea surface temperature observations. In the 3D experiment, surface cooling of up to 2.5 ∘C is simulated along the left hand side of the TC track, which shows more consistency with observations both in terms of intensity and spatial structure. In-depth cooling is also shown to extend to a much deeper depth, with a secondary maximum of nearly 1.5 ∘C simulated near 250 m. With respect to the uncoupled experiment, heat fluxes are reduced from about 20% in both 1D and 3D coupling configurations. The tropical cyclone intensity in terms of occurrence of 10-m TC wind is globally reduced in both cases by about 10%. 3D-coupling tends to asymmetrize winds aloft with little impact on intensity but rather a modification of the secondary circulation, resulting in a slight change in structure.

scholarly journals Upper-Ocean Response to the Super Tropical Cyclone Phailin (2013) over the Freshwater Region of the Bay of Bengal

2019 ◽  
Vol 49 (5) ◽  
pp. 1201-1228 ◽  
Author(s):  
Yun Qiu ◽  
Weiqing Han ◽  
Xinyu Lin ◽  
B. Jason West ◽  
Yuanlong Li ◽  
...  
Keyword(s):  
Tropical Cyclone ◽  
Bay Of Bengal ◽  
Heat Fluxes ◽  
Sea Surface ◽  
Sea Surface Salinity ◽  
Upper Ocean ◽  
Surface Salinity ◽  
Ocean Response ◽  
Upper Ocean Response ◽  
The Impact

AbstractThis study investigates the impact of salinity stratification on the upper-ocean response to a category 5 tropical cyclone, Phailin, that crossed the northern Bay of Bengal (BOB) from 8 to 13 October 2013. A drastic increase of up to 5.0 psu in sea surface salinity (SSS) was observed after Phailin’s passage, whereas a weak drop of below 0.5°C was observed in sea surface temperature (SST). Rightward biases were apparent in surface current and SSS but not evident in SST. Phailin-induced SST variations can be divided into the warming and cooling stages, corresponding to the existence of the thick barrier layer (BL) and temperature inversion before and erosion after Phailin’s passage, respectively. During the warming stage, SST increased due to strong entrainment of warmer water from the BL, which overcame the cooling induced by surface heat fluxes and horizontal advection. During the cooling stage, the entrainment and upwelling dominated the SST decrease. The preexistence of the BL, which reduced entrainment cooling by ~1.09°C day−1, significantly weakened the overall Phailin-induced SST cooling. The Hybrid Coordinate Ocean Model (HYCOM) experiments confirm the crucial roles of entrainment and upwelling in the Phailin-induced dramatic SSS increase and weak SST decrease. Analyses of upper-ocean stratification associated with 16 super TCs that occurred in the BOB during 1980–2015 show that intensifications of 13 TCs were associated with a thick isothermal layer, and 5 out of the 13 were associated with a thick BL. The calculation of TC intensity with and without considering subsurface temperature demonstrates the importance of large upper-ocean heat storage in TC growth.

scholarly journals The impact of climate model sea surface temperature biases on tropical cyclone simulations

2018 ◽  
Vol 53 (1-2) ◽  
pp. 173-192 ◽  
Author(s):  
Wei-Ching Hsu ◽  
Christina M. Patricola ◽  
Ping Chang
Keyword(s):  
Tropical Cyclone ◽  
Surface Temperature ◽  
Sea Surface Temperature ◽  
Climate Model ◽  
Sea Surface ◽  
The Impact

The impact of upper tropospheric temperature change on tropical cyclone

2021 ◽  
Author(s):  
Nawo Eguchi ◽  
Kenta Kobayashi ◽  
Kosuke Ito ◽  
Tomoe Nasuno
Keyword(s):  
Tropical Cyclone ◽  
Lower Stratosphere ◽  
Intensity Change ◽  
Tropospheric Temperature ◽  
Upward Motion ◽  
Sea Level Pressure ◽  
Upper Troposphere ◽  
Ocean Coupling ◽  
Cold Simulation ◽  
The Impact

<p>We evaluate the impact of temperature at the upper troposphere and lower stratosphere (UTLS) on the tropical cyclone (TC) generation and its development by using the nonhydrostatic atmosphere-ocean coupling axisymmetric numerical model [Rotunno and Emanuel, 1987; Ito et al., 2010]. In the case of cold simulation at UTLS, the maximum wind and the minimum sea level pressure are increased and decreased than the control run, respectively. The magnitude of intensity change is the approximately 4 times larger than the change estimated from the MPIs (Maximum Potential Intensity [Bister and Emanuel,1998; Holland, 1997]). Further, during the development phase, the cold air mass intrudes to the middle troposphere from the upper troposphere at the center of TC, which is not seen in the warm case, leading the atmosphere unstable and enhanced the upward motion and then the TC got stronger.</p>

scholarly journals The Role of Sea Surface Temperature Forcing in the Life-Cycle of Mediterranean Cyclones

2020 ◽  
Vol 12 (5) ◽  
pp. 825 ◽  
Author(s):  
Christos Stathopoulos ◽  
Platon Patlakas ◽  
Christos Tsalis ◽  
George Kallos
Keyword(s):  
Life Cycle ◽  
Surface Temperature ◽  
Sea Surface Temperature ◽  
Early Warning Systems ◽  
Life Cycles ◽  
Heat Fluxes ◽  
Sea Surface ◽  
Mediterranean Cyclones ◽  
The Mediterranean ◽  
The Impact

Air–sea interface processes are highly associated with the evolution and intensity of marine-developed storms. Specifically, in the Mediterranean Sea, the air–ocean temperature deviations have a profound role during the several stages of Mediterranean cyclonic events. Subsequently, this enhances the need for better knowledge and representation of the sea surface temperature (SST). In this work, an analysis of the impact and uncertainty of the SST from different well-known datasets on the life-cycle of Mediterranean cyclones is attempted. Daily SST from the Real Time Global SST (RTG_SST) and hourly SST fields from the Operational SST and Sea Ice Ocean Analysis (OSTIA) and the NEMO ocean circulation model are implemented in the RAMS/ICLAMS-WAM coupled modeling system. For the needs of the study, the Mediterranean cyclones Trixi, Numa, and Zorbas were selected. Numerical experiments covered all stages of their life-cycles (five to seven days). Model results have been analyzed in terms of storm tracks and intensities, cyclonic structural characteristics, and derived heat fluxes. Remote sensing data from the Integrated Multi-satellitE Retrievals (IMERG) for Global Precipitation Measurements (GPM), Blended Sea Winds, and JASON altimetry missions were employed for a qualitative and quantitative comparison of modeled results in precipitation, maximum surface wind speed, and wave height. Spatiotemporal deviations in the SST forcing rather than significant differences in the maximum/minimum SST values, seem to mainly contribute to the differences between the model results. Considerable deviations emerged in the resulting heat fluxes, while the most important differences were found in precipitation exhibiting spatial and intensity variations reaching 100 mm. The employment of widely used products is shown to result in different outcomes and this point should be taken into consideration in forecasting and early warning systems.

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 Impacts of Ocean–Atmosphere Coupling on Tropical Cyclone Intensity Change and Ocean Prediction in the Australian Region

2010 ◽  
Vol 138 (6) ◽  
pp. 2074-2091 ◽  
Author(s):  
P. A. Sandery ◽  
G. B. Brassington ◽  
A. Craig ◽  
T. Pugh
Keyword(s):  
Tropical Cyclone ◽  
Coupled Model ◽  
Atmospheric Model ◽  
Intensity Change ◽  
Limited Area ◽  
Ocean Reanalysis ◽  
Australian Region ◽  
Sst Cooling ◽  
Ocean Response ◽  
The Impact

Abstract This study investigates the impact of atmosphere–ocean coupling on predicted tropical cyclone (TC) intensity change and the ocean response in the Australian region. The coupled model comprises the Australian Bureau of Meteorology’s Tropical Cyclone Limited-Area Prediction System (TC-LAPS) and a regional version of the BLUElink ocean forecasting system. A series of case study forecasts are presented and the differences between coupled and uncoupled forecasts, operational forecasts, and posterior objective analyses are compared. A coupled model ensemble is also developed that uses different first-order approximations of the effects of surface waves on surface stress in an inertial coupling method. In each of the cases, the use of reanalyzed sea surface temperatures significantly improves the prediction of TC intensity change in the intensification phase. The results show that dynamic air–sea coupling has a modest impact on intensity in cases where SST cooling is significant and is likely to be important for predicting the rate of TC intensification, peak intensity, and deintensification. Results also show that there is a definite coupled signal and suggest inherent biases in the atmospheric model that could potentially be removed. With different parameterizations of surface wave effects, results show modest sensitivity in TC intensity of up to 10 hPa in minimum surface pressure; however, in some cases there was significant sensitivity in the predicted ocean response. The results also highlight the relative increased complexity of tropical cyclone prediction in the Australian region compared to other regions. In cases where the forecast TC track was reasonably skillful, there were improvements in the predicted ocean response with respect to observations compared to an ocean reanalysis.

scholarly journals Accurate Evaluation of Sea Surface Temperature Cooling Induced by Typhoons Based on Satellite Remote Sensing Observations

Water ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 1413
Author(s):  
Jiagen Li ◽  
Liang Sun ◽  
Yuanjian Yang ◽  
Hao Cheng
Keyword(s):  
Remote Sensing ◽  
Surface Temperature ◽  
Sea Surface Temperature ◽  
Satellite Remote Sensing ◽  
Mixed Layer Depth ◽  
Heat Content ◽  
Sea Surface ◽  
Northwest Pacific ◽  
Sst Cooling ◽  
The Impact

We introduce a novel method to accurately evaluate the satellite-observed sea surface temperature (SST) cooling induced by typhoons with complex tracks, which is widely used but only roughly calculated in previous studies. This method first records the typhoon forcing period and the SST response grid by grid, then evaluates the SST cooling in each grid by choosing the maximum decrease in SST within this time period. This grid-based flexible forcing date method can accurately evaluate typhoon-induced SST cooling and its corresponding date in each grid, as indicated by applying the method to the irregular track of Typhoon Lupit (2009) and three sequential typhoons in 2016 (Malakas, Megi, and Chaba). The method was used to accurately calculate the impact of Typhoon Megi by removing the influence of the other two typhoons. The SST cooling events induced by all typhoons in the northwest Pacific from 2004 to 2018 were extracted well using this method. Our findings provide new insights for accurately calculating the response of the ocean using multi-satellite remote sensing and simulation data, including the sea surface salinity, sea surface height, mixed layer depth, and the heat content of the upper levels of the ocean.

scholarly journals Contributions of Surface Sensible Heat Fluxes to Tropical Cyclone. Part I: Evolution of Tropical Cyclone Intensity and Structure

2015 ◽  
Vol 72 (1) ◽  
pp. 120-140 ◽  
Author(s):  
Zhanhong Ma ◽  
Jianfang Fei ◽  
Xiaogang Huang ◽  
Xiaoping Cheng
Keyword(s):  
Tropical Cyclone ◽  
Convective Available Potential Energy ◽  
Potential Temperature ◽  
Great Sensitivity ◽  
Heat Fluxes ◽  
Cold Pool ◽  
Sensible Heat ◽  
Near Surface ◽  
Budget Analysis ◽  
The Impact

Abstract The contributions of surface sensible heat fluxes (SHX) to the evolution of tropical cyclone (TC) intensity and structure are examined in this study by conducting cloud-resolving simulations. Results suggest that although the peak values of SHX could account for nearly 30% of those of the total surface latent and sensible heat fluxes, the impact of SHX on TC intensification is nonetheless not distinct. However, the TC size shows great sensitivity to the SHX that the storm is shrunk by over 20% after removing the SHX. A potential temperature budget analysis indicates that the adiabatic cooling accompanying the radial inflow is largely balanced by the transfer of sensible heat fluxes rather than the entrainment of subsiding air from aloft. If there is upward transfer of SHX from underlying ocean so that the near-surface potential temperature decreases upward, the SHX will play a vital role; instead, if the upward SHX are absent so that the potential temperature increases upward near the surface, the downward sensible heat fluxes become the dominant contributor to warm the inflow air. The changes in TC size are found to be primarily caused by the rainband activities. The SHX help maintain high convective available potential energy as well as the cold pool feature outside the eyewall, thus being crucial for the growth of outer rainbands. If without upward transport of SHX, the outer-rainband activities could be largely suppressed, thereby leading to a decrease of the TC size.

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