Transition of Low Clouds in the East China Sea and Kuroshio Region in Winter: A Regional Atmospheric Model Study

Abstract Influence of the Kuroshio in the East China Sea on the baiu rainband is examined using satellite observations, a reanalysis dataset, and a regional atmospheric model from 2003 to 2008. Satellite observations and reanalysis data reveal that precipitation over the Kuroshio is the highest in early summer (June), when the baiu rainband covers the East China Sea. The high rainfall is collocated with the warm sea surface temperature (SST) tongue of the Kuroshio. This locally enhanced precipitation is embedded in the large-scale baiu rainband, so that the amplitude of precipitation over the Kuroshio is twice as large as that in its surrounding area. The Kuroshio is also accompanied by high surface wind speed, energetic evaporation, and wind convergence. This wind convergence likely results from the SST influence on atmospheric pressure through not only temperature changes, but also humidity changes. Furthermore, the Kuroshio anchors the ascent motion and large diabatic heating with a peak in the midtroposphere, suggesting that the influence of the Kuroshio extends to the upper troposphere. It is also found that the East China Sea in June is the region of the strongest deep atmospheric response to western boundary currents along with the Gulf Stream region in summer. The observational results are well reproduced by the regional atmospheric model. The model indicates that when the SST tongue of the Kuroshio is smoothed, the enhanced precipitation, the energetic evaporation, and the wind convergence over the Kuroshio disappear, although the large-scale structure of the baiu rainband is not essentially changed.

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Corrigendum to "Influence of cross-shelf water transport on nutrients and phytoplankton in the East China Sea: a model study" published in Ocean Sci., 7, 27–43, 2010

Ocean Science ◽

10.5194/os-7-111-2011 ◽

2011 ◽

Vol 7 (1) ◽

pp. 111-111

Author(s):

L. Zhao ◽

X. Guo

Keyword(s):

Water Transport ◽

East China Sea ◽

East China ◽

Shelf Water ◽

The East China Sea ◽

China Sea ◽

Model Study

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Low-Cloud Transitions across the Kuroshio Front in the East China Sea

Journal of Climate ◽

10.1175/jcli-d-15-0589.1 ◽

2016 ◽

Vol 29 (12) ◽

pp. 4429-4443 ◽

Cited By ~ 11

Author(s):

Jing-Wu Liu ◽

Shang-Ping Xie ◽

Shuang Yang ◽

Su-Ping Zhang

Keyword(s):

East China Sea ◽

Large Scale ◽

East Asian Monsoon ◽

East China ◽

The East China Sea ◽

Asian Monsoon Region ◽

China Sea ◽

Low Clouds ◽

Low Cloud ◽

Different Seasons

Abstract The East China Sea Kuroshio (ECSK) flows in the East Asian monsoon region where the background atmospheric circulation varies significantly with season. A sea surface temperature (SST) front associated with the ECSK becomes narrower and sharper from winter to spring. The present study investigates how low clouds respond to the ECSK front in different seasons by synthesizing spaceborne lidar and surface visual observations. The results reveal prominent cross-frontal transitions in low clouds, which exhibit distinct behavior between winter and spring. In winter, cloud responses are generally confined below 4 km by the strong background descending motion and feature a gradual cloud-top elevation from the cold to the warm flank of the front. The ice clouds on the cold flank of the ECSK front transform into liquid water clouds and rain on the warm flank. The springtime clouds, by contrast, are characterized by a sharp cross-frontal transition with deep clouds reaching up to 7 km over the ECSK. In both winter and spring, the low-cloud morphology exhibits a large transformation from the cold to the warm flank of the ECSK front, including increases in cloud-top height, a decline in smoothness of cloud top, and the transition from stratiform to convective clouds. All this along with the atmospheric soundings indicates that the decoupling of the marine atmospheric boundary layer (MABL) is more prevalent on the warm flank of the front. Thus, long-term observations reveal prominent cross-frontal low-cloud transitions in morphology associated with MABL decoupling that resemble a large-scale cloud-regime transition over the eastern subtropical Pacific.

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Transition of low clouds in the East China Sea and Kuroshio region in winter: A regional atmospheric model study

10.5194/egusphere-egu2020-6420 ◽

2020 ◽

Author(s):

Jingchao Long ◽

Yuqing Wang ◽

Suping Zhang ◽

Jingwu Liu

Keyword(s):

East China Sea ◽

Vertical Mixing ◽

Atmospheric Model ◽

Cloud Layer ◽

Latent Heating ◽

The East China Sea ◽

Sst Front ◽

Regional Atmospheric Model ◽

The Kuroshio ◽

Kuroshio Region

<p>Bias in simulating the stratocumulus-to-cumulus transition remains a main source of uncertainties in regional climate projection and can significantly affect the energy budget in climate models. To gain insights into the transition, this study investigates the cloud transition forced by the sea surface temperature (SST) front and synoptic disturbances in the East China Sea and Kuroshio region in winter based on both observations and regional atmospheric model simulations. The Kuroshio SST front greatly accelerates cloud transition by enhancing surface turbulent heat flux, marine atmospheric boundary layer (MABL) dynamical adjustment and cloud-top entrainment. With the sharp SST increase from the cold flank to the Kuroshio SST warm tongue (KWT), surface wind convergence (SWC) over the KWT induced by the SST front and synoptic disturbances[Office1]&#160; enhances the coupling between the cloud layer and subcloud layer. An underlying positive feedback between the SWC and latent heating in the cloud layer can enhance abrupt change in cloud properties and maintain cloud band over the KWT against the decoupling through the so-called &#8220;Deepening-Warming&#8221; mechanism induced by latent heating. From the KWT downwind southward, the surface layer turbulent mixing weakens, while latent heating in the cloud layer and cloud-top longwave radiative cooling enhance buoyancy and vertical mixing in the cloud layer. This difference in vertical mixing between the cloud layer and subcloud layer facilitates the MABL decoupling and impedes upward moisture transport. Meanwhile, decreasing lower tropospheric stability is conducive to the entrainment of drier and warmer air from above into the cloud layer, strengthening cloud evaporation.</p>

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