Interannual variability of sea fog frequency in the Northwestern Pacific in July

Zhang, Suping; Chen, Yang; Long, Jingchao; Han, Geng

doi:10.1016/j.atmosres.2014.04.004

Cited by 15 publications

(6 citation statements)

References 19 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…On the other hand, the warm advection with the increased SSW can transport warm and humid air, thus enhancing the RH (Figure 7g). This correlation is consistent with the fact that for a persistent large-scale stratiform cloud, the air mass at the level of the cloud must be near saturation [36,37]. Different from the SENP, SHF had little effect on the increase in the LCF in this region (Figure 7e).…”

Section: Association With Meteorological Parameterssupporting

confidence: 84%

Subseasonal Variation Characteristics of Low-Cloud Fraction in Southeastern and Northwestern North Pacific

Wang,

Xu,

et al. 2023

Atmosphere

View full text Add to dashboard Cite

The subseasonal variability of the low-cloud fraction (LCF) over the southeastern North Pacific (SENP) and northwestern North Pacific (NWNP) was studied using satellite observations and the European Centre for Medium-Range Weather Forecasts (ECMWF) reanalysis. It is found that subseasonal variability of the LCF was closely related to variations in the estimated inversion strength (EIS), sea surface wind speed (SSW), sensible heat flux (SHF), sea surface temperature (SST), surface temperature advection (Tadv), relative humidity (RH), surface level pressure (SLP) and surface air temperature (SAT). An increase in the LCF over the SENP is associated with the development of an anomalous anticyclonic circulation, which is located on the west coast of America. The cold advection, together with the subsidence warming associated with the anticyclonic circulation, strengthens the temperature inversion, favoring the development of the LCF. In the NWNP, the maximum LCF anomaly was also correlated with the stable boundary layer. The southerly wind blows airflow over the Kuroshio Extension from the subtropics, which brings warm and moist air. When air flows to the colder sea surface, it is cooled and condensed by the intensified heat exchange. A lead-lag composite analysis indicates that the mechanisms are different between the SENP and the NWNP, possibly due to the different types of low-level clouds over these two regions. In the SENP, the trade cumulus dominates under a strong capping inversion over the subtropics, whereas fog and stratus often occur under a shallow capping inversion in the NWNP. The effects of atmospheric circulation are also discussed.

show abstract

Section: Association With Meteorological Parameterssupporting

confidence: 84%

Subseasonal Variation Characteristics of Low-Cloud Fraction in Southeastern and Northwestern North Pacific

Wang,

Xu,

et al. 2023

Atmosphere

View full text Add to dashboard Cite

show abstract

“…1a). The prevailing southerly winds on the western flank of the subtropical high carry warm and moist air across the steep SST front, resulting in frequent fog near the surface (Zhang et al 2014;Long et al 2016;Kora cin and Dorman 2017). The occurrence frequency of sea fog reaches maximum over the Kuril Islands to the northwest of the Oyashio Current, where the SST is colder than 108C in summer due to intense tidal mixing (Kora cin and Dorman 2017; Tokinaga and Xie 2009).…”

Section: Introductionmentioning

confidence: 99%

Transition from Fog to Stratus over the Northwest Pacific Ocean: Large-eddy Simulation

Liu

Xie

et al. 2021

Monthly Weather Review

View full text Add to dashboard Cite

Over the midlatitude northwest Pacific Ocean, summer fog frequents the Kuroshio-Oyashio front as a result of the warm advection by the prevailing southerly to southwesterly winds, and stratus clouds are prevalent downstream of the fog regime in the subpolar northwest Pacific. The present study tracks a boundary-layer air column along a typical northeastward trajectory along which fog on the sea surface temperature (SST) front makes its transition to stratus clouds. A turbulence-closure large-eddy simulation model can capture the evolution of the air column forced by the time-varying SST along the trajectory. Results show that the surface cooling effects across the SST front and the longwave radiative cooling (LRC) at the cloud top dominate the evolution of the boundary layer and the related turbulent processes. The sharp SST decrease across the SST front cools the surface layer, leading to condensation through shear-induced turbulence. Once the fog forms, the LRC at the fog top cools the boundary layer strongly through thermal turbulent mixing. The buoyancy-induced turbulence near the fog top entrains the warm and dry air from the free atmosphere into the boundary layer, reducing surface humidity and ultimately lifting the cloud base away from the sea surface to form stratus clouds. Sensitivity simulations also suggest that neither the latent heat flux from ocean nor and the diurnal solar variation is essential for the summer fog-to-stratus transition over the northwestern Pacific.

show abstract

“…One is the Aleutian Low, which brings persistent eastward winds to the midlatitude NCP at 1000 hPa (Figure 2A). Another is the NPSH, whose location shifts from the western to the eastern Pacific compared to summer (Zhang et al, 2015).…”

Section: Large-scale Circulationmentioning

confidence: 99%

“…Sugimoto et al (2013) indicate that the strengthened Okhotsk high and suppression of the northward extension of the northern Pacific surface high (NPSH) were responsible for the declining trend of MFF during 1931-2010 at Kushiro, Hokkaido, in July. Zhang et al (2015) suggest that the position and orientation of the NPSH is the most important factor influencing the MFF in the NWP.…”

Section: Introductionmentioning

confidence: 99%

Atmospheric conditions conducive to marine fog over the northeast Pacific in winters of 1979–2019

Zhang

Koračin

et al. 2022

Front. Earth Sci.

Self Cite

View full text Add to dashboard Cite

Observations show that the northeast Pacific (NEP) is a fog-prone area in winter compared with the northwest and central Pacific where fog rarely occurs in winter. By synthesizing observations and reanalysis results from 1979 to 2019, this study investigates the atmospheric circulation and marine atmospheric boundary layer structure associated with marine fog over the NEP in winter. Composite analysis shows that the eastern flank of the Aleutian low and the northwestern flank of the Pacific subtropical high jointly contribute to a northward air flow over the NEP. Under such conditions, warm and moist air flows through a cooler sea surface and facilitates the formation of advection-cooling fog. The air near the sea surface in foggy areas is cooled by the downward sensible heat flux. The smaller upward latent heat flux (∼10 W m−2) compared to the surrounding area (>60 W m−2) demonstrates that the moisture originates from the advection instead of local evaporation. The lower (at 925 to 875 hPa) and stronger (up to 0.08 K hPa−1) inversion layer, compared with cloudy cases and the turbulence in the lower atmosphere (below 975 hPa), also promotes fog formation and evolution. Approximately 68% of all fog cases (42242) show positive differences between surface air temperature (SAT) and sea surface temperature (SST), while 32% are negative, during southerly winds. Composite analysis of the latter shows lower specific humidity above the inversion bottom compared to the former. Dry air enhances longwave radiative cooling from the fog top, favoring cooling of the fog layer, gradually causing SAT to fall below SST.

show abstract

Interannual variability of sea fog frequency in the Northwestern Pacific in July

Cited by 15 publications

References 19 publications

Subseasonal Variation Characteristics of Low-Cloud Fraction in Southeastern and Northwestern North Pacific

Subseasonal Variation Characteristics of Low-Cloud Fraction in Southeastern and Northwestern North Pacific

Transition from Fog to Stratus over the Northwest Pacific Ocean: Large-eddy Simulation

Atmospheric conditions conducive to marine fog over the northeast Pacific in winters of 1979–2019

Contact Info

Product

Resources

About