TY - JOUR
T1 - Observed response of marine boundary layer cloud to the interannual variations of summertime Oyashio extension SST front
AU - Takahashi, Naoya
AU - Hayasaka, Tadahiro
AU - Qiu, Bo
AU - Yamaguchi, Ryohei
N1 - Funding Information:
This work was supported by a Grant-in-Aid for the Japan Society for the Promotion of Science (JSPS) Research Fellow JP18J10606 and a Grant-in-Aid for Scientific Research (B) 16H04046 from the JSPS. The Aqua/MODIS Cloud Daily L3 Global 1 Deg. CMG dataset was acquired from the Level-1 and Atmosphere Archive Distribution System (LAADS) Distributed Active Archive Center (DAAC), located in the Goddard Space Flight Center in Greenbelt, Maryland (https://ladsweb.nascom.nasa.gov/). CERES data were obtained from the NASA Langley Research Center CERES ordering tool at http://ceres.larc.nasa.gov/. OISST data were provided by NOAA. The global ocean heat flux and evaporation data provided by the Woods Hole Oceanographic Institution OAFlux project (http://oaflux.whoi.edu , last access: 06 November 2018) were funded by the NOAA Climate Observations and Monitoring (COM) program. ERA-Interim data were downloaded from the ECMWF data server at http://apps.ecmwf.int/datasets/. Roemmich-Gilson Argo Climatology dataset was provided by Scripps Institution of Oceanography (http://sio-argo.ucsd.edu/RG_Climatology.html). These data were collected and made freely available by the International Argo Program and the national programs that contribute to it. (http://www.argo.ucsd.edu , http://argo.jcommops.org). The Argo Program is part of the Global Ocean Observing System. The author thanks Kelvin Richards and Niklas Schneider from the University of Hawaii at Manoa for their helpful comments and discussion.
Funding Information:
This work was supported by a Grant-in-Aid for the Japan Society for the Promotion of Science (JSPS) Research Fellow JP18J10606 and a Grant-in-Aid for Scientific Research (B) 16H04046 from the JSPS. The Aqua/MODIS Cloud Daily L3 Global 1 Deg. CMG dataset was acquired from the Level-1 and Atmosphere Archive Distribution System (LAADS) Distributed Active Archive Center (DAAC), located in the Goddard Space Flight Center in Greenbelt, Maryland ( https://ladsweb.nascom.nasa.gov/ ). CERES data were obtained from the NASA Langley Research Center CERES ordering tool at http://ceres.larc.nasa.gov/ . OISST data were provided by NOAA. The global ocean heat flux and evaporation data provided by the Woods Hole Oceanographic Institution OAFlux project ( http://oaflux.whoi.edu , last access: 06 November 2018) were funded by the NOAA Climate Observations and Monitoring (COM) program. ERA-Interim data were downloaded from the ECMWF data server at http://apps.ecmwf.int/datasets/ . Roemmich-Gilson Argo Climatology dataset was provided by Scripps Institution of Oceanography ( http://sio-argo.ucsd.edu/RG_Climatology.html ). These data were collected and made freely available by the International Argo Program and the national programs that contribute to it. ( http://www.argo.ucsd.edu , http://argo.jcommops.org ). The Argo Program is part of the Global Ocean Observing System. The author thanks Kelvin Richards and Niklas Schneider from the University of Hawaii at Manoa for their helpful comments and discussion.
Publisher Copyright:
© 2021, The Author(s), under exclusive licence to Springer-Verlag GmbH, DE part of Springer Nature.
PY - 2021/6
Y1 - 2021/6
N2 - Active roles of both sea surface temperature (SST) and its frontal characteristics to the atmosphere in the mid-latitudes have been investigated around the western boundary current regions, and most studies have focused on winter season. The present study investigated the influence of the variation of the summertime Oyashio extension SST front (SSTF) in modulating low-level cloud properties (i.e., low-level cloud cover [LCC], cloud optical thickness [COT], and shortwave cloud radiative effect [SWCRE]) on inter-annual timescales, based on available satellite and Argo float datasets during 2003–2016. First, we examined the mechanism of summertime SSTF variability itself. The strength of the SSTF (SSSTF), defined as the maximum horizontal gradient of SST, has clear inter-annual variations. Frontogenesis equation analysis and regression analysis for subsurface temperature indicated that the inter-annual variations of the summertime SSSTF in the western North Pacific are closely related to the variations of not surface heat flux, but western boundary currents, particularly the Oyashio Extensions. The response of low-level cloud to intensified SSSTF is that negative SWCRE with positive COT anomaly in the northern flank of the SSTF can be induced by cold SST anomalies. The spatial scale of the low-level cloud response was larger than the SST frontal scale, and the spatial distribution of the response was mainly constrained by the pathways of Kuroshio and Oyashio Extensions. Multi-linear regression analysis revealed that the local SST anomaly played largest role in modulating the SWCRE and COT anomalies among the cloud controlling factors (e.g., estimated inversion strength, air-temperature advection) accounting for more than 50% of the variation. This study provides an observational evidence of the active role of local SST anomalies in summertime associated with the western boundary currents to the oceanic low-level cloud.
AB - Active roles of both sea surface temperature (SST) and its frontal characteristics to the atmosphere in the mid-latitudes have been investigated around the western boundary current regions, and most studies have focused on winter season. The present study investigated the influence of the variation of the summertime Oyashio extension SST front (SSTF) in modulating low-level cloud properties (i.e., low-level cloud cover [LCC], cloud optical thickness [COT], and shortwave cloud radiative effect [SWCRE]) on inter-annual timescales, based on available satellite and Argo float datasets during 2003–2016. First, we examined the mechanism of summertime SSTF variability itself. The strength of the SSTF (SSSTF), defined as the maximum horizontal gradient of SST, has clear inter-annual variations. Frontogenesis equation analysis and regression analysis for subsurface temperature indicated that the inter-annual variations of the summertime SSSTF in the western North Pacific are closely related to the variations of not surface heat flux, but western boundary currents, particularly the Oyashio Extensions. The response of low-level cloud to intensified SSSTF is that negative SWCRE with positive COT anomaly in the northern flank of the SSTF can be induced by cold SST anomalies. The spatial scale of the low-level cloud response was larger than the SST frontal scale, and the spatial distribution of the response was mainly constrained by the pathways of Kuroshio and Oyashio Extensions. Multi-linear regression analysis revealed that the local SST anomaly played largest role in modulating the SWCRE and COT anomalies among the cloud controlling factors (e.g., estimated inversion strength, air-temperature advection) accounting for more than 50% of the variation. This study provides an observational evidence of the active role of local SST anomalies in summertime associated with the western boundary currents to the oceanic low-level cloud.
KW - Air–sea interaction
KW - Interannual variability
KW - Marine boundary layer cloud
KW - Sea surface temperature front
KW - Summertime North Pacific
UR - http://www.scopus.com/inward/record.url?scp=85099954989&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85099954989&partnerID=8YFLogxK
U2 - 10.1007/s00382-021-05649-4
DO - 10.1007/s00382-021-05649-4
M3 - Article
AN - SCOPUS:85099954989
SN - 0930-7575
VL - 56
SP - 3511
EP - 3526
JO - Climate Dynamics
JF - Climate Dynamics
IS - 11-12
ER -
