Interannual variability of winter precipitation linked to upper ocean heat content off the east coast of Korea

Abstract

We present a link between highly variable winter precipitation (e.g. occasional heavy snow) in the mountainous cities along the east coast of Korea and upper ocean heat content (OHC) in the western part of the East Sea (Japan Sea). After removing annual climatological cycle, OHC (as well as sea surface temperature, SST) variability coherent with the winter sea surface wind (SSW) is extracted using maximum covariance analysis (MCA). The first‐mode MCA pattern, explaining 68% of the total covariance, indicates that the stronger westerly (easterly) winter SSW links to larger (smaller) OHC in the upper 400 m or higher (lower) SST of the western part of the sea. Time series of the first‐mode MCA are comparable to winter precipitation variability at three local cities along the coast (Gangneung, Donghae, and Uljin) with significantly high correlation coefficients (0.84, 0.68, and 0.56, respectively). The links between OHC and SSW and between SSW and precipitation are discussed because zonal contrast of OHC drives zonal tilt of northerly monsoonal wind in winter by canonical turbulent momentum exchange within the marine planetary boundary layer (MPBL). The momentum exchange within the MPBL yields the interannual variability of SSW and thus, winter precipitation in the coastal cities.

Decadal Changes in Meridional Overturning Circulation in the East Sea (Sea of Japan)

“…In addition, HYCOM could reasonably simulate realistic intermediate circulation in the southwestern ES, yielding, e.g., decadal changes of ESIW properties associated with the AO (Cui and Senjyu 2010;Tanaka 2014;Nam et al 2016). The formation, properties, volume, and distribution of the ESIW vary from year to year and over the decades, being influenced by the upper 500-m ocean circulation in the ES, as well as atmospheric forcing linked to AO Teague et al 2005;Chang et al 2016;Nam et al 2016;Park and Nam 2018). This influence is particularly prominent in the western ES, where water formation processes, such as subduction and the footprint of shallow convection in the northwestern ES (area A in Fig.…”

Factors Contributing to Disaster Evacuation: The Case of South Korea

“…Telephone surveys were conducted targeting adults (at least 20 years old) residing in South Korea between 1 September and 15 September 2017, and during June 2018. The responses, numbering 541, were collected and utilized South Korea has been affected by numerous natural disasters, such as torrential rains [38], typhoons [39], heavy snow [40], and landslides [41], with flooding caused by the annual monsoon season in July and August being one of the main natural disasters. Moreover, concerns about earthquakes have increased due to the recent earthquake events in the southeast area.…”

Long-Term Variability of the East Sea Intermediate Water Thickness: Regime Shift of Intermediate Layer in the Mid-1990s

“…The satellite-derived sea surface height (SSH) data were also utilized to analyze whether spatial distribution and temporal variability of the ESIW thickness depend on the upper ocean circulation patterns. The spatial structures of the upper ocean circulation in the southern part of the ES are clearly shown in the SSH maps (Choi et al, 2004;Park and Nam, 2018). The SSH data are a merged product of multiple altimeter missions, daily gridded onto 0.25° × 0.25° over the time period January 1993 to December 2020 (https://resources.marine.copernicus.eu/).…”

“…The temporal change of spatial pattern of the thickness is not likely affected by the upper ocean circulation patterns (Figures 8A). The East Korea Warm Current and the Ulleung Warm Eddy are dominant features that control the surface circulation in the southwestern part of the ES, manifested in the spatial map of SSH that mostly represents the first baroclinic structure (Choi et al, 2004;Park and Nam, 2018 ). The SSH map shows that the East Korea Warm Current moves northward along the east coast, and then separates from the coast at a latitude of 37°N-38°N and flows southward at around 131°E.…”