The Interannual Variation Of Atmospheric Response To Winter Kuroshio Extension SST Front

As is the most important region where the ocean releases heat to the atmosphere,the remarkable effects on the atmosphere by Kuroshio extension SST front has beeninvestigated in the climatology time scale by the predecessors. The present studyinvestigate the interannual variation of the local atmospheric response to winterKuroshio extension SST front by using a series of high-resolution satellite observation,reanalysis data, and the composite analysis, something innovative is founded asfollows:1. The variation of winter Kuroshio extension SST front position in interannualscale is much larger than that in intraseasonal scale, while the strength of it in thetwo time-scale equivalents to each other on the whole.2. In spite of the interannual variation of the large-scale atmospheric circulation, thewinter kuroshio extension SST front anchors the cloud liquid water (CLW) inevery year (more in the southern and less in the northern). The CLW also has theevident interannual variation, which is due to the large-scale atmosphericcirculation: when the northwesterly is strengthened (weaken), which brings muchcolder (warmer) and drier (wetter) air mass, the CLW in south of the SST front ismuch less (more) as a result of warm air uplifting caused by condensation. Inaddition, the vertical velocity is weak(strong). The cross-frontal secondarycirculation (upward/downward motion in south/north of the SST front),caused bywinter kuroshio extension SST front, is affected by the large-scale circulation to acertain degree (about20%), and the top of which can reach to above400hPa.3. The position and the strength of Kuroshio Extension SST front has an evidentinterannual variation due to the ocean dynamics, a north (south) position usuallycorresponds a strong (weak) intensity of the Kuroshio Extension SST front, andthe magnitude of intensity is about30%of the climatology. After removing the impact of interannual variability of large-scale atmospheric circulation, when theSST front is further north (south) and stronger (weaker), the sea-air temperaturedifference is larger (smaller) and the static stability of atmosphere is weaker(stronger) in south of SST front, the horizontal pressure gradient is strengthened(weakened); the differences of surface turbulent heat flux, surface wind speed,surface wind convergence, and the height of planetary boundary layer betweenboth sides of SST front is30%larger (smaller) than climatology, and thelow-SLP trough is deepened (weakened). The local secondary circulation causedby SST front is33%stronger (weaker) than climatology in further north (south)and stronger (weaker) SST front years; the differences mainly reflected in the lowaltitude below700hPa, and the height of secondary circulation doesn’t vary indifferent years.