| Description |
Frequent and prolific sea-effect snowfall events occur over the Sea of Japan (SOJ) and adjoining Japanese SOJ coast when cold northwesterly flow from Asia moistens, warms, and becomes less stable over the SOJ. This work begins with a regional climatology of SOJ sea-effect clouds and precipitation, then focuses on a frequent contributor to heavy precipitation known as the Japan-Sea Polar-Airmass Convergence Zone (JPCZ). Climatological results using A-Train satellite data show the bulk of SOJ region clouds and precipitation occur during sea-effect periods and spatial variations in the frequency, amount, and height of precipitation are influenced by the JPCZ, orographic effects, land-sea interactions, and latitude. Numerical simulations show the formation and maintenance of the JPCZ are strongly modulated by upstream orographic effects from the Korean Highlands and low-elevation pathways including valleys and lowlands. Airstream temperatures converging at the JPCZ vary based on the SOJ fetch and the JPCZ evolution, resulting in a frequent thermal gradient and airmass boundary at the JPCZ. Secondary circulations across the JPCZ are found to be similar to those in some Great Lakes' cloud bands and the symmetry of these circulations is influenced by the strength of the thermal gradient. Sensitivity studies near the Japanese SOJ coast suggest the absence of the JPCZ produces less continuous precipitation and shiftsmaximum accumulated precipitation from the SOJ to the Japanese mountains. Finally, the Japanese mountains, among other forcings, influence the strength and location of the inland precipitation maximum. |
