A Study on Low-level Jets and Temperature Inversion over the Arctic Ocean by Using SHEBA Data

Utilizing GPS sounding data collected during the Surface Heat Budget of the Arctic Ocean campaign over the period of one year (SHEBA, October 1997-October 1998), the authors characterized the boundary layer inversion and low-level jet over the Arctic Ocean. The results showed that 96% of the soundings (1115 UTC and 2315 UTC) had near-surface inversion layers, where 22% were surface-based and 70% were between 250 m and 850 m. During the winter months, the frequency of the surface-based inversion, the inversion depth, and the temperature change in the inversion layer were stronger than that during the summer months. During the year, the low-level jets occurred with a frequency of 41% and their average height was 520 m. The jets appeared mostly around 150 m, and 70% were below 600 m. The mean speed of the jets was 10.6 m·s^-1 and the predominant wind direction was east and northeast; 75% of the wind speeds recorded ranged between 4 m·s^-1 and 13 m·s^-1. The analysis of the turning angle distribution between the jet core and the ground wind indicated that inertial oscillation was the main cause of the low-level jet in the Arctic region.