【摘要】 本文利用北京325米气象塔取得的连续观测资料,分析了1979年9月5日夜间低空急流风温场的时空演变过程,这种低空急流的极值在夜间达到最大,其极值位置与逆温层顶的生长密切配合。低空急流是超地转的,超地转气流有一个惯性振荡周期。 低空急流的发展是起伏式的。急流的消散较快,当Ri ≤0.25达到切变不稳定的临界条件时加速崩溃。更多还原

【Abstract】 Detailed continuous information on wind and temperature in the lower atmosphere layer observed at the 325 meters meteorological tower during the evolution and the breakdown of a lower nocturnal jet in the nigh of 5 September 1979 is analysed. A maximum of the wind speed is observed in the night. The maximum of the wind speed is closely relative to the growth of the top of the nocturnal inversion. The lower jet is supergeostrophic, it is suggested that a period of inertial oscillation is induced.The evolution of the lower jet is fluctuated. The lower jet is rapidly breakdown when Ri≤ 0.25 reach to it’s critical condition of the shearing instability.更多还原