摘要
本文用多维谱分析的方法,研究了1984年夏季张掖地区辐射参数的中短期和超短期振荡特征。1984年夏季,张掖地区辐射等参数存在着3—5天的中短期振荡及30分钟、50分钟和80分钟的超短期振荡。准3天振荡主要存在于热力边界层,振荡是由西向东传播的,影响高度大致力400 hPa。超短期振荡强度有着明显的日际变化,其变化周期也大致力3—5天。在大气中各种时间尺度的振荡之间存在着某种联系。准3天振荡可能是青藏高原地面热力扰动影响的一种反映;准30分钟的超短期振荡强度与天气系统的关系不明显,而与热力状况及主要云状却有一定的关系。
A multi—spectral method is used to study medium-short and very-short range oscillationcharacteristics of radiation parameters observed in the Zhangye region of China in the summer of1984. Medium-short range oscillation are defined as a sort of the variations occurring on the timescale of 3—5 days; the very-short range oscillations occur over the periods of approximately30—80 minutes. The quasi-three day oscillation is also found in the thermal boundary layer.These oscillations propagate from west to east within the height range of about 400 hPa. The am-plitudes of the very-short range oscillations of the radiation parameters over the Zhangye regionvary with a period of 3—5 days. However, there are certain relationships among all sorts of thescales of the oscillations in the atmosphere. The quasi-three day oscillation may be a response tothe thermal disturbance on the Qinghai—Xizang Plateau. There seems no distinct relationship be-tween the very-short range oscillation and synoptic systems. but the oscillations appear to varywith the thermal state near the surface and prevalent cloud type.
