Application Analysis of Atmospheric Thermal Instability Based on a Microwave Radiometer
HUANG Fei
WANG Shiqiang
ZHAN Tang
LIU Yang
XU Yang
Abstract：To investigate the atmospheric static stability conditions along the western coast of the Pearl River Estuary and their potential key role in operational forecasting and early warning of convective weather,this study analyzes the characteristics of atmospheric thermal instability on the west coast of the Pearl River Estuary and explores its implications for thermal convective precipitation.This is achieved by calculating three physical quantities—convective temperature,lifting condensation level(LCL)and convective conden-sation level(CCL)—using temperature and humidity profiles from a microwave radiometer.The results indi-cate:(1)The diurnal variability profiles of atmospheric temperature and humidity exhibit opposite trends:below the boundary layer,the diurnal variability of atmospheric temperature is more pronounced,while it gradually decreases above the boundary layer.In contrast,the diurnal variation rate of relative humidity is greater in the middle and upper atmosphere,with minimal variation observed in the lower atmosphere.(2)The seasonal variation amplitude of the CCL is significantly greater than that of the LCL.The LCL is mostly less than 0.5 km,increasing to approximately 1 km during autumn and winter.In contrast,the CCL is most-ly below 0.8 km during the summer but remains relatively high in autumn and winter,with monthly maxi-mum values exceeding 7 km.Notably,May and June represent the peak period for rainstorms in the coastal warm monsoon region,during which the LCL is often 0.2 km or lower,and the CCL is predominantly below 0.4 km.Additionally,the atmosphere is in a state of very high thermal instability during this period.(3)From May to July and September,there is a high probability that the difference between surface temperature and convective temperature is above-0.5℃,with July showing the highest likelihood.This period also co-incides with a high frequency of convective precipitation.Conversely,the possibility of thermal convective weather occurring in December and January is minimal.(4)The continuous evolution of LCL and CCL,a-long with surface temperatures approaching or exceeding convective temperature,provides indicative signifi-cance for short-term forecasting of thermal convective precipitation.
Keywords：convective temperaturelifting condensation levelconvective condensation levelthermal instabilitythermal convective precipitation
Publication Date：2025-04-20
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：5( 23-27 )