Characteristics of Turbulence Intermittency, Fine Structures, and Flux Correction in the Taklimakan Desert

Abstract

Taklimakan Desert is one of key climate regions in East Asia, both highly influencing and highly sensitive to local/regional climate change. Based on comprehensive observation experiment from 1 to 31 May 2022 in the hinterland of the Taklimakan Desert, the characteristics and mechanisms of turbulence intermittency are investigated in this study, with the purpose to correct turbulent fluxes. Using an improved algorithm to decompose turbulence and submeso motions, two intermittency regimes are recognized in the Taklimakan Desert, namely D&T intermittency and onD intermittency. The former occurs under strongly stable conditions, characterized by the coexistence of dynamic and thermodynamic turbulence intermittency. The latter occurs under strongly unstable conditions and represents only dynamic turbulence intermittency. Physically, the D&T intermittency regime is related to submeso waves, whereas the onD regime is caused by the horizontal convergence/divergence of convective circulations. With the influence of intermittency and submeso motions, the observed turbulent statistics deviate from reality, which would mask the similarity relationships. To overcome the problem, turbulent statistics are corrected by removing submeso components from original fluctuations. The effectiveness of this method is demonstrated based on the flux-gradient relationships. It is also suggested that, for a big dataset, the impact of onD intermittency can be simply corrected by a correction factor while that of D&T intermittency not. The results of this study are helpful to develop the parameterization of turbulent exchange processes in the Taklimakan Desert, which is significant to improve the accuracy of weather forecasting and climate prediction.