Characteristics of Eddy Dissipation Rates in Atmosphere Boundary Layer Using Doppler Lidar

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Abstract

The eddy dissipation rate (EDR, or turbulence dissipation rate) is a crucial parameter in the study of the atmospheric boundary layer(ABL). However, existing Doppler lidar-based estimates of EDR seldom offer long-term comparisons that span the entire ABL. Building upon prior research utilizing Doppler lidar wind field data, we optimized the EDR retrieval algorithm using a genetic adaptive approach. The newly developed algorithm demonstrates enhanced accuracy in EDR estimation. The daily evolution of EDR reveals a distinct diurnal pattern in its variation. A detailed four consecutive days study on turbulence generated by Low-Level Jets (LLJ) indicated that EDR driven by heat flux (~10⁻² m²/s³) is significantly stronger than that produced by wind shear (~10⁻³ m²/s³). Subsequently, we examined seasonal variations in EDR at different mixing layer heights (MLH, Zi): elevated EDR values in summer (~7 × 10⁻³ m²/s³ at 0.1Zi) contrasted with reduced levels in winter (~6 × 10⁻⁴ m²/s³ at 0.1Zi). In the early morning, EDR decreases with height for 1 magnitude, while in later stages, it remains relatively stable within 0.1 order of magnitude across 0.1Zi to 0.9Zi. Notably, the EDR during DJF exceeds that of MAM and SON in the afternoon. This suggests that ML turbulence is not solely dependent on surface fluxes (SHF + LHF) but may also be influenced by MLH. A lower MLH (smaller volume), even with reduced surface fluxes, could potentially result in stronger EDR. Finally, we compared the evolution of EDR and MLH in the boundary layer using Doppler lidar data from ARM sites and the PBL Moving Active Profiling System (PBLMAPS) Airborne Doppler Lidar (ADL). The results show that when the ADL is positioned near ARM Southern Great Plains (SGP) sites C1 or E37, the vertical wind data exhibit strong consistency (R = 0.96). The ADL's mobility and flexibility provide significant advantages for future field experiments, particularly in challenging environments such as mountainous or complex terrains. This study not only highlights the potential of utilizing Doppler lidar alone for EDR calculations but also extensively explores the development patterns of EDR within the ABL.

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