Comparative Analysis of Selected Ceilometers for Practice and Academic Purposes

Choma, Ladislav; Musil, Tomáš; Nemethova, Helia; Jevcak, J.; Petricek, P.; Makó, Sebastián; Pilát, Marek; Balla, F.

doi:10.1109/mosatt48908.2019.8944110

Cited by 1 publication

(1 citation statement)

References 4 publications

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“…The selected time step is 404 s when the vertically integrated kinetic energy does not vary much with time (14). The boundary layer height is retrieved from Lufft CHM 15k ceilometer (45), which is used to detect the top of an elevated aerosol layer. The ceilometer backscatter profiles can be used to retrieve the ABL height for convective conditions when the ABL is well mixed and there are significant differences between the aerosol content of the ABL and the free troposphere (46).…”

Section: Dns Of Convective Boundary Layersmentioning

confidence: 99%

Logarithmic profile of temperature in sheared and unstably stratified atmospheric boundary layers

Cheng

et al. 2021

Phys. Rev. Fluids

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Wall-bounded turbulent flows are widely observed in natural and engineering systems, such as air flows near the Earth's surface, water flows in rivers, and flows around a car or a plane. The universal logarithmic velocity profile in wall-bounded turbulent flows proposed by von Kármán in 1930 is one of the few exact physical descriptions of turbulence. However, the mean velocity and temperature profiles cannot be adequately described by this universal log law when buoyancy effects are present. Monin-Obukhov similarity theory (MOST), proposed in 1954, has been the cornerstone theory to account for these buoyancy effects and to describe the atmospheric boundary layer. MOST has been used in almost all global weather, climate and hydrological models to describe the dependence of the mean velocity, temperature and scalar profiles on buoyancy. According to MOST, the logarithmic temperature profile breaks down as buoyancy effects become important. In contrast, here we show that this long-standing MOST theory does not apply for temperature. We propose a new theory for the logarithmic profile of near-wall temperature, which corrects MOST pitfalls and is supported by both high-resolution direct numerical simulations and field observations of the convective atmospheric boundary layer. Buoyancy effects do not modify the logarithmic nature but instead modulate the slope of the temperature profile compared to the universal von Kármán slope. The new formulation has widespread applications such as in climate models, where the proposed new temperature log law should lead to more realistic continental surface temperature, which are strongly impacted by buoyancy.

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Section: Dns Of Convective Boundary Layersmentioning

confidence: 99%

Logarithmic profile of temperature in sheared and unstably stratified atmospheric boundary layers

Cheng

et al. 2021

Phys. Rev. Fluids

View full text Add to dashboard Cite

show abstract

Comparative Analysis of Selected Ceilometers for Practice and Academic Purposes

Cited by 1 publication

References 4 publications

Logarithmic profile of temperature in sheared and unstably stratified atmospheric boundary layers

Logarithmic profile of temperature in sheared and unstably stratified atmospheric boundary layers

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