Atmospheric Turbulence Characteristics Over a Temperature-Inhomogeneous Land Surface. Part II: The Effect of Small-Scale Inhomogeneities of Surface Temperature on Some Characteristics of the Atmospheric Surface Layer

1998 ◽  
Vol 86 (1) ◽  
pp. 103-124 ◽  
Author(s):  
L.R. Tsvang ◽  
V.P. Kukharets ◽  
V.G. Perepelkin
Keyword(s):  
Surface Layer ◽  
Surface Temperature ◽  
Atmospheric Turbulence ◽  
Land Surface ◽  
Atmospheric Surface Layer ◽  
Small Scale ◽  
Turbulence Characteristics ◽  
Surface Part

scholarly journals Mathematical Modeling of Vegetation Heterogeneity and Complex Topography Effects on Turbulent Exchange of GHG within the Atmospheric Surface Layer

Proceedings ◽  
2018 ◽  
Vol 2 (20) ◽  
pp. 1310
Author(s):  
Iuliia Mukhartova ◽  
Alexander Krupenko ◽  
Polina Mangura ◽  
Alexander Olchev
Keyword(s):  
Surface Layer ◽  
Land Surface ◽  
Atmospheric Surface Layer ◽  
Air Flow ◽  
3D Models ◽  
Forest Edge ◽  
Co2 Exchange ◽  
Finite Difference Schemes ◽  
Complex Topography ◽  
Vegetation Heterogeneity

The local-scale 2D and 3D models of greenhouse gases (GHG) exchange between a non-uniform land surface and the atmosphere were developed. They are based on solution of the system of averaged Navier-Stokes, continuity and diffusion-advection equations. For numerical solution of the differential equations the stable finite-difference schemes were suggested. The models were applied to derive effects of complex topography and vegetation heterogeneity on 2D-3D air flow patterns, as well as on CO2 exchange within the atmospheric surface layer. Several numerical experiments were also provided to describe the air-flow re-establishing after its interaction with some obstacle (e.g., forest edge). Quantitative criteria for selection of the experimental sites for continuous eddy covariance flux measurements characterized by minimum effects of horizontal advection on measured fluxes were suggested.

Observations of the ABL Structures over a Heterogeneous Land Surface during IHOP_2002

2007 ◽  
Vol 8 (2) ◽  
pp. 221-244 ◽  
Author(s):  
Song-Lak Kang ◽  
Kenneth J. Davis ◽  
Margaret LeMone
Keyword(s):  
Temperature Distribution ◽  
Surface Temperature ◽  
Land Surface ◽  
Joint Probability ◽  
Surface Flux ◽  
Weather Conditions ◽  
Surface Heterogeneity ◽  
Small Scale ◽  
Mesoscale Circulations ◽  
Obukhov Length

Abstract This study analyzes data collected by aircraft and surface flux sites over a 60-km north–south-oriented aircraft track for five fair-weather days during the International H2O Project (IHOP_2002) to investigate the atmospheric boundary layer (ABL) structures over a heterogeneous land surface under different background weather conditions. The surface skin temperature distribution over the aircraft track in this case is mostly explained by the soil thermal properties and soil moisture, and corresponds to the observed ABL depths except one day having a weak surface temperature gradient and a weak capping inversion. For the other four days, the blending height of the surface heterogeneity likely exceeds the ABL depth and thus the ABL establishes equilibrium with local surface conditions. Among the four days, two days having relatively small Obukhov lengths are evaluated to show the background weather conditions under which small-scale surface heterogeneity can influence the entire ABL. In fact, on one of these two days, relatively small-scale features of the surface temperature distribution can be seen in the ABL depth distribution. On the two small Obukhov length days multiresolution spectra and joint probability distributions, which are applied to the data collected from repeated low-level aircraft passes, both imply the existence of surface-heterogeneity-generated mesoscale circulations on scales of 10 km or more. Also on these two small Obukhov length days, the vertical profiles of dimensionless variances of velocity, temperature, and moisture show large deviations from the similarity curves, which also imply the existence of mesoscale circulations.

scholarly journals Turbulent heat exchange characterisics in sea ice ridges areas

2020 ◽  
Vol 66 (3) ◽  
pp. 364-380
Author(s):  
B. V. Ivanov ◽  
A. V. Urazgildeeva ◽  
A. N. Paramzin ◽  
S. S. Sirovetkin ◽  
D. V. Drabenko
Keyword(s):  
Surface Layer ◽  
Heat Conduction ◽  
Heat Exchange ◽  
Sea Ice ◽  
Surface Temperature ◽  
Atmospheric Surface Layer ◽  
Windward Side ◽  
Leeward Side ◽  
Turbulent Heat ◽  
Turbulent Heat Exchange

The studies of the features of turbulent heat exchange were carried out for the first time in domestic practice near ice ridge areas of sea ice using an unmanned aerial vehicle (UAV) as part of the expedition "Transarktika-2019" onboard the R/V “Akademik Tryoshnikov”. An original measuring complex designed in AARI, was used to assess the characteristics of the ice surface (ice ridges, flat areas of ice). This made it possible to obtain comparative estimates of the albedo and surface temperature of different morphometric structures of the sections of the ice field, where the expedition's ice camp was organized. Measurements of air temperature and wind velocity were carried in the atmospheric surface layer on flat snow-covered areas of sea ice out from the windward and leeward sides of the ridge in parallel with the UAV flights. As a result of the experiments, it was found that the ice ridges areas have a lower albedo and surface temperature compared to neighboring areas of flat sea ice on average. Turbulent heat fluxes from the windward side of the hummock ridge exceed similar values recorded from the leeward side under conditions of unstable stratification in the atmospheric surface layer and exceed the fluxes calculated for conditions of flat ice on the sections with absence of hummocks, on average. In total, the nature and intensity of turbulent heat conduction in the ice ridges area differs from the analogous values observed on the flat sea ice cover. It is possible that the assessment of heat conduction with the atmosphere requires a certain revision, against the background (within the conditions) of thin first-year ice increasing which is more prone to hummocking than multi-year ice.

scholarly journals Unmanned aerial vehicles reveal the impact of a total solar eclipse on the atmospheric surface layer

2019 ◽  
Vol 475 (2229) ◽  
pp. 20190212 ◽  
Author(s):  
Sean C. C. Bailey ◽  
Caleb A. Canter ◽  
Michael P. Sama ◽  
Adam L. Houston ◽  
Suzanne Weaver Smith
Keyword(s):  
Surface Layer ◽  
Unmanned Aerial Vehicles ◽  
Solar Eclipse ◽  
Atmospheric Surface Layer ◽  
Small Scale ◽  
Stable Layer ◽  
Holistic View ◽  
Near Surface ◽  
Aerial Vehicles ◽  
The Impact

We use unmanned aerial vehicles to interrogate the surface layer processes during a solar eclipse and gain a comprehensive look at the changes made to the atmospheric surface layer as a result of the rapid change of insolation. Measurements of the atmospheric surface layer structure made by the unmanned systems are connected to surface measurements to provide a holistic view of the impact of the eclipse on the near-surface behaviour, large-scale turbulent structures and small-scale turbulent dynamics. Different regimes of atmospheric surface layer behaviour were identified, with the most significant impact including the formation of a stable layer just after totality and evidence of Kelvin–Helmholtz waves appearing at the interface between this layer and the residual layer forming above it. The decrease in surface heating caused a commensurate decrease in buoyant turbulent production, which resulted in a rapid decay of the turbulence in the atmospheric surface layer both within the stable layer and in the mixed layer forming above it. Significant changes in the wind direction were imposed by the decrease in insolation, with evidence supporting the formation of a nocturnal jet, as well as backing of the wind vector within the stable layer.

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