Scholarlink

<p>The slope-normal structure of turbulence in anabatic winds is investigated analyzing data from measurement campaigns performed over diverse topographical configurations and surfaces under the projects METCRAX, MATERHORN, and MAP-RIVIERA. In particular, the near-surface structure of the first- and second-order moments of velocity and temperature exhibit comparable structures across the diverse situations covered by the field measurements. After onset, anabatic winds rarely reach a steady state, but rather continuously evolve with increasing intensity. The height of the wind speed maximum <InlineEquation ID="IEq1"> <EquationSource Format="TEX">\(\varvec{z_j}\)</EquationSource> </InlineEquation> is challenging to determine due to data scarcity at upper levels. However, it typically increases with time until the evening transition. Furthermore, downward slope-normal velocity components of the order <InlineEquation ID="IEq2"> <EquationSource Format="TEX">\(\varvec{\sim -0.1 \; \text {m} \, \text {s}^{-1}}\)</EquationSource> </InlineEquation> are often detected. Unlike in katabatic winds, turbulent kinetic energy (TKE) increases in the first meters above ground before reaching an asymptotic value above. A linear relationship is found between surface fluxes of heat and momentum, suggesting a connection among these quantities, i.e., surface heat flux determines momentum flux. Also, a linear connection is found between <InlineEquation ID="IEq3"> <EquationSource Format="TEX">\(\varvec{z_j}\)</EquationSource> </InlineEquation> and a combination of factors (i.e., slope angle <InlineEquation ID="IEq4"> <EquationSource Format="TEX">\(\varvec{\alpha }\)</EquationSource> </InlineEquation>, buoyancy frequency <InlineEquation ID="IEq5"> <EquationSource Format="TEX">\(\varvec{N}\)</EquationSource> </InlineEquation> and friction velocity <InlineEquation ID="IEq6"> <EquationSource Format="TEX">\(\varvec{u_*}\)</EquationSource> </InlineEquation>). Finally, standard deviations of the vertical wind velocity component and of temperature exhibit a fairly good scaling with Obukhov length <i>L</i>, albeit with a different structure than over flat terrain.</p>

错误：搜索内容不能为空，请输入英文关键词
错误：关键词超出字数限制，请精简
高级检索

Determining the slope-normal structure of first- and second-order turbulence moments in anabatic winds from diverse field observations

  • 期刊论文

  • 发表日期：

    2026年8月3日

查看全文
  • Sofia Farina,
  • Dino Zardi

摘要

The slope-normal structure of turbulence in anabatic winds is investigated analyzing data from measurement campaigns performed over diverse topographical configurations and surfaces under the projects METCRAX, MATERHORN, and MAP-RIVIERA. In particular, the near-surface structure of the first- and second-order moments of velocity and temperature exhibit comparable structures across the diverse situations covered by the field measurements. After onset, anabatic winds rarely reach a steady state, but rather continuously evolve with increasing intensity. The height of the wind speed maximum \(\varvec{z_j}\) is challenging to determine due to data scarcity at upper levels. However, it typically increases with time until the evening transition. Furthermore, downward slope-normal velocity components of the order \(\varvec{\sim -0.1 \; \text {m} \, \text {s}^{-1}}\) are often detected. Unlike in katabatic winds, turbulent kinetic energy (TKE) increases in the first meters above ground before reaching an asymptotic value above. A linear relationship is found between surface fluxes of heat and momentum, suggesting a connection among these quantities, i.e., surface heat flux determines momentum flux. Also, a linear connection is found between \(\varvec{z_j}\) and a combination of factors (i.e., slope angle \(\varvec{\alpha }\) , buoyancy frequency \(\varvec{N}\) and friction velocity \(\varvec{u_*}\) ). Finally, standard deviations of the vertical wind velocity component and of temperature exhibit a fairly good scaling with Obukhov length L, albeit with a different structure than over flat terrain.