{"title":"Effects of Soil Moisture Heterogeneity on Temperature-Humidity Dissimilarity in the Convective Boundary Layer","authors":"Cheng Liu, Heping Liu, Jianping Huang, Xiaozhen Fang, Ren-Guo Zhu, Wei Guo, YuanYuan Pan","doi":"10.1029/2025JD043698","DOIUrl":null,"url":null,"abstract":"<p>Surface moisture heterogeneity degrades temperature-humidity (<span></span><math>\n <semantics>\n <mrow>\n <mi>θ</mi>\n </mrow>\n <annotation> $\\theta $</annotation>\n </semantics></math>-<span></span><math>\n <semantics>\n <mrow>\n <mi>q</mi>\n </mrow>\n <annotation> $q$</annotation>\n </semantics></math>) similarity in the atmospheric surface layer, yet the underlying physical mechanisms driving this dissimilarity remain underexplored. This study employs large-eddy simulations coupled with a land-surface model to investigate <span></span><math>\n <semantics>\n <mrow>\n <mi>θ</mi>\n </mrow>\n <annotation> $\\theta $</annotation>\n </semantics></math>-<span></span><math>\n <semantics>\n <mrow>\n <mi>q</mi>\n </mrow>\n <annotation> $q$</annotation>\n </semantics></math> similarity in the convective boundary layer (CBL) over surfaces with varying scales of surface moisture heterogeneity. Results reveal that as the heterogeneity scale increases, patch-scale thermally induced circulations develop and interact with cellular turbulent organized structures, significantly altering scalar transport and turbulence dynamics. The patch-scale thermally induced circulations enhance horizontal advection, modify the production and transport of scalar variances, and lead to a disproportionate increase in the standard deviations of temperature (<span></span><math>\n <semantics>\n <mrow>\n <msub>\n <mi>σ</mi>\n <mi>θ</mi>\n </msub>\n </mrow>\n <annotation> ${\\sigma }_{\\theta }$</annotation>\n </semantics></math>) and humidity (<span></span><math>\n <semantics>\n <mrow>\n <msub>\n <mi>σ</mi>\n <mi>q</mi>\n </msub>\n </mrow>\n <annotation> ${\\sigma }_{q}$</annotation>\n </semantics></math>), accompanied by a reduction in <span></span><math>\n <semantics>\n <mrow>\n <mi>θ</mi>\n </mrow>\n <annotation> $\\theta $</annotation>\n </semantics></math>-<span></span><math>\n <semantics>\n <mrow>\n <mi>q</mi>\n </mrow>\n <annotation> $q$</annotation>\n </semantics></math> covariance (<span></span><math>\n <semantics>\n <mrow>\n <mover>\n <mrow>\n <msup>\n <mi>θ</mi>\n <mo>′</mo>\n </msup>\n <msup>\n <mi>q</mi>\n <mo>′</mo>\n </msup>\n </mrow>\n <mo>‾</mo>\n </mover>\n </mrow>\n <annotation> $\\overline{{\\theta }^{\\mathit{\\prime }}{q}^{\\mathit{\\prime }}}$</annotation>\n </semantics></math>). As a result, <span></span><math>\n <semantics>\n <mrow>\n <mi>θ</mi>\n </mrow>\n <annotation> $\\theta $</annotation>\n </semantics></math>-<span></span><math>\n <semantics>\n <mrow>\n <mi>q</mi>\n </mrow>\n <annotation> $q$</annotation>\n </semantics></math> similarity is substantially reduced throughout the CBL. Spectral analysis reveals that <span></span><math>\n <semantics>\n <mrow>\n <mi>θ</mi>\n </mrow>\n <annotation> $\\theta $</annotation>\n </semantics></math>-<span></span><math>\n <semantics>\n <mrow>\n <mi>q</mi>\n </mrow>\n <annotation> $q$</annotation>\n </semantics></math> dissimilarity is most strongly influenced by turbulent motions at scales corresponding to patch lengths. The findings offer insights into the role of surface heterogeneity in shaping scalar similarity in the CBL, with implications for land-atmosphere interactions and parameterization in numerical models.</p>","PeriodicalId":15986,"journal":{"name":"Journal of Geophysical Research: Atmospheres","volume":"130 12","pages":""},"PeriodicalIF":3.8000,"publicationDate":"2025-06-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2025JD043698","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of Geophysical Research: Atmospheres","FirstCategoryId":"89","ListUrlMain":"https://onlinelibrary.wiley.com/doi/10.1029/2025JD043698","RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"METEOROLOGY & ATMOSPHERIC SCIENCES","Score":null,"Total":0}
引用次数: 0
Abstract
Surface moisture heterogeneity degrades temperature-humidity (-) similarity in the atmospheric surface layer, yet the underlying physical mechanisms driving this dissimilarity remain underexplored. This study employs large-eddy simulations coupled with a land-surface model to investigate - similarity in the convective boundary layer (CBL) over surfaces with varying scales of surface moisture heterogeneity. Results reveal that as the heterogeneity scale increases, patch-scale thermally induced circulations develop and interact with cellular turbulent organized structures, significantly altering scalar transport and turbulence dynamics. The patch-scale thermally induced circulations enhance horizontal advection, modify the production and transport of scalar variances, and lead to a disproportionate increase in the standard deviations of temperature () and humidity (), accompanied by a reduction in - covariance (). As a result, - similarity is substantially reduced throughout the CBL. Spectral analysis reveals that - dissimilarity is most strongly influenced by turbulent motions at scales corresponding to patch lengths. The findings offer insights into the role of surface heterogeneity in shaping scalar similarity in the CBL, with implications for land-atmosphere interactions and parameterization in numerical models.
期刊介绍:
JGR: Atmospheres publishes articles that advance and improve understanding of atmospheric properties and processes, including the interaction of the atmosphere with other components of the Earth system.