Land–Atmosphere Interactions: The LoCo Perspective

Abstract

Land–atmosphere (L-A) interactions are a main driver of Earth’s surface water and energy budgets; as such, they modulate near-surface climate, including clouds and precipitation, and can influence the persistence of extremes such as drought. Despite their importance, the representation of L-A interactions in weather and climate models remains poorly constrained, as they involve a complex set of processes that are difficult to observe in nature. In addition, a complete understanding of L-A processes requires interdisciplinary expertise and approaches that transcend traditional research paradigms and communities. To address these issues, the international Global Energy and Water Exchanges project (GEWEX) Global Land–Atmosphere System Study (GLASS) panel has supported “L-A coupling” as one of its core themes for well over a decade. Under this initiative, several successful land surface and global climate modeling projects have identified hot spots of L-A coupling and helped quantify the role of land surface states in weather and climate predictability. GLASS formed the Local Land–Atmosphere Coupling (LoCo) project and working group to examine L-A interactions at the process level, focusing on understanding and quantifying these processes in nature and evaluating them in models. LoCo has produced an array of L-A coupling metrics for different applications and scales and has motivated a growing number of young scientists from around the world. This article provides an overview of the LoCo effort, including metric and model applications, along with scientific and programmatic developments and challenges.

Land–atmospheric feedbacks during droughts and heatwaves: state of the science and current challenges

“…More mechanistic approaches have focused on the effects of soil moisture and vegetation on the state and evolution of the atmospheric boundary layer, and how these effects affect convection, air temperature, and rainfall . To do so, a wide range of diagnostics have been developed in recent decades that characterize the effect of land on local convection and rainfall, many of them being embraced within the international Global Energy and Water Exchanges (GEWEX) Local Land–Atmosphere Coupling (LoCo) project, dedicated to examining these interactions to yield new process understanding . However, only recently, some of these studies have focused specifically on periods of drought .…”

Sensitivity of Surface Temperature to Land Use and Land Cover Change‐Induced Biophysical Changes: The Scale Issue

“…Recently, there have been many studies employing simple models to quantify or interpret the sensitivities of surface temperature to LULCC‐induced biophysical changes (Baldocchi & Ma, ; Boisier et al, ; Cronin, ; Juang, Katul, et al, ; Lee et al, ; Luyssaert et al, ; Rigden & Li, ). Nearly all of these models can find their roots in earlier work on local land‐atmosphere interaction and coupling (see recent reviews by Betts, and Santanello et al, ). A common assumption in local land‐atmosphere interaction studies is that the land surface is horizontally homogenous or uniform and thus land‐atmosphere coupling is strictly a vertical problem.…”

Large‐eddy simulation of catchment‐scale circulation

“…The variation in surface heat fluxes determines the horizontal temperature gradient, which in turn determines the near‐surface pressure gradient creating ensuing circulations (Mahrt et al, ; Courault et al, ; Maronga and Raasch, ). Several observation campaigns were also carried out recently to improve the understanding of land–atmosphere interactions and boundary‐layer processes over heterogeneous surfaces (Santanello et al, ; Wulfmeyer et al, ).…”