Land-Atmosphere Interactions

by

Geoffrey M. Henebry, Nathan J. Moore, Jiquan Chen

• LAST MODIFIED: 15 January 2020
• DOI: 10.1093/obo/9780199874002-0218

Introduction

Land-atmosphere interactions encompass a multitude of processes that link the land surface with the atmospheric boundary layer. Interactions are bidirectional, include energy and material exchanges, and can include feedbacks that can amplify or attenuate coupled processes. Shortwave radiation drives most of the biogeophysical processes at the land surface. Photosynthetically active radiation (PAR) is the subset of shortwave radiation (400–700 nanometers) and is critical for most life on the planet. Thermal infrared is the more energetic subset of terrestrial radiation that results primarily from interactions of solar radiation with the land surface. Microwaves are an important subset of terrestrial radiation that facilitate monitoring both atmosphere and land surface. Net radiation is the energy left over after accounting for incoming direct and indirect solar radiation less outgoing solar radiation reflected by the surface, plus incoming longwave radiation (from water vapor and other gases in the atmosphere and terrestrial materials within view of the surface), less outgoing longwave radiation from the land surface. This radiation remaining at an “ideal surface” can be simply partitioned into energy transferred into the surface (ground heat flux) plus energy transferred to heat the atmosphere above the surface (sensible heat flux) plus energy transferred via evapotranspiration (latent heat flux) to moisten the atmosphere. Additionally, objects on the surface can absorb radiation and later radiate this stored heat. Photosynthesis uses only a small portion of incident energy. Precipitation on the surface may (1) return to the atmosphere as water vapor (latent heat flux), (2) move as liquid laterally to another surface point (runoff), (3) move as liquid below the surface (drainage), (4) be retained at or below the surface, including in the soil (storage), (5) be transported away, if frozen, from the surface by wind (advection), or combinations of these. Material exchanges between surface and atmosphere include mineral dust, organic particles, biota, and biological materials such as pollen, seeds, combustion products, volcanic ash and ejecta, trace gas emissions, and anthropogenic emissions from stationary and mobile sources. Interactions between the land surface and lower portion of the atmosphere at various time scales from seconds to centuries are influenced by the amount and type of incident sunlight, radiative characteristics of the materials at the surface, amount of moisture at and below the surface, vegetation amount and type, soils and substrate, vertical structures at the surface that affect wind, land cover type and arrangement, atmospheric constituents, and recent weather. Here we focus on interactions moving from land to the atmosphere.

General Overviews

Betts, et al. 1996 reviews how the atmosphere’s behavior is driven by multiple processes controlled by the land surface at a variety of scales. Seneviratne, et al. 2010 illustrates how vegetation, soil moisture, agriculture, and other surface characteristics strongly influence the surface energy budget and partitioning between latent and sensible heat fluxes, which in turn affect temperature and precipitation. Pitman 2003 describes how these land characteristics and processes have been incorporated into increasingly complex computer simulations at global to regional scales. At the mesoscale, Pielke 2001 demonstrates how spatial distributions of soils and vegetation can also influence the boundary layer. Mahmood, et al. 2014 reviews current understanding of the multiple influences of land cover change on climate and identifies open questions, making recommendations for future research.

• Betts, A. K., J. H. Ball, A. C. Beljaars, M. J. Miller, and P. A. Viterbo. “The Land Surface‐Atmosphere Interaction: A Review Based on Observational and Global Modeling Perspectives.” Journal of Geophysical Research: Atmospheres 101.D3 (1996): 7209–7225.

  DOI: 10.1029/95JD02135

  Describes the framework for how land processes moderate fluxes, with more focus at regional scales and mesoscales.

• Pielke, R. A., Sr. “Influence of the Spatial Distribution of Vegetation and Soils on the Prediction of Cumulus Convective Rainfall.” Reviews of Geophysics 39.2 (2001): 151–177.

  DOI: 10.1029/1999RG000072

  Provides an overview of how spatial patterns in the surface energy budget affect atmospheric processes.

• Pitman, A. J. “The Evolution of, and Revolution in, Land Surface Schemes Designed for Climate Models.” International Journal of Climatology 23.5 (2003): 479–510.

  DOI: 10.1002/joc.893

  An overview of how the land surface is digitized and represented in climate models, and the limitations.

• Mahmood, R., R. A. Pielke Sr., K. G. Hubbard, et al. “Land Cover Changes and Their Biogeophysical Effects on Climate.” International Journal of Climatology 34.4 (2014): 929–953.

  DOI: 10.1002/joc.3736

  Reviews changes in major types of land (agriculture, deforestation, urbanization, and desertification) and how these fit into the climate system.

• Seneviratne, S. I., T. Corti, E. L. Davin, et al. “Investigating Soil Moisture–Climate Interactions in a Changing Climate: A Review.” Earth-Science Reviews 99.3–4 (2010): 125–161.

  DOI: 10.1016/j.earscirev.2010.02.004

  Excellent starting point for examining land-atmosphere feedbacks. A concise summary about quantifying how soil moisture, vegetation, precipitation, and temperature and which processes are and are not well understood.