Scaling Land‐Atmosphere Interactions: Special or Fundamental?

Abstract

Viewed from billions of kilometers away in space, Earth appears as a single "Pale Blue Dot," in the immortalized phrase of Carl Sagan bestowed upon the image taken by the Voyager 1 space probe. Coming closer, though, a sharper image emerges (Figure 1).One finds structure to that dot, shades of green and brown continents, a dark ocean, a bright cryosphere, and a hazy, thin blue atmosphere. Zooming further in, those components break into patterns of mountains and rivers, seas and bays, forests and grasslands, layers, and cloud decks. And getting closer, one finds each component has oscillations and variations of branches and rivulets, canyons and plateaus, currents and coastlines. These objects keep revealing more structure in finer, often self-similar form, like Mandelbrot's fractals, down to eddies and organisms, and further into leaves, cells, enzymes, molecules, and atoms.And then, if you wait seconds, days, decades, or eons, landscape patterns change. Bigger things typically take longer than smaller ones. As a result, the pattern changes-sometimes occurring slowly and subtly, ebbing and flowing in an oscillatory manner, or they can occur quickly and abruptly, morphing into a new state of order.Each element and its dynamics come with variations in space and time that can be encompassed by the concept of scale. Earth systems science is preoccupied with the interactions of these elements, which cannot be understood without a stipulation of the scales of interest (Ge et al., 2019). The most straightforward of these interactions are ones where common processes at all scales can be defined by a single relationship, often a power-law, leading to the concept of scale invariance (Paleri et al., 2022). The most interesting interactions are the ones that break those rules and lead to "upscale" and "downscale" behavior, whereby processes at one scale determine the shape and function of another scale. These are most common at the intersections of biology, hydrology, geology, and meteorology, often within what is termed the "critical zone." This interlocking also harkens to the origins of

Drivers of Decadal Carbon Fluxes Across Temperate Ecosystems

“…Some of this may be in our understanding of the footprint representation from the tall tower, while others may be in the importance of hot‐spots and hot‐moments in the landscape that contribute disproportionately to the flux but are difficult to sample with traditional flux tower techniques. Emerging approaches that account for footprint variation and landscape drivers of extreme fluxes (e.g., Xu et al., 2017 ) are essential to advance scaling fluxes needed for landscape ecology (Desai et al., 2022 ), natural climate solution verification (Novick et al., 2022 ), and global carbon budgeting and comparisons to top‐down estimates (Desai et al., 2010 ).…”

Airborne Measurements of Scale‐Dependent Latent Heat Flux Impacted by Water Vapor and Vertical Velocity Over Heterogeneous Land Surfaces During the CHEESEHEAD19 Campaign

“…Water vapor variability on scales has a significant impact on cloud and precipitation development, but it has not yet been fully understood and characterized comparable to the finest resolutions of climate and weather models due to the atmospheric responses from energy balance on land surface heterogeneity (Fischer et al., 2013; Sherwood et al., 2010; H. Wang et al., 2010). The land surface is usually heterogeneous over a wide range of spatial scales due to variability in (among other parameters) vegetation, terrain, soil texture and wetness, cloud cover, and urban areas (Desai et al., 2005; Desai, Paleri, et al., 2022; Mahrt, 2000). However, measurements at a single location, such as eddy correlation flux towers, are often used to represent the properties of a larger region.…”

“…Wang et al, 2010). The land surface is usually heterogeneous over a wide range of spatial scales due to variability in (among other parameters) vegetation, terrain, soil texture and wetness, cloud cover, and urban areas (Desai et al, 2005;Desai, Paleri, et al, 2022;Mahrt, 2000). However, measurements at a single location, such as eddy correlation flux towers, are often used to represent the properties of a larger region.…”

Airborne Measurements of Scale-Dependent Latent Heat Flux Impacted by Water Vapor and Vertical Velocity over Heterogeneous Land Surfaces During the CHEESEHEAD19 Campaign

“…The land surface is usually heterogeneous over a wide range of spatial scales due to variability in, among other parameters, vegetation, terrain, soil texture and wetness, cloud cover, and urban areas (Mahrt, 2000;Desai et al, 2005;Desai et al, 2022b). However, measurements at a single location, such as eddy correlation flux towers, are often used to represent the properties of a larger region.…”