Snowpack control over the thermal offset of air and soil temperatures in eastern North Dakota

Abstract

The close relationship between air and ground temperatures has been used to reconstruct paleoclimate conditions from ground temperatures. Unfortunately, the presence of snow decouples air and ground temperatures and obscures their relationship. The objective of this paper is to investigate the role that snowpack conditions play in affecting the relationship between air and soil temperatures. The annual thermal offset between mean annual soil and air temperatures is examined over a 12 year period (1990–2002) at Fargo, ND, using observed soil temperatures along with simulations from a physically based snowpack model. Early season snow cover does not necessarily lead to large thermal offsets. These snowpacks, while low in density, also tended to be shallow and therefore do not provide much thermal insulation. Winter snowpacks explain a greater portion of the annual thermal offset. While denser than fall snowpacks, the extra depth and longer persistence leads to superior insulation of the ground.

Advancement toward coupling of the VAMPER permafrost model within the Earth system model <I>i</I>LOVECLIM (version 1.0): description and validation

“…Values between 1 and 6 • C were reported by Gold and Lachenbruch (1973). Monitoring studies of the air-ground temperature relationship also fall within this range, e.g., Beltrami and Kellman (2003), Bartlett et al (2005), Grundstein et al (2005), and Zhang (2005). However, larger values of 10 • C have been recorded in Alaska (Lawrence and Slater, 2010).…”

Land surface insulation response to snow depth variability

“…This study focuses on the insulative property of varying snow depth in an effort to establish this specific relationship as a substantial contributor to the overall land surface energy balance response to snow cover. The scientific literature on heat diffusion through a snow‐covered land surface deals primarily with snow cover presence or duration [ Goodrich , 1982; Gosnold et al , 1997; Schmidt et al , 2001; Ling and Zhang , 2003], although some studies have recognized a measurable influence of snow thickness and its insulative capability [ Smith and Riseborough , 1996; Gong et al , 2004; Grundstein et al , 2005]. A modeling approach is employed here to gain further insight by isolating the heat diffusion response to varying initial snow depths including snow‐free conditions and by assessing the magnitude of associated temperature and insulative energy flux anomalies within the entire snowpack–soil column system.…”

Characterizing Land–Atmosphere Coupling and the Implications for Subsurface Thermodynamics

“…Comparisons between the temporal and spatial variation in GST reconstructions and direct measurements of SAT have widely validated these assumptions (e.g., Chisholm and Chapman 1992;Beltrami et al 1992;Bodri andCermak 1995, 1997;Gosnold et al 1997;Harris and Gosnold 1999;Huang et al 2000;Harris and Chapman 2001;Roy et al 2002;Pollack et al 2003;Pollack and Smerdon 2004). At daily, seasonal, and annual time scales, however, thermal coupling between the air and subsurface can be highly variable, depending on meteorological conditions (e.g., Putnam and Chapman 1996;Zhang et al 2001;Schmidt et al 2001;Beltrami 2001;Baker and Baker 2002;Stieglitz et al 2003;Lin et al 2003;Beltrami and Kellman 2003;Smerdon et al 2003Smerdon et al , 2004Bartlett et al 2004;Grundstein et al 2005;Hu and Feng 2005). Nevertheless, several investigations have shown that differences between air and subsurface temperatures at these short time scales can be captured with simple conductive models that couple the atmosphere and ground with time-varying boundary layers that change according to meteorological conditions (Bartlett et al 2004;Pollack et al 2005;Bartlett et al 2005) or with statistical models that use seasonal meteorological conditions as predictors of air and ground temperature differences (Smerdon et al 2006).…”