The Effect of Coherent Structures in the Atmospheric Surface Layer on Blowing-Snow Transport

Dry-Air Entrainment and Advection during Alpine Blowing Snow Events

“…a hairpin bursting process) due to the complexity of the flow in this complex terrain. It very well may be the case that the sweep signatures are caused by both outerlayer and inner-layer motions as previously suggested by Aksamit and Pomeroy [2017]. The ejections occur less often because of the rarity of large positive ' values close to the snow surface, and are thus present only during a less common generating mechanism.…”

“…The modified VITA algorithm categorized a turbulent event as a sweep or ejection if the parameterized curve ( ) = 〈 ] ( ), ] ( )〉 passes through only one of the two quadrants during the event. The same methods were used by Aksamit and Pomeroy [2017] to identify and couple turbulent gusts with blowing snow events. In this study, the concurrent sonic temperature signal response was also measured and the fluctuation from the 15-minute mean air temperature was computed to identify the presence of relatively warmer or colder air during a particular event with respect to mean conditions.…”

“…Here, is the recurrence frequency of a given modified VITA turbulence event type, h and are fitting parameters with h known as the characteristic frequency. This scaling analysis focused on the case where q = 1 as this resulted in a good compromise between too many and too few events detected and is a standard value previously used for turbulent motion identification at this site [Aksamit and Pomeroy, 2017]. Though the present modified VITA analysis involves an additional step in the identification algorithm as compared to the original work of Kailas and Narasimha [1994], a similar invariance (small standard deviation) in the log of the return frequency, ( ), was present over varying averaging times for each VITA threshold v .…”

A Finite Volume Blowing Snow Model for Use With Variable Resolution Meshes

“…When distributed, these models couple blowing snow transport and sublimation using three-dimensional wind fields computed from atmospheric models, for example, SURFEX in Meso-NH/Crocus (Vionnet et al, 2014(Vionnet et al, , 2017, Alpine3D (Lehning et al, 2006), and SnowDrift3D (Schneiderbauer & Prokop, 2011), substantially increasing the computational costs. Aksamit and Pomeroy (2017) note that most models of blowing snow transport have been conceptualized for steady-state conditions based on time-averaged field or wind tunnel observations of snow particle flux and dispersion (Lehning et al, 2006;Pomeroy, 1989;Schmidt, 1986). Thresholds for the initiation or cessation of transport have been based on air temperature, occurrence of melt or rain, and snowpack age (Li & Pomeroy, 1997a, 1997b as well as surface grain type (Guyomarc'h & Mérindol, 1998).…”

response to RC2 M. Lehning

“…The formulation of an official consensus may have been hindered by the use of analogous terminologies for the description of diverse meteorological conditions, (without systematic detailed explanations of the semantics used) to the extent that it would, maybe, ideally require a conciliation meeting some day. However, the definition using a standard level of 2 m in height as a distinction criteria has been widely employed over the recent years in publications dealing with snow transport in Antarctica (e.g., Leonard et al, 2011;Lenaerts et al, 2012;Gossart et al, 2017;Trouvilliez et al, 2014;Palm et al, 2017Palm et al, , 2018a while we found no clear evidence of a distinction involving analogy between drifting and saltating snow from one hand and blowing and suspended snow on the other hand, even in the most recent publications dedicated to the characterization of specific aeolian processes (e.g., Aksamit and Pomeroy, 2017;Crivelli et al, 2016;Huang and Wang, 2016;Sharma et al, 2018). In addition, and from our point of view, one could argue that this requires the use of different words for referring to the same mechanism C5 TCD Interactive comment Printer-friendly version Discussion paper (saltation/drifting and suspension/blowing) which could eventually be a bit confusing in some way.…”