Search USGS⌕ Search
Home/Archive/USGS

USGS · 70201211

Geometric versus anemometric surface roughness for a shallow accumulating snowpack

Jessica E. Sanow·Steven R. Fassnacht·David J. Kamin·Graham A. Sexstone·William L. Bauerle·Iuliana Oprea
View original source ↗Export metadata ↓

Abstract

When applied to a snow-covered surface, aerodynamic roughness length, z 0 , is typically considered as a static parameter within energy balance equations. However, field observations show that z 0 changes spatially and temporally, and thus z 0 incorporated as a dynamic parameter may greatly improve models. To evaluate methods for characterizing snow surface roughness, we compared concurrent estimates of z 0 based on (1) terrestrial light detection and ranging derived surface geometry of the snowpack surface (geometric, z 0 G ) and (2) vertical wind profile measurements (anemometric, z 0 A ). The value of z 0 G was computed from Lettau’s equation and underestimated z 0 A but compared well when scaled by a factor of 2.34. The Counihan method for computing z 0 G was found to be unsuitable for estimating z 0 on a snow surface. During snowpack accumulation in early winter, z 0 varied as a function of the snow-covered area (SCA). Our results show that as the SCA increases, z 0 decreases, indicating there is a topographic influence on this relation.

Explore related subjects

GeosciencesArticle

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Jessica E. Sanow, Steven R. Fassnacht, David J. Kamin, Graham A. Sexstone, William L. Bauerle, Iuliana Oprea. 2018-12-06. Geometric versus anemometric surface roughness for a shallow accumulating snowpack. https://doi.org/10.3390/geosciences8120463

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related USGS reports

USGS2026

The mineral chemistry networks of tin and tungsten reflect metallogenic eras of the Mesozoic

Continental remobilization is a crucial driver of metallogenesis and the formation of ore deposits. Some of the world’s largest mineral deposits of the economically valuable elements tin (Sn), tungsten (W), gold (Au), copper (Cu), lead (Pb), and zinc (Zn) formed during the Mesozoic Era. Additionally, the chemistry and distribution of the elements Sn and W have been investigated in previous studies to understand planetary formation and differentiation processes. These two elements are largely co-located during certain South China Mesozoic metallogenic events but are not co-located during other time periods in the same regions. Here, we investigated the mineral chemistry network similarities and dissimilarities of Sn and W to understand their mineral formation and distribution during the Mesozoic Era and throughout Earth history. Mineral chemistry network community detection analysis and electronegativity associations among mineral constituent elements of Sn minerals and W minerals indicate that the elements have similar chemistry among their oxide minerals. However, Sn forms a much wider range of minerals that also contain S compared to W, which occurs in a limited number of S-containing minerals. The divergent constituent element interactions among S-containing Sn minerals and W minerals reflect the redox sensitivity and importance of oxygen (O) fugacity in Sn mineral formation. Conversely, extensive W mineral deposits are known to form at both high and low O fugacities. The similarities and differences between the mineral chemistry networks of Sn and W reflect the mineral distribution of the two elements in the Sn-W mineralization event from 160 to 139 Ma vs. the Sn–uranium (U) mineralization event from 125 to 98 million years ago (Ma). The mineral chemistry and distribution of Mesozoic Sn and W deposits illustrate the contrasting importance of redox and O fugacity on the mineral formation of different elements, and the dynamic crustal evolution that took place during this period of Earth history.

Geosciences↗
USGS2023

Using an open-source tool to develop a three-dimensional hydrogeologic framework of the Kobo Valley, Ethiopia

Groundwater resource management requires understanding the groundwater basin’s hydrogeology and would be improved with the development of a three-dimensional hydrogeologic framework model (HFM). A wide range of methods and software exist to quantify the extent, structure, and properties of geologic systems. However, most geologic software is proprietary and cost-prohibitive for use in developing countries. GemPy is a Python-based, open-source (no-cost) tool for generating three-dimensional geological models. This study uses available data and GemPy to develop the Kobo Valley Hydrogeologic Framework Model (KV-HFM), a three-dimensional HFM for Kobo Valley in northern Ethiopia, which is part of the East African Rift System. The KV-HFM is a conceptual model that comprises the hydrostratigraphy, structural features, and hydraulic properties of the Kobo Valley groundwater system. The limited data described the extent and altitude of the hydrostratigraphic units using the GemPy implicit potential–field interpolation. The KV-HFM showed the existence of an east-to-west, structural-based groundwater divide composed of volcanic rock and clay. This divide splits the catchment into two groundwater systems with limited interconnected flow. This study illustrates the use of open-source software for developing an HFM using sparse, existing geologic data.

Afar Depression, Kobo Valley catchment↗
USGS2023

The relative stability of planktic foraminifer thermal preferences over the past 3 million years

Stationarity of species’ ecological tolerances is a first-order assumption of paleoenvironmental reconstruction based upon analog methods. To test this and other assumptions used in quantitative analysis of foraminiferal faunas for paleoceanographic reconstruction, we analyzed paired alkenone unsaturation ratio ( U 37 K ′ )   "> U K ′ 37 ) 37′) sea surface temperature (SST) estimates and relative abundances of planktic foraminifera within Late Pliocene assemblages. We established Pliocene temperature preferences for nine species in the North Atlantic: Dentoglobigerina altispira, Globorotalia menardii, Globoconella puncticulata, Neogloboquadrina atlantica, Neogloboquadrina incompta, Neogloboquadrina pachyderma, Trilobatus sacculifer, Globigerinita glutinata, and Globigerina bulloides. We compared these to the temperature preferences of the same extant species, and in the three cases where the species are now extinct ( Dentoglobigerina altispira, Neogloboquadrina atlantica, and Globoconella puncticulata ), comparisons were made to either the descendant species or other modern species commonly used as analogs. In general, the taxa tested show similar temperature responses in both Late Pliocene and present-day (core-top) distributions. The data from these comparisons are mostly encouraging, supporting past paleoceanographic conclusions, and are otherwise valuable for testing previous taxonomic grouping decisions that are often necessary for interpreting the paleoenvironment based upon Pliocene foraminiferal assemblages.

Geosciences↗