scholarly journals Shrub expansion modulates belowground impacts of changing snow conditions in alpine grasslands

2021 ◽  
Author(s):  
Arthur A. D. Broadbent ◽  
Michael Bahn ◽  
William J. Pritchard ◽  
Lindsay K. Newbold ◽  
Tim Goodall ◽  
...  
Keyword(s):  
Shrub Expansion ◽  
Alpine Grasslands ◽  
Snow Conditions

A Double Interaction Brush Model for Snow Conditions

2019 ◽  
Vol 47 (2) ◽  
pp. 118-140
Author(s):  
Artem Kusachov ◽  
Fredrik Bruzelius ◽  
Mattias Hjort ◽  
Bengt J. H. Jacobson
Keyword(s):  
Low Complexity ◽  
Large Set ◽  
Tire Model ◽  
Vehicle Handling ◽  
Real Time Applications ◽  
Snow Conditions ◽  
Double Interaction ◽  
Tire Models ◽  
Force Characteristics ◽  
Model Approach

ABSTRACT Commonly used tire models for vehicle-handling simulations are derived from the assumption of a flat and solid surface. Snow surfaces are nonsolid and may move under the tire. This results in inaccurate tire models and simulation results that are too far from the true phenomena. This article describes a physically motivated tire model that takes the effect of snow shearing into account. The brush tire model approach is used to describe an additional interaction between the packed snow in tire tread pattern voids with the snow road surface. Fewer parameters and low complexity make it suitable for real-time applications. The presented model is compared with test track tire measurements from a large set of different tires. Results suggest higher accuracy compared with conventional tire models. Moreover, the model is also proven to be capable of correctly predicting the self-aligning torque given the force characteristics.

Distribution characteristics of soil carbon during forage greening in different alpine grasslands of Eastern Qilian Mountains

2009 ◽  
Vol 17 (6) ◽  
pp. 1111-1116
Author(s):  
Cheng-De YANG ◽  
Xiu-Rong CHEN ◽  
Rui-Jun LONG ◽  
Li Xue ◽  
Zhen-Fen ZHANG
Keyword(s):  
Soil Carbon ◽  
Qilian Mountains ◽  
Distribution Characteristics ◽  
Alpine Grasslands

Soil C mineralization and temperature sensitivity in alpine grasslands of the Qinghai-Xizang Plateau

2014 ◽  
Vol 37 (11) ◽  
pp. 988-997 ◽  
Author(s):  
Li XU ◽  
Shu-Xia YU ◽  
Nian-Peng HE ◽  
Xue-Fa WEN ◽  
Pei-Li SHI ◽  
...  
Keyword(s):  
Temperature Sensitivity ◽  
C Mineralization ◽  
Alpine Grasslands ◽  
Soil C ◽  
Xizang Plateau

Patterns and processes of global shrub expansion

2011 ◽  
Vol 35 (4) ◽  
pp. 423-442 ◽  
Author(s):  
Adam T. Naito ◽  
David M. Cairns
Keyword(s):  
Simulation Modeling ◽  
Satellite Remote Sensing ◽  
Aerial Photograph ◽  
The Arctic ◽  
Shrub Expansion ◽  
Global Land ◽  
Technological Developments ◽  
Management Policies ◽  
Patterns And Processes ◽  
Land Types

Shrub expansion is a global phenomenon that is occurring on savannas, rangelands, and grasslands. In addition, this is an increasingly documented occurrence in the Arctic. Numerous recent studies have strived to pinpoint the drivers of this phenomenon, quantify the changes, and understand their implications for regional and global land use, disturbance regimes, and nutrient cycling. Inquiry into these topics has been facilitated by recent technological developments in satellite remote sensing, aerial photograph analysis, and computer simulation modeling. We provide a new review that accounts for more recent studies in these regions, Arctic shrub expansion, and technological and analytical developments. This four-part discussion focuses on observed patterns of shrub expansion in three rangeland types (desert grasslands, mesic grasslands, savannas) and the Arctic tundra, the primary causes of this expansion, critical comparisons and contrasts between these land types, and recommendations for future avenues of research. These new avenues can inform the development of future land management policies, as well as ongoing investigations to understand and mitigate the effects of climate change.

Declining human activity intensity on alpine grasslands of the Tibetan Plateau

2021 ◽  
Vol 296 ◽  
pp. 113198
Author(s):  
Meng Li ◽  
Xianzhou Zhang ◽  
Jianshuang Wu ◽  
Qiannan Ding ◽  
Ben Niu ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Human Activity ◽  
The Tibetan Plateau ◽  
Alpine Grasslands ◽  
Activity Intensity

scholarly journals Arctic riparian shrub expansion indicates a shift from streams gaining water to those that lose flow

2020 ◽  
Vol 1 (1) ◽  
Author(s):  
Anna K. Liljedahl ◽  
Ina Timling ◽  
Gerald V. Frost ◽  
Ronald P. Daanen
Keyword(s):  
Microbial Communities ◽  
Soil Microbial Communities ◽  
Late Summer ◽  
Field Measurements ◽  
The Arctic ◽  
Shrub Expansion ◽  
Riparian Ecosystems ◽  
Stream Length ◽  
Area Index ◽  
Soil Microbial

AbstractShrub expansion has been observed across the Arctic in recent decades along with warming air temperatures, but tundra shrub expansion has been most pronounced in protected landscape positions such as floodplains, streambanks, water tracks, and gullies. Here we show through field measurements and laboratory analyses how stream hydrology, permafrost, and soil microbial communities differed between streams in late summer with and without tall shrubs. Our goal was to assess the causes and consequences of tall shrub expansion in Arctic riparian ecosystems. Our results from Toolik Alaska, show greater canopy height and density, and distinctive plant and soil microbial communities along stream sections that lose water into unfrozen ground (talik) compared to gaining sections underlain by shallow permafrost. Leaf Area Index is linearly related to the change in streamflow per unit stream length, with the densest canopies coinciding with increasingly losing stream sections. Considering climate change and the circumpolar scale of riparian shrub expansion, we suggest that permafrost thaw and the resulting talik formation and shift in streamflow regime are occurring across the Low Arctic.

Two-source energy balance modeling of evapotranspiration in Alpine grasslands

2018 ◽  
Vol 209 ◽  
pp. 327-342 ◽  
Author(s):  
M. Castelli ◽  
M.C. Anderson ◽  
Y. Yang ◽  
G. Wohlfahrt ◽  
G. Bertoldi ◽  
...  
Keyword(s):  
Energy Balance ◽  
Alpine Grasslands
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