a r t i c l e i n f o The distribution of mountain permafrost along Trail Ridge Road (TRR) in Rocky Mountain National Park, Colorado, was modeled using 'frost numbers' and a 'temperature of permafrost model' (TTOP) in order to assess the accuracy of prediction models. The TTOP model is based on regional observations of air temperature and heat transfer functions involving vegetation, soil, and ...

Frost boils in northern Alaska vary from large, 2–3-m diameter, barren non-sorted circles to completely vegetated hummocks. Summer warmth increases southwards from the coast. Average thaw-layer thickness shows the opposite trend. Frost heave shows no trend along the climate gradient but is affected by soil texture. Heave is greatest on frost boils with fine-grained sediments. Biomass increases ...

Tree roots of northern hardwoods are shallow rooted, winter active, and minimally frost hardened; dieback is a winter freezing injury to roots incited by frost penetration in the absence of adequate snow cover and exacerbated by drought in summer. High soil water content greatly increases conductivity of frost. We develop a model based on the sum of z-scores of soil frost (December–February) an...

As one of the emerging soil improvement techniques, microbial induced calcite precipitation (MICP) can bond soil grains together and improve the engineering properties of soil [1]. bacteria produces urease enzyme can catalyze urea to carbonate and result in calcite precipitation in elevated pH environment. The forms of calcite precipitation around the bacteria limit the availability of oxygen a...

The effect of various electrolytes on the adsorption of poliovirus was measured in 250-cm-long soil columns with ceramic samplers at different depths. Viruses suspended in deionized water moved much farther through the soil than those suspended in tap water, whereas movement in sewage water was intermediate. The salt content of the tap water and sewage water promoted virus adsorption, but evide...

The genesis of some types of patterned ground, including hummocks, frost boils and sorted stone circles, has been attributed to differential frost heave (DFH). However, a theoretical model that adequately describes DFH has yet to be developed and validated. In this paper, we present a mathematical model for the initiation of DFH, and discuss how variations in physical (i.e. soil/vegetation prop...

Some of arid regions problems of Iran are saline and sodic soils. In improvement and reclamation of Iranian arid rangelands, some foreign species of Atriplex had been imported and adapted for many years ago. The most adapted species was Atriplex canescens. At the present research, some environmental factors, vegetative characteristics (Na, Ca, Mg and K), soil properties (moisture, EC, pH, solut...

The variation in the frost structure on a number of microgrooved brass surfaces is examined through an experimental study. The microgrooved samples are 45 mm x 45 mm in dimension with a broad range of groove dimensions. Frost is grown on these microgrooved surfaces under natural convection for a range of plate temperature (-8 to -18 C) and relative humidity (30-70%) conditions. The frost struct...