Historical late-winter and spring snowpack depth and equivalent water-content data for Maine

2005 ◽  
Author(s):  
Glenn A. Hodgkins ◽  
Robert W. Dudley ◽  
Marc C. Loiselle
Keyword(s):  
Water Content ◽  
Late Winter

scholarly journals Cold Hardiness of Floral Buds of Deciduous Azaleas: Dehardening, Rehardening, and Endodormancy in Late Winter

2007 ◽  
Vol 132 (1) ◽  
pp. 73-79 ◽  
Author(s):  
Scott R. Kalberer ◽  
Rajeev Arora ◽  
Norma Leyva-Estrada ◽  
Stephen L. Krebs
Keyword(s):  
Water Content ◽  
Cold Hardiness ◽  
Late Winter ◽  
Chilling Requirement ◽  
Early Winter ◽  
Freeze Injury ◽  
Woody Perennials ◽  
Freeze Thaw ◽  
Floral Buds ◽  
Chilling Units

Dehardening resistance and rehardening capacity in late winter and spring are important factors contributing to the winter survival of woody perennials. Previously the authors determined the midwinter hardiness, dehardening resistance, and rehardening capacities in deciduous azalea (Rhododendron L.) floral buds in early winter. The purpose of this study was to investigate how these parameters changed as winter progressed and to compare rehardening response at three treatment temperatures. Experiments were also conducted to measure bud water content during dehardening and chilling accumulation of 10 azalea genotypes. Buds of R. arborescens (Pursh) Torr., R. canadense (L.) Torr., R. canescens (Michx.) Sweet, and R. viscosum (L.) Torr. var. montanum Rehd. were acclimated in the field and were dehardened in the laboratory at controlled warm temperatures for various durations. Dehardened buds were rehardened for 24 hours at 2 to 4 °C, 0 °C, or –2 °C. Bud hardiness (LT50) was determined from visual estimates of freeze injury during a controlled freeze–thaw regime. The midwinter bud hardiness in the current study was ≈4 to 8 °C greater than in early winter. R. canadense and R. viscosum var. montanum dehardened to a larger extent in late winter than in the early winter study whereas R. arborescens and R. canescens did not. The rehardening capacities were larger in early than in late winter. Even though rehardening occurred throughout the first 8 days of dehardening (DOD) in early winter in the previous study, in the current study it was only observed after 10 DOD (R. viscosum var. montanum) or 15 DOD (R. arborescens). There was no difference among the rehardening capacities at the three rehardening temperatures for any genotype. Water content decreased throughout dehardening in all four genotypes examined. R. canadense had the lowest chilling requirement (CR) [450 chilling units (CU)], followed by R. atlanticum (Ashe) Rehd., R. austrinum (Small) Rehd., R. canescens, and R. calendulaceum (Michx.) Torr. with intermediate CR [820, 830, 830, and 1000 CU respectively). The CR of R. arborescens, R. prinophyllum (Small) Millais, R. prunifolium (Small) Millais, R. viscosum var. montanum, and R. viscosum var. serrulatum (Small) Millais exceeded 1180 CU. Results of this study indicate that the dehardening kinetics (magnitude and rate) and the rehardening capacity of azalea buds are influenced by the progression of winter and the depth of endodormancy.

Survey of microphysical properties of marine boundary-layer clouds in the Western North Atlantic 

2021 ◽  
Author(s):  
Simon Kirschler ◽  
Christiane Voigt ◽  
Andrew S. Ackerman ◽  
Bruce Anderson ◽  
Gao Chen ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Water Content ◽  
North Atlantic ◽  
Radiation Budget ◽  
Late Winter ◽  
Western Atlantic ◽  
Low Level ◽  
Aerosol Cloud ◽  
Microphysical Properties ◽  
Cloud Properties

<p>Oceanic low level clouds strongly affect the atmospheric radiation budget. Uncertainties in their microphysical properties and cover currently limit the accuracy of climate predictions. Further, studies quantifying the relative importance of aerosol and dynamics on cloud properties in specific meteorological regimes are poorly constrained by observations in the Western North Atlantic boundary layer.</p><p>Low level clouds were measured during the Aerosol Cloud meTereology Interactions oVer the western ATlantic Experiment (ACTIVATE) campaign in winter and summer 2020. The two NASA LaRC research aircraft HU-25 Falcon and UC-12 B-200 King Air conducted 35 simultaneous flights to investigate aerosol-cloud interactions of maritime clouds and their impact on radiation. Number concentration, liquid water content, ice water content, and particle size distribution in the size range of 3 µm to 1460 µm in diameter were measured with the fast forward scattering cloud probe (FCDP) and 2-dimensional optical array imaging probe (2D-S) onboard the Falcon. Here, we present an overview of late winter (February-March) and late summer (August-September) oceanic cloud properties in the region 65°W to 80°W and 30°N to 40°N. We compare cloud properties in these two seasons and investigate their dependence on meteorological parameters and aerosol abundance. In a case study, we present cloud observations in a cold air outbreak event on 1 March 2020 with a specific focus on mixed-phase clouds.</p>

Snow Wetness Influence on Impulse Radar Snow Surveys Theoretical and Laboratory Study

2000 ◽  
Vol 31 (2) ◽  
pp. 89-106 ◽  
Author(s):  
A. Lundberg ◽  
H. Thunehed
Keyword(s):  
Water Content ◽  
Liquid Water ◽  
Snow Water Equivalent ◽  
Liquid Water Content ◽  
Late Winter ◽  
Propagation Time ◽  
Reservoir Water ◽  
A Value ◽  
Wet Snow ◽  
Snow Water

The snow-water equivalent of late-winter snowpack is of utmost importance for hydropower production in areas where a large proportion of the reservoir water emanates from snowmelt. Impulse radar can be used to estimate the snow-water equivalent of the snowpack and thus the expected snowmelt discharge. Impulse radar is now in operational use in some Scandinavian basins. With radar technology the radar wave propagation time in the snowpack is converted into snow-water equivalent with help of a parameter usually termed the a-value. Use of radar technology during late winter brings about risk for measurements on wet snow. The a-value for dry snow cannot be used directly for wet snow. We have found that a liquid-water content of 5% (by volume) reduces the a-value by approximately 20%. In this paper an equation, based on snow density and snow liquid water content, for calculation of wet-snow a-value is presented.

Biomass production of several jack pine provenances at three Lake States locations

1981 ◽  
Vol 11 (2) ◽  
pp. 441-447 ◽  
Author(s):  
J. Zavitkovski ◽  
R. M. Jeffers ◽  
H. Nienstaedt ◽  
T. F. Strong
Keyword(s):  
Water Content ◽  
Biomass Production ◽  
Dry Weight ◽  
Jack Pine ◽  
Late Winter ◽  
Total Biomass ◽  
Component Distribution ◽  
Source Selection ◽  
Annual Biomass ◽  
Lake States

Total biomass, biomass production, component distribution, and water content of stems and branches were estimated in 24- and 25-year-old jack pine (Pinusbanksiana Lamb.) stands of four provenances planted at three Lake States locations. The initial spacing was 1.5 × 1.5 m (5 × 5 ft). Total biomass and mean annual biomass production (MAB) were negatively related to location latitude. The overall range of MAB was 2.6–5.8 t•ha−1•year−1 (about 1.2–2.6 tons•acre−1•year−1). The highest MAB was 58% higher than the maximum reported in the literature. Stems accounted for 64–75% and branches with needles for the rest of the aboveground biomass. Stem percentages decreased at the northernmost location. Stems of all harvested trees had a significantly higher water content (127–141% on a dry weight basis) than their branches with needles (100–115%). Water content was the lowest in late winter (March). The study showed that suitable seed source selection is a very important factor in increasing jack pine stand production in the Lake States.

Seasonal Water Content and Distribution in Eastern White Pine

1969 ◽  
Vol 45 (1) ◽  
pp. 38-43
Author(s):  
S. N. Linzon
Keyword(s):  
Water Content ◽  
Pinus Strobus ◽  
Late Winter ◽  
Early Winter ◽  
White Pine ◽  
Eastern White Pine ◽  
Seasonal Rhythm ◽  
Late Autumn ◽  
Early Autumn

Studies over a 30-month period revealed the presence of a seasonal rhythm in water content in the sapwood and in wet and dry portions of the heartwood of eastern white pine, Pinus strobus L. The data, indicated an increase in water content in late autumn and early winter, a drying out in late winter, a slight increase in the spring, fluctuations during the summer strongly influenced by weather, and a slight decrease in early autumn prior to the increase at the end of the year. The newest parts of the crown were the wettest in the tree. Outer rings in the sapwood of the crown were wetter than those in the bole and butt. Wet heartwood possessed as high a water content as sapwood, whereas dry heartwood contained the lowest water content of all the parts of the tree examined.

The role of seed water content for the perception of temperature signals that drive dormancy changes in Polygonum aviculare buried seeds

2021 ◽  
Vol 48 (1) ◽  
pp. 28
Author(s):  
Cristian Malavert ◽  
Diego Batlla ◽  
Roberto L. Benech-Arnold
Keyword(s):  
Soil Temperature ◽  
Water Content ◽  
Seedling Emergence ◽  
Population Based ◽  
Late Winter ◽  
Dormancy Release ◽  
Limited Information ◽  
Polygonum Aviculare ◽  
Buried Seeds ◽  
Seed Water Content

Seedling emergence in the field is strongly related to the dynamics of dormancy release and induction of the seed bank, which is mainly regulated by soil temperature. However, there is limited information on how temperature-driven effects on dormancy changes are modulated by the seed hydration-level. We investigated the effect of seed water content (SWC) on the dormancy release and dormancy induction in Polygonum aviculare L. seeds. We characterised quantitatively the interaction between seed water content (SWC) and temperature through the measurement of changes in the lower limit temperature for seed germination (Tl) during dormancy changes for seeds with different SWC. These relationships were inserted in existing population-based threshold models and were run against field obtained data. The model considering SWC was able to predict P. aviculare field emergence patterns. However, failure to consider SWC led to overestimations in the emergence size and timing. Our results show that in humid temperate habitats, the occurrence of eventual water shortages during late-winter or spring (i.e. short periods of water content below 31% SWC) can affect soil temperature effects on seed dormancy, and might lead reductions in the emergence size rather than to significant temporal displacements in the emergence window. In conclusion, SWC plays an important role for the perception of temperature signals that drive dormancy changes in buried seeds.

Changes in soil water content under annual, perennial, and shrub-based pastures in an intermittently dry, summer-rainfall environment

2010 ◽  
Vol 61 (4) ◽  
pp. 331 ◽  
Author(s):  
G. M. Lodge ◽  
M. A. Brennan ◽  
S. Harden ◽  
S. P. Boschma
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Perennial Ryegrass ◽  
Soil Depth ◽  
Soil Layer ◽  
Summer Rainfall ◽  
Late Winter ◽  
Herbaceous Plant ◽  
Annual Grass

Soil water content (SWC) was monitored in an intermittently dry environment in 2003–08, for the following pasture types: perennial ryegrass (Lolium perenne cv. Skippy), lucerne (Medicago sativa cv. Venus), phalaris (Phalaris aquatica cv. Atlas PG), a lucerne/phalaris mixture, digit grass (Digitaria eriantha ssp. eriantha cv. Premier), and old man saltbush (Atriplex nummalaria). Perennial ryegrass and phalaris pastures persisted until late winter–early spring 2005 and, after that time, were maintained as degraded annual grass pastures and bare fallows, respectively. For all pasture types, mean SWC was generally higher for the 0–0.9 m soil depth than the 0.9–2.1 m (63 v. 51 mm of water per 0.2 m soil layer). At a soil depth of 0–0.9 m, few significant differences in SWC occurred among pasture types. However, significant differences among pasture types were recorded in SWC at depths of 0.9–2.1 m for these perennial-based pastures with low herbaceous plant densities. At this depth the SWC of lucerne/phalaris was lower (P < 0.05) than that of perennial ryegrass and phalaris pasture types in March 2005 (Day 500), and that of the degraded annual grass pasture in August 2006 (Day 1000) and December 2007 (Day 1500). Overall, maximum extractable water was highest (P < 0.05) for digit grass and old man saltbush pasture types (~180 mm) and lowest for the bare fallow (99 mm). Estimates of root depth were highest (2.0 m) for the lucerne/phalaris pasture type.

Characterization of frozen hydrated biological specimens by low-loss EELS

1992 ◽  
Vol 50 (2) ◽  
pp. 1572-1573
Author(s):  
Songquan Sun ◽  
Richard D. Leapman
Keyword(s):  
Water Content ◽  
Direct Method ◽  
Internal Standard ◽  
Dry Weight ◽  
Dark Field ◽  
Protein Solutions ◽  
Subcellular Compartment ◽  
Differential Shrinkage ◽  
Electron Energy Loss

Analyses of ultrathin cryosections are generally performed after freeze-drying because the presence of water renders the specimens highly susceptible to radiation damage. The water content of a subcellular compartment is an important quantity that must be known, for example, to convert the dry weight concentrations of ions to the physiologically more relevant molar concentrations. Water content can be determined indirectly from dark-field mass measurements provided that there is no differential shrinkage between compartments and that there exists a suitable internal standard. The potential advantage of a more direct method for measuring water has led us to explore the use of electron energy loss spectroscopy (EELS) for characterizing biological specimens in their frozen hydrated state.We have obtained preliminary EELS measurements from pure amorphous ice and from cryosectioned frozen protein solutions. The specimens were cryotransfered into a VG-HB501 field-emission STEM equipped with a 666 Gatan parallel-detection spectrometer and analyzed at approximately −160 C.

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