WINTER SURVIVAL AND OUTBREAKS OF BERTHA ARMYWORM, MAMESTRA CONFIGURATA (LEPIDOPTERA: NOCTUIDAE), ON CANOLA

1985 ◽  
Vol 117 (6) ◽  
pp. 727-736 ◽  
Author(s):  
R.J. Lamb ◽  
W.J. Turnock ◽  
H.N. Hayhoe
Keyword(s):  
Spatial Distribution ◽  
Soil Temperature ◽  
Snow Cover ◽  
Snow Depth ◽  
Winter Survival ◽  
Winter Mortality ◽  
Computer Simulation Model ◽  
Mamestra Configurata ◽  
Soil Temperatures ◽  
Bertha Armyworm

AbstractThe winter survival of artificial and natural infestations of pupae of the bertha armyworm, Mamestra configurata Walker, are assessed in relation to soil temperature and snow depth. The results are discussed in relation to the hypothesis that winter mortality affects the spatial distribution and timing of outbreaks of this pest. Pupae did not survive a Manitoba winter in snow-free field plots, but 55% survived in plots with 5 or 10 cm of snow. Pupal survival in the plots was estimated accurately from daily soil temperatures using a computer simulation model, confirming that natural soil-temperature regimes can affect pupal survival. Based on the model, an equation was derived to relate pupal survival to the number of winter days with soil temperatures of −10°C or less. For natural populations in canola fields, the model, in conjunction with a model that estimated soil temperatures from standard meteorological data, could estimate the observed survivals. However, the estimates were sensitive to estimated snow cover and the measurements of snow cover in the fields were incomplete. There was a significant negative relationship between mortality and snow depth measured at the end of January up to about 20 cm. The sensitivity of soil temperature and therefore pupal survival to small changes in snow depth makes it difficult to predict pupal survival for large areas. Although the distribution of outbreaks of bertha armyworm coincided with the areas of the canola-growing region where winter soil temperatures were highest, the summers when outbreaks occurred were not preceded by winters with high soil temperatures, nor were summers without outbreaks associated with low soil temperatures during the preceding winters. Winter soil temperatures apparently affected the spatial distribution of outbreaks, but variation in pupal survival due to winter soil temperatures did not, by itself, initiate or terminate bertha-army worm outbreaks.

scholarly journals Effect of snow cover on soil frost penetration

2017 ◽  
Vol 47 (4) ◽  
pp. 287-297 ◽  
Author(s):  
Jaroslav Rožnovský ◽  
Jáchym Brzezina
Keyword(s):  
Soil Temperature ◽  
Snow Cover ◽  
Air Temperature ◽  
Snow Depth ◽  
Major Effect ◽  
Soil Frost ◽  
Temperature Range ◽  
Soil Temperatures ◽  
Frost Penetration ◽  
Actual Height

AbstractSnow cover occurrence affects wintering and lives of organisms because it has a significant effect on soil frost penetration. An analysis of the dependence of soil frost penetration and snow depth between November and March was performed using data from 12 automated climatological stations located in Southern Moravia, with a minimum period of measurement of 5 years since 2001, which belong to the Czech Hydrometeorological institute. The soil temperatures at 5 cm depth fluctuate much less in the presence of snow cover. In contrast, the effect of snow cover on the air temperature at 2 m height is only very small. During clear sky conditions and no snow cover, soil can warm up substantially and the soil temperature range can be even higher than the range of air temperature at 2 m height. The actual height of snow is also important – increased snow depth means lower soil temperature range. However, even just 1 cm snow depth substantially lowers the soil temperature range and it can therefore be clearly seen that snow acts as an insulator and has a major effect on soil frost penetration and soil temperature range.

Measurement of snow cover depth using 100 × 100 meters sampling plot and Structure from Motion method in Adventdalen, Svalbard

2016 ◽  
Vol 6 (2) ◽  
pp. 155-168
Author(s):  
Radim Stuchlík ◽  
Jan Russnák ◽  
Tomáš Plojhar ◽  
Zdeněk Stachoň
Keyword(s):  
Spatial Distribution ◽  
Snow Cover ◽  
Structure From Motion ◽  
Snow Depth ◽  
Surface Model ◽  
Snow Surface ◽  
Reference Volume ◽  
Snow Cover Depth ◽  
Sampling Plot ◽  
Motion Method

We tried to verify the concept of Structure from Motion method for measuring the volume of snow cover in a grid of 100×100 m located in Adventdalen, Central Svalbard. As referencing method we utilized 121 depth measurements in one hectare area. Using avalanche probe a snow depth was measured in mentioned 121 nodes of the grid. We detected maximum snow depth of 2.05 m but snowless parts as well. From gathered depths’ data we geostatistically (ordinary kriging) interpolated snow surface model which we used to determine reference volume of snow at research plot (5 569 m3). As a result, we were able to calculate important metrics and analyze topography and spatial distribution of snow cover at the plot. For taking photos for Structure from Motion method, bare pole in hands with a camera mounted was used. We constructed orthomosaic of research plot.

scholarly journals Modeling the Spatial Distribution of Snow Cover in the Dudhkoshi Region of the Nepal Himalayas

2012 ◽  
Vol 13 (1) ◽  
pp. 204-222 ◽  
Author(s):  
Maheswor Shrestha ◽  
Lei Wang ◽  
Toshio Koike ◽  
Yongkang Xue ◽  
Yukiko Hirabayashi
Keyword(s):  
Spatial Distribution ◽  
Snow Cover ◽  
Land Surface ◽  
Snow Depth ◽  
Hydrological Model ◽  
Lapse Rate ◽  
Distributed Hydrological Model ◽  
Snow Cover Area ◽  
Temperature Lapse Rate ◽  
Snow Cover Extent

Abstract In this study, a distributed biosphere hydrological model with three-layer energy-balance snow physics [an improved version of the Water and Energy Budget–based Distributed Hydrological Model (WEB-DHM-S)] is applied to the Dudhkoshi region of the eastern Nepal Himalayas to estimate the spatial distribution of snow cover. Simulations are performed at hourly time steps and 1-km spatial resolution for the 2002/03 snow season during the Coordinated Enhanced Observing Period (CEOP) third Enhanced Observing Period (EOP-3). Point evaluations (snow depth and upward short- and longwave radiation) at Pyramid (a station of the CEOP Himalayan reference site) confirm the vertical-process representations of WEB-DHM-S in this region. The simulated spatial distribution of snow cover is evaluated with the Moderate Resolution Imaging Spectroradiometer (MODIS) 8-day maximum snow-cover extent (MOD10A2), demonstrating the model’s capability to accurately capture the spatiotemporal variations in snow cover across the study area. The qualitative pixel-to-pixel comparisons for the snow-free and snow-covered grids reveal that the simulations agree well with the MODIS data to an accuracy of 90%. Simulated nighttime land surface temperatures (LST) are comparable to the MODIS LST (MOD11A2) with mean absolute error of 2.42°C and mean relative error of 0.77°C during the study period. The effects of uncertainty in air temperature lapse rate, initial snow depth, and snow albedo on the snow-cover area (SCA) and LST simulations are determined through sensitivity runs. In addition, it is found that ignoring the spatial variability of remotely sensed cloud coverage greatly increases bias in the LST and SCA simulations. To the authors’ knowledge, this work is the first to adopt a distributed hydrological model with a physically based multilayer snow module to estimate the spatial distribution of snow cover in the Himalayan region.

scholarly journals LiDAR snow cover studies on glacier surface: significance of snow- and ice dynamical processes

2013 ◽  
Vol 7 (2) ◽  
pp. 1787-1832 ◽  
Author(s):  
K. Helfricht ◽  
M. Kuhn ◽  
M. Keuschnig ◽  
A. Heilig
Keyword(s):  
Spatial Distribution ◽  
Standard Deviation ◽  
Snow Cover ◽  
Snow Depth ◽  
Laser Scanning ◽  
Snow Accumulation ◽  
Surface Elevation ◽  
High Mountain ◽  
Dynamical Processes ◽  
Elevation Changes

Abstract. The storage of water within the seasonal snow cover is a substantial source for runoff in high mountain catchments. Information about the spatial distribution of snow accumulation is necessary for calibration and validation of hydro-meteorological models. Generally only a small number of precipitation measurements deliver precipitation input for modeling in remote mountain areas. The spatial interpolation and extrapolation of measurements of precipitation is still difficult. Multi-temporal application of Light Detecting And Ranging (LiDAR) techniques from aircraft, so-called airborne laser scanning (ALS), enables to derive surface elevations changes even in inaccessible terrain. Within one snow accumulation season these surface elevation changes can be interpreted as snow depths as a first assumption for snow hydrological studies. However, dynamical processes in snow, firn and ice are contributing to surface elevation changes on glaciers. To evaluate the magnitude and significance of these processes on alpine glaciers in the present state, ALS derived surface elevation changes were compared to converted snow depths from 35.4 km of ground penetrating radar (GPR) profiles on four glaciers in the high alpine region of Ötztal Alps. LANDSAT data were used to distinguish between firn and ice areas of the glaciers. In firn areas submerging ice flow and densification of firn and snow are contributing to a mean relative deviation of ALS surface elevation changes from actually observed snow depths of −20.0% with a mean standard deviation of 17.1%. Deviations between ALS surface elevation changes and GPR snow depth are small along the profiles on the glacier tongues. At these areas mean absolute deviation of ALS surface elevation changes and GPR snow depth is 0.004 m with a mean standard deviation of 0.27 m. Emergence flow leads to distinct positive deviations only at the very front of the glacier tongues. Snow depths derived from ALS deviate less from actually measured snow depths than expected errors of in-situ measurements of solid precipitation. Hence, ALS derived snow depths are an important data source for both, spatial distribution and total sum of the snow cover volume stored on the investigated glaciers and in the corresponding high mountain catchments at the end of an accumulation season.

scholarly journals Estimating spatial distribution of daily snow depth with kriging methods: combination of MODIS snow cover area data and ground-based observations

2015 ◽  
Vol 9 (5) ◽  
pp. 4997-5020 ◽  
Author(s):  
C. L. Huang ◽  
H. W. Wang ◽  
J. L. Hou
Keyword(s):  
Spatial Distribution ◽  
Snow Cover ◽  
Snow Depth ◽  
Western China ◽  
Kriging Interpolation ◽  
Snow Cover Area ◽  
Smoothing Effects ◽  
Moderate Resolution ◽  
Resolution Imaging ◽  
Moderate Resolution Imaging Spectroradiometer

Abstract. Accurately measuring the spatial distribution of the snow depth is difficult because stations are sparse, particularly in western China. In this study, we develop a novel scheme that produces a reasonable spatial distribution of the daily snow depth using kriging interpolation methods. These methods combine the effects of elevation with information from Moderate Resolution Imaging Spectroradiometer (MODIS) snow cover area (SCA) products. The scheme uses snow-free pixels in MODIS SCA images with clouds removed to identify virtual stations, or areas with zero snow depth, to compensate for the scarcity and uneven distribution of stations. Four types of kriging methods are tested: ordinary kriging (OK), universal kriging (UK), ordinary co-kriging (OCK), and universal co-kriging (UCK). These methods are applied to daily snow depth observations at 50 meteorological stations in northern Xinjiang Province, China. The results show that the spatial distribution of snow depth can be accurately reconstructed using these kriging methods. The added virtual stations improve the distribution of the snow depth and reduce the smoothing effects of the kriging process. The best performance is achieved by the OK method in cases with shallow snow cover and by the UCK method when snow cover is widespread.

Irrigation and ground cover management effect on soil temperature in a mature peach orchard

1993 ◽  
Vol 73 (3) ◽  
pp. 857-870 ◽  
Author(s):  
C. S. Tan ◽  
R. E. C. Layne
Keyword(s):  
Soil Temperature ◽  
Snow Cover ◽  
Air Temperature ◽  
Prunus Persica ◽  
Ground Cover ◽  
Soil Surface ◽  
Soil Temperatures ◽  
Peach Orchard ◽  
Management Effect ◽  
Minimum Air Temperature

The purpose of this study was to assess the effect of two irrigation (trickle vs. no irrigation) and two ground cover treatments (temporary cover vs. permanent sod) on soil temperature in a mature peach [Prunus persica (L.) Batsch] orchard on Fox sand. The soil temperatures at the surface, 5, 10 and 20 cm depths were monitored continuously all-year during 1987 and 1988. Irrigation reduced the fluctuations in soil temperature during summer and winter. The average daily soil temperature in nonirrigated plots during the summer was as high as 34 °C at the soil surface and 28 °C at the 20-cm depth, while corresponding temperatures in irrigated plots were 28 and 26 °C, respectively. The average daily soil temperature in nonirrigated plots without snow cover during the winter was −12 °C at the soil surface and −5 °C at the 20-cm depth, while corresponding temperatures in irrigated plots were −6 and −1 °C, respectively. The effect of irrigation on soil temperature was greatly diminished by snow cover. The soil temperatures at all depths remained around 0 to −2 °C for both nonirrigated and irrigated plots under snow cover, even when the minimum air temperature dropped to −15 °C. The permanent sod cover provided some protection against cold although this effect was masked by snow cover. In the summer, the permanent sod cover reduced average daily soil temperature by 1.5 and 1 °C at the 10 and 20 cm depths. Key words: Prunus persica, snow cover, Fox sand

ANNUAL VARIABILITY OF MINIMUM SOIL TEMPERATURE

1975 ◽  
Vol 55 (2) ◽  
pp. 167-176
Author(s):  
C. E. OUELLET ◽  
R. L. DESJARDINS
Keyword(s):  
Confidence Interval ◽  
Soil Temperature ◽  
Minimum Temperature ◽  
Winter Survival ◽  
Crop Selection ◽  
Annual Variability ◽  
Soil Temperatures ◽  
The Mean ◽  
Uptake Of Nutrients

The variability of the monthly values from year to year of the mean and extreme minimum soil temperatures at the 10-cm depth was analyzed for nine representative Canadian stations for 1961–1970. It ranged from 1.0 to 16.5 C for the mean minimums and from 2.0 to 18.5 C for the extreme minimums. The 95% confidence interval exceeded the observed range of variability by 0.3–5.0 C. However, 7% of the observed mean minimums and 14% of the extreme minimums exceeded the confidence interval limits. For the cases studied, the variability of the mean minimum temperature was the largest for the winter months and the smallest for the summer months, and it increased from the warmest stations to the coldest ones. The implications of these features on length of period for seed emergence, plant winter survival, crop selection, and uptake of nutrients are discussed.

scholarly journals Application of Georadar for Snow Cover Surveying

1998 ◽  
Vol 29 (4-5) ◽  
pp. 361-370 ◽  
Author(s):  
Knut Sand ◽  
Oddbjørn Bruland
Keyword(s):  
Spatial Distribution ◽  
Snow Cover ◽  
Snow Depth ◽  
Snow Water Equivalent ◽  
Good Description ◽  
Areal Distribution ◽  
Snow Water

A commercial georadar was tested over in a Norwegian catchment in order to determine the areal mean snow water equivalent (SWE) and its spatial distribution. The methodology used and the results obtained are described. The radar was run along a number of selected snow courses, and the results were compared with manual measurements of snow depth and density. It was found that georadar is able to give accurate estimates of mean SWE with much less time spent in the field compared to conventional measurements. Georadar also gave a good description of the areal distribution of SWE.

scholarly journals Autumn, Winter and Spring Soil Temperatures in Okstindan, Norway

1974 ◽  
Vol 13 (69) ◽  
pp. 521-533
Author(s):  
Charles Harris
Keyword(s):  
Snow Cover ◽  
Snow Depth ◽  
Soil Surface ◽  
Soil Freezing ◽  
Dominant Factor ◽  
Freezing And Thawing ◽  
Short Term ◽  
Air Temperatures ◽  
Soil Temperatures ◽  
Freezing And Thawing Cycles

Soil temperatures were recorded over periods of several weeks in the years 1909 and 1970 in two sites to a depth of 100 cm. It was found that snow depth was of major importance in the rate of freezing of the soil in winter; where snow cover was less than 5 cm in depth freezing rates were almost double those where snow depth was over 1 m. Snow cover also insulated the soil surface from above-zero air temperatures during spring, and soil thawing commenced from the surface only following the clearance of snow. Similarly, insulation of the soil surface by snow prevented short-term freezing and thawing cycles penetrating the soil, although even where snow cover was absent such short-term cycles were not observed to penetrate the soil to depths in excess of 5 cm. This surficial freezing and thawing of the soil took place more readily in spring than in the autumn. It was concluded that the annual cycle of soil freezing and thawing was the dominant factor in the thermal regime of these soils, short-term freezing cycles affecting only the immediate surface soil layers.

Winter survivorship of hatchling painted turtles (Chrysemys picta) in Michigan

2000 ◽  
Vol 78 (2) ◽  
pp. 226-233 ◽  
Author(s):  
Roy D Nagle ◽  
Owen M Kinney ◽  
Justin D Congdon ◽  
Christopher W Beck
Keyword(s):  
Snow Cover ◽  
Air Temperature ◽  
Freeze Tolerance ◽  
Ambient Air ◽  
Chrysemys Picta ◽  
Winter Mortality ◽  
Painted Turtles ◽  
Subzero Temperatures ◽  
Soil Temperatures ◽  
The Impact

Hatchling painted turtles (Chrysemys picta) often exhibit delayed emergence by remaining in shallow sub- terranean nest cavities throughout winter. As a result, those at northern latitudes are sometimes exposed to lethal subzero temperatures. Our field study compared survivorship of hatchling C. picta during a winter in which low subzero temperatures coincided with the absence of insulating snow cover (1995-1996) with survivorship during the following three winters (1996-1997, 1997-1998, and 1998-1999), which were characterized by more moderate conditions. Ambient-air and soil temperatures were monitored at a weather station located within ~1 km of all nests. During the first winter of our study (1995-1996), minimum ambient-air temperature reached -25.6°C on 2 February, concomitantly with the complete absence of snow cover, and soil temperatures fell to between -7 and -9°C. Resultant over-winter hatchling mortality was 45%. Because some hatchlings survived temperatures well below the lethal limits described for freeze tolerance (-1 to -4°C), it is likely that hatchlings in Michigan sometimes survive by supercooling. During the following three winters, soil temperatures remained above -2°C, except during brief periods when they fell to -4°C in the absence of snow cover. Over-winter hatchling mortality was <3% during each of these last 3 years. Our study highlights the importance of insulating snow cover to survival of hatchling C. picta. Air temperature and snowfall data from southeastern Michigan over the past 33 years indicate that conditions associated with substantial winter mortality occurred in 3 out of 33 years (9.1%). We demonstrate that the impact of substantial over-winter mortality on hatchling recruitment is dependent on nest survivorship during the preceding nesting season.

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