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91.
Assessing Winter Wheat Responses to Climate Change Scenarios: A Simulation Study in the U.S. Great Plains 总被引:3,自引:0,他引:3
Hard red winter wheat (Triticum aestivum L.) is a major crop in the Great Plains region of the U.S. The goal of this assessment effort was to investigate the influence of two contrasting global climate change projections (U.K. Hadley Center for Climate Prediction and Research and Canadian Centre for Climate Modelling and Analysis) on the yield and percent kernel nitrogen content of winter wheat at three locations in Nebraska. These three locations represent sub-humid and semi arid areas and the transition between these areas and are also representative of major portions of the winter wheat growing areas of the central Great Plains. Climate scenarios based on each of the projections for each location were developed using the LARS-WG weather generator along with data from automated weather stations. CERES-Wheat was used to simulate the responses for two contrasting cultivars of wheat using two sowing dates. The first sowing date represented current sowing dates appropriate for each location. The second sowing date was later and represents the approximate date when the mean air temperature from the climate scenarios is the same as the mean air temperature from the actual climate data at the current sowing dates. The yield and percent kernel nitrogen content using the two climate scenarios generally decrease going from the sub-humid eastern to the semi arid western parts of Nebraska. Results from these simulations indicate that yield and percent kernel nitrogen content using the two climate scenarios could not both be maintained at levels currently simulated. Protein content (directly related to kernel nitrogen content) and end-use quality are the primary determinants for the use of hard red winter wheat in baked goods. Nitrogen management and new cultivars, which can enhance the uptake and translocation of nitrogen, will be proactive steps to meet the challenges of global climate change as represented by these climate scenarios. 相似文献
92.
NewUBV photoelectric observations of EB-type contact binary DO Cas were made on 4 nights from February 1986 to February 1987. The obtained light curves in combination with the radial-velocity curve of the primary published by Mannino (1958) of DO Cas have been solved simultaneously using the Wilson-Devinney synthesis code. The system is found to be a contact binary with a degree of overcontact of 14%. It may be concluded that DO Cas is an evolved contact binary. 相似文献
93.
Combined analysis of electrical resistivity and geotechnical SPT blow counts for the safety assessment of fill dam 总被引:1,自引:0,他引:1
Electrical resistivity survey and the geotechnical SPT blow counts (N value) method were simultaneously analyzed to investigate the stability of a center-core type earth-fill dam against the
seepage phenomenon. The coupling of these heterogeneous field methods provided a chance to understand the status of underground
material by comparing the geophysical and geotechnical view. The analysis shows that the zones with low resistivity value
generally have low N value, which means low stiffness. However, some zones with a high resistivity pattern are not accompanied by an increase
of its N value, and are even showing a lower N value. These results imply that one should be careful to directly correlate resistivity value with the real status of the
core material of a fill dam. And a highly resistive zone may be in poor status due to the effect of increase of resistivity
value as a result of the piping condition. Additional laboratory tests show that there is a deficiency of fine soil particles
believed as the clay at the troubled region, which means an increase in resistivity value. Therefore, multiple explorations
should be planned to reduce the uncertainty in application of geophysical methods to dam safety evaluation in order to compensate
the resistivity information of core material. 相似文献
94.
GPS Solutions - Measuring snow depth using the GPS interferometric reflectometry is an active microwave remote sensing technique and an emerging approach because of its relatively large spatial... 相似文献
95.
96.
Jinik Hwang So Yun Park Mirye Park Sukchan Lee Yeonhwa Jo Won Kyong Cho Taek-Kyun Lee 《Ocean Science Journal》2016,51(4):599-612
In this study, seawater samples were collected from Goseong Bay, Korea in March 2014 and viral populations were examined by metagenomics assembly. Enrichment of marine viral particles using FeCl3 followed by next-generation sequencing produced numerous sequences. De novo assembly and BLAST search showed that most of the obtained contigs were unknown sequences and only 0.74% of sequences were associated with known viruses. As a result, 138 viruses, including bacteriophages (87%), viruses infecting algae and others (13%) were identified. The identified 138 viruses were divided into 11 orders, 14 families, 34 genera, and 133 species. The dominant viruses were Pelagibacter phage HTVC010P and Roseobacter phage SIO1. The viruses infecting algae, including the Ostreococcus species, accounted for 9.4% of total identified viruses. In addition, we identified pathogenic herpes viruses infecting fishes and giant viruses infecting parasitic acanthamoeba species. This is a comprehensive study to reveal the viral populations in the Goseong Bay using metagenomics. The information associated with the marine viral community in Goseong Bay, Korea will be useful for comparative analysis in other marine viral communities. 相似文献
97.
Despite rapidly growing interest in the effects of ocean acidification on marine animals, the ability of deep-sea animals to acclimate or adapt to reduced pH conditions has received little attention. Deep-sea species are generally thought to be less tolerant of environmental variation than shallow-living species because they inhabit relatively stable conditions for nearly all environmental parameters. To explore whether deep-sea hermit crabs (Pagurus tanneri) can acclimate to ocean acidification over several weeks, we compared behavioral “boldness,” measured as time taken to re-emerge from shells after a simulated predatory attack by a toy octopus, under ambient (pH ~7.6) and expected future (pH ~7.1) conditions. The boldness measure for crab behavioral responses did not differ between different pH treatments, suggesting that future deep-sea acidification would not influence anti-predatory behavior. However, we did not examine the effects of olfactory cues released by predators that may affect hermit crab behavior and could be influenced by changes in the ocean carbonate system driven by increasing CO2 levels. 相似文献
98.
Sewook Oh 《Marine Georesources & Geotechnology》2016,34(1):57-64
In this study, it was attempted to assess soil parameters necessary for Lade's single surface work-hardening model that reviewed the physical and mechanical properties of granite soil located in Korea based on the results of triaxial compression tests. In addition, finite element analyses coupled with the determined soil parameters as inputs were conducted based on Lade's single surface work-hardening model and the results were compared with element test results. It could be seen that, in predicting undrained mechanical behavior, the single surface model was reproducing the stress-strain relation obtained through element tests at high accuracy. It is worthwhile to inform that these differences in the initial loading stage and the impossibility to predict swelling behavior are caused by the fact that there is no prediction model for changes in shear properties, especially in dilatancy properties due to particle crushing occurring while element tests are conducted. Hence, it is concluded that, to expand the applicability of Lade's single surface work-hardening constitutive model to practical problems, the model should be modified in relation to the dilatancy of soils. 相似文献
99.
An analytical model with three sub-regions for m2 tide in the yellow sea and the East China Sea 总被引:1,自引:0,他引:1
In this study an analytical tide model of uniform width with three sub-regions is presented. The three-subregions model takes
into account step-like variations in depths in the direction of the channel as a way to examine the M2 tide of the East China Sea (ECS) as well as the Yellow Sea (YS). A modified Proudman radiation condition has been applied
at the northern open head, while the sea surface elevation is specified at the southern open boundary. It is seen that, due
to the presence of an abrupt change in depth, co-amplitude lines of the M2 tide are splitted to the east and west near the end of the ECS shelf region. Variations in depths, bottom friction and the
open head boundary conditions all contribute to the determination of formation of amphidromes as well as overall patterns
of M2 tidal distribution. It is seen that increasing water depth and bottom friction in the ECS shelf results in the westward shift
of the southern amphidrome. There is however no hint at all of the well-known degenerated tidal pattern being formed. It is
inferred that a lateral variation of water depth has to be somehow incorporated to represent the tidal patterns in ECS in
a realistic manner. Regarding the radiation factor introduced by Fang et al. (1991), use of a value larger than one, possibly
with a phase shift, appears to be a proper way of incorporating the reflected waves from the northern Yellow Sea (NYS). Key
words - analytical model, M2 tide, Kelvin wave, Yellow Sea, East China Sea 相似文献
100.
A numerical model is presented to predict the interaction of multidirectional random surface waves with one or more rectangular submarine pits. The water depth is assumed uniform and the method involves the superposition of diffraction solutions based on linearized shallow water wave theory obtained by a two-dimensional boundary integral approach. The incident wave conditions are specified using a discrete form of the Mitsuyasu directional spectrum. The present numerical model has been validated through comparisons with previous theoretical results for regular waves. Good agreement was obtained in all cases. Based on these comparisons it is concluded that the present numerical model is an accurate and efficient tool to predict the wave field around multiple submarine pits and navigation channels in many practical situations. 相似文献