Frost heave pressure plays a pivotal role in driving the occurrence and expansion of rock cracks. Thus, understanding the distribution and evolution of frost heave pressure on rock crack surfaces is ...integral to elucidate the mechanism of rock mass damage caused by freeze-thaw. In this study, a unique frost heave pressure monitoring experiment was performed, employing a membrane pressure sensor to provide real-time monitoring of frost heave pressure distribution across an entire rock crack surface. Simultaneously, temperature changes within the crack during freeze-thaw were monitored. Various factors including freezing temperature, crack water content, and lithology, were analyzed for their influence on the frost heave pressure distribution on the crack surface. Findings indicate that the frost heave pressure evolution during freeze–thaw can be divided into five stages: incubation, eruption, fall, equilibrium, and dissipation. The frost heave pressure is not uniformly distributed across the rock crack surfaces, with 0 MPa pressure on the upper part of the crack. The distribution pattern of frost heave pressure on the crack surface features smaller edges surrounding a larger middle area. No obvious correlation is observed between the maximum frost heave pressure and the freezing temperature. However, as the freezing temperature decreases, the maximum pressure-bearing area on the rock crack surface gradually increases. Additionally, as the water content within the crack decreases, there is a noticeable decrease in the distribution of frost heave pressure on the rock crack surface. Regarding frost heave pressure monitoring tests under four different lithological conditions, crack expansion was observed in fine sandstone, granite, and limestone specimens, but not in coarse sandstone specimens. The findings from this research enrich our understanding of the incubation mechanism of rock mass freeze–thaw disasters in cold regions, and serve as a reference for calculations and numerical simulations of rock crack frost heave pressure in these areas.
•The evolution of frost heave pressure distribution on a rock crack surface was determined.•The frost heave pressure on the upper part of the crack was found to be 0 MPa.•Frost heave pressure was unevenly distributed across the crack surface.•A lower freezing temperature resulted in a larger pressure-bearing area on the crack surface.
As the climate changes, increasing variations in environmental factors directly influence crop cultivation at different magnitudes over a broad range of local communities worldwide. As a result, ...there is an urgent need to develop local impact assessments and adaptation strategies for use at local, rather than national or global, levels. In this study, we predicted the future frost damage of kiwifruit in the Jeonnam province, Korea, as a case study for the local impact assessment of climate change. This study included a series of models that integrated both the biological responses of plants and the physical influences of climatic factors. First, potential changes in the suitable area for kiwifruit cultivation under a changing climate were simulated using downscaled high resolution (1 km) climate data. Through the development of a frost‐forecasting model and linking it to a kiwifruit phenology model, we also assessed the interaction of plant and climatic factors. Because of the warming climate, the last frost date in spring occurred 13.7 days earlier in average under climate change. Nevertheless, the potential risk of spring frost damage of kiwifruit continued to exist at a similar magnitude in the future. Additional study at the county level indicated that the date of bud burst is advancing even faster than the last frost date (approximately 1 day per every decade), resulting in the increasing risk of spring frost damage for kiwifruit through 2100. In this study, the local impacts of climate change on kiwifruit frost damage were assessed using the integrated modelling approach. As such, local policy makers and stakeholders will be able to prepare more realistic adaptation strategies to cope with upcoming threats in a changing climate.
In this study, the local impacts of climate change on kiwifruit frost damage in the Jeonnam Province, Korea were assessed using an integrated modelling approach. First, optimal areas for kiwifruit cultivation under a changing climate were simulated, resulting in almost 98% of lands becoming “Highly suitable” in the 2080s. In addition, through the development of a frost‐forecasting model and linking it to a kiwifruit phenology model, we found that the potential risk of spring frost damage of kiwifruit continued to exist at a similar magnitude as shown in the figure below.
Water-bearing joints within rock engineering in cold areas are often subjected to frost heaving force in cold season due to water–ice phase transition. To evaluate the damage and stability of rock ...mass in cold regions, a 3D model that considers moisture migration loss during freezing and thawing was established to study the characteristics of frost heaving force within joints. Then, the numerical simulation of cyclic freeze-thawing of water-bearing joints was carried out through equivalent expansion coefficient and particle flow calculation methods. The distribution of frost heaving force in and around the joints was obtained. According to the results of the numerical tests and theoretical calculations, the frost heaving force in joints is basically stable, the tensile stress concentration area appears at the joint tip, and the frost heaving force decreases gradually away from the jointed rock mass area. The frost heaving force decreases considerably with increasing cycle number and moisture migration loss but it increases with increasing mechanical strength and joint geometric size of rock and ice. The comparison between the numerical solution of the equivalent expansion coefficient method and the theoretical solution shows that the force size and distribution law of frost heaving for the two methods are consistent.
•Dew and hoar frost formation contributes substantially to water budgets.•Dew formation may be of ecological relevance during droughts.•Penman-Monteith model can be used to estimate the formation of ...dew and hoar frost.
Non-rainfall events like dew or hoar frost formation are often neglected in the water budget, because either assumed to be too small or their determination requires time consuming and difficult measurements. These events supply in many dryland ecosystems a substantial amount of water, but their role for northern humid ecosystems is largely unknown. There is a general need to quantify the ecological relevance for ecosystems of the water amount from dew and hoar frost formation. Weighable precision lysimeters were used to determine dew and hoar frost formation for a low mountain range and alpine grassland site for the hydrological years 2013–2015.
Together dew and hoar frost formation ranged on a yearly basis between 42.1 and 67.7 mm, which corresponds to 4.2–6% of the total annual amount of precipitation. In drier months dew and hoar frost contributed up to 16.1% of total monthly precipitation amount. In winter months dew and hoar frost formation contributed up to 38% to the total monthly precipitation amount. Our investigation suggests, that dew and hoar frost formation are of ecological importance during droughts as well as cold periods. The amounts and seasonal patterns of dew and hoar frost formation could be predicted relatively well, based on standard meteorological variables with the Penman-Monteith equation. However, our results also showed, that the surface energy balance model from Penman-Monteith underestimated the amount of dew and hoar frost during colder periods and specific meteorological site conditions (i.e. high wind speeds at night). The mean underestimation between calculated and measured dew and hoar frost on a yearly scale were 63.2% and 16.6% at Rollesbroich and Gumpenstein, respectively. Dew and hoar frost formation contributes substantially to the water budgets of a low mountain range and alpine grassland.
With rapid economic development in China, the railway network extends from Northeast to Northwest China. Numerous tunnels are inevitably built in cold regions that experience frost damage. However, ...studies on the analytic solution of the stress and deformation for noncircular tunnels in cold regions are very limited. To solve this engineering problem and propose new theoretical insights for analysis and design, a novel noncircular solution is established in this paper. In this model, the infinite plane is divided into three parts, namely, the tunnel lining, frost heaving zone, and unfrozen surrounding rock. Then, the stress and displacement fields can be determined based on the continuity conditions of the three parts. Considering that part of the deformation of the rock mass occurs before the lining is applied, this release of the surrounding rock load is given through the support delay coefficient η. The Zhegu Mountain tunnel, as a numerical simulation case, is introduced to verify the analytic solution, which shows good consistency between the two. The additional stress of frost heaving is distributed unevenly at different positions, threatening the safety of tunnel structures. The reason why the frost heaving force of the analytic solution is generally larger than that of the field monitoring data is also addressed.
Radiant spring frosts occurring during reproductive developmental stages can result in catastrophic yield loss for wheat producers. To better understand the spatial and temporal variability of frost, ...the occurrence and impact of frost events on rain-fed wheat production was estimated across the Australian wheatbelt for 1957–2013 using a 0.05 ° gridded weather data set. Simulated yield outcomes at 60 key locations were compared with those for virtual genotypes with different levels of frost tolerance. Over the last six decades, more frost events, later last frost day, and a significant increase in frost impact on yield were found in certain regions of the Australian wheatbelt, in particular in the South-East and West. Increasing trends in frost-related yield losses were simulated in regions where no significant trend of frost occurrence was observed, due to higher mean temperatures accelerating crop development and causing sensitive post-heading stages to occur earlier, during the frost risk period. Simulations indicated that with frost-tolerant lines the mean national yield could be improved by up to 20% through (i) reduced frost damage (∼10% improvement) and (ii) the ability to use earlier sowing dates (adding a further 10% improvement). In the simulations, genotypes with an improved frost tolerance to temperatures 1 °C lower than the current 0 °C reference provided substantial benefit in most cropping regions, while greater tolerance (to 3 °C lower temperatures) brought further benefits in the East. The results indicate that breeding for improved reproductive frost tolerance should remain a priority for the Australian wheat industry, despite warming climates.
Post-head-emergence frost in wheat and barley Frederiks, T. M.; Christopher, J. T.; Sutherland, M. W. ...
Journal of experimental botany,
06/2015, Letnik:
66, Številka:
12
Journal Article
Recenzirano
Odprti dostop
Radiant frost is a significant production constraint to wheat (Triticum aestivum) and barley (Hordeum vulgare), particularly in regions where spring-habit cereals are grown through winter, maturing ...in spring. However, damage to winter-habit cereals in reproductive stages is also reported. Crops are particularly susceptible to frost once awns or spikes emerge from the protection of the flag leaf sheath. Post-head-emergence frost (PHEF) is a problem distinct from other cold-mediated production constraints. To date, useful increased PHEF resistance in cereals has not been identified. Given the renewed interest in reproductive frost damage in cereals, it is timely to review the problem. Here we update the extent and impacts of PHEF and document current management options to combat this challenge. We clarify terminology useful for discussing PHEF in relation to chilling and other freezing stresses. We discuss problems characterizing radiant frost, the environmental conditions leading to PHEF damage, and the effects of frost at different growth stages. PHEF resistant cultivars would be highly desirable, to both reduce the incidence of direct frost damage and to allow the timing of crop maturity to be managed to maximize yield potential. A framework of potential adaptation mechanisms is outlined. Clarification of these critical issues will sharpen research focus, improving opportunities to identify genetic sources for improved PHEF resistance.
Earth-based building materials are increasingly valued in green design for their low embodied energy, humidity-buffering ability, and thermal stability. These materials perform well in warm dry ...climates, but greater understanding of long-term durability is needed for successful adoption in colder and/or wetter climates. The presence of stabilizers dramatically improves resistance to surface erosion from wind and rain, compared to unstabilized adobe and cob counterparts, and the influences of soil composition, fiber type, and diverse binders, on rain and wind surface erosion have been investigated in detail. Frost and freeze-thaw resistance, however, have been less well-studied, despite strong interest in stabilized earth materials in northern North America, Europe, and Asia. In particular, recent studies have relied on a widespread misunderstanding of the mechanism by which frost damage occurs in porous materials that will impede efforts to create valid models for material design and improvement. In addition, the influence of radiative thermal stresses on wall surfaces has been overlooked in favor of focus on ambient air temperatures. Here, we apply contemporary understanding of cracking by segregated ice growth to develop a macroscopic damage index that enables comparison between performance of different materials subject to different weather patterns. An examination of predicted damage patterns for two stabilized earth building materials and two conventional materials in twelve cities over two time periods reveals the dominant factors that govern frost vulnerability. We find that the frost resilience of earth building materials is comparable to that of the conventional materials we examined, and that assessments that neglect expected variations in water content by assuming full saturation are likely to yield misleading results. Over recent years, increased winter temperatures in several cities we examined predict reduced material vulnerability to frost damage, but we also find that accompanying increases in humidity levels have made some cities much more vulnerable.
Late spring frost stress is one of the major environmental limiting factors for apricot in the warm zone in China. Investigation of frost exposure of apricot is of particular interest for estimating ...the frost risk, thus representing the potential damage for apricot production. In this study, daily minimum temperature (Tmin), disaster and phenological data of apricot from 1981 to 2020 in the warm zone were integrated to explore the temperature threshold on apricot at young fruit, facilitating the assessment of apricot frost exposure (E) under the background of climate warming. The daily Tmin was firstly extracted according to the historical disaster records, to identify the per‐ and ongoing weather conditions of the low‐temperature events. The overall accuracy and Receiver Operating Characteristics curve (ROC) were combined to identify the trigger threshold of apricot frost. 1.9°C was identified as the apricot frost trigger threshold in regional assessment, with relatively higher correct rate for disaster (90.2%) and lower incorrect rate for none‐disaster (23.4%). An area under the ROC curve (AUC) of 0.88 was obtained, demonstrating a good performance of Tmin as the trigger factor in discriminating between apricot frost and no frost. High frequency of days suffered from apricot and frost exposure at young fruit were mainly found in the northwestern and middle parts of the region, with frequencies of more than 2 days and E more than 3. Regional days suffered from apricot frost and E were found to have a negative trend with slope −0.0317 and −0.789, respectively, whereas the northwest and middle part of the study region were found to have an increasing trend. The results can provide technical and theoretical support for targeted apricot frost detection and risk assessment, and measures for apricot frost prevention and mitigation can be implemented according to the threshold‐based results.
Daily minimum temperature plays a good performance as the trigger factor in discriminating between apricot frost and no frost. 1.9°C was identified as the apricot frost trigger threshold in regional assessment, with relatively higher correct rate for disaster and lower incorrect rate for none‐disaster. A negative trend was detected for the past four decades, whereas frost exposure for apricot in north part of the warm temperate zone was increased.
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