scholarly journals Severe frost but not shade could limit the future growing season of Erythronium americanum

Botany ◽  
2021 ◽  
Author(s):  
Jack Tessier
Keyword(s):  
Air Temperature ◽  
Growing Season ◽  
Leaf Damage ◽  
Experimental Exposure ◽  
Canopy Trees ◽  
Late Frost ◽  
The Future ◽  
Erythronium Americanum ◽  
Soil Temperatures ◽  
The Impact

Changes in climate are leading to modifications in the timing of seasonal events such as migrations and flowering. Erythronium americanum (trout lily) can break bud early in response to warming, but changes to its growing season may be limited by early shade from canopy trees and frost. I experimentally assessed the impact of shade and frost on senescence in E. americanum and descriptively monitored the response of E. americanum to vernal air and soil temperatures in a garden setting. Early shade did not affect the timing of senescence. Experimental exposure to frost resulted in increased leaf damage, earlier senescence, and greater corm death than in control plants. Despite ten days in which the air temperature dropped below freezing, there was no evidence of leaf damage in the field. These results suggest that early shade from canopy trees will not hasten the end of the future growing season for E. americanum, but that late frost could bring about early senescence if that frost is sufficiently hard.

scholarly journals Seasonal dynamics of methane emissions from a subarctic fen in the Hudson Bay Lowlands

2013 ◽  
Vol 10 (7) ◽  
pp. 4465-4479 ◽  
Author(s):  
K. L. Hanis ◽  
M. Tenuta ◽  
B. D. Amiro ◽  
T. N. Papakyriakou
Keyword(s):  
Soil Temperature ◽  
Air Temperature ◽  
Growing Season ◽  
Near Surface ◽  
Growing Seasons ◽  
Air Temperatures ◽  
Soil Temperatures ◽  
Surface Soil Temperature ◽  
Filling Method ◽  
Highly Correlated

Abstract. Ecosystem-scale methane (CH4) flux (FCH4) over a subarctic fen at Churchill, Manitoba, Canada was measured to understand the magnitude of emissions during spring and fall shoulder seasons, and the growing season in relation to physical and biological conditions. FCH4 was measured using eddy covariance with a closed-path analyser in four years (2008–2011). Cumulative measured annual FCH4 (shoulder plus growing seasons) ranged from 3.0 to 9.6 g CH4 m−2 yr−1 among the four study years, with a mean of 6.5 to 7.1 g CH4 m−2 yr−1 depending upon gap-filling method. Soil temperatures to depths of 50 cm and air temperature were highly correlated with FCH4, with near-surface soil temperature at 5 cm most correlated across spring, fall, and the shoulder and growing seasons. The response of FCH4 to soil temperature at the 5 cm depth and air temperature was more than double in spring to that of fall. Emission episodes were generally not observed during spring thaw. Growing season emissions also depended upon soil and air temperatures but the water table also exerted influence, with FCH4 highest when water was 2–13 cm below and lowest when it was at or above the mean peat surface.

Snowpack energy balance and changes in the frequency and extremity of rain-on-snow events in the warming climate

2021 ◽  
Author(s):  
Ondrej Hotovy ◽  
Michal Jenicek
Keyword(s):  
Energy Balance ◽  
Air Temperature ◽  
Snow Water Equivalent ◽  
Hydrological Cycle ◽  
Winter Season ◽  
Catchment Scale ◽  
The Future ◽  
Snow Water ◽  
The Impact ◽  
Catchment Runoff

<p>Seasonal snowpack significantly influences the catchment runoff and thus represents an important input for the hydrological cycle. Changes in the precipitation distribution and intensity, as well as a shift from snowfall to rain is expected in the future due to climate changes. As a result, rain-on-snow events, which are considered to be one of the main causes of floods in winter and spring, may occur more frequently. Heat from liquid precipitation constitutes one of the snowpack energy balance components. Consequently, snowmelt and runoff may be strongly affected by these temperature and precipitation changes.</p><p>The objective of this study is 1) to evaluate the frequency, inter-annual variability and extremity of rain-on-snow events in the past based on existing measurements together with an analysis of changes in the snowpack energy balance, and 2) to simulate the effect of predicted increase in air temperature on the occurrence of rain-on-snow events in the future. We selected 40 near-natural mountain catchments in Czechia with significant snow influence on runoff and with available long-time series (>35 years) of daily hydrological and meteorological variables. A semi-distributed conceptual model, HBV-light, was used to simulate the individual components of the water cycle at a catchment scale. The model was calibrated for each of study catchments by using 100 calibration trials which resulted in respective number of optimized parameter sets. The model performance was evaluated against observed runoff and snow water equivalent. Rain-on-snow events definition by threshold values for air temperature, snow depth, rain intensity and snow water equivalent decrease allowed us to analyze inter-annual variations and trends in rain-on-snow events during the study period 1965-2019 and to explain the role of different catchment attributes.</p><p>The preliminary results show that a significant change of rain-on-snow events related to increasing air temperature is not clearly evident. Since both air temperature and elevation seem to be an important rain-on-snow drivers, there is an increasing rain-on-snow events occurrence during winter season due to a decrease in snowfall fraction. In contrast, a decrease in total number of events was observed due to the shortening of the period with existing snow cover on the ground. Modelling approach also opened further questions related to model structure and parameterization, specifically how individual model procedures and parameters represent the real natural processes. To understand potential model artefacts might be important when using HBV or similar bucket-type models for impact studies, such as modelling the impact of climate change on catchment runoff.</p>

The impact of increased temperatures on germination patterns of semi-aquatic plants

2019 ◽  
Vol 29 (3) ◽  
pp. 204-209
Author(s):  
Jade Dessent ◽  
Susan Lawler ◽  
Daryl Nielsen
Keyword(s):  
Soil Temperature ◽  
Air Temperature ◽  
Soil Seed Bank ◽  
Ambient Air ◽  
Future Climate Change ◽  
Ambient Air Temperature ◽  
Threshold Temperatures ◽  
Soil Temperatures ◽  
The Impact ◽  
Number Of Seeds

AbstractFuture climate change predictions indicate that there will be an increase in ambient air temperature. Increases in ambient air temperature will result in a corresponding increase in soil temperature. The consequences of further increases in soil temperature will potentially be detrimental for the soil seed bank of plants in terms of length of dormancy and viability of seeds. This experiment investigated the effect of different exposure temperatures and duration of exposure on the germination of semi-aquatic plant species. Seeds of four species (Alternanthera denticulata, Juncus usitatus, Persicaria lapathifolia and Persicaria prostrata) were exposed to temperatures ranging from 25 to 100°C for durations between 1 and 14 days, before being germinated in an incubator for 6 weeks. Germination occurred in all four species after exposure to temperatures ranging from 25 to 60°C. These temperatures appeared to promote germination as the temperature and duration of exposure increased. However, in P. lapathifolia and P. prostrata, the number of seeds germinating declined when exposed to 70°C and there was no germination for temperatures exceeding this. In contrast, A. denticulata and J. usitatus only began to decline when exposed to 80°C, with no germination at higher temperatures. These results suggest that soil temperatures exceeding potential threshold temperatures of 70 and 80°C will result in a decline in the number of seeds germinating and may potentially see a change in species distributions. As such soil temperatures are already being experienced throughout Australia, some species may already be close to their thermal threshold.

Influence of increasing elevation on growth characteristics at timberline

1986 ◽  
Vol 64 (11) ◽  
pp. 2517-2523 ◽  
Author(s):  
Katherine Hansen-Bristow
Keyword(s):  
Air Temperature ◽  
Growing Season ◽  
Shoot Elongation ◽  
Growth Characteristics ◽  
Alpine Tundra ◽  
Needle Length ◽  
Soil Temperatures ◽  
Temperature Inversions ◽  
Topographic Depressions

Significant differences in growing-season air and soil temperatures were found with increasing elevation in the upper montane and forest–alpine tundra ecotone. Temperature inversions in topographic depressions were frequent, especially during the growing season. Variability in bud flush timing with elevation was best accounted for by soil temperatures; however, air temperature recorded within a mat conifer also correlated well with bud flush timing. Significant differences in shoot elongation, needle length, and cuticular thickness were found with differences in climate and elevational changes.

scholarly journals The Impact of Air Temperature During the Growing Season on NEE of the Apple Orchard

2012 ◽  
Vol 45 (6) ◽  
pp. 1211-1215
Author(s):  
Gun-Yeob Kim ◽  
Seul-Bi Lee ◽  
Jong-Sik Lee ◽  
Eun-Jung Choi ◽  
Jong-Hee Ryu
Keyword(s):  
Air Temperature ◽  
Growing Season ◽  
Apple Orchard ◽  
The Impact

scholarly journals The Impact of Site Extremes on the Onset of Phenological Phases of Selected Tree Species

2014 ◽  
Vol 62 (5) ◽  
pp. 1117-1124
Author(s):  
Jana Škvareninová
Keyword(s):  
Air Temperature ◽  
Tree Species ◽  
Soil Depth ◽  
Average Length ◽  
Growing Season ◽  
Corylus Avellana ◽  
Extreme Conditions ◽  
Air Temperatures ◽  
The Impact ◽  
Phenological Phases

In the years 2007–2013 we performed phenological observations of common hazel (Corylus avellana L.), blackthorn (Prunus spinosa L.), and hawthorn (Crataegus oxyacantha L.) at two locations of central Slovakia situated at elevations of 300 m and 530 m a.s.l. The phenophase of first leaves of all tree species started in the second half of April on average, and was conditioned by the average daily air temperatures above 0 °C. The earliest onset was observed at both locations in 2007 due to the highest average air temperature during the observed period, which in March reached the value of 6.1 °C. Colouring of leaves started in the second and third decades of September. Both phenophases began earlier at the location situated at the higher elevation due to the effect of aspect, terrain, and soil depth. During the last 7 years, the average length of the growing season of tree species situated at an elevation of 300 m was from 136 to 152 days, in more extreme conditions at an elevation of 530 m the growing season was shorter by 12 days in the case of blackthorn and by 5 days in the case of hawthorn.

scholarly journals Projected Future Temporal Trends of Two Different Urban Heat Islands in Athens (Greece) under Three Climate Change Scenarios: A Statistical Approach

Atmosphere ◽  
2020 ◽  
Vol 11 (6) ◽  
pp. 637 ◽  
Author(s):  
Tim van der Schriek ◽  
Konstantinos V. Varotsos ◽  
Christos Giannakopoulos ◽  
Dimitra Founda
Keyword(s):  
Climate Change ◽  
Air Pollution ◽  
Air Temperature ◽  
Temporal Trends ◽  
Temperature Data ◽  
Rural Site ◽  
Future Climate Change ◽  
Climate Change Scenarios ◽  
The Future ◽  
The Impact

This is the first study to look at future temporal urban heath island (UHI) trends of Athens (Greece) under different UHI intensity regimes. Historical changes in the Athens UHI, spanning 1971–2016, were assessed by contrasting two air temperature records from stable meteorological stations in contrasting urban and rural settings. Subsequently, we used a five-member regional climate model (RCM) sub-ensemble from EURO-CORDEX with a horizontal resolution of 0.11° (~12 × 12 km) to simulate air temperature data, spanning the period 1976–2100, for the two station sites. Three future emissions scenarios (RCP2.6, RCP4.5, and RCP8.5) were implanted in the simulations after 2005 covering the period 2006–2100. Two 20-year historical reference periods (1976–1995 and 1996–2015) were selected with contrasting UHI regimes; the second period had a stronger intensity. The daily maximum and minimum air temperature data (Tmax and Tmin) for the two reference periods were perturbed to two future periods, 2046–2065 and 2076–2095, under the three RCPs, by applying the empirical quantile mapping (eqm) bias-adjusting method. This novel approach allows us to assess future temperature developments in Athens under two UHI intensity regimes that are mainly forced by differences in air pollution and heat input. We found that the future frequency of days with Tmax > 37 °C in Athens was only different from rural background values under the intense UHI regime. Thus, the impact of heatwaves on the urban environment of Athens is dependent on UHI intensity. There is a large increase in the future frequency of nights with Tmin > 26 °C in Athens under all UHI regimes and climate scenarios; these events remain comparatively rare at the rural site. This large urban amplification of the frequency of extremely hot nights is likely caused by air pollution. Consequently, local mitigation policies aimed at decreasing urban atmospheric pollution are expected to be highly effective in reducing urban temperatures and extreme heat events in Athens under future climate change scenarios. Such policies directly have multiple benefits, including reduced electricity (energy) needs, improved living quality and strong health advantages (heat- and pollution-related illness/deaths).

Simulating the impact of future climate change on runoff processes in selected catchments of Slovakia

2021 ◽  
Author(s):  
Roman Výleta ◽  
Milica Aleksić ◽  
Patrik Sleziak ◽  
Kamila Hlavcova
Keyword(s):  
Climate Change ◽  
Air Temperature ◽  
Climate Model ◽  
Hydrological Cycle ◽  
Future Climate Change ◽  
Time Horizons ◽  
The Future ◽  
The Impact ◽  
Impacts Of Climate Change

<p>The future development of the runoff conditions, as a consequence of climate change, is of great interest for water managers. Information about the potential impacts of climate change on the hydrological regime is needed for long-term planning of water resources and flood protection.</p><p>The aim of this study is to evaluate the possible impacts of climate change on the runoff regime in five selected catchments located in the territory of Slovakia. Changes in climatic characteristics (i.e., precipitation and air temperature) for future time horizons were prepared by a regional climate model KNMI using the A1B emission scenario. The selected climatic scenario predicts a general increase in air temperature and precipitation (higher in winter than in summer). For simulations of runoff under changed conditions, a lumped rainfall-runoff model (the TUW model) was used. This model belongs to a group of conceptual models and follows a structure of a widely used Swedish HBV model. The TUW model was calibrated for the period of 2011 – 2019. We assumed that this period would be similar (to recent/warmer climate) in terms of the average daily air temperatures and daily precipitation totals. The future changes in runoff due to climate change were evaluated by comparing the simulated long-term mean monthly runoff for the current state (1981-2010) and modelled scenarios in three time periods (2011-2040, 2041-2070, and 2071-2100). The results indicate that changes in the long-term runoff seasonality and extremality of hydrological cycle could be expected in the future. The runoff should increase in winter months compared to the reference period. This increase is probably related to a rise in temperature and anticipated snowmelt. Conversely, during the summer periods, a decrease in the long-term runoff could be assumed. According to modelling, these changes will be more pronounced in the later time horizons.</p><p>It should be noted that the results of the simulation are dependent on the availability of the inputs, the hydrological/climate model used, the schematization of the simulated processes, etc. Therefore, they need to be interpreted with a sufficient degree of caution</p>

Changes in snow storages and their impact on occurrence and extremity of runoff caused by rain-on-snow events

2020 ◽  
Author(s):  
Ondrej Hotovy ◽  
Michal Jenicek
Keyword(s):  
Air Temperature ◽  
Snow Water Equivalent ◽  
Hydrological Cycle ◽  
Winter Season ◽  
Model Performance ◽  
Catchment Scale ◽  
The Future ◽  
Snow Water ◽  
The Impact ◽  
Catchment Runoff

<p>Seasonal snowpack significantly influences the catchment runoff and thus represents an important input for the hydrological cycle. Changes in the precipitation distribution and intensity, as well as a shift from snowfall to rain is expected in the future due to climate changes. As a result, rain-on-snow events, which are considered to be one of the main causes of floods in winter and spring, may occur more frequently.</p><p>The objective of this study is 1) to evaluate the frequency, inter-annual variability and extremity of rain-on-snow events in the past based on existing measurements and 2) to simulate the effect of predicted increase in air temperature on the occurrence of rain-on-snow events in the future. We selected 59 near-natural mountain catchments in Czechia with significant snow influence on runoff and with available long-time series (>35 years) of daily hydrological and meteorological variables. A semi-distributed conceptual model, HBV-light, was used to simulate the individual components of the water cycle at a catchment scale. The model was calibrated for each of study catchments by using 100 calibration trials which resulted in respective number of optimized parameter sets. The model performance was evaluated against observed runoff and snow water equivalent. Rain-on-snow events definition by threshold values for air temperature, snow depth, rain intensity and snow water equivalent decrease allowed us to analyze inter-annual variations and trends in rain-on-snow events during the study period 1980-2014 and to explain the role of different catchment attributes.</p><p>The preliminary results show that a significant change of rain-on-snow events related to increasing air temperature is not clearly evident. Since both air temperature and elevation seem to be an important rain-on-snow drivers, there is an increasing rain-on-snow events occurrence during winter season due to a decrease in snowfall fraction. In contrast, a decrease in total number of events was observed due to the shortening of the period with existing snow cover on the ground. Modelling approach also opened further questions related to model structure and parameterization, specifically how individual model procedures and parameters represent the real natural processes. To understand potential model artefacts might be important when using HBV or similar bucket-type models for impact studies, such as modelling the impact of climate change on catchment runoff.</p>

scholarly journals Passage through phenophases by milkvetches introduced into the environments of the Kulunda Steppe

2020 ◽  
Vol 181 (1) ◽  
pp. 97-104
Author(s):  
T. V. Kornievskaya
Keyword(s):  
Climate Change ◽  
Relative Humidity ◽  
Air Temperature ◽  
Growing Season ◽  
Plant Phenology ◽  
Total Precipitation ◽  
Climate Factors ◽  
Dry Steppe ◽  
Average Relative Humidity ◽  
The Impact

Background. Recently, more and more attention has been paid to the study of plant phenology in the context of the global climate change. By now, the question of how climate factors affect the phenophases of plants has not yet been fully investigated. Accurate forecasts for biological responses of plant species to climate change require profound understanding of the impact produced by meteorological factors on plant phenology.Materials and methods. The research was targeted at Astragalus L. spp. introduced into the dry steppe areas of the Kulunda Plain. Meteorological indicators were selected for agrometeorological description of the plant introduction site to assess its hydrothermal conditions. The Pearson correlation coefficient was used to identify the level of correlations between the studied parameters.Results. High air temperature shortened the growing season of Astragalus cicer L., but lengthened its flowering and fruiting phases. An increase in relative air humidity shortened the flowering in A. cicer. Meteorological indicators did not significantly affect the duration of the phenophases in A. sulcatus L. For A. onobrychis L., an increase in the average relative humidity reduced the budding phase, while an increase in the average and maximum air temperature and an increase in the amount of precipitation increased the flowering period. A decrease in air temperature and average relative humidity, and an increase in the total precipitation lengthened the duration of fruiting in A. onobrychis. Increased average temperature and humidity reduced its fruiting phase.Conclusion. A. sulcatus is tolerant to the dry steppe environments. The phenophases of A. cicer and A. onobrychis are more responsive to changes in meteorological indicators. In A. onobrychis, the fruiting phase is susceptible to the combined impact of climate factors. The limiting factors for A. cicer are relative humidity, total precipitation and mean temperature during the growing season.

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