Diverse effects of climate at different times on grassland phenology in mid-latitude of the Northern Hemisphere

2020 ◽  
Author(s):  
Shilong Ren ◽  
Yating Li ◽  
Matthias Peichl
Keyword(s):  
Northern Hemisphere ◽  
Air Temperature ◽  
Time Window ◽  
Climatic Factors ◽  
Growing Season ◽  
Study Region ◽  
Growing Season Length ◽  
Continental Scale ◽  
Significant Prolongation ◽  
Window Opening

<p>Studying grassland phenology and its relationships to climate would deepen our understanding of vegetation-air interactions under global climate change. To date, however, our knowledge of the responses of grassland phenology to climatic factors is still limited at the continental scale. In this study, we retrieved the start (SOS) and end (EOS) of the growing season for mid-latitude (30°N~55°N) grasslands of the Northern Hemisphere during 1981-2014, and investigated their relations with previous temperature, rainfall, and snowfall (only for SOS) through trends analysis and time window analysis. Results illustrated a predominant significant advancing/delaying trend of SOS/EOS in 23.2%/20.5% of the study region. They jointly resulted in a primarily significant prolongation trend of growing season length in 22.7% of the study region. Next, a dominated negative correlation between air temperature/rainfall and SOS was found in 62.4%/57.6% of areas. Snowfall showed converse effects (positive/negative) among different grasslands. The time window opening date for air temperature to start to affect SOS was identified as the day 1-90 before the multi-year average SOS in 76.1% of areas, while the time window opening date for the effect of rainfall/snowfall on SOS was relatively evenly distributed between the 1st and 180th day before the multi-year average SOS. EOS was found to be significantly negatively/positively correlated with air temperature/precipitation in 74.8%/83.7% of areas. The time window opening date for the effect of air temperature on EOS was identified as the 90-180th day before the multi-year average EOS in 66.9% of areas, while the time window opening date for the effect of precipitation on EOS was mainly concentrated on the 60-120th day before the multi-year average EOS in 51.5% of areas. Overall, this study highlights the distinctly different time windows for the thermal-moisture effects on grassland vegetation phenology and this should be considered when establishing process-based phenological models.</p>

scholarly journals Unsynchronized Driving Mechanisms of Spring and Autumn Phenology Over Northern Hemisphere Grasslands

2021 ◽  
Vol 3 ◽  
Author(s):  
Nan Cong ◽  
Ke Huang ◽  
Yangjian Zhang
Keyword(s):  
Global Warming ◽  
Northern Hemisphere ◽  
Vegetation Index ◽  
Normalized Difference Vegetation Index ◽  
Climatic Factors ◽  
Dominant Role ◽  
Growing Season ◽  
Growing Season Length ◽  
Driving Mechanisms ◽  
Temperature And Precipitation

Global warming has impacted Northern Hemisphere (NH) grassland ecosystems to a great extent. Vegetation growing season length (GSL) has been extended by concurrent advances in spring green-up and postponements in autumn dormancy. However, the driving mechanisms of phenology are unclear as limited factors have been considered so far. Therefore, it is still elusive to what extent phenological changes shaped GSL. In this study, we used remote sensing normalized difference vegetation index (NDVI) to extract spring and autumn phenology of NH grasslands, and further explored the contribution of each phenophase to GSL through the coefficient of variation (CV) and contribution coefficient (CntC). We found that 65% of NH grasslands exhibited advanced start-of-season (SOS) and circa 58% showed delayed end-of-season (EOS) in the three decades. Changes in GSL was regulated more by EOS changes than by SOS changes, as evidenced by their respective 52 vs. 48% CntC. As for the relationship between phenology and environmental elements, the causing factor analysis revealed that climatic factors (temperature, precipitation, and their interactions) played a dominant role in SOS variations, while environmental and internal factors exerted dominant effects on EOS. Also, interactions of temperature and precipitation contributed a higher variation of SOS than either of them individually. The differentiated factors controlling the two bounding ends of the growing season suggested that it is impossible for GSL to continue to extend without limits under global warming.

scholarly journals Growing Season Length as a Key Factor of Cumulative Net Ecosystem Exchange Over the Pine Forest Ecosystems in Europe

2015 ◽  
Vol 29 (2) ◽  
pp. 129-135 ◽  
Author(s):  
Alina Danielewska ◽  
Marek Urbaniak ◽  
Janusz Olejnik
Keyword(s):  
Air Temperature ◽  
Measurement Data ◽  
Growing Season ◽  
Pine Forest ◽  
Pine Forests ◽  
Net Ecosystem Productivity ◽  
Ecosystem Productivity ◽  
Season Length ◽  
Important Species ◽  
Growing Season Length

Abstract The Scots pine is one of the most important species in European and Asian forests. Due to a widespread occurrence of pine forests, their significance in the energy and mass exchange between the Earth surface and the atmosphere is also important, particularly in the context of climate change and greenhouse gases balance. The aim of this work is to present the relationship between the average annual net ecosystem productivity and growing season length, latitude and air temperature (tay) over Europe. Therefore, CO2 flux measurement data from eight European pine dominated forests were used. The observations suggest that there is a correlation between the intensity of CO2 uptake or emission by a forest stand and the above mentioned parameters. Based on the obtained results, all of the selected pine forest stands were CO2 sinks, except a site in northern Finland. The carbon dioxide uptake increased proportionally with the increase of growing season length (9.212 g C m-2 y-1 per day of growing season, R2 = 0.53, p = 0.0399). This dependency showed stronger correlation and higher statistical significance than both relationships between annual net ecosystem productivity and air temperature (R2 = 0.39, p = 0.096) and annual net ecosystem productivity and latitude (R2 = 0.47, p = 0.058). The CO2 emission surpassed assimilation in winter, early spring and late autumn. Moreover, the appearance of late, cold spring and early winter, reduced annual net ecosystem productivity. Therefore, the growing season length can be considered as one of the main factor affecting the annual carbon budget of pine forests.

scholarly journals Long-Term Trends in Air Temperature Distribution and Extremes, Growing Degree‐Days, and Spring and Fall Frosts for Climate Impact Assessments on Agricultural Practices in Nebraska

2012 ◽  
Vol 51 (11) ◽  
pp. 2060-2073 ◽  
Author(s):  
Kari E. Skaggs ◽  
Suat Irmak
Keyword(s):  
Air Temperature ◽  
Central City ◽  
Agricultural Practices ◽  
Growing Season ◽  
Growing Degree Days ◽  
Degree Days ◽  
Temperature Changes ◽  
Growing Season Length ◽  
Average Maximum

AbstractAir temperature influences agricultural practices and production outcomes, making detailed quantifications of temperature changes necessary for potential positive and negative effects on agricultural management practices to be exploited or mitigated. Temperature trends of long-term data for five agricultural locations, ranging from the subhumid eastern to the semiarid western parts of Nebraska, were studied to determine local temperature changes and their potential effects on agricultural practices. The study quantified trends in annual and monthly average maximum and minimum air temperature (Tmax and Tmin), daily temperature range (DTR), total growing degree-days, extreme temperatures, growing‐season dates and lengths, and temperature distributions for five heavily agricultural areas of Nebraska: Alliance, Central City, Culbertson, Fremont, and Hastings. July and August were the months with the greatest decreases in Tmax for the central part of Nebraska—Culbertson, Hastings, and Central City. Alliance, Culbertson, and Fremont had year-round decreases in DTR. Central City and Hastings experienced growing‐season decreases in DTR. Increases in growing‐season length occurred at rates of 14.3, 16.7, and 11.9 days century−1 for Alliance, Central City, and Fremont, respectively. At Hastings, moderately earlier last spring frost (LS) at a rate of 6.6 days century−1 was offset by an earlier (2.7 days century−1) first fall frost (FF), resulting in only a 3.8 days century−1 longer growing season. There were only slight changes in LS and FF dates of around 2 days earlier and 1 day later per century, respectively, for Culbertson.

Holocene and Last Interglacial cloudiness in eastern Baffin Island, Arctic CanadaThis article is one of a series of papers published in this Special Issue on the theme Polar Climate Stability Network.GEOTOP Publication 2008-0027.

2008 ◽  
Vol 45 (11) ◽  
pp. 1221-1234 ◽  
Author(s):  
Bianca Fréchette ◽  
Anne de Vernal ◽  
Pierre J.H. Richard
Keyword(s):  
Air Temperature ◽  
Growing Season ◽  
Dwarf Shrub ◽  
Interglacial Period ◽  
Vegetation Changes ◽  
Baffin Island ◽  
Last Interglacial ◽  
The Holocene ◽  
Growing Season Length ◽  
Shrub Tundra

This study presents Last Interglacial and Holocene vegetation and climate changes at Fog Lake (67°11′N, 63°15′W) on eastern Baffin Island, Arctic Canada. The vegetation cover is reported as vegetation structural types (or biomes). July air temperature and sunshine during the growing season (June–July–August–September) were reconstructed from pollen assemblages using the modern analogue technique. The vegetation of the Last Interglacial period evolved from a prostrate dwarf-shrub tundra to a low- and high-shrub tundra vegetation. The succession of four Arctic biomes was distinguished from the Last Interglacial sediments, whereas only one Arctic biome was recorded in the Holocene sediments. From ca. 8300 cal. years BP to present, hemiprostrate dwarf-shrub tundra occupied the soils around Fog Lake. During the Last Interglacial, growing season sunshine was higher than during the Holocene and July air temperature was 4 to 5 °C warmer than present. A principal component analysis helped in assessing relationship between floristic gradients and climate. The major vegetation changes through the Last Interglacial and Holocene were driven by July air temperature variations, whereas the minor, or subtle, vegetation changes seem rather correlated to September sunshine. This study demonstrates that growing season sunshine conditions can be reconstructed from Arctic pollen assemblages, thus providing information on feedbacks associated with cloud cover and summer temperatures, and therefore growing season length.

The influence of climatic factors on the duration of the growing season and the yield of early maturing soybean varieties in the Central Region of the Non-Black Earth Zon

2021 ◽  
Author(s):  
T.D. Sikharulidze ◽  
◽  
A. S. Stefansky
Keyword(s):  
Air Temperature ◽  
Central Region ◽  
Climatic Factors ◽  
Growing Season ◽  
Average Yield ◽  
Early Maturing

The duration of the growing season of soybean varieties increased against the background of excessive precipitation and low air temperature. The smallest it was in the varieties Kasatka and Svetlaya (on average 100 and 102 days). The most productive is the Svetlaya variety - the average yield is 1.73 t / ha, the maximum - 2.76 t / ha.

scholarly journals Underestimated effects of low temperature during early growing season on carbon sequestration of a subtropical coniferous plantation

2011 ◽  
Vol 8 (6) ◽  
pp. 1667-1678 ◽  
Author(s):  
W.-J. Zhang ◽  
H.-M. Wang ◽  
F.-T. Yang ◽  
Y.-H. Yi ◽  
X.-F. Wen ◽  
...  
Keyword(s):  
Carbon Sequestration ◽  
Air Temperature ◽  
Growing Season ◽  
Carbon Uptake ◽  
Summer Drought ◽  
Eddy Flux ◽  
Season Length ◽  
Growing Season Length ◽  
Coniferous Plantation ◽  
The Impact

Abstract. The impact of air temperature in early growing season on the carbon sequestration of a subtropical coniferous plantation was discussed through analyzing the eddy flux observations at Qianyanzhou (QYZ) site in southern China from 2003 to 2008. This site experienced two cold early growing seasons (with temperature anomalies of 2–5 °C) in 2005 and 2008, and a severe summer drought in 2003. Results indicated that the low air temperature from January to March was the major factor controlling the inter-annual variations in net carbon uptake at this site, rather than the previously thought summer drought. The accumulative air temperature from January to February showed high correlation (R2=0.970, p<0.001) with the annual net ecosystem production (NEP). This was due to the controls of early-month temperature on the plant phenology developing and the growing season length at this subtropical site. The cold spring greatly shortened the growing season length and therefore reduced the carbon uptake period. The eddy flux observations showed a carbon loss of 4.04 g C m−2 per growing-season day at this coniferous forest site. On the other hand, the summer drought also reduced the net carbon uptake strength because the photosynthesis was more sensitive to water deficit stress than the ecosystem respiration. However, the impact of summer drought occurred within a relatively shorter period and the carbon sequestration went back to the normal level once the drought was relieved.

scholarly journals Contributions of Climatic Factors to Interannual Variability of the Vegetation Index in Northern China Grasslands

2020 ◽  
Vol 33 (1) ◽  
pp. 175-183 ◽  
Author(s):  
Wei Zhao ◽  
Zhongmin Hu ◽  
Qun Guo ◽  
Genan Wu ◽  
Ruru Chen ◽  
...  
Keyword(s):  
Relative Humidity ◽  
Solar Radiation ◽  
Air Temperature ◽  
Vegetation Index ◽  
Climatic Factors ◽  
Explanatory Power ◽  
Regional Scale ◽  
Temperate Grasslands ◽  
Study Region ◽  
Vegetation Activities

AbstractUnderstanding the atmosphere–land surface interaction is crucial for clarifying the responses and feedbacks of terrestrial ecosystems to climate change. However, quantifying the effects of multiple climatic factors to vegetation activities is challenging. Using the geographical detector model (GDM), this study quantifies the relative contributions of climatic factors including precipitation, relative humidity, solar radiation, and air temperature to the interannual variation (IAV) of the normalized difference vegetation index (NDVI) in the northern grasslands of China during 2000 to 2016. The results show heterogeneous spatial patterns of determinant climatic factors on the IAV of NDVI. Precipitation and relative humidity jointly controlled the IAV of NDVI, illustrating more explanatory power than solar radiation and air temperature, and accounting for higher proportion of area as the determinant factor in the study region. It is noteworthy that relative humidity, a proxy of atmospheric aridity, is as important as precipitation for the IAV of NDVI. The contribution of climatic factors to the IAV of NDVI varied by vegetation type. Owing to the stronger explanatory power of climatic factors on NDVI variability in temperate grasslands, we conclude that climate variability may exert more influence on temperate grasslands than on alpine grasslands. Our study highlights the importance of the role of atmospheric aridity to vegetation activities in grasslands. We suggest focusing more on the differences between vegetation types when addressing the climate–vegetation relationships at a regional scale.

scholarly journals Trends in temperature and growing season length in idaho-usa during the past few decades

2015 ◽  
Vol 30 (4) ◽  
pp. 359-370 ◽  
Author(s):  
Carlos Antonio Costa dos Santos ◽  
Tantravahi Venkata Ramana Rao ◽  
Ricardo Alves de Olinda
Keyword(s):  
Air Temperature ◽  
Regional Scale ◽  
Temporal Correlation ◽  
Growing Season ◽  
General Idea ◽  
Quality Data ◽  
Daily Maximum ◽  
Season Length ◽  
Growing Season Length ◽  
Minimum Air Temperature

ABSTRACT This study attempts to provide new information on seasonal and annual trends, on a regional scale, using records of daily air temperature over Idaho, USA, through the analysis of the Growing Season Length (GSL), and maximum and minimum air temperature data from multiple stations in the region, as well as, to obtain the temporal correlation between the daily air temperature and Sea Surface Temperature (SST) indices. The analyses were conducted using long-term and high quality data sets for 35 meteorological stations for the period between 1970 and 2006. The results suggest that both daily maximum and minimum temperatures had increasing trends, but the minimum air temperature is increasing faster than the maximum air temperature. On average, the GSL has increased by 7.5 days/decade during the period 1970-2006, associated with increasing temperatures. Trends in regional air temperature and their indication of climate change are of interest to Idaho and the rest of the world. The trends obtained herein corroborate with the general idea that during the last century the globe has warmed.

Crop specific assessment of droughts in the growing season considering the spatiotemporal variability in phenology

2021 ◽  
Author(s):  
Erik Tijdeman ◽  
Lucas Menzel
Keyword(s):  
Soil Moisture ◽  
Water Balance ◽  
Winter Wheat ◽  
Time Window ◽  
Grid Cell ◽  
Growing Season ◽  
Agricultural Drought ◽  
Spatiotemporal Variability ◽  
Study Region ◽  
Phenological Phases

&lt;p&gt;In the context of climate change, it is important to understand whether drought conditions over the growing season of agricultural crops have changed over the past decades. Common drought metrics used for such assessments compare hydrometeorological anomalies using a static time window. However, the growing season varies among crops as well as in space; driven by climatic differences, and time; driven by e.g. changes in climate or crop-genotypes. Focusing on Southwestern Germany, we aim to investigate how the ranking of drought years varies between crops as well as among static and spatiotemporally varying growing season scenarios. First, we derived annual information on the timing of different phenological phases of two crops, winter wheat and maize, resp. early and late covering, from observations available from the German Weather Services. We then interpolated the timing of these phenological phases to 1 km resolution grids covering all agricultural areas in the study region, using static and spatiotemporally varying interpolation scenarios. Following, we extracted climatological timeseries for all agricultural grid cells and used those to simulate the climatic water balance as well as soil moisture for each grid cell with the hydrological model TRAIN. Finally, we derived for each year different drought metrics, i.e. anomalies in precipitation, temperature, climatic water balance and minimum soil moisture, and correlated those with crop yield anomalies. Results revealed distinct differences in the start and end of the growing season among considered crops. Further, the timing of different phenological phases varied by over a month in both space and time. During the most prominent drought years (2003, 2015, 2018), the growing season of both crops was particularly dry, independent on whether a fixed or variable growing season was considered. On the other hand, there were also some crop specific drought years, e.g., 1991 for maize or 2008 for winter wheat. The difference in hydrometeorological anomalies derived for static and variable growing seasons mainly relates to differences in temperature, but also affected the ranking of some drought years according to other hydrometeorological variables. More apparent were differences between drought metrics, e.g. between the climatic water balance and minimum soil moisture. From these metrics, especially minimum soil moisture correlated well with maize yields, whereas correlations with winter wheat were generally weak for all metrics. To conclude, crop specific agricultural drought assessments could benefit from a crop-relevant growing season specific definition of drought.&lt;/p&gt;

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