scholarly journals Effects of temperature variability and extremes on spring phenology across the contiguous United States from 1982 to 2016

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Lingling Liu ◽  
Xiaoyang Zhang
Keyword(s):  
United States ◽  
Interannual Variation ◽  
Vegetation Index ◽  
Climate Modeling ◽  
Terrestrial Ecosystems ◽  
Spring Phenology ◽  
Warming Climate ◽  
Spring Temperatures ◽  
Term Data

Abstract Warming climate and its impact on vegetation phenological trends have been widely investigated. However, interannual variability in temperature is considerably large in recent decades, which is expected to trigger an increasing trend of variation in vegetation phenology. To explore the interannual phenological variation across the contiguous United States (CONUS), we first detected the onset of vegetation greenup using the time series of the daily two-band Enhanced Vegetation Index (EVI2) observed from the AVHRR Long-Term Data Record (1982–1999) and the MODIS Climate Modeling Grid (2000–2016). We then calculated the interannual variation in greenup onset during four decadal periods: 1982–1989, 1990–1999, 2000–2009 and 2010–2016. Further, the trend of interannual variation in greenup onset from 1982 to 2016 was analyzed at pixel and state levels. Extreme phenological events were also determined using a greenup onset anomaly for each pixel. Similar approaches were applied to spring temperatures to detect extreme years and to the temporal trend of interannual variation to explain the phenological variation. The results revealed that 62% of pixels show an increasing interannual variation in greenup onset, and in 44% of pixels, this variation could be explained by the temperature. Although extreme phenology occurred locally in different years, three nationwide extreme phenological years were distinguished. The extreme warm spring that occurred in 2012 resulted in the occurrence of greenup onset as much as 20 days earlier than normal in large parts of the CONUS. In contrast, greenup onset was much later (up to 30 days) in 1983 and 1996 due to cool spring temperatures. These findings suggest that interannual variation in spring phenology could be much stronger in the future in response to climate variation, which could have more significant impacts on terrestrial ecosystems than the regular long-term phenological trend.

Laying date of marsh tits Parus palustris in relation to climate change

Biologia ◽  
2006 ◽  
Vol 61 (5) ◽  
Author(s):  
Zdravko Dolenec
Keyword(s):  
Climate Change ◽  
Life History Traits ◽  
Laying Date ◽  
Bird Breeding ◽  
Spring Temperatures ◽  
The Mean ◽  
The Relationship ◽  
Marsh Tit ◽  
Term Data

AbstractIncreasing evidence suggests that climate change affects bird breeding phenology and other life-history traits of wildlife. This study is based on the mean spring temperatures (February, March, April) and laying dates of first eggs of the marsh tit Parus palustris. We collected data from 1984 to 2004 for the Mokrice area in NW Croatia. Correlation between laying date and mean spring temperatures was significant. The relationship between mean laying date (y) and air temperature (x) can be expressed as y = 44.69 − 2.08x. Results indicate that spring temperatures are a good predictor of timing of laying eggs. Such long-term data could than be used in order to assess the effects on biological systems if human activities influence climate.

scholarly journals A dataset of 30-meter annual vegetation phenology indicators (1985–2015) in urban areas of the conterminous United States

2019 ◽  
Author(s):  
Xuecao Li ◽  
Yuyu Zhou ◽  
Lin Meng ◽  
Ghassem R. Asrar ◽  
Chaoqun Lu ◽  
...  
Keyword(s):  
United States ◽  
Urban Areas ◽  
Vegetation Index ◽  
National Level ◽  
Temporal Trends ◽  
Google Earth ◽  
Vegetation Phenology ◽  
Moderate Resolution ◽  
Dynamics Of Vegetation

Abstract. Fine-resolution satellite observations show great potential for characterizing seasonal and annual dynamics of vegetation phenology in urban domains, from local to regional and global scales. However, most previous studies were conducted using coarse or moderate resolution data, which are inadequate for characterizing the spatiotemporal dynamics of vegetation phenology in urban domains. In this study, we produced an annual vegetation phenology dataset in urban ecosystems for the conterminous United States (US), using all available Landsat images on the Google Earth Engine (GEE) platform. First, we characterized the long-term mean seasonal pattern of phenology indicators of the start of season (SOS) and the end of season (EOS), using a double logistic model. Then, we identified the annual variability of these two phenology indicators by measuring the difference of dates when the vegetation index in a specific year reaches the same magnitude as its long-term mean. The derived phenology indicators agree well with in-situ observations from PhenoCam network and Harvard Forest. Comparing with results derived from the moderate resolution imaging spectroradiometer (MODIS) data, our Landsat derived phenology indicators can provide more spatial details. Also, temporal trends of phenology indicators (e.g., SOS) derived from Landsat and MODIS are consistent overall, but the Landsat derived results from 1985 have a longer temporal span compared to MODIS from 2001. In general, there is a spatially explicit pattern of phenology indicators from the North to the South in cities in the conterminous US, with an overall advanced SOS in the past three decades. The derived phenology product in the US urban domains at the national level is of great use for urban ecology studies for its fine spatial resolution (30 m) and long temporal span (30 years). The data are available at https://doi.org/10.6084/m9.figshare.7685645.v2.

scholarly journals Why has catchment evaporation increased in the past 40 years? A data-based study in Austria

2018 ◽  
Author(s):  
Doris Duethmann ◽  
Günter Blöschl
Keyword(s):  
Soil Moisture ◽  
Vegetation Index ◽  
Global Radiation ◽  
The Past ◽  
Available Energy ◽  
Vegetation Activity ◽  
Regional Evapotranspiration ◽  
Monteith Equation ◽  
Term Data

Abstract. Global warming has increased regional evapotranspiration in many parts of the world in the last decades, but the drivers of these increases are widely debated. Part of the difficulty lies in the scarcity of high-quality long term data on evapotranspiration. In this paper, we analyze changes in catchment evapotranspiration estimated from the water balances of 156 catchments in Austria over the period 1977–2014 and attribute them to changes in atmospheric demand and available energy, vegetation, and soil moisture as possible drivers. Trend analyses suggest that evapotranspiration has significantly increased in 60 % of the catchments (p ≤ 0.05) with an average increase of 29 ± 14 mm y−1 decade−1 (±standard deviation) or 4.9 ± 2.3 % decade−1. A pooled pan evaporation series based on 22 stations has, on average, increased by 29 ± 5 mm y−1 decade−1 or 6.0 ± 1.0 % decade−1. Reference evaporation over the 156 catchments estimated by the Penman-Monteith equation has increased by 18 ± 5 mm y−1 decade−1 or 2.8 ± 0.7 % decade−1. Of these, 2.1 % are due to increased global radiation and 0.5 % due to increased air temperature according to the Penman-Monteith equation. A satellite-based vegetation index (NDVI) has increased by 0.02 ± 0.01 decade−1 or 3.1 ± 1.1 % decade−1. Estimates of reference evaporation accounting for changes in stomata resistance due to changes in NDVI indicate that the increase in vegetation activity has led to a similar increase in reference evaporation as changes in the climate parameters. A regression between trends in evapotranspiration and precipitation, as a proxy of soil moisture, yields a sensitivity of 0.30 ± 0.04 mm y−2 increase in evapotranspiration to 1  y−2 increase in precipitation. A synthesis of the data analyses suggests that 38 ± 13 % of the observed increase in catchment evapotranspiration can be directly attributed to increased atmospheric demand and available energy, 30 ± 12 % to increased vegetation activity, and 32 ± 5 % to increased soil moisture due to increases in precipitation.

scholarly journals A dataset of 30 m annual vegetation phenology indicators (1985–2015) in urban areas of the conterminous United States

2019 ◽  
Vol 11 (2) ◽  
pp. 881-894 ◽  
Author(s):  
Xuecao Li ◽  
Yuyu Zhou ◽  
Lin Meng ◽  
Ghassem R. Asrar ◽  
Chaoqun Lu ◽  
...  
Keyword(s):  
United States ◽  
Urban Areas ◽  
Vegetation Index ◽  
Seasonal Pattern ◽  
National Level ◽  
Temporal Trends ◽  
Google Earth ◽  
Vegetation Phenology ◽  
Dynamics Of Vegetation

Abstract. Medium-resolution satellite observations show great potential for characterizing seasonal and annual dynamics of vegetation phenology in urban domains from local to regional and global scales. However, most previous studies were conducted using coarse-resolution data, which are inadequate for characterizing the spatiotemporal dynamics of vegetation phenology in urban domains. In this study, we produced an annual vegetation phenology dataset in urban ecosystems for the conterminous United States (US), using all available Landsat images on the Google Earth Engine (GEE) platform. First, we characterized the long-term mean seasonal pattern of phenology indicators of the start of season (SOS) and the end of season (EOS), using a double logistic model. Then, we identified the annual variability of these two phenology indicators by measuring the difference of dates when the vegetation index in a specific year reaches the same magnitude as its long-term mean. The derived phenology indicators agree well with in situ observations from the PhenoCam network and Harvard Forest. Comparing with results derived from the moderate-resolution imaging spectroradiometer (MODIS) data, our Landsat-derived phenology indicators can provide more spatial details. Also, we found the temporal trends of phenology indicators (e.g., SOS) derived from Landsat and MODIS are consistent overall, but the Landsat-derived results from 1985 offer a longer temporal span compared to MODIS from 2001 to present. In general, there is a spatially explicit pattern of phenology indicators from the north to the south in cities in the conterminous US, with an overall advanced SOS in the past 3 decades. The derived phenology product in the US urban domains at the national level is of great use for urban ecology studies for its medium spatial resolution (30 m) and long temporal span (30 years). The data are available at https://doi.org/10.6084/m9.figshare.7685645.v5.

AQUACOSM-plus: an International Network for Aquatic Mesocosm Facilities Supporting Experimental Ecosystem Studies and cross-disciplinary RI- RI collaborations

2021 ◽  
Author(s):  
Jens C Nejstgaard ◽  
Stella A Berger ◽  
Katharina Makower ◽  
Robert Ptacnik ◽  
Herwig Stibor ◽  
...  
Keyword(s):  
Experimental Studies ◽  
Terrestrial Ecosystems ◽  
Biodiversity Loss ◽  
Grand Challenges ◽  
Wide Range ◽  
Underlying Mechanisms ◽  
Research Facilities ◽  
Term Data ◽  
The Eu

<p>To understand underlying mechanisms of aquatic ecosystem functioning in relating to the global Grand Challenges (climate change, biodiversity loss, eutrophication, emerging pollutants, etc.), it is necessary to consider processes in adjacent systems, such as atmosphere and adjacent aquatic and terrestrial systems. For freshwater and coastal systems, the aquatic-terrestrial coupling on the watershed level is specifically important. We argue that for a better understanding of both aquatic and terrestrial ecosystems a combination of long-term data from connected environments, coupled with experimental ecosystem-scale experiments, have a greater potential for successful model testing and development of predictive concepts, than using only long-term data (without experiments) from separate systems. This talk will present the EU-funded RI-project<strong> AQUACOSM-plus</strong> (<strong>www.aquacosm.eu</strong>, 2020-2024) that offers access to >60 research facilities across the EU and is linked to world-wide cooperation through the <strong>MESOCOSM.EU</strong> portal, a virtual network of >100 research facilities. These networks<strong> </strong>comprise mesocosm facilities in all aquatic systems, including rivers, ponds, lakes, estuaries and marine systems – offering unique opportunities to conduct ecosystem-scale experimental studies of relevance to aquatic-terrestrial coupling. These facilities allow for process studies to test models based on trend or response observations from long-term-data, in order to better understand underlying mechanisms of ecosystem responses to the present global Grand Challenges. The AQUACOSM-plus mesocosm facilities, are also open for conducting ecosystem solution-based experiments to enable effective management in aquatic ecosystems. The AQUACOSM network will open calls to fund access to >13.000 days for a wide range of external users. We will also present examples of developing RI-RI collaborations and development of technological solutions and instrumentation to enhance the mobility of mesocosms and increase opportunities for relevant scenario-testing by the scientific community at large.</p>

scholarly journals Relationship between Winter Snow Cover Dynamics, Climate and Spring Grassland Vegetation Phenology in Inner Mongolia, China

2019 ◽  
Vol 8 (1) ◽  
pp. 42 ◽  
Author(s):  
Dejing Qiao ◽  
Nianqin Wang
Keyword(s):  
Snow Cover ◽  
Air Temperature ◽  
Inner Mongolia ◽  
Vegetation Index ◽  
Terrestrial Ecosystems ◽  
Onset Date ◽  
Vegetation Phenology ◽  
Grassland Vegetation ◽  
Spring Phenology ◽  
Winter Snow

The onset date of spring phenology (SOS) is regarded as a key parameter for understanding and modeling vegetation–climate interactions. Inner Mongolia has a typical temperate grassland vegetation ecosystem, and has a rich snow cover during winter. Due to climate change, the winter snow cover has undergone significant changes that will inevitably affect the vegetation growth. Therefore, improving our ability to accurately describe the responses of spring grassland vegetation phenology to winter snow cover dynamics would enhance our understanding of changes in terrestrial ecosystems due to their responses to climate changes. In this study, we quantified the spatial-temporal change of SOS by using the Advanced Very High Resolution Radiometer (AVHRR) derived Normalized Difference Vegetation Index (NDVI) from 1982 to 2015, and explored the relationships between winter snow cover, climate, and SOS across different grassland vegetation types. The results showed that the SOS advanced significantly at a rate of 0.3 days/year. Winter snow cover dynamics presented a significant positive correlation with the SOS, except for the start date of snow cover. Moreover, the relationship with the increasing temperature and precipitation showed a significant negative correlation, except that increasing Tmax (maximum air temperature) and Tavg (average air temperature) would lead a delay in SOS for desert steppe ecosystems. Sunshine hours and relative humidity showed a weaker correlation.

scholarly journals Urban warming advances spring phenology but reduces the response of phenology to temperature in the conterminous United States

2020 ◽  
Vol 117 (8) ◽  
pp. 4228-4233 ◽  
Author(s):  
Lin Meng ◽  
Jiafu Mao ◽  
Yuyu Zhou ◽  
Andrew D. Richardson ◽  
Xuhui Lee ◽  
...  
Keyword(s):  
United States ◽  
Rural Areas ◽  
Urban Areas ◽  
Environmental Changes ◽  
Terrestrial Ecosystems ◽  
Urban Heat Islands ◽  
Heat Accumulation ◽  
Spring Phenology ◽  
Heat Islands ◽  
Urban Rural

Urbanization has caused environmental changes, such as urban heat islands (UHIs), that affect terrestrial ecosystems. However, how and to what extent urbanization affects plant phenology remains relatively unexplored. Here, we investigated the changes in the satellite-derived start of season (SOS) and the covariation between SOS and temperature (RT) in 85 large cities across the conterminous United States for the period 2001–2014. We found that 1) the SOS came significantly earlier (6.1 ± 6.3 d) in 74 cities and RT was significantly weaker (0.03 ± 0.07) in 43 cities when compared with their surrounding rural areas (P < 0.05); 2) the decreased magnitude in RT mainly occurred in cities in relatively cold regions with an annual mean temperature <17.3 °C (e.g., Minnesota, Michigan, and Pennsylvania); and 3) the magnitude of urban−rural difference in both SOS and RT was primarily correlated with the intensity of UHI. Simulations of two phenology models further suggested that more and faster heat accumulation contributed to the earlier SOS, while a decrease in required chilling led to a decline in RT magnitude in urban areas. These findings provide observational evidence of a reduced covariation between temperature and SOS in major US cities, implying the response of spring phenology to warming conditions in nonurban environments may decline in the warming future.

scholarly journals Asymmetric Effects of Daytime and Nighttime Warming on Boreal Forest Spring Phenology

2019 ◽  
Vol 11 (14) ◽  
pp. 1651 ◽  
Author(s):  
Guorong Deng ◽  
Hongyan Zhang ◽  
Xiaoyi Guo ◽  
Yu Shan ◽  
Hong Ying ◽  
...  
Keyword(s):  
Boreal Forest ◽  
Vegetation Index ◽  
Terrestrial Ecosystem ◽  
Terrestrial Ecosystems ◽  
Maximum Temperature ◽  
Spring Phenology ◽  
Asymmetric Effects ◽  
Terrestrial Ecosystem Model ◽  
Diurnal Temperatures ◽  
Nighttime Warming

Vegetation phenology is the most intuitive and sensitive biological indicator of environmental conditions, and the start of the season (SOS) can reflect the rapid response of terrestrial ecosystems to climate change. At present, the model based on mean temperature neglects the role of the daytime maximum temperature (TMAX) and the nighttime minimum temperature (TMIN) in providing temperature accumulation and cold conditions at leaf onset. This study analyzed the spatiotemporal variations of spring phenology for the boreal forest from 2001 to 2017 based on the moderate-resolution imaging spectro-radiometer (MODIS) enhanced vegetation index (EVI) data (MOD13A2) and investigated the asymmetric effects of daytime and nighttime warming on the boreal forest spring phenology during TMAX and TMIN preseason by partial correlation analysis. The results showed that the spring phenology was delayed with increasing latitude of the boreal forest. Approximately 91.37% of the region showed an advancing trend during the study period, with an average advancement rate of 3.38 ± 0.08 days/decade, and the change rates of different land cover types differed, especially in open shrubland. The length of the TMIN preseason was longer than that of the TMAX preseason and diurnal temperatures showed an asymmetrical increase during different preseasons. The daytime and nighttime warming effects on the boreal forest are asymmetrical. The TMAX has a greater impact on the vegetation spring phenology than TMIN as a whole and the effect also has seasonal differences; the TMAX mainly affects the SOS in spring, while TMIN has a greater impact in winter. The asymmetric effects of daytime and nighttime warming on the SOS in the boreal forest were highlighted in this study, and the results suggest that diurnal temperatures should be added to the forest terrestrial ecosystem model.

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