scholarly journals Quantitative Assessment of the Influences of Snow Drought on Forest and Grass Growth in Mid-High Latitude Regions by Using Remote Sensing

2021 ◽  
Vol 13 (4) ◽  
pp. 668
Author(s):  
Hezhen Lou ◽  
Xijin Wu ◽  
Xiaoyu Ren ◽  
Shengtian Yang ◽  
Mingyong Cai ◽  
...  
Keyword(s):  
Remote Sensing ◽  
High Latitude ◽  
Global Climate ◽  
Meteorological Data ◽  
Sanjiang Plain ◽  
Snow Accumulation ◽  
Extreme Weather Events ◽  
The Sanjiang Plain ◽  
The Past ◽  
Grass Growth

Global climate change, especially the snow drought events, is causing extreme weather events influencing regional vegetation growth and terrestrial ecosystem stability in a long-term and persistent way. In this study, the Sanjiang Plain was selected, as this area has been experiencing snow drought in the past two decades. Logistic models, combined with multisource remote sensing and unmanned aerial vehicle (UAV) data, as well as the meteorological data over the past 20 years, were used to calculate sixteen phenological periods and biomass. The results show that (1) over the past two decades, snow drought has been based on the snow accumulation and has been occurring more frequently, wider-ranging and more severely; (2) snow drought has advanced the forest start of season (SOS)/end of season (EOS) by 6/5 days, respectively; (3) if the snowfall is greater than 80% of a normal year, the SOS/EOS of grass is postponed by 8/6 days; conversely, if it is less than 80%, the SOS/EOS are advanced by 7/5 days; and (4) biomass decreased approximately 0.61%, compared with an abundant snowfall year. Overall, this study is the first to explore how snow drought impacts the phenological period in a mid-high latitude area, and more attention should be paid to these unknown risks to the ecosystem.

scholarly journals Monitoring Changes to Arctic Vegetation and Glaciers at Ny-Ålesund, Svalbard, Based on Time Series Remote Sensing

2021 ◽  
Vol 13 (19) ◽  
pp. 3845
Author(s):  
Guangbo Ren ◽  
Jianbu Wang ◽  
Yunfei Lu ◽  
Peiqiang Wu ◽  
Xiaoqing Lu ◽  
...  
Keyword(s):  
Climate Change ◽  
Remote Sensing ◽  
Time Series ◽  
High Latitude ◽  
Global Climate ◽  
Meteorological Data ◽  
Remote Sensing Data ◽  
Vegetation Coverage ◽  
Coastal Regions ◽  
Average Annual Temperature

Climate change has profoundly affected global ecological security. The most vulnerable region on Earth is the high-latitude Arctic. Identifying the changes in vegetation coverage and glaciers in high-latitude Arctic coastal regions is important for understanding the process and impact of global climate change. Ny-Ålesund, the northern-most human settlement, is typical of these coastal regions and was used as a study site. Vegetation and glacier changes over the past 35 years were studied using time series remote sensing data from Landsat 5/7/8 acquired in 1985, 1989, 2000, 2011, 2015 and 2019. Site survey data in 2019, a digital elevation model from 2009 and meteorological data observed from 1985 to 2019 were also used. The vegetation in the Ny-Ålesund coastal zone showed a trend of declining and then increasing, with a breaking point in 2000. However, the area of vegetation with coverage greater than 30% increased over the whole study period, and the wetland moss area also increased, which may be caused by the accelerated melting of glaciers. Human activities were responsible for the decline in vegetation cover around Ny-Ålesund owing to the construction of the town and airport. Even in areas with vegetation coverage of only 13%, there were at least five species of high-latitude plants. The melting rate of five major glaciers in the study area accelerated, and approximately 82% of the reduction in glacier area occurred after 2000. The elevation of the lowest boundary of the five glaciers increased by 50–70 m. The increase in precipitation and the average annual temperature after 2000 explains the changes in both vegetation coverage and glaciers in the study period.

scholarly journals Impacts of Intensified Agriculture Developments on Marsh Wetlands

2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
Zhaoqing Luan ◽  
Demin Zhou
Keyword(s):  
Agricultural Development ◽  
Agricultural Landscape ◽  
Nature Reserve ◽  
Spatiotemporal Analysis ◽  
Sanjiang Plain ◽  
Natural Marsh ◽  
The Sanjiang Plain ◽  
Wetland Ecosystems ◽  
The Past ◽  
Remote Sensing Techniques

A spatiotemporal analysis on the changes in the marsh landscape in the Honghe National Nature Reserve, a Ramsar reserve, and the surrounding farms in the core area of the Sanjiang Plain during the past 30 years was conducted by integrating field survey work with remote sensing techniques. The results indicated that intensified agricultural development had transformed a unique natural marsh landscape into an agricultural landscape during the past 30 years. Ninety percent of the natural marsh wetlands have been lost, and the areas of the other natural landscapes have decreased very rapidly. Most dry farmland had been replaced by paddy fields during the progressive change of the natural landscape to a farm landscape. Attempts of current Chinese institutions in preserving natural wetlands have achieved limited success. Few marsh wetlands have remained healthy, even after the establishment of the nature reserve. Their ecological qualities have been declining in response to the increasing threats to the remaining wetland habitats. Irrigation projects play a key role in such threats. Therefore, the sustainability of the natural wetland ecosystems is being threatened by increased regional agricultural development which reduced the number of wetland ecotypes and damaged the ecological quality.

scholarly journals The Effect of Climate Change on Variations in Dew Amount in a Paddy Ecosystem of the Sanjiang Plain, China

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Yingying Xu ◽  
Baixing Yan ◽  
Jie Tang
Keyword(s):  
Global Warming ◽  
Relative Humidity ◽  
Meteorological Data ◽  
Warming Trend ◽  
Sanjiang Plain ◽  
Dew Point ◽  
The Sanjiang Plain ◽  
Growing Seasons ◽  
Paddy Ecosystem ◽  
Dew Amount

Due to global warming, a drying and warming trend has been observed over the last 50 years in the Sanjiang Plain of Heilongjiang Province, China, which could significantly affect the condensation of vapor in paddy ecosystems. Dew is a crucial factor in the water and nutrient cycling of farmland ecosystems, and it exerts an important influence on fertilization and other agricultural activities. In order to reveal the effects of global warming on dew variation in a paddy ecosystem, anin situexperiment was conducted in paddy fields in the Sanjiang Plain during the growing seasons of 2011 to 2013. Dew was collected and measured with a poplar stick. The results of correlation analysis between meteorological factors and dew intensity in the paddy ecosystem indicate that the dew point temperature and relative humidity significantly influenced the dew intensity. Based on synchronous meteorological data, a stepwise linear multivariation regression model was established to predict dew amount. The model successfully interpreted the relationship between simulated and measured dew intensity. The results suggest that a warmer and drier climate would lead to a reduction in dew amount because water cannot condense when relative humidity falls below 71%.

scholarly journals Fire in ice: two millennia of boreal forest fire history from the Greenland NEEM ice core

2014 ◽  
Vol 10 (5) ◽  
pp. 1905-1924 ◽  
Author(s):  
P. Zennaro ◽  
N. Kehrwald ◽  
J. R. McConnell ◽  
S. Schüpbach ◽  
O. J. Maselli ◽  
...  
Keyword(s):  
Black Carbon ◽  
Biomass Burning ◽  
High Latitude ◽  
Fire History ◽  
Global Climate ◽  
Ice Cores ◽  
Back Trajectories ◽  
The Past ◽  
Isotopic Analyses ◽  
Fire Activity

Abstract. Biomass burning is a major source of greenhouse gases and influences regional to global climate. Pre-industrial fire-history records from black carbon, charcoal and other proxies provide baseline estimates of biomass burning at local to global scales spanning millennia, and are thus useful to examine the role of fire in the carbon cycle and climate system. Here we use the specific biomarker levoglucosan together with black carbon and ammonium concentrations from the North Greenland Eemian (NEEM) ice cores (77.49° N, 51.2° W; 2480 m a.s.l) over the past 2000 years to infer changes in boreal fire activity. Increases in boreal fire activity over the periods 1000–1300 CE and decreases during 700–900 CE coincide with high-latitude NH temperature changes. Levoglucosan concentrations in the NEEM ice cores peak between 1500 and 1700 CE, and most levoglucosan spikes coincide with the most extensive central and northern Asian droughts of the past millennium. Many of these multi-annual droughts are caused by Asian monsoon failures, thus suggesting a connection between low- and high-latitude climate processes. North America is a primary source of biomass burning aerosols due to its relative proximity to the Greenland Ice Cap. During major fire events, however, isotopic analyses of dust, back trajectories and links with levoglucosan peaks and regional drought reconstructions suggest that Siberia is also an important source of pyrogenic aerosols to Greenland.

scholarly journals Spatial and temporal variability studies of precipitation considering the future climate scenarios, with emphasis on extreme events

2019 ◽  
Author(s):  
Luiza Marchezan Bezerra ◽  
Ana Maria Heuminski de Avila ◽  
Vânia Rosa Pereira
Keyword(s):  
Global Climate ◽  
Meteorological Data ◽  
Extreme Rainfall ◽  
Future Climate ◽  
Extreme Weather Events ◽  
Spatial And Temporal Variability ◽  
Climate Scenarios ◽  
Natural Ecosystems ◽  
Intergovernmental Panel ◽  
Extreme Rainfall Events

The Intergovernmental Panel on Climate Change (IPCC) affirms that in future climate scenarios, the frequency and intensity of extreme weather events may intensify as a result of changes in the global climate, causing negative impacts on the population and natural ecosystems. Therefore, the impacts caused by these events will require adaptations which, in turn, will be based on future projections carried out through simulations of various global and regional models. Thus, this scientific initiation project had the objective of studying the frequency and spatial variability of extreme rainfall events in the city of Campinas, through simulations carried out using the regional model ETA-HADGEM2-ES and surface meteorological data, considering present and future scenarios.

scholarly journals Spatial and temporal variation of reference evapotranspiration under climate change: a case study in the Sanjiang Plain, Northeast China

2017 ◽  
Vol 49 (1) ◽  
pp. 251-265 ◽  
Author(s):  
Xinyi Song ◽  
Kui Zhu ◽  
Fan Lu ◽  
Weihua Xiao
Keyword(s):  
Sensitivity Analysis ◽  
Wind Speed ◽  
Reference Evapotranspiration ◽  
Sunshine Duration ◽  
Meteorological Data ◽  
Negative Influence ◽  
Sanjiang Plain ◽  
Spatial And Temporal Variation ◽  
The Sanjiang Plain ◽  
Mountainous Regions

Abstract It is essential to understand the changing patterns in reference evapotranspiration (ET0) and its relation to climate variables. In this study, meteorological data obtained from the Sanjiang Plain (SJP) between 1959 and 2013 are used to calculate ET0 via the Penman–Monteith method. This study analyses the spatial and temporal changes of ET0 and determines which meteorological variables have an impact on this. The Mann–Kendall test, moving t-test, sensitivity analysis and simulated results have been used to conduct these analyses. The results demonstrate the following. (1) Spatially, there is an increasing trend in the annual ET0 values in agricultural areas. However, significant decreasing trends (P < 0.05) can be found in mountainous regions. (2) Temporally, two abrupt changes can be detected in the early 1980s and the late 1990s for the entire SJP, leading to large inter-annual differences. (3) Sensitivity analysis shows that relative humidity (RH) is the most sensitive climate variable and has a negative influence on ET0, followed by temperature, sunshine duration and wind speed, all of which exert positive impacts. (4) The simulated result shows that ET0 is most sensitive to RH. However, significant reductions in wind speed can exert large influences on the ET0 values.

scholarly journals Glacier area changes in the Pumqu river basin, Tibetan Plateau, between the 1970s and 2001

2005 ◽  
Vol 51 (175) ◽  
pp. 607-610 ◽  
Author(s):  
Rui Jin ◽  
Xin Li ◽  
Tao Che ◽  
Lizong Wu ◽  
Pradeep Mool
Keyword(s):  
Remote Sensing ◽  
Tibetan Plateau ◽  
River Basin ◽  
Meteorological Data ◽  
Glacier Area ◽  
Remote Sensing Images ◽  
Glacier Inventory ◽  
The Past ◽  
Digital Elevation ◽  
Elevation Model

AbstractGlacier area changes in the Pumqu river basin, Tibetan Plateau, between the 1970s and 2001 are analyzed, based on the Chinese Glacier Inventory and ASTER images. A new glacier inventory is obtained by visually interpreting the remote-sensing images and the digital elevation model. By comparing the two inventories, glacier area changes over the past 30 years are revealed. The results show that the area loss is about 9.0% and the shrinkage trend continues according to the meteorological data.

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