scholarly journals Characterizing Spatiotemporal Pattern of Vegetation Greenness Breakpoints on Tibetan Plateau Using GIMMS NDVI3g Dataset

IEEE Access ◽  
2020 ◽  
Vol 8 ◽  
pp. 56518-56527 ◽  
Author(s):  
Yong Ni ◽  
Yuke Zhou ◽  
Junfu Fan
Keyword(s):  
Tibetan Plateau ◽  
Spatiotemporal Pattern ◽  
Vegetation Greenness ◽  
Gimms Ndvi3g

scholarly journals Elevational Movement of Vegetation Greenness on the Tibetan Plateau: Evidence from the Landsat Satellite Observations during the Last Three Decades

Atmosphere ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 161
Author(s):  
Liheng Lu ◽  
Xiaoqian Shen ◽  
Ruyin Cao
Keyword(s):  
Tibetan Plateau ◽  
Spatial Resolution ◽  
Climate Warming ◽  
Vertical Movement ◽  
The Tibetan Plateau ◽  
Upward Movement ◽  
Vegetation Growth ◽  
Vegetation Greenness ◽  
Mountainous Regions ◽  
Vegetation Activities

The Tibetan Plateau, the highest plateau in the world, has experienced strong climate warming during the last few decades. The greater increase of temperature at higher elevations may have strong impacts on the vertical movement of vegetation activities on the plateau. Although satellite-based observations have explored this issue, these observations were normally provided by the coarse satellite data with a spatial resolution of more than hundreds of meters (e.g., GIMMS and MODIS), which could lead to serious mixed-pixel effects in the analyses. In this study, we employed the medium-spatial-resolution Landsat NDVI data (30 m) during 1990–2019 and investigated the relationship between temperature and the elevation-dependent vegetation changes in six mountainous regions on the Tibetan Plateau. Particularly, we focused on the elevational movement of the vegetation greenness isoline to clarify whether the vegetation greenness isoline moves upward during the past three decades because of climate warming. Results show that vegetation greening occurred in all six mountainous regions during the last three decades. Increasing temperatures caused the upward movement of greenness isoline at the middle and high elevations (>4000 m) but led to the downward movement at lower elevations for the six mountainous regions except for Nyainqentanglha. Furthermore, the temperature sensitivity of greenness isoline movement changes from the positive value to negative value by decreasing elevations, suggesting that vegetation growth on the plateau is strongly regulated by other factors such as water availability. As a result, the greenness isoline showed upward movement with the increase of temperature for about 59% pixels. Moreover, the greenness isoline movement increased with the slope angles over the six mountainous regions, suggesting the influence of terrain effects on the vegetation activities. Our analyses improve understandings of the diverse response of elevation-dependent vegetation activities on the Tibetan Plateau.

Mismatch in elevational shifts between satellite observed vegetation greenness and temperature isolines during 2000-2016 on the Tibetan Plateau

2018 ◽  
Vol 24 (11) ◽  
pp. 5411-5425 ◽  
Author(s):  
Shuai An ◽  
Xiaolin Zhu ◽  
Miaogen Shen ◽  
Yafeng Wang ◽  
Ruyin Cao ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
The Tibetan Plateau ◽  
Vegetation Greenness

scholarly journals Sedimentary evolution of the foreland basin in the NE Tibetan Plateau and the growth of the Qilian Shan since 7 Ma

2019 ◽  
Vol 131 (9-10) ◽  
pp. 1744-1760 ◽  
Author(s):  
Xiaofei Hu ◽  
Dianbao Chen ◽  
Baotian Pan ◽  
Jinjun Chen ◽  
Jian Zhang ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Foreland Basin ◽  
Sedimentary Facies ◽  
Coarse Grained ◽  
Spatiotemporal Pattern ◽  
Sedimentary Sequence ◽  
Long Distance ◽  
Abrupt Decrease ◽  
Sedimentary Evolution ◽  
Ne Tibetan Plateau

AbstractWe studied the magnetostratigraphy and sedimentary facies of a 550-m-long drill core from the Jiudong Basin in the NE Tibetan Plateau. Our aims were to reconstruct the late Cenozoic sedimentary evolution of this foreland basin, and to determine the spatiotemporal pattern of growth of the Qilian Shan. The magnetostratigraphy indicates that the sedimentary sequence was deposited during ca. 7–0 Ma. From ca. 6.7–3.0 Ma, the sediment accumulation rate increased gradually from ∼30 mm/k.y. to 120 mm/k.y., which was associated with the gradual evolution of sedimentary facies from a shallow lake/delta front to braided rivers. The progradation of the depositional system from 7 Ma to 3 Ma probably reflects the growth of the relief of the Qilian Shan caused by tectonic uplift. The occurrence of a continuous braided river environment from 3 Ma to the present suggests that the high relief of the Qilian Shan developed before 3 Ma. An abrupt decrease of the sedimentation rate to ∼46 mm/k.y. during 3.0–1.8 Ma, and the deposition of coarse-grained sediments, indicates the uplift of the basin center. We interpret this to reflect the propagation of the thrust system of the Qilian Shan into the basin along a southward-dipping décollement from ca. 3 Ma. Climatic changes may have influenced the sedimentary sequence by introducing long-distance-transported thin coarse sand/gravel layers which are sandwiched within the sequence, and likely were a response to cooling events or climatic transitions. The widespread occurrence of deformation within the basin region in the NE Tibetan Plateau at ca. 3 Ma indicates that this date marks the basinward growth of the deformation system.

The long-term trends (1982–2006) in vegetation greenness of the alpine ecosystem in the Qinghai-Tibetan Plateau

2014 ◽  
Vol 72 (6) ◽  
pp. 1827-1841 ◽  
Author(s):  
Li Zhang ◽  
HuaDong Guo ◽  
CuiZhen Wang ◽  
Lei Ji ◽  
Jing Li ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Alpine Ecosystem ◽  
Vegetation Greenness ◽  
Long Term Trends

scholarly journals Contrasting Effects of Temperature and Precipitation on Vegetation Greenness along Elevation Gradients of the Tibetan Plateau

2020 ◽  
Vol 12 (17) ◽  
pp. 2751
Author(s):  
Yan Wang ◽  
Dailiang Peng ◽  
Miaogen Shen ◽  
Xiyan Xu ◽  
Xiaohua Yang ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Vegetation Index ◽  
Normalized Difference Vegetation Index ◽  
Global Climate ◽  
The Tibetan Plateau ◽  
Elevation Gradients ◽  
Vegetation Greenness ◽  
Temperature And Precipitation ◽  
Variation Rate ◽  
Effects Of Temperature

The Tibetan Plateau (TP) is one of the most sensitive regions to global climate warming, not only at the inter-annual time scale but also at the altitudinal scale. We aim to investigate the contrasting effects of temperature and precipitation on vegetation greenness at different altitudes across the TP. In this study, interannual and elevational characteristics of the Normalized Difference Vegetation Index (NDVI), temperature, and precipitation were examined during the growing season from 1982 to 2015. We compared the elevational movement rates of the isolines of NDVI, temperature, and precipitation, and the sensitivities of elevational NDVI changes to temperature and precipitation. The results show that from 1982 to 2015, the elevational variation rate of isolines for NDVI mismatched with that for temperature and precipitation. The elevational movements of NDVI isolines were mostly controlled by precipitation at elevations below 2400 m and by the temperature at elevations above 2400 m. Precipitation appears to plays a role similar to temperature, and even a more effective role than the temperature at low elevations, in controlling elevational vegetation greenness changes at both spatial and interannual scales in the TP. This study highlights the regulation of temperature and precipitation on vegetation ecosystems along elevation gradients over the whole TP under global warming conditions.

scholarly journals Vegetation Dynamics on the Tibetan Plateau (1982–2006): An Attribution by Ecohydrological Diagnostics

2015 ◽  
Vol 28 (11) ◽  
pp. 4576-4584 ◽  
Author(s):  
Danlu Cai ◽  
Klaus Fraedrich ◽  
Frank Sielmann ◽  
Ling Zhang ◽  
Xiuhua Zhu ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Tibetan Plateau ◽  
State Space ◽  
Weather Data ◽  
Target Area ◽  
The Tibetan Plateau ◽  
Net Radiation ◽  
Vegetation Greenness ◽  
Mountainous Regions ◽  
Second Period

Abstract Vegetation greenness distributions [based on remote sensing normalized difference vegetation index (NDVI)] and their change are analyzed as functional vegetation–climate relations in a two-dimensional ecohydrological state space spanned by surface flux ratios of energy excess (U; loss by sensible heat H over supply by net radiation N) versus water excess (W; loss by discharge Ro over gain by precipitation P). An ecohydrological ansatz attributes state change trajectories in (U, W) space to external (or climate) and internal (or anthropogenic) causes jointly with vegetation greenness interpreted as an active tracer. Selecting the Tibetan Plateau with its complex topographic, climate, and vegetation conditions as target area, ERA-Interim weather data link geographic and (U, W) state space, into which local remote sensing Global Inventory Modeling and Mapping Studies (GIMMS) data (NDVI) are embedded; a first and second period (1982–93 and 1994–2006) are chosen for change attribution analysis. The study revealed the following results: 1) State space statistics are characterized by a bimodal distribution with two distinct geobotanic regimes (semidesert and steppe) of low and moderate vegetation greenness separated by gaps at aridity D ~ 2 (net radiation over precipitation) and greenness NDVI ~ 0.3. 2) Changes between the first and second period are attributed to external (about 70%) and internal (30%) processes. 3) Attribution conditioned joint distributions of NDVI (and its change) show 38.2% decreasing (61.8% increasing) area cover with low (moderate) greenness while high greenness areas are slightly reduced. 4) Water surplus regions benefit most from climate change (showing vegetation greenness growth) while the energy surplus change is ambiguous, because ecohydrological diagnostics attributes high mountainous regions (such as the Himalayas) as internal without considering the heat storage deficit due to increasing vegetation.

scholarly journals ANALYZING THE VELOCITY OF VEGETATION PHENOLOGY OVER THE TIBETAN PLATEAU USING GIMMS NDVI3g DATA

2018 ◽  
Vol XLII-3 ◽  
pp. 2575-2578
Author(s):  
Y. K. Zhou
Keyword(s):  
Tibetan Plateau ◽  
Global Environmental Change ◽  
Growing Season ◽  
The Tibetan Plateau ◽  
Vegetation Phenology ◽  
Terrestrial Vegetation ◽  
Velocity Change ◽  
Growing Season Length ◽  
Change Context ◽  
Gimms Ndvi3g

Global environmental change is rapidly altering the dynamics of terrestrial vegetation, and phenology is a classic proxy to detect the response of vegetation to the changes. On the Tibetan Plateau, the earlier spring and delayed autumn vegetation phenology is widely reported. Remotely sensed NDVI can serve as a good data source for vegetation phenology study. Here GIMMS NDVI3g data was used to detect vegetation phenology status on the Tibetan Plateau. The spatial and temporal gradients are combined to depict the velocity of vegetation expanding process. This velocity index represents the instantaneous local velocity along the Earth’s surface needed to maintain constant vegetation condition. This study found that NDVI velocity show a complex spatial pattern. A considerable number of regions display a later starting of growing season (SOS) and earlier end of growing season (EOS) reflected by the velocity change, particularly in the central part of the plateau. Nearly 74 % vegetation experienced a shortened growing season length. Totally, the magnitude of the phenology velocity is at a small level that reveals there is not a significant variation of vegetation phenology under the climate change context.

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