Calibration of MODIS-based gross primary production over an alpine meadow on the Tibetan Plateau

2012 ◽  
Vol 38 (2) ◽  
pp. 157-168 ◽  
Author(s):  
Gang Fu ◽  
Zhenxi Shen ◽  
Xianzhou Zhang ◽  
Peili Shi ◽  
Yongtao He ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Primary Production ◽  
Alpine Meadow ◽  
Gross Primary Production ◽  
The Tibetan Plateau

scholarly journals Precipitation and aridity index regulating spatial patterns of vegetation production and species diversity based on alpine grassland transect, Tibetan Plateau

2016 ◽  
Author(s):  
Jian Sun
Keyword(s):  
Tibetan Plateau ◽  
Primary Production ◽  
Alpine Meadow ◽  
Net Primary Production ◽  
Aridity Index ◽  
Alpine Grassland ◽  
The Tibetan Plateau ◽  
Aboveground Net Primary Production ◽  
Alpine Steppe ◽  
Unimodal Pattern

Although the relationship between the aboveground net primary production (ANPP) and speciesdiversity (SR) have been widely reported, there is considerable disagreement about the fitting patterns of SR–ANPP, which has been variously described as ‘positive’, ‘negative’, ‘unimodal’, ‘U-shaped’ and so on. Not surprisingly, the effect-factors including precipitation, aridity index and geographic conditions (e.g.,altitude, longitude and latitude) on ANPP and SR continue to interest researchers, especially the effects at high altitude regions. We investigated ANPP and SR from 113 sampled sites (399 plots) across alpine meadow and steppe in the Tibetan Plateau, which included Tibet, Qinghai and Sichuan province. The effects of various environmental factors (precipitation, temperature, aridity index, altitude, longitude,latitude and vegetation type on SR and ANPP) were explored. The results indicate that a unimodal pattern was confirmed between ANPP and SR in alpine steppe (R 2 =0.45, P <0.0001), alpine meadow ( R 2 =0.4, P <0.0001), and all samples across alpine grassland ( R 2 =0.52, P <0.0001). For the aboveground net primary production, the appropriate precipitation and aridity is 600mm and 42, respectively. Under thesame moisture conditions, the maximum value of diversity is 0.75. Longitude ( R 2 =0.69, P <0.0001) and altitude ( R 2 =0.48, P <0.0001) have positive and negative effects on aboveground net primary production, and a similar relationship exists with diversity ( R 2 =0.44, P <0.0001 and R 2 =0.3, P <0.0001).The same patterns of diversity and production responding to precipitation and the aridity index were evident in alpine steppe and meadow, and a unimodal pattern was confirmed between ANPP and SR in both locations.

scholarly journals Biophysical effects on the interannual variation in carbon dioxide exchange of an alpine meadow on the Tibetan Plateau

2016 ◽  
Author(s):  
Lei Wang ◽  
Huizhi Liu ◽  
Jihua Sun ◽  
Yaping Shao
Keyword(s):  
Carbon Dioxide ◽  
Tibetan Plateau ◽  
Air Temperature ◽  
Interannual Variation ◽  
Alpine Meadow ◽  
Ecosystem Respiration ◽  
Gross Primary Production ◽  
Seasonal Pattern ◽  
Carbon Dioxide Exchange ◽  
The Tibetan Plateau

Abstract. Eddy covariance measurements from 2012 to 2015 were used to investigate the interannual variation in carbon dioxide exchange and its control over an alpine meadow on the southeast margin of the Tibetan Plateau. The annual net ecosystem exchange (NEE) from 2012 to 2015 was −114.2, −158.5, −159.9 and −212.6 g C m−2 yr−1 and generally decreased with the mean annual air temperature (MAT). An exception occurred in 2014, which had the highest MAT. This was attributed to higher ecosystem respiration (RE) and similar gross primary production (GPP) in 2014 because the GPP increased with MAT but became saturated due to the photosynthesis capacity limit. In the spring (March to May) of 2012, lower air temperature (Ta) and drought events delayed grass germination and reduced GPP. In the late wet season (September to October) of 2012 and 2013, the lower Ta in September and its negative effects on vegetation growth caused earlier grass senescence and significantly lower GPP. This indicates that the seasonal pattern of Ta greatly affected the annual total GPP, which is consistent with the result of the homogeneity-of-slopes model. The model shows that the climatic seasonal variation explained 48.6 % of the GPP variability, and the percentage of climatic interannual variation and the ecosystem functional change were 9.7 % and 10.6 %, respectively.

scholarly journals Tower-Based Validation and Improvement of MODIS Gross Primary Production in an Alpine Swamp Meadow on the Tibetan Plateau

2016 ◽  
Vol 8 (7) ◽  
pp. 592 ◽  
Author(s):  
Ben Niu ◽  
Yongtao He ◽  
Xianzhou Zhang ◽  
Gang Fu ◽  
Peili Shi ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Primary Production ◽  
Gross Primary Production ◽  
The Tibetan Plateau

scholarly journals Biophysical effects on the interannual variation in carbon dioxide exchange of an alpine meadow on the Tibetan Plateau

2017 ◽  
Vol 17 (8) ◽  
pp. 5119-5129 ◽  
Author(s):  
Lei Wang ◽  
Huizhi Liu ◽  
Jihua Sun ◽  
Yaping Shao
Keyword(s):  
Carbon Dioxide ◽  
Tibetan Plateau ◽  
Air Temperature ◽  
Interannual Variation ◽  
Alpine Meadow ◽  
Ecosystem Respiration ◽  
Gross Primary Production ◽  
Seasonal Pattern ◽  
Carbon Dioxide Exchange ◽  
The Tibetan Plateau

Abstract. Eddy covariance measurements from 2012 to 2015 were used to investigate the interannual variation in carbon dioxide exchange and its control over an alpine meadow on the south-east margin of the Tibetan Plateau. The annual net ecosystem exchange (NEE) in the 4 years from 2012 to 2015 was −114.2, −158.5, −159.9 and −212.6 g C m−2 yr−1, and generally decreased with the mean annual air temperature (MAT). An exception occurred in 2014, which had the highest MAT. This was attributed to higher ecosystem respiration (RE) and similar gross primary production (GPP) in 2014 because the GPP increased with the MAT, but became saturated due to the limit in photosynthetic capacity. In the spring (March to May) of 2012, low air temperature (Ta) and drought events delayed grass germination and reduced GPP. In the late wet season (September to October) of 2012 and 2013, the low Ta in September and its negative effects on vegetation growth caused earlier grass senescence and significantly lower GPP. This indicates that the seasonal pattern of Ta has a substantial effect on the annual total GPP, which is consistent with results obtained using the homogeneity-of-slopes (HOS) model. The model results showed that the climatic seasonal variation explained 48.6 % of the GPP variability, while the percentages explained by climatic interannual variation and the ecosystem functional change were 9.7 and 10.6 %, respectively.

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