scholarly journals Simulated annual changes in plant functional types and their responses to climate change on the northern Tibetan Plateau

2016 ◽  
Vol 13 (12) ◽  
pp. 3533-3548 ◽  
Author(s):  
Lan Cuo ◽  
Yongxin Zhang ◽  
Shilong Piao ◽  
Yanhong Gao
Keyword(s):  
Climate Change ◽  
Water Resources ◽  
Tibetan Plateau ◽  
Soil Temperature ◽  
Root Zone ◽  
Plant Functional Types ◽  
Atmospheric Conditions ◽  
Dynamic Global Vegetation Model ◽  
Northern Tibetan Plateau ◽  
Functional Types

Abstract. Changes in plant functional types (PFTs) have important implications for both climate and water resources. Still, little is known about whether and how PFTs have changed over the past decades on the northern Tibetan Plateau (NTP) where several of the top largest rivers in the world are originated. Also, the relative importance of atmospheric conditions vs. soil physical conditions in affecting PFTs is unknown on the NTP. In this study, we used the improved Lund–Potsdam–Jena Dynamic Global Vegetation Model to investigate PFT changes through examining the changes in foliar projective coverages (FPCs) during 1957–2009 and their responses to changes in root zone soil temperature, soil moisture, air temperature, precipitation and CO2 concentrations. The results show spatially heterogeneous changes in FPCs across the NTP during 1957–2009, with 34 % (13 %) of the region showing increasing (decreasing) trends. Dominant drivers responsible for the observed FPC changes vary with regions and vegetation types, but overall, precipitation is the major factor in determining FPC changes on the NTP with positive impacts. Soil temperature increase exhibits small but negative impacts on FPCs. Different responses of individual FPCs to regionally varying climate change result in spatially heterogeneous patterns of vegetation changes on the NTP. The implication of the study is that fresh water resources in one of the world's largest and most important headwater basins and the onset and intensity of Asian monsoon circulations could be affected because of the changes in FPCs on the NTP.

scholarly journals Annual changes in plant functional types and their responses to climate change on the Northern Tibetan Plateau

2016 ◽  
Author(s):  
Lan Cuo ◽  
Yongxin Zhang ◽  
Shilong Piao ◽  
Yanhong Gao
Keyword(s):  
Climate Change ◽  
Water Resources ◽  
Tibetan Plateau ◽  
Soil Temperature ◽  
Root Zone ◽  
Plant Functional Types ◽  
Atmospheric Conditions ◽  
Dynamic Global Vegetation Model ◽  
Northern Tibetan Plateau ◽  
Functional Types

Abstract. Changes in plant functional types (PFTs) have important implications for both climate and water resources. Still, little is known about whether and how PFTs have changed over the past decades on the Northern Tibetan Plateau (NTP) where several of the top largest rivers in the world are originated. Also, the relative importance of atmospheric conditions versus soil physical conditions in affecting PFTs is unknown on the NTP. In this study, we used the improved Lund-Potsdam-Jena Dynamic Global Vegetation Model to investigate PFT changes through examining the changes in foliar projective coverages (FPCs) during 1957–2009 and their responses to changes in root zone soil temperature, soil moisture, air temperature, precipitation and CO2 concentrations. The results show spatially heterogeneous changes in FPCs across the NTP during 1957–2009, with 34 % (13 %) of the region showing increasing (decreasing) trends. Dominant drivers responsible for the observed FPC changes vary with regions and vegetation types, but overall, precipitation is the major factor in determining FPC changes on the NTP with positive impacts. Soil temperature increase exhibits small but negative impacts on FPCs. Different responses of individual FPCs to regionally varying climate change result in spatially heterogeneous patterns of vegetation changes on the NTP. The implication of the study is that fresh water resources in one of the world's largest and most important headwater basins and the onset and intensity of Asian monsoon circulations could be affected because of the changes in FPCs on the NTP.

Fluvial sediment fluxes response to modern climate change and human activities in the Tibetan Plateau and its margins

2021 ◽  
Author(s):  
Dongfeng Li ◽  
Xixi Lu ◽  
Ting Zhang
Keyword(s):  
Climate Change ◽  
Water Resources ◽  
Tibetan Plateau ◽  
Air Temperature ◽  
Human Activities ◽  
Sediment Flux ◽  
The Tibetan Plateau ◽  
Fluvial Sediment ◽  
Sediment Fluxes ◽  
Cold Environments

<p>Sediment flux in cold environments is a crucial proxy to link glacial, periglacial, and fluvial systems and highly relevant to hydropower operation, water quality, and the riverine carbon cycle. However, the long-term impacts of climate change and multiple human activities on sediment flux changes in cold environments remain insufficiently investigated due to the lack of monitoring and the complexity of the sediment cascade. Here we examine the multi-decadal changes in the in-situ observed fluvial sediment fluxes from two types of basins, namely, pristine basins and disturbed basins, in the Tibetan Plateau and its margins. The results show that the fluvial sediment fluxes in the pristine Tuotuohe headwater have substantially increased over the past three decades (i.e., a net increase of 135% from 1985–1997 to 1998–2017) due to the warming and wetting climate. We also quantify the relative impacts of air temperature and precipitation on the increases in the sediment fluxes with a novel attribution approach and finds that climate warming and intensified glacier-snow-permafrost melting is the primary cause of the increased sediment fluxes in the pristine cold environment (Tuotuohe headwater), with precipitation increase and its associated pluvial processes being the secondary driver. By contrast, the sediment fluxes in the downstream disturbed Jinsha River (southeastern margin of the Tibetan Plateau) exhibit a net increase of 42% from 1966-1984 to 1985-2010 mainly due to human activities such as deforestation and mineral extraction (contribution of 82%) and secondly because of climate change (contribution of 18%). Then the sediment fluxes dropped by 76% during the period of 2011-2015 because of the operations of six cascade reservoirs since 2010. In an expected warming and wetting climate for the region, we predict that the sediment fluxes in the pristine headwaters of the Tibetan Plateau will continue to increase throughout the 21st century, but the rising sediment fluxes from the Tibetan Plateau would be mostly trapped in its marginal reservoirs.</p><p>Overall, this work has provided the sedimentary evidence of modern climate change through robust observational sediment flux data over multiple decades. It demonstrates that sediment fluxes in pristine cold environments are more sensitive to air temperature and thermal-driven geomorphic processes than to precipitation and pluvial-driven processes. It also provides a guide to assess the relative impacts of human activities and climate change on fluvial sediment flux changes and has significant implications for water resources stakeholders to better design and manage the hydropower dams in a changing climate. Such findings may also have implications for other cold environments such as the Arctic, Antarctic, and other high mountainous basins.</p><p>Furthermore, this research is under the project of "Water and Sediment Fluxes Response to Climate Change in the Headwater Rivers of Asian Highlands" (supported by the IPCC and the Cuomo Foundation) and the project of "Sediment Load Responses to Climate Change in High Mountain Asia" (supported by the Ministry of Education of Singapore). Part of the results are also published in Li et al., 2018 Geomorphology, Li et al., 2020 Geophysical Research Letters, and Li et al., 2021 Water Resources Research.</p>

scholarly journals Improved representation of plant functional types and physiology in the Joint UK Land Environment Simulator (JULES v4.2) using plant trait information

2016 ◽  
Author(s):  
Anna Harper ◽  
Peter Cox ◽  
Pierre Friedlingstein ◽  
Andy Wiltshire ◽  
Chris Jones ◽  
...  
Keyword(s):  
Climate Change ◽  
Leaf Nitrogen ◽  
Plant Functional Types ◽  
Deciduous Trees ◽  
C4 Grasses ◽  
Plant Trait ◽  
Functional Types ◽  
C3 And C4 Grasses ◽  
Hadley Centre ◽  
The Uk

Abstract. Dynamic global vegetation models are used to predict the response of vegetation to climate change. They are essential for planning ecosystem management, understanding carbon cycleclimate feedbacks, and evaluating the potential impacts of climate change on global ecosystems. JULES (the Joint UK Land Environment Simulator) represents terrestrial processes in the UK Hadley Centre family of models and in the first generation UK Earth System Model. Previously, JULES represented five plant functional types (PFTs): broadleaf trees, needle-leaf trees, C3 and C4 grasses, and shrubs. This study addresses three developments in JULES. First, trees and shrubs were split into deciduous and evergreen PFTs to better represent the range of leaf lifespans and metabolic capacities that exists in nature. Second, we distinguished between temperate and tropical broadleaf evergreen trees. These first two changes result in a new set of nine PFTs: tropical and temperate broadleaf evergreen trees, broadleaf deciduous trees, needle-leaf evergreen and deciduous trees, C3 and C4 grasses, and evergreen and deciduous shrubs. Third, using data from the TRY database, we updated the relationship between leaf nitrogen and the maximum rate of carboxylation of Rubisco (Vcmax), and updated the model phenology to include a trade-off between leaf lifespan and leaf mass per unit area.

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