17 research outputs found
The paleoclimatic footprint in the soil carbon stock of the Tibetan permafrost region
Data and code availability The authors declare that the majority of the data supporting the findings of this study are available through the links given in the paper. The unpublished data are available from the corresponding author upon request. The new estimate of Tibetan soil carbon stock and R code are available in a persistent repository (https://figshare.com/s/4374f28d880f366eff6d). Acknowledgements This study was supported by the Strategic Priority Research Program (A) of the Chinese Academy of Sciences (XDA20050101), the National Natural Science Foundation of China (41871104), Key Research and Development Programs for Global Change and Adaptation (2017YFA0603604), International Partnership Program of the Chinese Academy of Sciences (131C11KYSB20160061) and the Thousand Youth Talents Plan project in China. Jinzhi Ding acknowledges the General (2017M620922) and the Special Grade (2018T110144) of the Financial Grant from the China Postdoctoral Science Foundation.Peer reviewedPublisher PD
Net exchanges of CO2, CH4, and N2O between China's terrestrial ecosystems and the atmosphere and their contributions to global climate warming
Author Posting. © American Geophysical Union, 2011. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research 116 (2011): G02011, doi:10.1029/2010JG001393.China's terrestrial ecosystems have been recognized as an atmospheric CO2 sink; however, it is uncertain whether this sink can alleviate global warming given the fluxes of CH4 and N2O. In this study, we used a process-based ecosystem model driven by multiple environmental factors to examine the net warming potential resulting from net exchanges of CO2, CH4, and N2O between China's terrestrial ecosystems and the atmosphere during 1961â2005. In the past 45 years, China's terrestrial ecosystems were found to sequestrate CO2 at a rate of 179.3 Tg C yrâ1 with a 95% confidence range of (62.0 Tg C yrâ1, 264.9 Tg C yrâ1) while emitting CH4 and N2O at rates of 8.3 Tg C yrâ1 with a 95% confidence range of (3.3 Tg C yrâ1, 12.4 Tg C yrâ1) and 0.6 Tg N yrâ1 with a 95% confidence range of (0.2 Tg N yrâ1, 1.1 Tg N yrâ1), respectively. When translated into global warming potential, it is highly possible that China's terrestrial ecosystems mitigated global climate warming at a rate of 96.9 Tg CO2eq yrâ1 (1 Tg = 1012 g), substantially varying from a source of 766.8 Tg CO2eq yrâ1 in 1997 to a sink of 705.2 Tg CO2eq yrâ1 in 2002. The southeast and northeast of China slightly contributed to global climate warming; while the northwest, north, and southwest of China imposed cooling effects on the climate system. Paddy land, followed by natural wetland and dry cropland, was the largest contributor to national warming potential; forest, followed by woodland and grassland, played the most significant role in alleviating climate warming. Our simulated results indicate that CH4 and N2O emissions offset approximately 84.8% of terrestrial CO2 sink in China during 1961â2005. This study suggests that the relieving effects of China's terrestrial ecosystems on climate warming through sequestering CO2 might be gradually offset by increasing N2O emission, in combination with CH4 emission.This study has been supported by NASA
LCLUC Program (NNX08AL73G_S01) , NASA IDS Program
(NNG04GM39C), and Chinaâs Ministry of Science and Technology
(MOST) 973 Program (2002CB412500)
Evolution of dimerized phase in a one-dimensional correlated electron system
The one-dimensional half-filled correlated electron system with on-site (U), nearest-neighbor
(V) and
pair hopping (Y) repulsions is studied analytically at weak
coupling, combined the Abelian bosonization with renormalization group methods. The
corresponding ground-state phase diagram consists of three insulating phases, a
charge-density-wave (CDW) phase for U â 2V< â
2Y, a spin-density-wave (SDW) phase for
U â
2V> 2Y, and
a bond-charge-density-wave (BOW) phase for |
U â 2V | <
2Y. The pair hopping, which breaks an accident
symmetry and splits the frustrating line U â 2V = 0, provides a possibility
for the dimerized BOW phase between the CDW and SDW phases. In the phenomenological
parameter regime, the superconducting (SC) and bond-spin-density-wave (BSDW) phases are
briefly discussed
Phase diagram of a generalized PensonâKolbâHubbard chain with the occupation-dependent hopping
At half filling, we study analytically a one-dimensional correlated electronic system modeled by an extended PensonâKolbâHubbard (PKH) chain with the occupation-dependent hopping. The modification of the electron hopping amplitude is exhibited to induce the additional correlated-hopping interactions. At weak coupling, we use the field theory to obtain ground-state phase diagram, including the SDW, BCDW, BSDW, SS and TS phases for U>0. The induced three-body attractive interaction accounts for the superconductivity absent in the usual PKH model
Ground-state instabilities in a Hubbard-type chain with particular correlated hopping at non-half-filling
At non-half-filling, a one-dimensional interacting electronic model (tâUâR) is studied analytically. The particular correlated hopping keeps particleâhole symmetry of the Hubbard model. Physically, the model involved is equivalent to an extended Hubbard chain incorporating a two-body (X) and a three-body (XË) site-bond interactions with XË=2X. The analysis of weak-coupling theory leads to the ground-state phase diagram, which consists of three types of metallic phases, characterized by the charge- (CDW) and spin-density-wave (SDW) and singlet-superconductivity (SS) instabilities
Superconductivity in the extended Hubbard chain with three-electron density interaction
At weak coupling and at half filling, we analytically study effects of an intersite three-electron density interaction (P) of the one-dimensional extended Hubbard model in addition to the usual two-electron density interactions (U,V). By the bosonization and renormalization group approaches, we obtain the ground-state phase diagram of the model. In particular, we find that even in the presence of repulsive U and V, the attractive P may give rise to the superconducting phases for 2Vâ€min{2|P|;4|P|âU}