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1. Using gross ecosystem product (GEP) to value nature in decision making

   https://doi.org/10.1073/pnas.1911439117  

   Ouyang, Zhiyun; Song, Changsu; Zheng, Hua; Polasky, Stephen; Xiao, Yi; Bateman, Ian J.; Liu, Jianguo; Ruckelshaus, Mary; Shi, Faqi; Xiao, Yang; et al (June 2020, Proceedings of the National Academy of Sciences)

   Gross domestic product (GDP) summarizes a vast amount of economic information in a single monetary metric that is widely used by decision makers around the world. However, GDP fails to capture fully the contributions of nature to economic activity and human well-being. To address this critical omission, we develop a measure of gross ecosystem product (GEP) that summarizes the value of ecosystem services in a single monetary metric. We illustrate the measurement of GEP through an application to the Chinese province of Qinghai, showing that the approach is tractable using available data. Known as the “water tower of Asia,” Qinghai is the source of the Mekong, Yangtze, and Yellow Rivers, and indeed, we find that water-related ecosystem services make up nearly two-thirds of the value of GEP for Qinghai. Importantly most of these benefits accrue downstream. In Qinghai, GEP was greater than GDP in 2000 and three-fourths as large as GDP in 2015 as its market economy grew. Large-scale investment in restoration resulted in improvements in the flows of ecosystem services measured in GEP (127.5%) over this period. Going forward, China is using GEP in decision making in multiple ways, as part of a transformation to inclusive, green growth. This includes investing in conservation of ecosystem assets to secure provision of ecosystem services through transregional compensation payments. 

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2. Phase state and viscosity of secondary organic aerosols over China simulated by WRF-Chem

   https://doi.org/10.5194/egusphere-2023-1444  

   Zhang, Zhiqiang; Li, Ying; Ran, Haiyan; An, Junling; Qu, Yu; Zhou, Wei; Xu, Weiqi; Hu, Weiwei; Xie, Hongbin; Wang, Zifa; et al (August 2023, EGU)

   Abstract. Secondary organic aerosols (SOA) can exist in liquid, semi-solid or amorphous solid states, which are rarely accounted for in current chemical transport models (CTMs). Missing the information of SOA phase state and viscosity in CTMs impedes accurate representation of SOA formation and evolution, affecting the predictions of aerosol effects on air quality and climate. We have previously developed a method to estimate the glass transition temperature (Tg) of an organic compound based on volatility. In this study, we apply this method to predict the phase state and viscosity of SOA particles over China in summer of 2018 using the Weather Research and Forecasting model coupled to Chemistry (WRF-Chem). This is the first time that spatial distributions of the SOA phase state over China are investigated by a regional CTM. Simulations show that Tg values of dry SOA range from ~287 K to 305 K, with higher values in the northwestern China where SOA particles have larger mass fractions of low volatility compounds. Considering water uptake by SOA particles, the SOA viscosity also shows a prominent geospatial gradient that highly viscous or solid SOA particles are mainly found in the northwestern China. The lowest and highest SOA viscosity values both occur over the Qinghai-Tibet Plateau that the solid phase state is predicted over dry and high-altitude areas and the liquid phase state is predicted mainly in the south of the plateau with high relative humidity during the summer monsoon season. The characteristic mixing timescale of organic molecules in 200 nm SOA particles is calculated based on the simulated particle viscosity and the bulk diffusion coefficient of organic molecules. Calculations show that during the simulated period the percent time of the mixing timescale longer than 1 h is > 70 % at the surface and at 500 hPa in most areas of the northern China, indicating that kinetic partitioning considering the bulk diffusion in viscous particles may be required for more accurate prediction of SOA mass concentrations and size distributions over these areas. Sensitivity simulations show that including the formation of extremely low-volatile organic compounds, the percent time that a SOA particle is in the liquid phase state decreases by up to 12 % in the southeastern China during the simulated period. With an assumption that the organic and inorganic compounds are always internally mixed in one phase, we show that the water absorbed by inorganic species can significantly lower the simulated viscosity over the southeastern China. This indicates that constraining the uncertainties in simulated SOA volatility distributions and accurately predicting the occurrence of phase separation would improve prediction of viscosity in multicomponent particles in southeastern China. 

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3. Tectonic inversion of an intracontinental rift basin: An example from the opening and closure of the Paleo-Tethys Ocean, northern Tibetan Plateau

   https://doi.org/10.1130/B37605.1  

   Li, Jie; Wu, Chen; Li, Xiaogang; Zuza, Andrew V; Haproff, Peter J; Zhao, Yonghui; Zhao, Wentao; Yue, Yahui; Ding, Lin (May 2024, Geological Society of America Bulletin)

   Suture zones located across the Tibetan region clearly demarcate the rift-and-drift and continental accretion history of the region. However, the intraplate responses to these marginal plate-tectonic events are rarely quantified. Our understanding of the Paleo-Tethyan orogenic system, which involved ocean opening and closing events to grow the central Asian continent, depends on the tectonic architecture and histories of major late Paleozoic−early Mesozoic orogenic belts. These opening and collision events were associated with coupled intracontinental deformation, which has been difficult to resolve due to subsequent overprinting deformation. The late Paleozoic−early Mesozoic Zongwulong Shan−Qinghai Nanshan belt in northern Tibet separates the Qilian and North Qaidam regions and is composed of Carboniferous−Triassic sedimentary materials and mantle-derived magmatic rocks. The tectonic setting and evolutional history of this belt provide important insight into the paleogeographic and tectonic relationships of the Paleo-Tethyan orogenic system located ∼200 km to the south. In this study, we integrated new and previous geological observations, detailed structural mapping, and zircon U-Pb geochronology data from the Zongwulong Shan−Qinghai Nanshan to document a complete tectonic inversion cycle from intraplate rifting to intracontinental shortening associated with the opening and closing of the Paleo-Tethyan Ocean. Carboniferous−Permian strata in the Zongwulong Shan were deposited in an intracontinental rift basin and sourced from both the north and the south. At the end of the Early−Middle Triassic, foreland molasse strata were deposited in the southern part of the Zongwulong Shan during tectonic inversion in the western part of the tectonic belt following the onset of regional contraction deformation. The Zongwulong Shan−Qinghai Nanshan system has experienced polyphase deformation since the late Paleozoic, including: (1) early Carboniferous intracontinental extension and (2) Early−Middle Triassic tectonic inversion involving reactivation of older normal faults as thrusts and folding of pre- and synrift strata. We interpret that the Zongwulong Shan−Qinghai Nanshan initiated as a Carboniferous−Early Triassic intracontinental rift basin related to the opening of the Paleo-Tethyan Ocean to the south, and it was then inverted during the Early−Middle Triassic closing of the Paleo-Tethyan Ocean. This work emphasizes that pre-Cenozoic intraplate structures related to the opening and closing of ocean basins in the Tethyan realm may be underappreciated across Tibet. 

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4. An Efficient Alternating Algorithm for the Lp-Norm Cross-Gradient Joint Inversion of Gravity and Magnetic Data Using the 2-D Fast Fourier Transform

   https://doi.org/10.1109/TGRS.2020.3033043  

   Vatankhah, Saeed; Liu, Shuang; Renaut, Rosemary Anne; Hu, Xiangyun; Hogue, Jarom David; Gharloghi, Mostafa (November 2020, IEEE Transactions on Geoscience and Remote Sensing)

   An efficient algorithm for the Lp -norm joint inversion of gravity and magnetic data using the cross-gradient constraint is presented. The presented framework incorporates stabilizers that use Lp -norms ( 0≤p≤2 ) of the model parameters, and/or the gradient of the model parameters. The formulation is developed from standard approaches for independent inversion of single data sets, and, thus, also facilitates the inclusion of necessary model and data weighting matrices, for example, depth weighting and hard constraint matrices. Using the block Toeplitz Toeplitz block structure of the underlying sensitivity matrices for gravity and magnetic models, when data are obtained on a uniform grid, the blocks for each layer of the depth are embedded in block circulant circulant block matrices. Then, all operations with these matrices are implemented efficiently using 2-D fast Fourier transforms, with a significant reduction in storage requirements. The nonlinear global objective function is minimized iteratively by imposing stationarity on the linear equation that results from applying linearization of the objective function about a starting model. To numerically solve the resulting linear system, at each iteration, the conjugate gradient algorithm is used. This is improved for large scale problems by the introduction of an algorithm in which updates for the magnetic and gravity parameter models are alternated at each iteration, further reducing total computational cost and storage requirements. Numerical results using a complicated 3-D synthetic model and real data sets obtained over the Galinge iron-ore deposit in the Qinghai province, north-west (NW) of China, demonstrate the efficiency of the presented algorithm. 

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5. Integrating plant wax abundance and isotopes for paleo-vegetation and paleoclimate reconstructions: a multi-source mixing model using a Bayesian framework

   https://doi.org/10.5194/cp-18-2181-2022  

   Yang, Deming; Bowen, Gabriel J. (January 2022, Climate of the Past)

   Abstract. Plant wax n-alkane chain length distribution and isotopeshave been studied in modern ecosystems as proxies to reconstruct vegetationand climate of the past. However, most paleo-proxies focus on eitherconcentrations or isotopes, whereas both carry complementary information onthe mixing sources. We propose a multi-source mixing model in a Bayesianframework that evaluates both chain length distributions and isotopessimultaneously. The model consists of priors that include user-definedsource groups and their associated parametric distributions of n-alkaneconcentration and δ13C. The mixing process involves newlydefined mixing fractions such as fractional leaf mass contribution (FLMC)that can be used in vegetation reconstruction. Markov Chain Monte Carlo isused to generate samples from the posterior distribution of these parametersconditioned on both data types. We present three case studies from distinctsettings. The first involves n-C27, n-C29, and n-C31 alkanes in lake surface sediments of Lake Qinghai, China. The model provides more specific interpretations on the n-alkane input from aquatic sources than the conventional Paq proxy. The second involves n-C29, n-C31, and n-C33 alkanes in lake surface sediments in Cameroon, western Africa. Themodel produces mixing fractions of forest C3, savanna C3, andC4 plants, offering additional information on the dominant biomescompared to the traditional two-end-member mixing regime. The third couplesthe vegetation source model to a hydrogen isotope model component, usingbiome-specific apparent fractionation factors (εa) toestimate the δ2H of mean annual precipitation. By leveraging chain length distribution, δ13C, and δ2H data offour n-alkane chains, the model produces estimated precipitation δ2H with relatively small uncertainty limits. The new framework shows promise for interpretation of paleo-data but could be further improved by including processes associated with n-alkane turnover in plants, transport,and integration into sedimentary archives. Future studies on modern plantsand catchment systems will be critical to develop calibration datasets thatadvance the strength and utility of the framework. 

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