bluuebunny/crossref_metadata_2025 huggingface dataset:
Hemispheric shift of the zonal mean ITCZ during the last deglaciation
Authors: Jalihal Chetankumar , Mikolajewicz Uwe , Kapsch Marie-Luise
Published: March 2021

The zonal-annual mean inter-hemispheric convergence zone (ITCZ) is located in the northern hemisphere in the modern climate. A transient simulation of the last deglaciation using the Max Planck Institute Earth System Model (MPI-ESM), suggests that the ITCZ was located in the southern hemisphere 14 kyrs ago. This shift is due to a substantial cooling of the northern hemisphere relative the southern hemisphere, after the release of melt water pulse 1a. The ITCZ compensates for these changes in the surface temperature by shifting south, thereby leading to a northward atmospheric heat transport away from the southern hemisphere. Along with the southward shift, the intensity of the precipitation within the ITCZ decreases. These changes in the intensity of precipitation can be explained by using a framework based on the moist static energy budget. We find that these changes are primarily related to the changes in the large-scale vertical motion of the atmosphere in the tropics. This affects the vertical transport of the moist static energy, and hence total gross moist stability (TGMS). 
Mapping of Flooded Heritage Structures Using SAR Polarimetry and Google Earth Engine
Authors: Adhikari Ruma
Published: March 2021

The growing flood events and the associated risk in heritage structures are an increasingly crucial issue for India, which possesses heritage richness. However, it is more critical for developing countries where often the case is poorly understudied. Hampi, also referred to as the Group of Monuments, is a UNESCO World Heritage Site located in east-central Karnataka, India. Several monuments at the heritage site of Hampi along the Tungabhadra river are inundated several times within a year. After every flood, the river changes its course, inundating areas that were supposed to be safe from floods. The post-flood silt deposition over structures makes them more vulnerable to erosion and distortion. So, to restore, mapping of flooded structures is crucial. The changes in the cultural landscape should be monitored on a spatial and temporal basis. Rapid and precise extraction of the flooded areas is key to supporting emergency-response planning and providing damage assessment in spatial and temporal measurements to monuments.

The European Space Agency's (ESA) Copernicus is one of the most ambitious Earth Observation (EO) programs having operational satellite constellations providing continuous, accurate, and easily accessible satellite data for the entire globe. This study demonstrates the use of Google Earth Engine (GEE) and Dual polarized (VV and VH) Sentinel-1 Synthetic Aperture Radar (SAR) data for mapping flooded areas. Change detection and thresholding methodology have been adopted in Google Earth Engine (Python-based) Platform to determine the extent of flooding using multiple Sentinel‐1 SAR images captured before and after the floods of August 2019 in Hampi. Thresholding is one of the most commonly adopted SAR imagery methods to discriminate between water and non-water surface. An automatic thresholding approach using the Otsu algorithm is optimal for large thresholding objects from the background, which means that it is strongly dependent on the histogram's bimodality. SAR Polarimetry backscatter properties being used effectively for stone structure extraction. The Wishart distance classification method has been used in PolsarPro software, which fits for the homogenous area. GEE can be effectively used for planning disaster risk reduction, damage assessment, affected areas, and can be used well along with cultural landscape information.
Hygroscopicity of organic compounds as a function of organic functionality, water solubility, molecular weight and organic oxidation level
Authors: han shuang , Hong Juan , Luo Qingwei , Xu Hanbing , Tan Haobo , Wang Qiaoqiao , Tao Jiangchuan , Ma Nan , Cheng Yafang , Su Hang
Published: March 2021

Hygroscopic properties of 23 organic compounds with different physico-chemical properties including carboxylic acids, amino acids, sugars and sugar alcohols were measured using a Hygroscopicity Tandem Differential Mobility Analyzer (HTDMA). We converted our experimental GF data of organics at 90% RH to κ to facilitate the comparison and we find that organic compounds with different molecular functionality present quite different hygroscopicity. Compounds with extra functional groups usually show higher hygroscopicity compared to their parental molecular compounds. Moreover, some compounds share the same molecular structure or functionality but vary differently in hygroscopicity. In general, the hygroscopicity of organics increase with functional groups in the following order: (-CH3/-NH2) < (-OH) < (-COOH/C=C/C=O). For highly soluble organics, the hygroscopicity decreases with molecular weight; while for slightly soluble organics which are not fully dissolved in aerosol droplets, their hygroscopicity can be divided into two categories. One is non-hygroscopic compounds, which may not fully deliquesce in the aerosol droplets. The other is moderate hygroscopic compounds, of which the hygroscopicity is mainly limited by their water solubility. Moreover, the hygroscopicity of organic compounds generally increased linearly with O:C ratios, although some of them have the same O:C ratio of but with different hygroscopicity. The experimental determined hygroscopicity are also compared with model predictions using the Extended Aerosol Inorganics Model (E-AIM) and the UManSysProp at 10-90% RH. Both models poorly represent the hygroscopic behavior of some organics, which may due to that the phase transition and intermolecular interactions are not considered in the simulations.
Differentiated vulnerability proposition for multi-risk adaptation planning 
Authors: Shukla Roopam , Murken Lisa , Gornott Christoph
Published: March 2021

Adaptation actions are imperative for building societal resilience to unforeseen and unavoidable impacts. With increasing extreme events and the need for sustainable development planning, a shift from reactive to more active anticipatory planning is essential to foster resilience within communities. Since assessments of vulnerability form the initial step to develop adaptation outcomes, we argue the need for differentiated vulnerability approaches for anticipatory adaptation planning for responding to the impacts of climate change-induced risks and social risks in the global south. The dominant conceptualization of adaptation within policy circles at regional and local levels remains overly simplistic with limited attention is to the ‘spatial’ and ‘social’ causes that differentiate vulnerability and adaptive capacity. The study proposes a differential vulnerability framework, based on our empirical findings in India, Ghana, and Ethiopia. We highlight the integration of differential vulnerability perspective, corresponding adaptation planning principles, and inclusive policy approach for overcoming the ‘adaptation deficit’ in the global south. Usage of differential vulnerability approach extends the anticipatory adaptation planning to not only incorporate the anticipation of multiple risks through future scenarios but also to identify locations that will be more acutely affected as a result of existing structural vulnerabilities. We emphasize the need to explicitly address the proximate causes of vulnerability emanating from the broader social and political regimes and help in the transformation of a prevailing governance mechanism for being more equitable, effective, and anticipatory.
Understanding CoVid-19’s chaotic dynamics
Authors: Necesito Imee , Kim Donghyun , Lee Junhyeong , Eom Junghyun , Kim Deok-Woo , Kim Hung Soo
Published: March 2021

As we move towards the more critical age of technology and learning, understanding the underlying dynamics of events such as the unforeseen and unpredictable pandemics in the ecologival system are deemed invaluable and important. In this paper, we examine how daily cases of CoVid-19 behaves chaotically enough to affect a large population. The data used were from the different countries mostly concentrated to Southeast Asia. The authors believe that the data currently available does not allow reliable forecast because of the presence of untested asymptomatic cases, therefore understanding the chaotic dynamics may provide possible reasons or justifications for the prevalent CoVid-19 outbreaks.
Different scales of salt-sediment interaction around passive diapirs
Authors: Rowan Mark , Giles Katherine
Published: March 2021

Passive diapirism entails ongoing, near-surface syndepositional growth of a salt stock or wall. As such, the diapirs and intervening minibasins influence the development and geometries of associated sedimentary strata. In this short overview, we distinguish between two scales and aspects of salt-sediment interaction that reflect a depositional continuum from the topographic highs of diapir roofs to the lows of depocenters. At the larger, multi-km scale, minibasin tectonostratigraphic successions form bowls, troughs, wedges, or layers that respond to differential evacuation of the deep salt layer. These successions have internal concordant, onlapping, or truncated geometries, and they stack into different patterns based on the evolution of active salt tectonic processes. At the smaller scale, passive diapirs create local sea-floor scarps due to drape folding of the diapir roof over the edge of the rising diapir. Depending primarily on the thickness of the roof, this results in tabular or tapered composite halokinetic sequences within 1 km or less of the diapir edge. It is important to keep these geometries and processes separate as they have distinct implications for sediment transport and deposition as well as the definition and detailed geometries of hydrocarbon traps in three-way truncations against diapirs and welds.
Characterization of the craters’ surface at Ryugu using NIR spectroscopy
Authors: Riu Lucie , Pilorget Cédric , Milliken Ralph , Kitazato Kohei , Nakamura Tomoki , Cho Yuichiro , Matsuoka Moe , Sugita Seiji , Abe Masanao , Matsuura Shuji , Ohtake Makiko , Kameda Shingo , Sakatani Naoya , Tatsumi Eri , Yokota Yasuhiro , Iwata Takahiro
Published: March 2021

Asteroid Ryugu was observed up close for almost a year and a half by the instruments on-board the Japanese Aerospace eXploration Agency (JAXA) Hayabusa2 spacecraft. It has been shown that in the near-infrared wavelength ranges, the asteroid exhibits relatively homogeneous spectral characteristics: including a very low reflectance factor, a slight red slope towards longer wavelengths, and a narrow and weak absorption feature centered at 2.72 μm. Numerous craters have been identified at the surface of Ryugu. These features provide good candidates for studying more recently exposed near-surface material to further assess potential spectral/compositional heterogeneities of Ryugu. We present here the results of a spectral survey of all previously identified and referenced craters (Hirata et al. 2020) based on reflectance data acquired by the NIRS3 spectrometer. Globally, we find that the spectral properties inside and outside of craters are very similar, indicating that subsurface material is either compositionally similar to material at the surface that has a longer exposure age or that material at Ryugu’s optical surface is spectrally altered over relatively short timescales by external factors such as space weathering. The 2.72 μm band depth, present on the overall surface, exhibits a slight anti-correlation with the reflectance factor selected at 2 μm, which could indicate different surface properties (e.g., grain size and/or porosity) or different alteration processes (e.g., space weathering, shock metamorphism and/or solar heating). We identified four different spectral classes based on their reflectance factor at 2 μm and 2.72 μm absorption strength. The most commonly spectral behavior associated with crater floors, is defined by a slightly lower reflectance at 2 μm and deeper band depth. These spectral characteristics are similar to those of subsurface material excavated by the Hayabusa2 small carry-on impactor (SCI) experiment, suggesting these spectral characteristics may represent materials with a younger surface exposure age. Conversely, these materials may have experienced significant solar heating and desiccation to form finer grains that subsequently migrated towards and preferentially accumulated in areas of low geopotential, such as craters floors. Detailed analyses of the returned samples of Ryugu that are now being investigated at the curation facility in ISAS will allow for further testing of these formation and alteration hypotheses. 
Mitigation of nitrous oxide emissions from an acidic soil by valorization of industrial waste
Authors: Yin Junhui , Liu Rui , Chen Qing
Published: March 2021

Increasing evidence suggests that alkaline mineral amendments from industrial wastes (e.g., phosphorus tailing, PT) have potential to ameliorate soil acidification and improve agriculture sustainability. However, the effects of such amendment on nitrous oxide (N2O) production remain elusive. To fill this knowledge gap, an incubation experiments were conducted with an acidic soil of pH 4.80 treated with i) control (CK, no amendments), ii) urea at 60 mg N kg-1 (U), iii) 10 g kg-1 amendments (S) and iv) 10 g kg-1 amendments plus urea at 60 mg N kg-1 (S+U). A 184-h experiment was conducted with a robotized incubation system for monitoring real-time gases (O2, N2O, N2, CO2) dynamics. Results from this batch experiment showed that the soil pH was significantly increased with the amendment addition (S and S+U) from 4.80 to above 6.00. Meanwhile, the mineralization, nitrification and denitrification processes were stimulated with the amendment addition. The N2O production was reduced by an average of 65.7% with the amendment addition compared to that without the amendment application. After incubation, higher N2 productions were observed from the soil with amendment addition (S and S+U) than untreated soil (P<0.05). The findings suggest that the N2O emissions from acidic soils can be considerably controlled by valorization of PT.
A physically-based soil surface model and its combination with numerical models for predicting bare-soil evaporation rates
Authors: Liu Xiaocheng , Zhang Chenming , Liu Yue , Lockington David , Li Ling
Published: March 2021

Estimation of evaporation rates from soils is significant for environmental, hydrological, and agricultural purposes. Modeling of the soil surface resistance is essential to estimate the evaporation rates from bare soil. Empirical surface resistance models may cause large deviations when applied to different soils. A physically-based soil surface model is developed to calculate the surface resistance, which can consider evaporation on the soil surface when soil is fully saturated and the vapor flow below the soil surface after dry layer forming on the top. Furthermore, this physically-based expression of the surface resistance is added into a numerical model that considers the liquid water transport, water vapor transport, and heat transport during evaporation. The simulation results are in good agreement with the results from six soil column drying experiments.  This numerical model can be applied to predict or estimate the evaporation rate of different soil and saturation at different depths during evaporation.
Revised chronology of central Tibet uplift and its implications
Authors: Fang Xiaomin , Dupont-Nivet Guillaume , Wang Chengshan , Song Chunhui , Meng Qingquan , Zhang Weilin , Nie Junsheng , Zhang Tao , Mao Ziqiang
Published: March 2021

Understanding the Tibetan Plateau (TP) topographic history is essential to determining its building mechanisms and its role in driving regional climate, environments and biodiversity. The Lunpola Basin (central-southern Tibet) is the key place to constrain the Tibet building because it deposits the most complete Cenozoic stratigraphy sequence in the central TP and bears many layers of tuffs, abundant fossil plants and mammals and paleosols. It is also the first place that stable isotope based paleoaltimetry was applied to, which suggested that similar to present elevation was attained in the central TP at least 35 Ma ago, implying a much earlier uplift of the TP than before. This view was soon widely accepted by international society but was challenged by recent discoveries of low elevations tropical fossil apparently deposited at 25.5 Ma. However, we use magnetostratigraphic and radiochronologic dating to robustly revise the chronology of regional elevation estimates both from the stable isotope and fossils in the Lunpola Basin. The results indicate that both ages estimated for the stable and fossil based elevations are wrong with the former from ~40 Ma revising to ~26-21 Ma and the later from ~26 Ma to ~40 Ma. Thus this revised chronology demonstrates that central Tibet was generally low (<2.3 km) since at least ~40 Ma and became high (3.5-4.5 km) since at least ~26 Ma. This supports the Eocene existence of a lowland between the Gangdese Shan and Tanggula Shan until their early Miocene uplift. This later uplift of central-southern Tibet has important implications for Tibetan Plateau (TP) growth mechanisms and agrees well with recently updated studies of the TP-imposed impacts on Asian atmospheric circulations, surface processes and biotic evolution and diversification differentiation.
Contrasting  effect of coniferous and broadleaf trees on soil carbon storage during reforestation of mature soils and afforestation of immature soils
Authors: Hublova Lucie , Frouz Jan
Published: March 2021

Soils and forest soil in particular represent important pools of carbon (C). Here, we present a quantitative review of common garden experiments in which various tree species were planted alongside each other in European countries to answer following questions: Does soil sequester more C under broadleaf than under conifer trees? and How do the effects of tree species and litter quality on soil C sequestration change with soil development (i.e., maturity) and other soil properties? We found that the effects of broadleaf and coniferous trees on C sequestration differed with the stage of soil development. In mature soils, more C was stored under coniferous trees than under broadleaf trees. In soils in early stages of soil development, on post-mining spoil heaps, the opposite trend was found, i.e., more C was stored under broadleaf. C sequestration under broadleaf trees was highest in immature soils and in soils with high pH. C sequestration was negatively correlated with the litter C:N ratio in post-mining soils but not in other more mature soils. Similarly C sequestration was negatively correlated with the litter C:N  in alkaline soils and in soil with high clay content. These results suggest that C sequestration mechanisms differ in immature vs. mature soils such that C storage is greater under broadleaf trees in immature soils but is greater under coniferous trees in mature soils. The study was supported by LIFE17/IPE/CZ/000005 project
Study of ageostrophy during strong, nonlinear eddy-front interaction in the Gulf of Mexico
Authors: Hiron Luna , Nolan David , Shay Lynn
Published: March 2021

Mesoscale eddies drive a large fraction of the variability in the ocean. Eddies with strong tangential velocity compared to their translation speed are able to stay coherent and travel long distances, carrying water mass properties, heat, nutrients, and particles around the ocean. The nonlinearity of these mesoscale features is greater for stronger flow and greater curvature, which, consequently, is associated with greater centrifugal force.

The Gulf of Mexico Loop Current (LC) system has long been assumed to be close to geostrophic balance despite its strong flow and the development of large meanders and strong frontal eddies during unstable phases. The region between the LC meanders and its frontal eddies was shown to have high Rossby numbers indicating nonlinearity; however, the effect of the nonlinear term on the flow has not been studied so far. In this study, the ageostrophy of the LC meanders is assessed using a high-resolution numerical model and geostrophic velocities from altimetry. The method used in this study can be applied in any region where the centrifugal force is important. A formula to compute the radius of curvature of the flow from the velocity field is also presented.

The results indicate that during strong meandering, especially before and during LC shedding and in the presence of frontal eddies, the centrifugal force becomes as important as the Coriolis force and the pressure-gradient force: LC meanders are in gradient-wind balance. The centrifugal force modulates the balance and modifies the flow speed, resulting in a subgeostrophic flow in the LC meander trough around the frontal eddies and supergeostrophic flow in the LC meander crest. The same pattern is found when correcting the geostrophic velocities from altimetry to account for the centrifugal force. The ageostrophic percentage in the cyclonic and anticyclonic meanders is 47% ± 1% and 78% ± 8% in the model and 31% ± 3% and 78% ± 29% in the altimetry dataset, respectively. Thus, the ageostrophic velocity is an important component of the LC flow and cannot be neglected when studying the LC system.

 

 

 
Controlled large scale ecosystem manipulation to explore key ecosystem components at multiple scales
Authors: Frouz Jan
Published: March 2021

Understanding how natural processes arise from complex interactions between particular processes at small spatiotemporal scales and in turn how these processes form patterns at large spatiotemporal scales is one of the current principal questions in environmental science. The problem is very complicated, as in many cases, key processes are often studied by researchers in separate disciplines such as ecology, soil science or hydrology. One of the major obstacles is that the processes at a landscape scale are difficult to manipulate and, in many cases, even measure. In particular, the belowground processes are in many cases overlooked or at least understudied. Here we briefly describe a methodological solution used to cope with this problem and describe artificial catchments designed for experimental manipulation at the level of a landscape, called FALCON. This array has two treatments: one mimics a site reclaimed using an alder plantation and the other was left to unassisted primary succession. For each treatment, there were two replicates in four similar catchments. Individual catchments are hydrologically isolated from the environment and equipped with instruments, so that all the main processes and all significant flows of substances and energy in the ecosystem can be monitored, including the cycling of water, nutrients and gas between the ecosystem and the atmosphere. In addition, in each catchment there are sets of lysimeters, which allow the study of small-scale processes and how these can be extrapolated to the catchment scale. In addition, two lysimetric fields exist alongside the catchments for monitoring the effects of the experimental manipulation.
Mid-long term change of particulate/dissolved 137Cs concentration in river water and the impact of Typhoon Hagibis in 2019
Authors: Tsuji Hideki , Ozaki Hirokazu , Hayashi Seiji
Published: March 2021

In Fukushima Prefecture, radiocesium as the particulate and dissolved form has been discharging from the mountains and forests since the Fukushima Dai-ichi nuclear power plant (FDNPP) accident in 2011. In particular, in October 2019, the watershed around the FDNPP was subjected to extensive flooding due to Typhoon Hagibis, resulting in significant changes in the hydrological environment. In this study, we investigated the characteristics of changes in particulate/dissolved 137Cs concentrations in the main 3 rivers in the north region of FDNPP 3–9 years after the nuclear accident and the impact of the typhoon on 137Cs dynamics in river water.

Monthly observations of river waters in baseflow conditions showed a decrease in dissolved 137Cs concentration with an environmental half-life of 2–10 years, and seasonal fluctuation such as increasing in summer and decreasing in winter. The annual amplitude of the dissolved 137Cs concentration in water released from dams was smaller and the peak of the concentration was observed later than that in river sites where the influence of dams is small. The 137Cs concentrations in the suspended solids did not show any significant seasonal variation, and the environmental half-life of 1–8 years was relatively faster than the dissolved forms observed at the same site. Immediately after Typhoon Hagibis in 2019, the dissolved 137Cs concentration decreased significantly compared to the previous years, especially at two dam lake discharge sites. At the two sites, the dissolved 137Cs concentration did not recover to the level predicted by the pre-typhoon data even one year after the typhoon event, but no significant decrease in 137Cs concentration in suspended solids was observed. These differences in the environmental behavior of 137Cs in different forms suggest that there are limitations in predicting particulate and dissolved 137Cs concentrations with a fixed parameter such as partition coefficient.
Localization of seismicity prior to large earthquakes
Authors: Zaliapin Ilya , Ben-Zion Yehuda
Published: March 2021

We present results aimed at understanding preparation processes of large earthquakes by tracking progressive localization of earthquake deformation with three complementary analyses: (i) estimated production of rock damage by background events, (ii) spatial localization of background seismicity within damaged areas, and (iii) progressive coalescence of individual earthquakes into clusters. Techniques (i) and (ii) employ declustered catalogs to avoid the occasional strong fluctuations associated with aftershock sequences, while technique (iii) examines developing clusters in entire catalog data. The different techniques provide information on different time scales and on the spatial extent of weakened damaged regions. The analyses reveal generation of earthquake-induced rock damage on a decadal timescale around eventual rupture zones, and progressive localization of background seismicity on a 2-3 yr timescale before several M > 7 earthquakes in southern and Baja California and M7.9 events in Alaska. This is followed by coalescence of earthquakes into growing clusters that precede the mainshocks. Corresponding analysis around the 2004 M6 Parkfield earthquake in the creeping section of the San Andreas fault shows contrasting tendencies to those associated with the large seismogenic faults. The results are consistent with observations from laboratory experiments and physics-based models with heterogeneous materials not dominated by a pre-existing failure zone. Continuing studies with these techniques, combined with analysis of geodetic data and insights from laboratory experiments and model simulations, may allow developing an integrated multi-signal procedure to estimate the approaching time and size of large earthquakes.
Relationships between eddy representation and vertical structure
Authors: Yankovsky Elizabeth , Zanna Laure , Smith Shafer
Published: March 2021

The representation of energetic transfers associated with ocean mesoscale eddies is a leading challenge in the development of modern climate models. Here we investigate the relationships between eddy representation and vertical structure. We employ the GFDL-MOM6 in an idealized, one-basin, stacked-shallow water configuration and consider four resolutions of otherwise-identical simulations: 1/4, 1/8, 1/16, and 1/32 degree. We assess the degree of eddy representation by: (1) the ratio of the deformation scale to the model grid spacing; and (2) using linear QG instability analysis to compute the fastest growing wavenumber and comparing it to the model resolution. We then analyze the available potential energy (APE) and kinetic energy (KE) distributions for each simulation. KE is found to broadly increase with increasing resolution. The KE is decomposed into barotropic (BT) and baroclinic (BC) components, which are further split into temporally-defined “eddy” and “mean” parts. The dominant trend in eddy representation vs. vertical structure is an increasing fraction of KE going into the BT mode, particularly the BT-eddy component, as eddy representation increases. We attribute this to the inaccurate representation of BC energy transfers in the low-resolution models which leads to buildup of BC energy and lack of barotropization. The end goal of this work is contributing to the development of scale-aware, energetically-consistent mesoscale eddy parameterizations by constraining the vertical structure of eddy energy.
The response of surface ozone to current mitigation strategies for reducing air pollution in Chinese megacity clusters
Authors: Zhang Yijuan
Published: March 2021

China, with rapid urbanization and industrialization, has experienced severe air quality deterioration in recent decades. To release heavy air pollution in China, Chinese government implement the Clean Air Action Plan initiated in 2013. Fine particles (PM2.5) concentrations have shown significant declines over the nationwide, which attribute to mitigating anthropogenic emission of primary PM2.5, and precursor gases of nitrogen oxides (NOx), sulfur dioxide (SO2), and carbon monoxide (CO). However, surface ozone concentrations have unexpectedly increased during the implementation of 2013 to 2019. China has an average trend of 1.9 ppbv a-1 in same period, measured by ambient monitoring station of China’s Ministry of Environment and Ecology (China MEE). Notably, surface ozone has faster increased trend in megacity clusters, with 3.3 ppbv a-1 inBeijing-Tianjin-Hebei, 1.6 ppbv a-1 in Yangtze River Delta, 1.1 ppbv a-1 in Pearl River Delta. At shorter temporal scale, the lockdown during outbreak of COVID-19, in which human activities dramatically decreased with reduction of industry and transport emission, witnessed exceeding 30% increase of maximum daily 8h average (MDA8) O3, in major cities (e.g., Shanghai, Hangzhou, Hefei etc.). The investigated results suggested simultaneous controlling concentration of PM2.5 and ozone should coordinate inner physical and chemical processes. In this study, the weather Research and Forecasting with Chemistry was applied to reproduce the following two pathways: (1) The response of surface ozone to modification of photolysis by changed radiation budgets induced by scattering and absorbing aerosols; (2) The further impacts of altered atmospheric oxidizing capacity on surface ozone and aerosols concentrations. This study can provide reasonable advice to air pollution control strategies in Chinese megacity clusters.
Assessing the impact of permafrost-vegetation interaction on treeline dynamics in Siberia with the individual-based, spatially explicit treeline model LAVESI coupled to the permafrost land-surface model CryoGrid
Authors: Kruse Stefan , Stünzi Simone M. , Langer Moritz , Boike Julia , Herzschuh Ulrike
Published: March 2021

Tundra-taiga ecotone dynamics play a relevant role in the global carbon cycle. However, it is rather uncertain whether these ecosystems could develop into a carbon source rather than continuing atmospheric carbon sequestration under global warming. This knowledge gap stems from the complex permafrost-vegetation interactions, not yet fully understood. Consequently, shedding light on the role of current and future active layer dynamics is crucial for an accurate prediction of treeline dynamics, and thus for aboveground forest biomass and carbon stock developments.

We make use of a coupled model version combining CryoGrid, a one-dimensional permafrost land-surface model, with LAVESI, an individual-based and spatially explicit forest model for larch species (Larix Mill.) in Siberia. Following a parametrization against an extensive field data set of 100+ forest inventories conducted along the Siberian treeline (97-169° E), we run simulations for the upcoming centuries forced by climatic change scenarios.

The coupled model setup benefits from the detailed process implementation gained while developing the individual models. Therefore, we can reproduce the energy transfer and thermal regime in permafrost ground as well as the radiation budget, nitrogen and photosynthetic profiles, canopy turbulence, and leaf fluxes, while at the same time, predicting the expected establishment, die-off, and treeline movements of larch forests. In our analyses, we focus on vegetation and permafrost dynamics and reveal the magnitudes of different feedback processes between permafrost, vegetation, and current and future climate in Northern Siberia.
Value of satellite-derived soil moisture data to improve the internal consistency of process-based ecohydrological models
Authors: Duethmann Doris , Smith Aaron , Kleine Lukas , Soulsby Chris , Tetzlaff Doerthe
Published: March 2021

It is widely acknowledged that calibrating and evaluating hydrological models only against streamflow may lead to inconsistencies of internal model states and large parameter uncertainties. Soil moisture is a key variable for the energy and water balance, which affects the partitioning of solar radiation into latent and sensible heat as well as the partitioning of precipitation into direct runoff and catchment storage. In contrast to ground-based measurements, satellite-derived soil moisture (SDSM) data are widely available and new data products benefit from improved spatio-temporal resolutions. Here we use a soil water index product based on data fusion of microwave data from METOP ASCAT and Sentinel 1 CSAR for calibrating the process-based ecohydrological model EcH2O-iso in the 66 km² Demnitzer Millcreek catchment in NE Germany. Available field measurements in and close to this intensively monitored catchment include soil moisture data from 74 sensors and water stable isotopes in precipitation, stream and soil water. Water stable isotopes provide information on flow pathways, storage dynamics, and the partitioning of evapotranspiration into evaporation and transpiration. Accounting for water stable isotopes in the ecohydrologic model therefore provides further insights regarding the consistency of internal processes. We first compare the SDSM data to the ground-based measurements. Based on a Monte Carlo approach, we then investigate the trade-off between model performance in terms of soil moisture and streamflow. In situ soil moisture and water stable isotopes are further consulted to evaluate the internal consistency of the model. Overall, we find relatively good agreements between satellite-derived and ground based soil moisture dynamics. Preliminary results suggest that including SDSM in the model calibration can improve the simulation of internal processes, but uncertainties of the SDSM data should be accounted for. The findings of this study are relevant for reliable ecohydrological modelling in catchments that lack detailed field measurements for model evaluation.
Analyze the energy balance and energy-saving benefits of  green roofs
Authors: Pang Chuan Ching
Published: March 2021

In the context of rapid global urbanization, problems such as urban thermal effects often occur, which may cause the increase in building energy consumption. Green roofs have the effect to regulating the indoor temperature of buildings. This study is expected to evaluate the cooling and energy-saving benefits of green roofs and build an experimental to simulation buildings situation , the control group without green roof and the experimental group with green roof, compare the indoor temperature and heat flux changes in the control group and the experimental group, and calculate the radiant heat, latent heat, sensible heat, conduction heat in the green roof layer , And build a model to simulation energy project to discuss the energy balance of the green roof and the impact on the energy of the buildings below, and analyze the cooling and energy saving effects of the green roof.
Spatial distribution of groundwater-surface water connectivity in the Kosimegafan, north India
Authors: Beg Zafar , Joshi Suneel Kumar , Gaurav Kumar , Kumar Sudhir
Published: March 2021

We conducted a systematically integrated surface water and groundwater interaction study in the Kosimegafan in north India using the stable isotopes (δ18O and δ2H) of water and depth to water level data. In a field campaign in December 2019, we have collected a water sample from 65 different locations for isotopic analysis. This includes 21 samples from the groundwater and 44 from different surface water bodies (Kosi River-02, streams-09, waterlogged patches-29, and canal-04).

The δ18O and D-excess values of groundwater and waterlogged samples show marked spatial variation across the study area. Using a two-component mixing model, we estimate the fraction contribution of streams and rainwater in the groundwater and waterlogged patches. This shows a marked spatial and depth-related variability in stream water contribution to the groundwater recharge and varies from about 83% (maximum) at 6 m below ground level (bgl) to 45% (minimum) at 9 m bgl. We also analysed the spatial and temporal variation in groundwater levels from 1996 to 2017. During this period, the water level shows a significant variation from 1.1 to 7.8 m bgl. Further, using the water table fluctuation approach, we estimate the recharge rate. We found a higher recharge rate (22 mm/year) in the central part of the western lobe and northern part of the central lobe, and minimum (1 mm/year)in both the northern part of the western and southern part of the central lobe of the Kosi fan. This study provides new insight into the recharge processes in the study area.
Drop Size Distribution Characteristics of Typhoon Haishen (2020) in Korea
Authors: Kim Jeong A , Lee Dong-In
Published: March 2021

Recently the frequency of autumn typhoons has increased on the Korean Peninsula and their damage has also increased. The Korea Meteorological Administration (KMA) established a super-strong stage to raise awareness of such a powerful typhoon, Typhoon Haishen (2020). In usual the life cycle of the typhoon is divided into three stages: developing, mature, decaying. To analyze the impact of typhoon Haishen on the Korean Peninsula, this study focused on the landfall and decaying stage. To investigate the microphysical characteristics of the typhoon over time, the drop size distribution (DSD) at the azimuthal direction of the typhoon was studied. DSD variables were obtained by using PARSIVEL (PARticle SIze and VELocity) disdrometers at eleven observation sites from Geoje (34.88°N, 128.57°E) to Ulsan (35.58°N, 129.33°E) that located along the southern coast of Korea. As typhoon Haishen landed at the vicinity of Ulsan (35.3°N,129.3°E), the observation sites were included between the centre of the typhoon and the wind impact radius. Four days before typhoon Haishen landed, typhoon Maysak (2020) landed at the vicinity of Busan (35.4°N,128.9°E) and decayed. The intensity of typhoon Maysak was weakened and the form of convective cells became unclear after landing. Typhoon Haishen was also slightly weakened after landing, however, the form of convective cells and wind impact radius were continuously maintained.
Inversion of One Dimensional Electrical Resistivity Data in Anisotropic Media via Artificial Neural Networks 
Authors: Durdağ Doğukan , Pekşen Ertan
Published: March 2021

There are some parameters that affect the resistivity values in the electrical resistivity method which is one of the most fundamental methods in near surface geophysics. One of these parameters is electrical anisotropy which is defined as the change in resistivity depending on the direction. The anisotropy coefficient is calculated by square root of the vertical resistivity to the horizontal resistivity of the layer. Average resistivity in anisotropic media is the geometric mean of the vertical resistivity and the horizontal resistivity of the layer. Artificial Neural Networks (ANN) is a method uses in many different areas for learning, classification, generalization and optimization etc. ANN available to estimate the thickness, vertical and horizontal resistivity values of layers. In this study, a MATLAB code was developed for the inversion of one-dimensional electrical resistivity data in anisotropic medium by using artificial neural networks. Neural Network Toolbox of MATLAB was utilized in the developed program. The code was tested on both noisy-free and five percent noisy synthetic data. Thicknesses, vertical and horizontal resistivity of the layers are estimated by using the code. The mean resistivity values and anisotropy coefficients of each layer were calculated via the estimated parameters. The estimated parameters and the parameters of the subsurface model were similar with acceptable error rates.
Soil water dynamics in forested and irrigated sites in Cyprus 
Authors: Eliades Marinos , Bruggeman Adriana , Djuma Hakan , Siakou Melpomeni , Venetsanou Panagiota , Zoumides Christos , Huebner Christof
Published: March 2021

The water storage in soil is a dynamic process that changes with soil, vegetation and climate properties. Water retention curves, that describe the relationship between the soil water content (θ) and the soil water potential (ψ), are used to model soil water flow and root water uptake by the plants. The overall objective of this study is to derive the retention curves of soils at two forested (Agia Marina, Platania) and two irrigated (Galata, Strakka) sites in Cyprus from in-situ soil moisture and soil water potential observations. 
The long-term (1980 – 2010) average annual rainfall at Strakka olive grove (255 m elevation), Agia Marina P. brutia forest (640 m), Galata peach orchard (784 m) and Platania P. brutia forest (1160 m) is 298, 425, 502 and 839 mm, respectively.  The average soil depth at Agia Marina is 14 cm, while at other sites it is around 1 m. We installed a total of 18 TEROS21 soil water potential sensors, 37 5TM and 19 SMT100 soil moisture sensors, at different soil depths at the four sites. 
Results from January 2019 to January 2021 show differences in the water retention curves of the four sites due to different soil textures. At the forested sites, θ reached wilting point at the summer period, indicating that trees extend their roots beyond the soil profile, to the bedrock in order to survive. At the irrigated sites, θ exceeds field capacity during irrigation, indicating over-irrigation. We found different water retention relations after rainfall and after irrigation, indicating that irrigation has an uneven spatial distribution. These findings suggest that the irrigation in these fields is not optimal and farmers may need to increase the number of irrigation drippers, while reducing the irrigation amount per dripper. From a monitoring perspective, increasing the number of sensors may give a better representation of the soil moisture conditions. 
The research has received financial support from the ERANETMED3 program, as part of the ISOMED project (Environmental Isotope Techniques for Water Flow Accounting), funded through the Cyprus Research and Innovation Foundation.
Improved eddy covariance flux based transpiration estimates at high relative humidity and comparison to sap flux
Authors: Zhang Weijie , A. Nelson Jacob , Poyatos Rafael , Miralles Diego , Migliavacca Mirco , Reichstein Markus , Jung Martin
Published: March 2021

Eddy covariance (EC) directly measures evapotranspiration (ET), which consists of transpiration and evaporation (E) from the soil and other surfaces. For process understanding it is pivotal to separate ET into its components. Yet, its computation is highly sensitive to the methodology used to estimate T. Among the multiple methods proposed in recent years, T has been estimated from EC via the Transpiration Estimation Algorithm (TEA, Nelson et al., 2020), and from the sap flux measurement network SAPFLUXNET (Poyatos et al., 2020). These methods are applicable to a large number of measurement sites worldwide, and can help constrain the global estimates of the ratio of T to ET, T/ET. While EC measures water and carbon fluxes across ecosystems globally, water vapor flux measurements can be underestimated at high relative humidity (Ibrom et al., 2007; Mammarella et al., 2009) causing errors in the measured ET and propagating into the predicted T.

Here we report a method to detect and correct the high relative humidity error caused by attenuation of high frequency in water vapor measurements of a closed-path EC system. Our results of the comparison between present water use efficiency (WUE) with previous TEA-based WUE show that the corrected WUE is lower at high relative humidity than that derived from previous TEA at the sub-daily scale. Besides, we compare the corrected T estimates from EC to concurrent SAPFLUXNET sites to show an improved relationship between sap flux and EC based T, T/ET, and WUE. Finally, we explore the main abiotic factors, such as vapor pressure deficit, air temperature, and precipitation, influencing WUE estimated from different T estimation methodologies. These results provide an improved data-driven approach to the ongoing research on ET partitioning and the factors influencing the WUE across ecosystems globally.

 

Ibrom, A. et al. (2007) ‘Strong low-pass filtering effects on water vapour flux measurements with closed-path eddy correlation systems’, Agricultural and Forest Meteorology. doi.org/10.1016/j.agrformet.2007.07.007.

Mammarella, I. et al. (2009) ‘Relative humidity effect on the high-frequency attenuation of water vapor flux measured by a closed-path eddy covariance system’, Journal of Atmospheric and Oceanic Technology. doi.org/10.1175/2009JTECHA1179.1.

Nelson, J. A. et al. (2020) ‘Ecosystem transpiration and evaporation: Insights from three water flux partitioning methods across FLUXNET sites’, Global Change Biology. doi: 10.1111/gcb.15314.

Poyatos, R. et al. (2020) ‘Global transpiration data from sap flow measurements: the SAPFLUXNET database’, Earth System Science Data. doi:10.5194/essd-2020-227.
Satellite altimeter to estimate discharge of the Ganga River
Authors: Rai Atul Kumar , Gaurav Kumar
Published: March 2021

We use satellite altimeter data to estimate average monthly discharge at seven different locations in the middle and lower parts of the Ganga River. We have obtained the water level from different satellite altimeter mission ERS-2 (1995 - 2007), Envisat (2002 - 2010), and Jason-2 (2008 - 2017) through publicly available databases Hydroweb and DAHITI. To make the water level comparable with the gauge stations, we applied the datum and offset correction to the altimetry datasets. The corrected water level data well accord with the ground measurements with RMSE values in a range between (22 - 71) cm. 

We then established stage-discharge rating curves from the water-level derived from satellite altimeter and the corresponding discharge measured at the nearest gauge station. We use these rating curves to estimate discharge of the Ganga River in the middle (Kachla bridge, Kanpur, Shahzadpur, Prayagraj and Mirzapur) and lower (Azmabad and Farakka) reaches from the water-level from satellite altimeter. Our estimates of discharge compare with the monthly average discharge recorded at the nearest ground station.

We observed that the uncertainty in the discharge estimate is relatively high in the middle than the lower reaches of the Ganga River. This is probably associated with the low discharge and shallow flow depth of the Ganga River in the middle reaches as compare to the high flow depth and discharge in the lower reaches. Overall performance analysis of statistical parameters (NSE, RSR, PBIAS, and R2), suggests that except for the Kanpur station, our estimates of discharge can be categories into "good" to "satisfactory".