bluuebunny/crossref_metadata_2025 huggingface dataset:
Oxidative Potential and Chemical Characteristics of Ambient PM2.5 in Guangzhou, China
Authors: Cheng Peng , Zhang Manman , Li Yongjie
Published: March 2020

The dithiothreitol (DTT) assay is widely used to characterize the Oxidation Potential (OP) of atmospheric particulate matter (PM), which can cause adverse effects on human health. However, it’s under debate which chemical species determines the consumption rate of DTT. During January and April 2018, we measured the improved DTT assay of daily PM2.5 samples collected in Guangzhou, China with complimentary measurements of water-soluble ions, organic/elemental carbon (OC/EC) and metal elements. The average sampled air volume normalized consumption rate of DTT (DTTv) was 4.67 ±1.06 and 4.45 ± 1.02 nmol min-1 m-3, in January and April, respectively while the average PM2.5 mass normalized consumption rate of DTT (DTTm) was 13.47 ± 3.86 and 14.66 ± 4.49 pmol min-1 μg-1. Good correlations were found between DTTv and concentration of PM2.5, OC, and EC while no correlation was found between DTTm and concentrations of water-soluble ions, OC, EC or metal element, which is consistent with most early observations. We also evaluated the contribution of soluble metals to DTT assay by addition of EDTA, a strong metal chelator. We found that nearly 90% of DTTv and DTTm were reduced by EDTA, suggesting a dominant role of soluble metals in determining the response of DTT to ambient PM2.5. Based on responses of DTT to soluble metals in literature, we found that Cu(II) and Mn(II) are the major contributors to OP of PM2.5 in Guangzhou. The correlation coefficient between DTTm and OC shows a clear increase after addition of EDTA, implying that the response of DTT to quinones is not strongly suppressed by EDTA.
Seasonality of Submesoscale processes in the Bay of Bengal
Authors: Li Lanman , Cheng Xuhua
Published: March 2020

Mesoscale eddies that known as a dominant reservoir of kinetic energy has been studied extensively for its dynamics and variation.In order to maintain energy budget equilibrium,the energy stored in mesoscale eddies is dissipated by small scale processes around centimeters.Submesoscale processes that lie between mesoscale and microscale motions effectively extract energy from mesoscale motions and transfer to smaller scales.The Bay of Bengal(the BOB) receives large fresh water from precipitation and river runoff resulting in strong salinity fronts that conducive to the generation of submesoscale processes.Using the Regional Ocean Modeling System(ROMS) data with two horizontal resolutions:a high-resolution(~1.6km) that is partially resolve submesoscale,and a low-resolution(~7km) that not resolves submesoscale,we focus on the seasonality of submesoscale processes in the Bay of Bengal.To ensure that only the submesoscale motions is considered,we choose 40km as the length to separate submesoscale from the flow field.Results show that submesocale processes is ubiquitous in the BOB,mainly trapped in the mixed layer.As resolution increasing,submesoscale motions become much stronger.Seasonality of submesoscale in the BOB is apparent and is different from the Gulf stream region  which is strongest in winter and weakest in summer.Submesoscale features in this region mostly present in fall,which the most important mechanisms is frontogenesis due to strong horizontal buoyancy flux associated with large strain.Submesoscale motions is also vigorous in winter.The proposed mechanism is that the depth of mixed layer is deep enough which contributes to the occurrence of mixed layer instability.During the whole year,mesoscale strain field is weakest in summer,which makes submesoscale weakest.
Influence of spring phenology on seasonal net primary productivity in the alpine grassland on the Tibetan Plateau
Authors: Zheng Zhoutao , Zhu Wenquan , Zhang Yangjian , Huang Ke , Cong Nan
Published: March 2020

Vegetation phenology is recognized to exert crucial influences on carbon sequestration and the role of vegetation phenology in mediating carbon cycle varies with ecosystem type. However, the relationship between vegetation phenology and productivity has not been fully understood in the alpine ecosystem due to a lack of field observations, poor model performances and their complex mechanisms. In this study, we examined the spatio-temporal variation in beginning of growing season (BGS) and net primary productivity (NPP) for the alpine grassland on the Tibetan Plateau (TP) and the regulation effects of spring phenology on seasonal NPP by integrating field observations, remote sensing monitoring and ecosystem model simulation. The ecosystem model performances were improved by optimizing ecosystem parameters from field observations. The results indicated a significant advance in BGS with a rate of 0.31 days/yr (P < 0.1) in the alpine grassland during 2001-2015 while the annual NPP increased significantly at a rate of 1.25 gC/m2/yr (P < 0.01). With regard to the relationship between BGS and NPP, large spatial heterogeneities were identified. Overall, a negative but non-significant correlation (R = -0.34, P > 0.1) was observed between BGS and annual NPP for the entire grassland ecosystem on the TP. But responses of NPP to BGS varied with seasons. Specifically, BGS showed significant negative correlation with spring NPP (R = -0.73, P < 0.01), and advanced spring led to increased spring NPP. The positive effects of advanced BGS on NPP tended to weaken in summer. Moreover, BGS was significantly and positively correlated with autumn NPP in some relatively arid zones of the southwestern TP, suggesting the suppressing effects of earlier spring on carbon assimilation during the later growing season in water limited areas. This study improved our understanding on the impacts of biotic factors on carbon cycles of the alpine ecosystem and implies that the effects of phenology can’t be concluded simply for an annual sum, and their relationships for each separate season are also critical.
Measurements of atmospheric gaseous elemental mercury (GEM) and GEM fluxes in the seas of Southeast Asia in October-December 2019
Authors: Kalinchuk Viktor , Lopatnikov Evgeny , Astakhov Anatoly , Ivanov Maksim , Shakirov Renat , Cuong Do Huy
Published: March 2020

Measurements of gaseous elemental mercury (GEM) in the marine boundary layer (MBL) and GEM evasion fluxes were carried out during the Russian-Vietnam cruise conducted from the Sea of Japan to the South China Sea from October 25 to December 7, 2019. All GEM measurements were performed using two RA-915M mercury analysers (Lumex LLC, Russia). Atmospheric GEM concentrations were measured at two levels (about 2 m and 20 m above the sea surface) with a time resolution of 30 minutes. GEM fluxes were measured in the South China Sea using a dynamic flux chamber.

GEM concentrations ranged between 0.56 ng/m3 and 25.47 ng/m3, and between 0.39 ng/m3 and 23.95 ng/m3 with medians of 1.38 ng/m3 and 1.45 ng/m3 for 2 m and 20 m measurements, respectively. GEM concentrations were significantly affected by air transport of GEM. Concentration Weighted Trajectory (CWT) analysis showed several source regions potentially influencing GEM concentrations in the ambient air during the cruise: the south of the South China Sea, Vietnam, the southeastern China, the south of Japan and the Korean peninsula. Maximum concentrations (up to 25 ng/m3) were registered in Haiphong (Vietnam).

Hg(0) fluxes measured at 7 stations in the South China Sea ranged from 1.1 ng/m2/h to 2.5 ng/m2/h, with median value of 2.07 ng/m2/h. These values were 1,5 times higher than those that were measured by the same method in the Sea of Japan and the Sea of Okhotsk a month earlier.

This work was supported by the Russian Science Foundation (RSF) (Project № 19-77-10011).
Spectral Sensitivity of Heavy Metal Concentration in Mine Soils: A case study of Gagok mine, South Korea
Authors: Kim Hyesu , Yu Jaehyung , Kim Jieun , Koh Sangmo , Lee Bumhan
Published: March 2020

 Heavy metal contamination in soils of mining area accompanies contaminations in drainage and vegetation. The traditional soil survey methods for heavy metal contamination requires significant investment of time, labor, and money although the methods can drive accurate assessment. Moreover, the point-based survey is problematic to understand spatial distribution with limited sample numbers. Remote sensing approaches may provide alternative solutions to understand spatial distribution of contamination with minimal investment of time and labor. It is very critical to understand spectral signals associated with heavy metal concentration to apply the phenomenon to remote sensing approaches. This study investigated spectral signals associated with heavy metal concentration in mine soils based on chemical analysis, mineral composition analysis, and spectral analysis. The study site is a Pb-Zn skarn ore deposit located in Gangwon province, South Korea, where the ore was formed by granite intrusion to slate and limestone. The chemical analysis revealed that the soils are contaminated with heavy metals. Mineral composition classified the soils into two time with silicate/clay mineral group and silicate/carbonate/clay mineral groups. Spectral analysis showed that sensitive spectral bands to heavy metal concentration is located in SWIR region for silicate/clay mineral group and VNIR region for silicate/carbonate/clay mineral group. It reveals that mineral composition and geochemical reaction play an important role in spectral signals manifested by heavy metal concentration.

 
MOSAiC’s Pan Arctic Water Isotope Network: Sea ice-water vapor isotope interactions and transport processes within, into and out of the Arctic
Authors: Kopec Ben , Klein Eric , Noone David , Bailey Hannah , Mustonen Kaisa-Riikka , Akers Pete , Bonne Jean-Louis , Werner Martin , Steen-Larsen Hans Chirstian , Wahl Sonja , Aemisegger Franziska , Klove Bjorn , Hubbard Alun , Welker Jeff
Published: March 2020

MOSAiC is a one of a kind, year-long study of the Arctic Basin’s behavior focused in large part on interactions between sea ice, atmospheric processes, ecosystem dynamics and oceanography, as well as connections between the Arctic and the mid-latitudes. Our MOSAiC project is focused on how the Arctic Basin’s water cycle behaves throughout the year, especially now that sea ice loss allows for a new source of moisture to the atmosphere during times when this basin was formerly frozen over. These massive changes in open water and corresponding fluxes in conjunction with significant shifts in atmospheric circulation, are altering how moisture is transported into, within, and out of the Arctic Basin. In order to help quantify these Arctic hydrologic cycle variations, we have established the AWIN (Arctic Water Isotope Network) that uses continuous water vapor isotope measurements (δD, δ18O, and deuterium excess) at eight land-based stations from Barrow in Alaska to Ny Alesund in Svalbard, as well as on board the Polarstern.

With a network of sites rather than a single station, we gain the significant advantage of being able to track water vapor and how it varies from site to site, allowing us to identify the sources of moisture, and how and where that moisture is transported into, within, and out of the Arctic. For this analysis, we focus on the first months of the expedition (October-December 2019) to closely examine cases of critical events including a major low-pressure system in mid-November that impacted much of the Arctic Ocean basin and three key repeating transport regimes – 1) transport into the Arctic from the North Atlantic via the Greenland Sea, 2) transport into the Arctic via Baffin Bay, and 3) transport out of the Arctic via the Greenland Sea, as well as transport within the Arctic during each of these regimes. For example, in the scenario of transport into the Arctic via Baffin Bay, at our site in Thule, Greenland, we see significant reductions in deuterium excess each time the southerly flow initiates, suggesting significant moisture evaporating from nearby in Baffin Bay. We then can track that moisture to another site to observe how much of that locally-sourced vapor is transported to a given downwind location, allowing us to quantify vapor fluxes and isotopic fractionation processes across the Arctic. By examining these scenarios under varying sea ice conditions and large-scale atmospheric circulation patterns, this circum-Arctic network of water isotope measurements is transforming our understanding of the Arctic hydrologic cycle during MOSAiC.
The magnetic flux transport along the -Esw direction in the magnetotails on Mars and Venus
Authors: Chai Lihui , Slavin James , Wei Yong , Wan Weixing , Bowers Charlie F. , DiBraccio Gina , Dubinin Eduard , Fraenz Markus , Exner Willi , Feyerabend Moritz , Motschmann Uwe , Li Kun , Cui Jun , Zhang Tielong
Published: March 2020

The induced magnetotails on Mars and Venus are considered to arise through the interplanetary magnetic field (IMF) draping around the planet and the solar wind deceleration due to the mass loading effect. They have very similar structures as that on Earth, two magnetic lobes of opposite radial magnetic fields and a plasma sheet in between. However, the orientation and geometry of the induced magnetotails are controlled by the IMF, not the planetary intrinsic magnetic field. In this study, we present another characteristic of the induced magnetotails on Mars and Venus with the observations of MAVEN and Venus Express. It is found that the magnetic flux in the induced magnetotails on Mars and Venus are inhomogeneous. There is more magnetic flux in the +E hemisphere than -E hemisphere. The magnetic flux is observed to transport gradually from the +E hemisphere to the -E hemisphere along the magnetotail. The magnetotail magnetic flux transport seems to be faster on Mars than that at Venus. Based on these observations, we suggest that the finite gyro-radius effect of the planetary ions that are picked up by the solar wind is responsible to the magnetic flux inhomogeneity and transport in the induced magnetotails. The role of the magnetic pressure gradient in the magnetotail will be discussed.
Deriving paleo-perspectives on polar systems: Continued results from the 2012 Sawtooth Lake (Ellesmere Island) and 2015 Petermann (North Greenland) Expeditions
Authors: Stoner Joseph , Reilly Brendan , Mix Alan , Jakobsson Martin , Walczak Maureen , Abbott Mark , Lapointe Francois , Francus Pierre , Balascio Nicholas , Jennings Anne , Hogan Kelly , Mayer Larry
Published: March 2020

Deriving paleo-perspectives on polar systems in so-called “last ice” regions of North Greenland and the High Canadian Arctic have been traditionally challenged by logistical/accessibility issues and paleo proxy (including chronology) limitations. Sea-ice retreat and proxy development are changing this paradigm, allowing the region to be mapped, materials collected, and paleo-records developed that provide new insights on the evolution of the region.  Here we report on continued progress from the joint US/Swedish 2015 Petermann Expedition to North Greenland and the joint US/Canadian 2012 Sawtooth Lake Expedition to Ellesmere Island, where new developments in physical properties and chronology are changing our understanding of the region. Computed tomography, X-Ray fluorescence, ice-rafted debris counts, and the magnetic properties of specific particle size fractions constrain changes in depositional processes and sediment sources providing info on glacial retreat and advance and other environmental changes. While an improved understanding of the geomagnetic field supported by radiocarbon dating enables regional magnetic synchronization allowing Holocene ice sheet and environmental dynamics to be placed in the context of High Arctic climate evolution.
Incorporating groundwater disequilibrium in large-scale, isotopically-constrained water budgets
Authors: Bowen Gabriel , Allen Scott , Good Stephen
Published: March 2020

Stable isotope ratios of H and O in water are powerful tracers that have supported estimation and partitioning of hydrological fluxes at scales from individual catchments to the globe. Most studies, however, assume for simplicity and lack of constraints that isotopic fluxes associated with groundwater recharge and abstraction are in balance. We present a critical assessment of this assumption based on new gridded, 3-dimensional maps of the isotopic composition of groundwaters across the contiguous United States. These show that 1) the isotopic composition of shallow (recently recharged) groundwater differs from that of incident or basinally-integrated precipitation across much of the study area, implying selective recharge of precipitation, and 2) the approximate production-weighted isotope ratios of groundwater differ substantially from recently recharged water in many regions, implying an imbalance in isotope fluxes to/from the subsurface. Accounting for these imbalances leads us to revised estimates of the relative roles of various runoff generation processes and evapotranspiration sources in US-wide isotope mass balances.
Improving Earth hot-spot detection from MODIS data using MODVOLC algorithm
Authors: Gabrieli Andrea , Wright Robert , Garbeil Harold , Pilger Eric
Published: March 2020

Space-borne hot-spot detection on the Earth surface is key to monitoring and studying volcanic activity, wildfires and anthropogenic heat sources from space. Lower intensity thermal emission hot-spots, which often represent the onset of volcanic eruptions and large wildfires, are difficult to detect. We are improving the MODVOLC algorithm, which monitors Earth’s surface for hot-spots by analyzing Moderate Resolution Imaging Spectroradiometer (MODIS) data every 48 hours, to allow lower intensity thermal emission detection. Improving the existing MODVOLC algorithm for hot-spot detection from MODIS image data is not trivial. A new approach, which we refer it to as the Maximum Radiance Algorithm for MODIS, has been explored. The new approach requires a MODIS 4 µm and accompanying 12 µm global radiance time-series at ~1 km grid spacing. This reference data set describes the maximum radiance that has been measured from each square km of Earth’s surface over a ten year period (having first excluded high natural and anthropogenic heat sources from the time-series, using the existing MODVOLC approach). For each new geolocated MODIS image data, the observed radiance for each pixel is compared with this reference, and if its radiance exceeds the historical maximum, it can be considered a potential hot-spot. A dynamic tolerance is used to then confirm if the potential hot-spot is an actual hot-spot. We show that this new approach for hot-spot detection offers significant advantage over existing techniques for lower intensity thermal emission hot-spot detection during both day and nighttime conditions.
Southeast Asian anthropogenic emission changes: An analysis from regional and global emission inventories
Authors: Lam Yun fat , Roy Shimul , Chui Ka Wing
Published: March 2020

In ASEAN (Southeast Asia) countries, anthropogenic emissions have increased significantly over the last two decades from a variety of sources, including power and heating, industries, road-transportation, residential, and agricultural activities. In this study, we analyzed different emission inventories (i.e., MICS-Asia, REAS, EDGAR) to provide the integrated emissions for ASEAN during the period 2000-2010. The study found that anthropogenic emission contribution from ASEAN countries to the total Asian emission was notable during that period. For instance, from the MIX-Asian EI, our analysis shows that the average contribution was the highest from the transportation sector (34%), followed by residential (29%), power (24%), and industrial sector (14%), respectively in 2010. However, similar to the sector-specific emission contribution in 2000 in ASEAN countries, residential sector was the most significant contributor for CO (53%), PM10 (48%), PM2.5 (63%), BC (76%), OC (79%) in 2010, although it is in decreasing trend compared to other sectors. On the contrary, emission contribution of SO2 was the highest from the industrial sector (47%), followed by power (36%), while NOx and NMVOC were contributed mainly by transportation sector (55% and 45%, respectively). Spatially, the emission intensities of SO2, CO, NOx, NMVOC, PM10, PM2.5, BC, OC, and CO2 were high in the major urban cities of Thailand, Vietnam, Malaysia, Philippines, and Indonesia except CH4, N2O, and NH3, which were high in the rural areas of ASEAN countries.
Gradient Boosting for Forecasting Groundwater Levels from Sparse Data Sets in an Alluvial Aquifer Subjected to Heavy Pumping and Flooding
Authors: Xiao Shuang , Cendón Dioni , Kelly Bryce
Published: March 2020

In most catchments, there is usually inadequate information to build an accurate three-dimensional representation of the sediment type and associated hydraulic properties. This makes it challenging to build a physics-based groundwater flow model that accurately replicates measured fluctuations in the groundwater level, and it also results in considerable uncertainty in forecasting the groundwater level under various climate scenarios. However, in many catchments in Australia, and around the world, there are 100 year-long rainfall and streamflow records. Good groundwater level data sets often date from mid last century, when advances in pumping technology enable high volume groundwater extractions to support irrigated agriculture. For the lower Murrumbidgee alluvial aquifer in Australia, which covers an area of 33,000 km2, we demonstrate that it is possible to train the gradient boosting algorithm to predict the annual change in the groundwater level to within a few centimetres.

The lower Murrumbidgee aquifer, which is up to 300 m thick, is an important but highly stressed aquifer system in Australia. Annually the groundwater level fluctuates many metres due to groundwater withdrawals and occasional flooding.  Some portions of the alluvial aquifer are unconfined and other portions semi-confined. Under current groundwater pumping conditions, groundwater levels decline in the semi-confined portions of the aquifer during extended periods of below average rainfall. In other portions of the catchment, there have been periods of groundwater level rise due to deep drainage beneath irrigated crops.

Despite the catchment size, groundwater levels throughout the region are driven by four primary processes: ongoing river leakage, pumping, deep drainage and occasional flooding. Combined with knowledge of the hydrogeological setting, we successfully used just rainfall, streamflow and annual groundwater withdrawal records to build a gradient boosting model to predict where the groundwater level will rise and fall, in both space and time. Under existing annual pumping rates, the gradient boosting model forecasts that the groundwater level will fall many metres if the catchment has a period of below average rainfall as occurred from 1917 to 1949. This fall in the groundwater level will trigger groundwater access restrictions in some portions of the aquifer.
The sensitivity of sea ice growth to the choice of ice shelf-ocean coupling algorithms.
Authors: Jendersie Stefan , Malyarenko Alena
Published: March 2020

To quantify Antarctic ice mass loss and the subsequent sea level rise the geophysical modelling community is pushing towards frameworks that fully couple increasingly complex models of atmosphere, ocean, sea ice and ice sheets & shelves.  One particular hurdle remains the accurate representation of the vertical ocean-ice interaction at the base of ice shelves.  Parameterizations that are tuned to particular data sets naturally perform best in comparable ice shelf cavity environments. This poses the challenge in continental scale ocean-ice shelf models to chose one melt parameterizaton that performs sufficiently well in diverse cavity environment.  Thus adding uncertainty in ice shelf induced ocean freshening crucially affects modelled sea ice growth.  The impact magnitude of ice shelf supplied melt water on growth rates, thickness and extent of sea ice in the open ocean is currently debated in the literature.  
We reviewed and compared 16 commonly utilized melting/freezing parameterizations in coupled ocean-ice shelf models.  Melt rates differ hugely, in identical idealized conditions between 0.1m/yr to 3m/yr.  In this talk we present results of a realistic circum-Antarctic ice shelf and sea ice coupled ocean model (CICE, ROMS), where we look at the effects of the chosen ice shelf melt parameterization on modeled sea surface conditions and sea ice growth, regionally and circum Antarctic.
Drought responses of Amazon forests under climate change: Separating the roles of soil moisture and canopy responses
Authors: Wey Hao-wei , Naudts Kim , Pongratz Julia , Nabel Julia , Boysen Lena
Published: March 2020

The Amazon forests are one of the largest ecosystem carbon pools on Earth. While more frequent and prolonged droughts have been predicted under future climate change there, the vulnerability of Amazon forests to drought has yet remained largely uncertain, as previous studies have shown that few land surface models succeeded in capturing the vegetation responses to drought. In this study, we present an improved version of the land surface model JSBACH, which incorporates new formulations of leaf phenology and litter production based on intensive field measurement from the artificial drought experiments in the Amazon. Coupling the new JSBACH with the atmospheric model ECHAM, we investigate the drought responses of the Amazon forests and the resulting feedbacks under RCP8.5 scenario. The climatic effects resulted from (1) direct effects including declining soil moisture and stomatal responses, and (2) soil moisture-induced canopy responses are separated to give more insights, as the latter was poorly simulated. Preliminary results show that for net primary production and soil respiration, the direct effects and canopy responses have similar spatial patterns with the magnitude of the latter being 1/5 to 1/3 of the former. In addition, declining soil moisture enhances rainfall in Northern Amazon and suppresses rainfall in the south, while canopy responses have negligible effects on rainfall. Based on our findings, we suggest cautious interpretation of results from previous studies. To address this uncertainty, better strategy in modeling leaf phenology such as implemented in this study should be adopted.
Model structure uncertainty of SOC dynamics studied in a single modeling framework
Authors: Vasilyeva Nadezda , Vladimirov Artem , Vasiliev Taras
Published: March 2020

The aim of our study is the source of uncertainty in soil organic carbon (SOC) models which comes from the model structure. For that we have developed a family of mathematical models for SOC dynamics with switchable biological and physical mechanisms. Studies mechanisms include microbial activity with constant or dynamic carbon use efficiency (CUE) and constant or dynamic microbial turnover rate; priming effect: decay of stable SOC pool in the presence of labile SOC pool; temperature and moisture dependencies of SOC decomposition rates; dynamic adsorption strength and occlusion. Model SOC cycle includes measurable C pools in soil size and density fractions, each comprised of two estimated theoretical C pools (labile and stable - biochemical C cycle). Reaction rates of the biochemical cycle are modified according to its physical state: decay accelerates with size, accelerates with the amount of adsorbed C (density: heavy to light) and decelerates with soil microaggregation (occluded state). The models family was tested on C and 13C dynamics detailed data of a long-term bare fallow chronosequence.

Analysis of SOC models family with different combinations of mechanisms showed that the best (estimated by BIC) description of SOC dynamics in physical fractions was with microbially-explicit models only in case of a feedback via dynamics of microbial turnover and CUE. First, we estimated uncertainty of all mechanism-specific parameters for every model in the family. We calculated density distributions for parameters characterizing functional properties and stability of soil components (such as energy of activation, adsorption capacity, CUE, 13C distillation coefficient) for the models family weighted with models likelihoods. These parameter values were then compared with common experimental values.

We discuss the use of the study results to estimate relevance of observed parameter and structural uncertainties for global SOC projections obtained using different model structures.
Report on science classes and a workshop for teen students to learn geography and geology using Minecraft
Authors: Iwahashi Junko , Nishioka Yoshiharu , Kawabata Daisaku , Ando Akinobu , Okada Shinsuke , Shiraishi Takahisa
Published: March 2020

In this presentation, we report science classes in which the purpose was to learn the history of local geology, and a workshop to learn the relationship between landforms and natural hazards using Minecraft. Minecraft (Mojang/Microsoft) is a sandbox computer game for exploration and crafting in 3-D virtual worlds. It is very popular among the young generation (100 million users in the world), and by using the game it is easy to construct virtual worlds and exploration mechanisms. The science classes were conducted twice for students aged 12 to 13 in a junior high school in Miyagi Prefecture, Japan. Using Minecraft, we have constructed a virtual world tailored to their school, including the school buildings and paleoenvironments. In the game, students travel around the school buildings to learn and to solve basic knowledge questions based on references from their school science textbooks, then they go to the underground strata and into past worlds to learn and to solve advanced questions which refer to papers on regional geology. A questionnaire which was given to over 150 students after the first class showed that the students enjoyed the class and obtained a general understanding of geological knowledge. The second class was based on a reviced game after referring to the results of the questionnaire. In the workshop, we used a 3-D topographic model of Japanese flood plains and surrounding terraces and mountains. This example was conducted for 15 to 18-year-old students as a workshop with a small number of students, less than 10. At first, we explained to the students how landforms are associated with natural hazards such as flooding and earthquake shaking, and explained how to find and view thematic maps like hazard maps that could be observed as interactive web maps published by Japanese public agencies and institutes. Next, the students were asked where they wanted to build a house on the virtual terrain. Through their constructions, we considered the balance between playing and learning. This study was supported by JSPS KAKENHI Grant Number JP18K18548.
Characterization and light absorption of Brown Carbon in Sichuan Basin, Southwestern China: Impacts of biomass burning and secondary formation
Authors: Chen Yang
Published: March 2020

Brc Carbon is a class of light-absorbing organic species, playing important roles on solar radiation budget and therefore influences climate forcing over regional and even global scales. We analyzed and evaluated the light absorption and radiative forcing of BrC in Chongqing, Wanzhou (Three Gorges Reservoir region), and Chengdu in the Sichuan Basin of Southwest China. The light-absorbing properties were evaluated, including mass absorption efficiency, absorption Ångström exponent, and contributions to radiative forcing. The sources of BrC are also identified, including the contribution of secondary aerosol formation and primary emissions. This study contributes to the understandings of sources and the impact of brown carbon in the Sichuan Basin, southwestern China.
IoT-based Flood Depth Sensors in Artificial Intelligent Urban Flood Warning Systems
Authors: Chang Li-Chiu , Chang Fi-John
Published: March 2020

In the face of increasingly flood disasters, on-line regional flood inundation forecasting in urban areas is vital for city flood management, while it remains a significant challenge because of the complex interactions and disruptions associated with highly uncertain hydro-meteorological variables and the lack of high-resolution hydro-geomorphological data. Effective on-line flood forecasting models through the rapid dissemination of inundation information regarding threatened areas deserve to develop appropriate technologies for early warning and disaster prevention. Artificial Intelligence (AI) becomes one of the popular techniques in the study of flood forecasts in the last decades. We apply the AI techniques with the newly implemented IoT-based real-time monitoring flood depth data to build an urban AI flood warning system. The AI system integrates the self-organizing feature mapping networks (SOM) with the recurrent nonlinear autoregressive with exogenous inputs network (R-NARX) for modelling the regional flooding prediction. The proposed AI model with the IoT-based real-time monitoring flood depth datasets can increase the value-added application of diversified disaster prevention information and improve the accuracy of flood forecasting. We develop an on-line correction algorithm for continuously learning and correcting model’s parameters, automatic operation modules, forecast results output modules, and web page display interface. The proposed AI system can provide the smart early flooding warnings in the urban area and help the Water Resources Agency to promote the intelligent water disaster prevention services.

Keywords:

Artificial Intelligence (AI); Artificial Neural Networks (ANN); Internet of Things (IoT); Regional flood inundation forecast; Spatial-temporal distribution
Long-term variability of shortwave absorption under abrupt-4xCO2 climate forcing and its visible and near-IR contributions
Authors: Hakuba Maria Z. , Bodas-Salcedo Alejandro , Stephens Graeme
Published: March 2020

While ongoing global warming is largely the result of reduced outgoing longwave radiation (OLR), climate feedbacks associated with changes in atmospheric water vapor and surface albedo are expected to enhance the absorption of shortwave radiation (ASR) and to sustain global warming on centennial time scales beyond the OLR modulations. These feedbacks as well as positive cloud feedbacks reduce the reflected shortwave (SW) flux at the top-of-atmosphere (TOA) and are a result of scattering and absorbing processes that differ by their near-infrared (NIR) and visible (VIS) contributions. Since direct measurements of broadband NIR (~0.7-5 mm) and VIS (~0.2-0.7 mm) radiation flux do not exist, we utilize UKESM1 simulations to study SW, NIR, and VIS climate feedbacks under preindustrial and abrupt-4xCO2 climate forcing.

Besides its global long-term behavior, the spatial variability and key physical controls of ASR are not well characterized either. A prominent example is the unexplained hemispheric symmetry in planetary albedo that is consistently missed by current global climate models yielding unrealistic precipitation and circulation patterns. Although energetically equivalent, the observed hemispheric albedos differ spectrally, reflecting the uneven distribution of clouds and land masses. We use the same UKESM1 simulations to contrast inter-hemispheric differences in SW, NIR and VIS, and their relation to changes in clouds, the gaseous atmosphere and surface properties to shed light on processes relevant to the present-day symmetry, model biases, and potential future changes.
A new operational model that increases experiment diversity and shortens time to publication for research Seismology
Authors: Baturan Dario , Townsend Bruce , Moores Andrew
Published: March 2020

Traditionally, the ability to study seismic phenomena is dependant on both the available hardware and time for processing data needed to produce a research grade catalogue. Consequently, shortages in either of these resources constrain the scope of studies available to the research scientist. This is becoming especially challenging as networks become larger and more dense, and as the community moves towards Large-N networks and arrays. We will look at alternative solutions to address these resource constraints and open the scientist up to a broader field of study.

Ownership of equipment or waiting in a queue for loan pool assets are the two most common methods for acquiring the hardware necessary to conduct a scientific study. Further, once the data has been collected, a good deal of time is spent processing that data to produce a catalogue before the scientific inquiry can begin.   

There is now an alternative model for acquiring and processing data in seismology that shortens the time and effort necessary to produce a research grade catalogue. We will demonstrate how we can customize acquisition arrays to meet experimental goals and apply proven processing models and AI techniques to deliver a bespoke research grade catalogue at a fraction of the time and cost of traditional acquisition and processing methods. This removes several of the challenging aspects of running an experiment in order to enable researchers to get straight to their science and shortening the time to publication.
Importance of Spectroscopic Effects in Laser-based Flux Measurements
Authors: Burba George , Anderson Tyler , Komissarov Anatoly
Published: March 2020

A significant portion of the production and consumption of trace gases (e.g. CO2, CH4, N2O, NH3, etc.) occurs in areas without sufficient infrastructure or easily available grid power to run traditional closed-path flux stations. Open-path analyzer design allows such measurements with power consumption 10-150 times below present closed-path technologies, helping to considerably expand the global coverage and improve the estimates of gas emissions and budgets, informing the remote sensing and modeling communities and policy decisions, all the way to IPCC reports. Broad-band NDIR devices have been used for open-path CO2 and H2O measurements since the late 1970s, but since recently, a growing number of new narrow-band laser-based instruments are being rapidly developed.

The new design comes with its own challenges, specifically: (i) mirror contamination, and (ii) uncontrolled air temperature, pressure and humidity, affecting both the gas density and the laser spectroscopy of the measurements. While the contamination can be addressed via automated cleaning, and density effects can be addressed via the Webb-Pearman-Leuning approach, the spectroscopic effects of the in-situ temperature, pressure and humidity fluctuations on laser-measured densities remain a standing methodological question.

Here we propose a concept accounting for such effects in the same manner as Webb et al. (1980) proposed to account for respective density effects. Derivations are provided for a general case of flux of any gas, examined using a specific example of CH4 fluxes from a commercially available analyzer, and then tested using "zero-flux" experiment.

The proposed approach helps reduce errors in open-path, enclosed, and temperature- or pressure-uncontrolled closed-path laser-based flux measurements due to the spectroscopic effects from few percent to multiple folds, leading to methodological advancement and geographical expansion of the use of such systems providing reliable and consistent results for process-level studies, remote sensing and Earth modeling applications, and GHG policy decisions.
Impact of the November Eurasian teleconnection on the following January Arctic Oscillation
Authors: Qiao Shaobo
Published: March 2020

Using observations and model simulations, the impact of the November Eurasian (EU) teleconnection on the following January Arctic Oscillation (Arctic Oscillation) and the possible mechanisms are investigated in this study.        We found that the positive (negative) phase of the November EU pattern favors the negative (positive) phase of AO during the subsequent January, and both the stratosphere-troposphere interactionsand the tropospheric Blocking High (BH) activity anomalies over the Euro-Atlantic sector play an important role in their connections. When the EU pattern is positive (negative) phase in November, the increased (decreased) vertical wave activity over Eurasia and North Atlantic gradually weakens (enhances) the Stratospheric polar vortex (SPV)from November to the following early January, which is then conducive to a downward propagation of positive height anomalies from the stratosphere to troposphere. On the other hand, due to the persistent stronger (weaker) and southward (northward) shifted storm tracks over the Euro-Atlantic sector from November to the following early January, the BH activities over this region are significantly decreased (increased) during the same period, whichthen contributesto positive (negative) height anomalies over the Arctic via the propagation of a zonal wave number 1-3. As both the SPVand BHanomalies over the Euro-Atlantic sector reach the maximum around the late December-early January, the resultant equivalent barotropic AO dipole patterndevelops and finally establishes during the following January.These results are useful for the predictability of the middle winter climate
3D Anisotropic velocity model of the Los Humeros geothermal field, Mexico, using seismic ambient noise tomography.
Authors: Granados Chavarria Ivan , Calò Marco , Figueroa Soto Ángel , Jousset Philippe
Published: March 2020

In the framework of the international collaboration between Mexico and Europe for the development of geothermal energy (GEMex consortium), a seismic network of 45 seismic stations (25 broad-band and 20 short-period) was installed around the super-hot geothermal system of Los Humeros (Mexico) for more than one year. Los Humeros power plant is nested inside a quaternary caldera located in the eastern part of the Trans-Mexican Volcanic Belt that crosses the whole country from the Pacific coast to the Gulf of Mexico.

Among the several targets of the data collected by this network, an important task is to produce a seismic image of the caldera and of the geothermal reservoir. Here we present the 3D anisotropic shear wave velocity models retrieved by the seismic ambient noise tomography.

Thanks to the severe pre-processing of the whole seismic database we were able to obtain reliable and highly resolved models.

To carry out the model we applied a rigorous data quality assessment consisting in: 1) correction of the orientation of the sensors using the polarization of surface waves associated with tele-seismic and regional earthquakes, 2) assessment of the synchronization of the stations and correction of the times using daily cross-correlations functions, 3) finally to asses the quality of the stacked cross-correlations, knowed as Green’s functions (GF), we analyzed the noise sources directivity, inter-station distance and level of emergence of surface waves depending on the type of sensor used.

The processing allowed to pick clearly about 600 dispersion curves per velocity type (group and phase of R and L waves), using the NDCP code (Noisy Dispersion Curve Picking), that allows to display and select dispersion patterns both in time and frequency domain, for both causal and anti-causal part of the GF.

2D tomography maps were calculated from 0.5 to 9 s for each type of velocity. Depth inversion for the whole velocities types was carried out using surf96, allowing reconstructing the 3D anisotropic structure of the caldera for the first time.

The resulting models provides a larger view of the caldera and its anisotropic patterns down to 10 km depth. In these models, we were able to define the depth of the caldera rim, some important features of the internal part of the caldera and a low velocity body that could be associated with the hot sources feeding the reservoir. Our model are in strong agreement with those retrieved applying other geophysical methodologies (e.g. magnetotelluric, passive travel-time tomography, gravimetric, etc.).

This work is performed in the framework of the Mexican European consortium GeMex (Cooperation in Geothermal energy research Europe-Mexico, PT5.2 N: 267084 funded by CONACyT-SENER : S0019, 2015-04, and Horizon 2020, grant agreement No. 727550).
Modeling of greenhouse gas emissions from fires in the Brazilian Cerrado
Authors: Cardoso Manoel , Castro Aline , von Randow Celso , Sanches Marcos
Published: March 2020

Vegetation fires have a large impact on greenhouse gas emissions in Brazil. In the Brazilian Cerrado, fires occur as part of the natural dynamics of the leading savanna landscapes, but can have their frequency and extent greatly increased by changes in land cover and use, and climate. In addition to atmospheric composition, fires are also linked to deforestation and land degradation, so modeling tools to estimate their occurrence and effects are of significant interest in analyses of climate forcing and sustainable management of the study region.  In order to contribute to modeling tools that may support quantifying the impacts of vegetation fires and help sustainable management of the Cerrado in Brazil, we are working on improving the Integrated Model of Land-surface Processes (INLAND) to estimate fire emissions based on the model’s calculation of vegetation properties and burned area.  Based on data from remote sensing, we are calibrating INLAND burned area outputs, which in combination to modeled vegetation biomass will provide the basis for the emissions estimates, following the Intergovernmental Panel on Climate Change (IPCC) guidelines for greenhouse gas inventories. Our current estimates present correct timing and spatial patterns at regional scales, which we plan to improve to match information from other studies and databases.
Effects of model resolution on ice shelf-ocean boundary layer
Authors: Malyarenko Alena , Jendersie Stefan , Williams Mike , Robinson Natalie , Langhorne Pat
Published: March 2020

Boundary layer mixing at the ice-ocean thermodynamic interface is represented by turbulent transfer coefficients, ΓT and ΓS. Commonly used expressions for these are based on observations at the sea ice-ocean and ice shelf-ocean boundaries, and result in values ranging over 5 orders of magnitude (10-7< ΓT< 10-2). To demonstrate the potential effect of the choice of turbulent transfer parameterisation we applied all of the available transfer coefficient values (12) to an idealised ice shelf-ocean cavity model experiment using the ISOMIP domain with ROMS. The mean ablation rate in warm cavity scenarios varies between 2.1 and 4.7 m/year, and in cold cavity scenarios between 0.03 and 0.17 m/year.

 ΓT and ΓS not only directly determine the ablation rate, but have effects on fresh water distribution in the ocean boundary layer. High Γ values develop deep mixed layers, while low Γ values stratify the top ocean grid cells. Thus the ocean boundary layer structure directly depends on vertical resolution in the ocean model and how well the mixing scheme can handle the stratification effects. The experiment results we are presenting here include comprehensively tested and quantified effects of tidal forcing, mixing schemes, vertical flux distribution and ocean model resolution on the ablation rates and the ocean boundary layer structure.