bluuebunny/crossref_metadata_2025_split huggingface dataset:
An Examination of Temperature Trends at High Elevations Across the Tibetan Plateau: The Use of MODIS LST to Understand Patterns of Elevation‐Dependent Warming
Authors: Pepin Nick , Deng Haijun , Zhang Hongbo , Zhang Fan , Kang Shichang , Yao Tandong 
Published: May 2019

AbstractResearch has revealed systematic changes in warming rates with elevation (EDW) in mountain regions. However, weather stations on the Tibetan plateau are mostly located at lower elevations (3,000‐4,000 m) and are nonexistent above 5,000 m, leaving critical temperature changes unknown. Satellite LST (Land Surface Temperature) can fill this gap but needs calibrating against in situ air temperatures (Tair). We develop a novel statistical model to convert LST to Tair, developed at 87 high‐elevation Chinese Meteorological Administration stations. Tair (daily maximum/minimum temperatures) is compared with Moderate Resolution Imaging Spectroradiometer (MODIS) Aqua LST (1330 and 0130 local time) for 8‐day composites during 2002‐2017. Typically, 80‐95% of the difference between LST and Tair (ΔT) is explained using predictors including LST diurnal range, morning heating/nighttime cooling rates, the number of cloud free days/nights, and season (solar angle). LST is corrected to more closely represent Tair by subtracting modeled ΔT. We validate the model using an AWS on Zhadang Glacier (5800 m). Trend analysis at the 87 stations (2002‐2017) shows corrected LST trends to be similar to original Tair trends. To examine regional contrasts in EDW patterns, elevation profiles of corrected LST trends are derived for three ranges (Qilian Mountains, NyenchenTanglha, and Himalaya). There is limited EDW in the Qilian mountains. Maximum warming is observed around 4,500‐5,500 m in NyenchenTanglha, consistent with snowline retreat. In common with other studies, there is stabilization of warming at very high elevations in the Himalaya, including absolute cooling above 6,000 m, but data there are compromised by frequent cloud.
Drivers and Surface Signal of Interannual Variability of Boreal Stratospheric Final Warmings
Authors: Thiéblemont R. , Ayarzagüena B. , Matthes K. , Bekki S. , Abalichin J. , Langematz U. 
Published: May 2019

AbstractSpringtime stratospheric final warming (SFW) variability has been suggested to be linked to the tropospheric circulation, particularly over the North Atlantic sector. These findings, however, are based on reanalysis data that cover a rather short period of time (1979 to present). The present work aims to improve the understanding of drivers, trends and surface impact of dynamical variability of boreal SFWs using chemistry‐climate models. We use multidecadal integrations of the fully coupled chemistry‐climate models Community Earth System Model version 1 (Whole Atmosphere Community Climate Model) and ECHAM/Modular Earth Submodel System Atmospheric Chemistry‐O. Four sensitivity experiments are analyzed to assess the impact of external factors; namely, the quasi‐biennial oscillation, sea surface temperature (SST) variability, and anthropogenic emissions. SFWs are classified into two types with respect to their vertical development; that is, events which occur first in the midstratosphere (10‐hPa first SFWs) or first in the upper stratosphere (1‐hPa first SFWs). Our results confirm previous reanalysis results regarding the differences in the time evolution of stratospheric conditions and near‐surface circulation between 10 and 1‐hPa first SFWs. Additionally, a tripolar SST pattern is, for the first time, identified over the North Atlantic in spring months related to the SFW variability. Our analysis of the influence of remote modulators on SFWs revealed that the occurrence of major warmings in the previous winter favors the occurrence of 10‐hPa first SFWs later on. We further found that quasi‐biennial oscillation and SST variability significantly affect the ratio between 1‐hPa first and 10‐hPa first SFWs. Finally, our results suggest that ozone recovery may impact the timing of the occurrence of 1‐hPa first SFWs.
Response of the Northern Stratosphere to the Madden‐Julian Oscillation During Boreal Winter
Authors: Yang Chengyun , Li Tao , Xue Xianghui , Gu Sheng‐yang , Yu Chao , Dou Xiankang 
Published: May 2019

AbstractIn this study, the effects of the Madden‐Julian oscillation (MJO) on the northern stratosphere during boreal winter are investigated, especially in cases with the absence of a stratospheric sudden warming (SSW) event. During the wintertime, the polar cap temperature is expected to increase following MJO phase 2 (P2), P3, P4, and P7. However, the responses after P2 and P3 are much weaker if the dates from 50 days before to 50 days after the SSW central days are excluded from the composite. This result implies that the stratospheric polar warming following MJO P2 and P3 is sensitive to the occurrence of SSWs. After excluding the SSW events from the composite, the subsequent temperature anomalies strengthen and become more significant approximately 30 days after MJO P4 and 10 days after MJO P7. Planetary wave (PW) anomalies are enhanced in the midlatitudes of the upper troposphere, lagging MJO P4 by 15–25 days and lagging MJO P7 by 5–15 days. Thus, the upward propagation and dissipation of PWs in the stratosphere are significantly enhanced, further strengthening the Brewer‐Dobson circulation in the Northern Hemisphere stratosphere. The WN1, which is induced by the MJO in the stratosphere, is the dominant component of PW perturbation. The enhanced PW dissipation in the high latitudes of the stratosphere is weaker in terms of lagging MJO P4, so the zonal wind and temperature anomalies after MJO P4 are less significant in the polar region, especially in the lower stratosphere.
Ensemble Spatial Precipitation Analysis From Rain Gauge Data: Methodology and Application in the European Alps
Authors: Frei Christoph , Isotta Francesco A. 
Published: May 2019

AbstractThe deterministic nature of conventional precipitation data sets complicates their utility in applications. The underlying estimation principle (minimizing errors) involves biases in extremes, and conventional uncertainty quantification (cross‐validation) is impractical. We present a method to derive spatial analyses of daily precipitation, probabilistically, as an ensemble, conditional on the available rain gauge data. The method builds on and extends previous techniques using conditional simulation with Gaussian Random Fields. The extension involves trans‐Gaussian and piecewise covariance modeling to let the ensemble respond to regional precipitation conditions, Bayesian inference to account for parameter uncertainty, and simulation on a primary grid to ensure the ensemble has a well‐defined areal support. While addressing prevalent issues of existing techniques, our method involves a compromise in global consistency that limits the utility of the ensemble over large domains. We apply the method to derive ensembles of area‐mean precipitation for hydrological area units in the Alps. The ensembles are demonstrated to plausibly capture variations in uncertainty with rainfall condition, rain gauge density, and averaging area. Evaluations suggest that the probabilistic estimates are internally consistent and of good statistical reliability. There is a tendency to underestimate uncertainty for light precipitation. Results point to remarkable uncertainties, even with the dense gauge networks in the Alps: For means over 500‐km2 areas we find the ensemble spread to be typically a factor of 2–4 (factor of 1.5) for intense convective (stratiform) events. This also implies nonnegligible uncertainty in climate indices. Probabilistic representation of interpolation uncertainty in spatial data sets allows users to track them into applications.
Regional Snow Parameters Estimation for Large‐Domain Hydrological Applications in the Western United States
Authors: Sun Ning , Yan Hongxiang , Wigmosta Mark S. , Leung L. Ruby , Skaggs Richard , Hou Zhangshuan 
Published: May 2019

AbstractIn snow‐dominated regions, a key source of uncertainty in hydrologic prediction and forecasting is the magnitude and distribution of snow water equivalent (SWE). With ensemble simulations, this work demonstrates that SWE variability across the mountain ranges of the western United States (represented by 246 Snow Telemetry stations) can largely be captured at the daily time scale by a simple mass and energy‐balance snow model with four physically reasonable parameters—three snow albedo parameters and one snow temperature threshold for precipitation partitioning. The model skill is lower in the maritime Pacific Northwest where SWE variability is more sensitive to errors associated with simulated energy balance (e.g., downward radiation fluxes) and the temperature‐only precipitation partitioning approach. Poor model skill in high‐altitude, windy locations in the Northern Rockies can be attributed to precipitation undercatch and underrepresented wind processes. For the purpose of large‐domain hydrologic applications, regional snow parameters were developed for eight ecoregions characterized by a distinct hydroclimatic regime across the western United States. Results suggest that regionally coherent snow parameterizations are able to capture daily variations in SWE at most Snow Telemetry stations, suggesting that areas with a similar hydroclimate share a similar snow regime. While the three albedo parameters show limited spatial variability across all regions, the regional snow temperature threshold (Ts) shows marked spatial variation correlated with relative humidity; the Ts values increase from 0.2 °C in the higher‐humidity Pacific Northwest to 4.0 °C in the colder, lower‐humidity Rocky Mountains.
Retrieval of Snow Water Equivalent, Liquid Water Content, and Snow Height of Dry and Wet Snow by Combining GPS Signal Attenuation and Time Delay
Authors: Koch Franziska , Henkel Patrick , Appel Florian , Schmid Lino , Bach Heike , Lamm Markus , Prasch Monika , Schweizer Jürg , Mauser Wolfram 
Published: May 2019

AbstractFor numerous hydrological applications, information on snow water equivalent (SWE) and snow liquid water content (LWC) are fundamental. In situ data are much needed for the validation of model and remote sensing products; however, they are often scarce, invasive, expensive, or labor‐intense. We developed a novel nondestructive approach based on Global Positioning System (GPS) signals to derive SWE, snow height (HS), and LWC simultaneously using one sensor setup only. We installed two low‐cost GPS sensors at the high‐alpine site Weissfluhjoch (Switzerland) and processed data for three entire winter seasons between October 2015 and July 2018. One antenna was mounted on a pole, being permanently snow‐free; the other one was placed on the ground and hence seasonally covered by snow. While SWE can be derived by exploiting GPS carrier phases for dry‐snow conditions, the GPS signals are increasingly delayed and attenuated under wet snow. Therefore, we combined carrier phase and signal strength information, dielectric models, and simple snow densification approaches to jointly derive SWE, HS, and LWC. The agreement with the validation measurements was very good, even for large values of SWE (>1,000 mm) and HS (> 3 m). Regarding SWE, the agreement (root‐mean‐square error (RMSE); coefficient of determination (R2)) for dry snow (41 mm; 0.99) was very high and slightly better than for wet snow (73 mm; 0.93). Regarding HS, the agreement was even better and almost equally good for dry (0.13 m; 0.98) and wet snow (0.14 m; 0.95). The approach presented is suited to establish sensor networks that may improve the spatial and temporal resolution of snow data in remote areas.
Large Earthquake Reshapes the Groundwater Flow System: Insight From the Water‐Level Response to Earth Tides and Atmospheric Pressure in a Deep Well
Authors: Zhang H. , Shi Z. , Wang G. , Sun X. , Yan R. , Liu C. 
Published: May 2019

AbstractQuantitative evaluation of earthquake‐induced permeability changes is important for understanding key geological processes, such as advective transport of heat and solute and the generation of elevated fluid pressure. Many studies have independently documented permeability changes in either an aquifer or an aquitard, but the effects of an earthquake on both the aquifer and aquitard of the same aquifer system are still poorly understood. In this study, we use the well water‐level response to earth tides and atmospheric pressure to study the changes in hydraulic properties in an aquifer and an overlying confining layer in Beijing, China, following the 11 March 2011 Tohoku earthquake in Japan. Our results show that both the tidal response amplitude and the phase shift increased and that the phase shift changed from negative to positive after the earthquake. We identified increased permeability in both the aquifer and aquitard by the barometric response function method. The horizontal transmissivity of the aquifer increased by a factor of 6, and the vertical diffusivity of the aquitard doubled.
RENU2 UV PMT Observations of the Cusp
Authors: Fritz Bruce A. , Lessard Marc R. , Dymond Kenneth F. , Kenward David R. , Lynch Kristina A. , Hecht James H. , Clemmons James H. , Cook Timothy , Chakrabarti Supriya , Solomon Stanley C. 
Published: May 2019

AbstractThe Rocket Experiment for Neutral Upwelling 2 (RENU2) sounding rocket launched from the Andøya Space Center on 13 December 2015 into the dayside polar cusp. An ultraviolet photomultiplier tube (UV PMT) on the RENU2 payload was oriented to look up along the spin axis for emissions of neutral atomic oxygen above the payload. Data from the UV PMT have been compared to predicted auroral emissions calculated by the Global Airglow (GLOW) model. The comparison between GLOW calculations driven by RENU2 electron precipitation measurements and UV PMT data suggest enhanced neutral density in the cusp at altitudes above the RENU2 trajectory.
Dynamical Seasonal Prediction of Tropical Cyclone Activity: Robust Assessment of Prediction Skill and Predictability
Authors: Zhang Gan , Murakami Hiroyuki , Gudgel Rich , Yang Xiaosong 
Published: May 2019

AbstractImproving the seasonal prediction of tropical cyclone (TC) activity demands a robust analysis of the prediction skill and the inherent predictability of TC activity. Using the resampling technique, this study analyzes a state‐of‐the‐art prediction system and offers a robust assessment of when and where the seasonal prediction of TC activity is skillful. We found that uncertainties of initial conditions affect the predictions and the skill evaluation significantly. The sensitivity of predictions to initial conditions also suggests that landfall and high‐latitude activity are inherently harder to predict. The lower predictability is consistent with the relatively low prediction skill in these regions. Additionally, the lower predictability is largely related to the atmospheric environment rather than the sea surface temperature, at least for the predictions initialized shortly before the hurricane season. These findings suggest the potential for improving the seasonal TC prediction and will help the development of the next‐generation prediction systems.
Phenology Dynamics of Dryland Ecosystems Along the North Australian Tropical Transect Revealed by Satellite Solar‐Induced Chlorophyll Fluorescence
Authors: Wang Cong , Beringer Jason , Hutley Lindsay B. , Cleverly James , Li Jing , Liu Qinhuo , Sun Ying 
Published: May 2019

AbstractAccurate phenological characterization of dryland ecosystems has remained a challenge due to the complex composition of plant functional types, each having distinct phenological dynamics, sensitivity to climate, and disturbance. Solar‐Induced chlorophyll Fluorescence (SIF), a proxy for photosynthesis, offers potential to alleviate such challenge. We here explore this potential using dryland systems along the North Australian Tropical Transect with SIF derived from Orbiting Carbon Observatory‐2. SIF identified the seasonal onset and senescence of Gross Primary Production at eddy covariance sites with improved accuracy over Enhanced Vegetation Index and Near‐Infrared Reflectance of terrestrial Vegetation from Moderate Resolution Imaging Spectroradiometer, especially at inland xeric shrublands. At regional scale, SIF depicted both earlier onset and senescence across North Australian Tropical Transect. We hypothesized that SIF outperformed Enhanced Vegetation Index and Near‐Infrared Reflectance of terrestrial Vegetation mainly because, unlike reflectance, it is not contaminated by background soil, and its total signal is contributed by mixed plant species in additive way.
Dissolved Organic Radiocarbon in the Central Pacific Ocean
Authors: Druffel Ellen R. M. , Griffin Sheila , Wang Ning , Garcia Noreen G. , McNichol Ann P. , Key Robert M. , Walker Brett D. 
Published: May 2019

AbstractWe report marine dissolved organic carbon (DOC) concentrations, and DOC ∆14C and δ13C values in seawater collected from the central Pacific. Surface ∆14C values are low in equatorial and polar regions where upwelling occurs and high in subtropical regions dominated by downwelling. A core feature of these data is that 14C aging of DOC (682 ± 86 14C years) and dissolved inorganic carbon (643 ± 40 14C years) in Antarctic Bottom Water between 54.0°S and 53.5°N are similar. These estimates of aging are minimum values due to mixing with deep waters. We also observe minimum ∆14C values (−550‰ to −570‰) between the depths of 2,000 and 3,500 m in the North Pacific, though the source of the low values cannot be determined at this time.
Estimation of Metal Emissions From Tropical Peatland Burning in Indonesia by Controlled Laboratory Experiments
Authors: Das Reshmi , Wang Xianfeng , Itoh Masayuki , Shiodera Satomi , Kuwata Mikinori 
Published: May 2019

AbstractThe tropical peatland burning in Indonesia is one of the most significant types of wildfires on a global scale. Previous studies indicated the importance of metal emissions from Indonesian wildfires. However, metal emission profiles from Indonesian wildfires have not been quantified well yet. To address this issue, we analyzed metals and metalloids emitted from combustion experiments of peat and vegetation growing over peatland in Indonesia. The analyzed elements include Mg, Al, Ca, V, Cr, Fe, Co, Ni, Cu, Zn, Se, Sn, and Pb. The emission ratios of aerosol particles emitted from combustion of the ombrotrophic peat and vegetation agreed within a factor of few, regardless of the variability in the elemental compositions of the original fuel. In both cases, the emission ratios of Ca were the highest, followed by crustal elements Fe and Al. The concentration ratios of crustal and biogenic elements (Fe/Al and Zn/Fe) were found to be a useful metric to infer dominant fuel types. Namely, the concentration ratio of Fe/Al was high (6.2 ± 4.4) for peat combustion particles, while the value was lower (1.9 ± 1.3) when plant burning was conducted. The emission ratios of the metals were combined with an existing emission inventory to estimate the emission rates of the analyzed metals. The emission rates of carcinogenic metals, such as Cr and Ni, were estimated to be 0.02 and 0.013 Gg/year, respectively. The analysis also indicated that the peatland burning could be one of the important sources of atmospheric Fe in the region.
Atmospheric Photolysis of Methyl Ethyl, Diethyl, and Propyl Ethyl Ketones: Temperature‐Dependent UV Absorption Cross Sections
Authors: Brewer Jared F. , Papanastasiou Dimitrios K. , Burkholder James B. , Fischer Emily V. , Ren Yangang , Mellouki Abdelwahid , Ravishankara A. R. 
Published: May 2019

AbstractKetone photolysis is a potentially important source of HOx radicals in the upper troposphere. To represent this photolysis, models need to include actinic flux, quantum yield, and absorption cross sections over a range of atmospherically relevant conditions. This work seeks to improve the representation of ketone ultraviolet (UV) absorption by quantifying it as a function of temperature. We present observations of 1‐nm resolution absorption cross sections from 200 to 335 nm of methyl ethyl ketone (MEK) and diethyl ketone (DEK) at temperatures between 242 and 320 K, as well as propyl ethyl ketone (PEK) cross sections at 296 K. Our measured room temperature absorption cross sections agree to within 2%, 2%, and 5% with previous studies for MEK, DEK, and PEK spectra, respectively. We parameterize the temperature dependence of the cross sections of MEK and DEK using a two‐state model, which reproduces our experimental results well. With additional assumptions, this model can be applied to the temperature dependence of PEK in the absence of experimental data. This model is appropriate for atmospherically relevant temperatures both inside and outside the temperatures used in this study and is suitable for incorporation into model atmospheric photolysis schemes. R programs to facilitate usage of these data are included in the supporting information. Inclusion of temperature‐dependent absorption cross sections in atmospheric photolysis calculations decreased the rate coefficients of MEK, DEK, and PEK photolysis in the upper troposphere when compared to those calculated using only the room temperature cross sections; the decrease can be as large as 20–25%.
An archaeal symbiont-host association from the deep terrestrial subsurface
Authors: Schwank Katrin , Bornemann Till L V , Dombrowski Nina , Spang Anja , Banfield Jillian F , Probst Alexander J 
Published: May 2019

Abstract
DPANN archaea have reduced metabolic capacities and are diverse and abundant in deep aquifer ecosystems, yet little is known about their interactions with other microorganisms that reside there. Here, we provide evidence for an archaeal host-symbiont association from a deep aquifer system at the Colorado Plateau (Utah, USA). The symbiont, Candidatus Huberiarchaeum crystalense, and its host, Ca. Altiarchaeum hamiconexum, show a highly significant co-occurrence pattern over 65 metagenome samples collected over six years. The physical association of the two organisms was confirmed with genome-informed fluorescence in situ hybridization depicting small cocci of Ca. H. crystalense attached to Ca. A. hamiconexum cells. Based on genomic information, Ca. H. crystalense potentially scavenges vitamins, sugars, nucleotides, and reduced redox-equivalents from its host and thus has a similar metabolism as Nanoarchaeum equitans. These results provide insight into host-symbiont interactions among members of two uncultivated archaeal phyla that thrive in a deep subsurface aquifer.
Checkpoint blockade and nanosonosensitizer-augmented noninvasive sonodynamic therapy combination reduces tumour growth and metastases in mice
Authors: Yue Wenwen , Chen Liang , Yu Luodan , Zhou Bangguo , Yin Haohao , Ren Weiwei , Liu Chang , Guo Lehang , Zhang Yifeng , Sun Liping , Zhang Kun , Xu Huixiong , Chen Yu 
Published: May 2019

AbstractCombined checkpoint blockade (e.g., PD1/PD-L1) with traditional clinical therapies can be hampered by side effects and low tumour-therapeutic outcome, hindering broad clinical translation. Here we report a combined tumour-therapeutic modality based on integrating nanosonosensitizers-augmented noninvasive sonodynamic therapy (SDT) with checkpoint-blockade immunotherapy. All components of the nanosonosensitizers (HMME/R837@Lip) are clinically approved, wherein liposomes act as carriers to co-encapsulate sonosensitizers (hematoporphyrin monomethyl ether (HMME)) and immune adjuvant (imiquimod (R837)). Using multiple tumour models, we demonstrate that combining nanosonosensitizers-augmented SDT with anti-PD-L1 induces an anti-tumour response, which not only arrests primary tumour progression, but also prevents lung metastasis. Furthermore, the combined treatment strategy offers a long-term immunological memory function, which can protect against tumour rechallenge after elimination of the initial tumours. Therefore, this work represents a proof-of-concept combinatorial tumour therapeutics based on noninvasive tumours-therapeutic modality with immunotherapy.