Miracle-dz/UniFAR-FTUs huggingface dataset:
Application of active optical sensors to probe the vertical structure of the urban boundary layer and assess anomalies in air quality model PM2.5forecasts

In this paper, the simulations of the Weather Research and Forecast (WRF) and Community Multiscale Air Quality (CMAQ) Models applied to the New York City (NYC) area are assessed with the aid of vertical profiling and column integrated remote sensing measurements. First, we find that when turbulent mixing processes are dominant, the WRFderived planetary boundary layer (PBL) height exhibits a strong linear correlation (R>0.85) with lidar-derived PBL height. In these comparisons, we estimate the PBL height from the lidar measurements using a Wavelet Covariance Transform (WCT) approach that is modified to better isolate the convective layer from the residual layer (RL). Furthermore, the WRF-Lidar PBL height comparisons are made using different PBL parameterization schemes, including the Asymmetric Convective Model-version2 (ACM2) and the Modified Blackadar (BLK) scheme (which are both runs using hindcast data), as well as the Mellor-Yamada-Janjic (MYJ) scheme run in forecast mode. Our findings show that the correlations for these runs are high (>0.8), but the hindcast runs exhibit smaller overall dispersion (≈0.1) than the forecast runs. We also apply continuous 24-hour/7-day vertical ceilometer measurements to assess WRFCMAQ model forecasts of surface PM2.5 (particulate matter has aerodynamic diameter <2.5μm). Strong overestimations in the surface PM2.5 mass that are observed in the summer prior to sunrise are particularly shown to be strongly connected to underestimations of the PBL height and less to enhanced emissions. This interpretation is consistent with observations that TEOM (Tapered Element Oscillating MicroBalance) PM2.5 measurements are better correlated to pathintegrated CMAQ PM2.5 than the near-surface measurements during these periods.
The Pacific zonal asymmetry and its influence on Southern Hemisphere sea ice variability

Abstract At monthly and annual timescales, the zonally asymmetric circulation over the Southern Ocean is dominated by two quasi-stationary anticyclones: a western anticyclone approximately located south of New Zealand, and an eastern anticyclone located over the Drake Passage region. In this research their influence on late 20th century Antarctic sea ice is explored. During early winter, sea ice in the Weddell, Amundsen and Bellingshausen seas is influenced by the location of the east anticyclone. During late winter, the strength and location of the west anticyclone influences sea ice primarily in the Ross and Amundsen seas. The anticyclones have some effect on wind-driven sea ice motion, but the primary mechanism explaining their link to sea ice appears to be meridional atmospheric thermal advection. A western shift in the west anticyclone may be partly responsible for observed increases in ice cover in the Ross Sea over the late 20th century, but there is little evidence in existing data to support a link between the east anticyclone and observed sea ice trends.
Heat Transport by Mesoscale Eddies in an Ocean Circulation Model

Abstract The role of mesoscale eddies in the poleward heat transport in the ocean is investigated; in particular, the compensation of poleward eddy heat transport by an eddy-induced mean meridional circulation is examined. A multilayer isopycnic primitive equation model of an idealized western North Atlantic is presented to test whether compensation also occurs within an isopycnic model and when the poleward eddy heat transport becomes comparable to the mean transport. Also, in this model configuration compensation of the poleward eddy heat transport arises. It is brought about by a westward eddy heat transport in the midlatitude jet, which results in a pressure drop across the basin and consequently in a modified mean meridional overturning. This compensation is discussed within the framework of wave–mean flow interaction. It is demonstrated that compensation results from eddy–mean flow interaction when the diabatic forcing is sufficiently weak; rings are recaptured before their SST anomaly is modified s.
Influence of convective processes on the isotopic composition (δ18O and δD) of precipitation and water vapor in the tropics: 1. Radiative‐convective equilibrium and Tropical Ocean–Global Atmosphere–Coupled Ocean‐Atmosphere Response Experiment (TOGA‐COARE) simulations

[1] Cumulus convection constitutes a key process in the control of tropical precipitation and the vertical transport of atmospheric water. To better understand the influence of convective processes on the isotopic composition of precipitation and water vapor, water stable isotopes (H218O and HDO) are introduced into a single column model including the Emanuel convective parameterization. This paper analyzes unidimensional simulations of the tropical atmosphere in a state of radiative-convective equilibrium, and simulations forced by data from the Tropical Ocean–Global Atmosphere–Coupled Ocean-Atmosphere Response Experiment (TOGA-COARE). This study shows that deep convective atmospheres are associated with robust isotopic features such as an isotopic composition of the air below the tropical tropopause layer (around 12–13 km) close to the typical values observed in the lower tropical stratosphere, and an isotopic enrichment of the upper tropospheric water that starts well below the tropopause. It highlights the critical role of condensate lofting and convective detrainment in these features, and the role of convective unsaturated downdrafts in the control of the isotopic composition of precipitation. Finally, it shows that the so-called “amount effect” primarily reveals the influence of large-scale atmospheric circulation changes on the isotopic composition of the precipitation, and that temperature changes not associated with circulation changes lead to an “anti–amount effect”. The detailed analysis of the physical processes underlying the “amount effect” is presented in a companion paper.
Geodetic observations of an earthquake cycle at the Sumatra subduction zone: Role of interseismic strain segmentation

[1] We use survey mode and continuous GPS data from 1991 to 2007 to examine fault segmentation in the earthquake cycle at the Sumatra megathrust, site of the 26 December 2004 Mw 9.1 Sumatra-Andaman, the 28 March 2005 Mw 8.7 Nias-Simeulue, and the 12 September 2007 Mw 8.4 Mentawai earthquakes. These data, including new observations from 2006 and 2007, allow us to observe the final few years of one earthquake cycle and the beginning of the next. Our analysis reveals that the megathrust is segmented, a characteristic that may persist through multiple earthquake cycles. The Nias-Simeulue earthquake ruptured approximately the same region that broke in 1861, a 300 km long segment abutting the Sumatra-Andaman rupture zone. Farther southeast, the Mentawai segment of the megathrust (0.5°S–5°S), which produced M > 8 earthquakes in 1797 and 1833, is fully locked in the interseismic period but is flanked by two freely slipping regions, the Batu Islands in the NW and Enggano in the SE. The 12 September 2007 Mentawai earthquake sequence ruptured only the southern one third of the 1833 rupture zone. We model postseismic deformation from the Sumatra-Andaman and Nias-Simeulue earthquakes and find that afterslip was concentrated updip and downdip, respectively, from the main shocks. Comparing the velocity fields before and after 2001, we find the subduction zone underneath the Batu Islands and Enggano, which, prior to the earthquakes, was partially to fully coupled, appears now to be slipping freely. Thus, while the segmentation of the subduction zone is preserved, interseismic coupling on the subduction fault may vary with time.
QoS enabled routing in mobile ad hoc networks

The aim of this work is to present a QoS enabled routing protocol in ad hoc networks and compare it with a normal routing protocol. Results demonstrate how a QoS enable routing mechanism makes the resource consumption more efficient by minimising the unnecessary signalling and stopping the sessions that cannot meet the demanded QoS requirement. The performance of both routing and QoS routing protocols are evaluated in the presence of information achieved from the link layer. The QoS enabled routing protocol shows a significant improvement in the protocol performance metrics applied in our measurements, such as packet delay and protocol overhead. The results achieved from this experiment lead us to analyse our proposed mechanism to add link layer information in control routing messages. Measuring wireless resources, such as bandwidth, with the help of periodic signalling packets makes both the routing and the QoS routing protocols react slower to wireless link changes. This problem can be overcome by more frequent advertisements.
Effects of fertiliser N and slurry on nitrate leaching – lysimeter studies on 5 soils

The results of a two-year lysimeter investigation into the effects of fertiliser nitrogen (N) combined with pig or cattle slurry applied in winter or early spring on nitrate (NO3-N) leaching are presented. Soil type, fertiliser N and a combination of fertiliser plus slurry N affected concentrations of NO3-N in the drainage water. Peak concentrations were recorded usually in the December-February period. In the drainage water the maximum admissible concentration (MAC) of NO33-N for drinking water was breached to the greatest degree by pig slurry (Year 2) applied in November (117 kg per hectare) combined with fertiliser N (300 kg per hectare).
Effect of the Missing Indonesian Throughflow in the Fine Resolution Antarctic Model

Abstract South of Tasmania, the Fine Resolution Antarctic Model (FRAM) shows a narrow band of westward flow in the surface layer. The authors argue that this is caused by the closure of the Indonesian passage in FRAM. This is supported by numerical experiments carried out by Hirst and Godfrey and by recent radiocarbon observations in the Great Australian Bight (Ribbe et al.). The FRAM surface temperature and salinity distribution exhibits distinct anomalies in the southeast Indian Ocean, in good agreement with anomalies observed in the Hirst and Godfrey model. Indonesian Throughflow water advects heat into the Indian Ocean; its absence in FRAM results in a lack of thermal energy to warm the Indian Ocean in the model. The surface salinity anomaly is most likely caused by an overestimated Ekman transport. The weakened heat and salinity transport in FRAM restricts surface convection in the midlatitude region to approximately 350 m. The effect of the Indonesian Throughflow closure in FRAM is even more dramati.
Plant nutrient status of soils of the Lusikisiki area, Eastern Cape Province

The aim of the paper is to Identify major soil plant fertility constraints for 15 soil profiles from the Lusikisiki area of the Eastern Cape Province of South Africa. Phosphorus levels were very low, with 87% of the A horizons having a Bray-1 extractable P content of < 3 mg kg−1. Most soils (80%) will require K fertilization for adequate crop yields. The Ca status is adequate in 73% of the A horizons, albeit at the lower end of the recommended scale. Extractable Mg contents were adequate in most soils, an unexpected finding for this highly leached environment. The exchangeable Ca: Mg ratio is low and only four profiles have values of > 2 in the A horizons. The lowest ratio was 0.25. The organic carbon content is high for South African conditions, averaging 3.63% in the A horizons. The Sum of base cations as well as the CEC are more closely related to soil organic matter than to exchange sites of the clay minerals and an average of 70% of the CEC in the A horizons is associated with organic carbon. The decomposition of small amounts of organic matter will therefore lead to a significant reduction in the CEC.
Investigation of multifrequency/multipolarization radar signatures of rain cells over the ocean using SIR‐C/X‐SAR data

Radar signatures of rain cells are investigated using multifrequency/multipolarization synthetic aperture radar (SAR) images acquired from the space shuttle Endeavour during the spaceborne imaging radar-C/X-band SAR (SIR-C/X-SAR) missions in April and October 1994. In SIR-C/X-SAR images, radar signatures of rain cells over the ocean usually consist of irregularly shaped bright and dark patches that strongly depend on radar frequency and polarization. The radar signatures of rain cells observed in SIR-C/X-SAR imagery of the ocean originate from (1) the scattering and attenuation of the microwaves by raindrops and ice particles in the atmosphere and (2) the modification of the sea surface roughness induced by the impact of raindrops and by wind gusts associated with rain cells. Raindrops impinging on the sea surface generate ring waves, which enhance the sea surface roughness, but they also generate turbulence in the upper water layer, which reduces the sea surface roughness. Depending on the radar wavelength, ocean areas struck by rain can have higher or lower normalized radar cross section (NRCS) than the surrounding rain-free area; in ocean areas where heavy rain is impinging on the sea surface, the X- and C-band NRCS is usually enhanced, and the L-band NRCS is reduced. From the phase difference between the horizontally and vertically copolarized signals, estimates of the rain rate are obtained. The present analysis shows further that the presently used wind speed retrieval algorithms for the scatterometers aboard the ERS and ADEOS satellites may yield biased wind fields if several rain cells lie within a scatterometer resolution cell.
Moist Static Energy Budget of MJO-like Disturbances in the Atmosphere of a Zonally Symmetric Aquaplanet

AbstractA Madden–Julian oscillation (MJO)-like spectral feature is observed in the time–space spectra of precipitation and column-integrated moist static energy (MSE) for a zonally symmetric aquaplanet simulated with Superparameterized Community Atmospheric Model (SPCAM). This disturbance possesses the basic structural and propagation features of the observed MJO.To explore the processes involved in propagation and maintenance of this disturbance, this study analyzes the MSE budget of the disturbance. The authors observe that the disturbances propagate both eastward and poleward. The column-integrated longwave heating is the only significant source of column-integrated MSE acting to maintain the MJO-like anomaly balanced against the combination of column-integrated horizontal and vertical advection of MSE and latent heat flux. Eastward propagation of the MJO-like disturbance is associated with MSE generated by both column integrated horizontal and vertical advection of MSE, with the column longwave heatin.
PORPHYRY COPPER-GOLD MINERALIZATION AT YULONG, CHINA, PROMOTED BY DECREASING REDOX POTENTIAL DURING MAGNETITE ALTERATION

The Yulong porphyry Cu (Au) deposit occurs on the eastern margin of the Tibetan plateau and is one of the largest porphyry Cu (Au) deposits in China, containing more than 6 million tons of Cu metal. Similar to other porphyry Cu deposits in the world, the Yulong porphyry is highly oxidized. Sulfate is the dominant sulfur species in fluid inclusions hosted by magmatic quartz phenocrysts, and no sulfide is observed, indicating an oxygen fugacity above the SSO buffer during magmatic processes. The sulfur species changed from sulfate dominant during magmatic processes to sulfide dominant during the main mineralization processes, with sulfate and sulfide mineral assemblages observed in fluid inclusions in mineralized quartz veinlets and only sulfides in the orebodies, corresponding to a decrease in redox potential from the porphyry to the hydrothermal fluid. Magnetite crystallization was coincident with the onset of major sulfate reduction, indicating that magnetite isolated trivalent iron, reducing sulfate, and consequently leading to the formation of porphyry Cu-Au mineralization. Most porphyry Cu-Au ore deposits are spatially associated with, and genetically related to, oxidized felsic magmas. Our results indicate that sulfate reduction promoted by magnetite crystallization is essential for the final precipitation of Cu-Au–bearing sulfides, i.e., decreasing redox potential of the fluid is the key to, and direct cause of, ore formation in Yulong. Initial high redox potential is a prerequisite for and may be an indirect indicator of most mineralization of this kind, because it enables efficient transportation of Cu-Au. Redox potential fluctuations can be well preserved in zircon, a resistant accessory mineral commonly found in porphyries, which might be developed as a handy and reliable exploration tool for porphyry Cu deposits associated with magnetite.
Isotopic stratigraphy suggests Neoproterozoic ages and Laurentian ancestry for high-grade marbles from the North-Central Norwegian Caledonides

Carbon and strontium isotope stratigraphy has been applied to constrain the depositional ages of high-grade marble sequences in the Ofoten district of the North-Central Norwegian Caledonides. Two marble formations hosted by diverse schists from the Bogen Group, all previously correlated over long distances with a Late Ordovician–Early Silurian, low-grade, fossiliferous succession, have been studied for carbon, oxygen and strontium isotopes. The least altered 87Sr/86Sr ratios ranging between 0.7062 and 0.7068, and the best preserved δ13C values falling between +5.0 and +6.5‰ obtained from two marble formations, are consistent with a seawater composition in the time interval 700–600 Ma. The results obtained do not support the previously proposed correlation of the Bogen Group with an Ordovician–Silurian lithostratigraphic succession further north. The apparent depositional ages suggest that the tectonostratigraphic succession studied is inverted and that the tectonostratigraphy of the region requires revision. The Neoproterozoic depositional ages combined with the palaeogeographic position of Baltica imply that carbonates were initially accumulated in seas on a continental shelf, probably Laurentia, and were tectonically transported onto Baltica during Early Silurian, Scandian collision, at c. 425 Ma. Prospecting for new dolomite marble deposits of the Hekkelstrand type and carbonate-hosted manganese–iron ores should be restricted to 700–600 Ma sequences in the Uppermost Allochthon of the Norwegian Caledonides.
Sedimentary Infillings of Fossils and Cavities in Limestone at Treak Cliff, Derbyshire

ABSTRACT Observations of partial and complete sedimentary infillings of fossils and rock cavities at two localities on Treak Cliff, Castleton, Derbyshire, lead to the conclusion that at these localities the present dip of the limestones is largely or entirely depositional in origin. This conclusion agrees, more or less, with claims made in previous publications but, so far as the authors are aware, this is the first time that direct evidence of high initial dips at Treak Cliff has been recorded.
Geology, mineralogy, and chemistry of sediment-hosted clastic massive sulfides in shallow cores, Middle Valley, northern Juan de Fuca Ridge

Middle Valley is a sediment-covered rift near the northern end of Juan de Fuca Ridge. Hydrothermal fluids are presently being discharged at two vent fields about 3 km apart, Bent Hill and the area of active venting. The hydrothermally active chimneys at both Bent Hill and the area of active venting consist of anhydrite and Mg-rich silicates with minor pyrite, Cu-Fe sulfide, sphalerite, and galena. Hydrothermal discharge in these areas appears to be focused along extensional faults. At the Bent Hill massive sulfide deposit, clastic sulfide layers are interbedded with hydrothermally altered and unaltered hemipelagic and turbiditic sediment along the flanks of the sulfide mound. Sulfide textures and mineralogy suggest that the Bent Hill sulfide mound formed by the build-up and collapse of sulfide chimneys, the resedimentation of sulfide debris and the formation of clastic sulfide layers, and the infilling and replacement of clastic sulfides by hydrothermal fluids near vents. Sulfur isotope values that are consistently more positive than basaltic sulfur support the addition of seawater sulfur. Pb isotope values for the Bent Hill deposit that are transitional between midocean ridge basalt (MORB) and Middle Valley sediments indicate that the sulfides probably formed from fluids which originated in the oceanicmore » crust but which have been modified by reaction with lower temperature (<274 C) fluids generated in the sedimentary pile, similar to those now venting in Middle Valley. « less
Nonmigrating diurnal tides in the thermosphere

[1] Horizontal wind measurements from the HRDI and WINDII instruments on the Upper Atmosphere Research Satellite are analyzed to reveal the most prominent nonmigrating diurnal tidal components at 95 km: the eastward propagating diurnal tide with zonal wave number s = 3 (DE3), the standing (s = 0) diurnal oscillation (D0), and the westward propagating diurnal tide with s = 2 (DW2). The strongest DE3 occurs primarily during Northern Hemisphere summer/fall with maximum eastward winds near the equator of order 15 ms−1 and is a vertical extension of the s = 3 Kelvin wave. The first antisymmetric mode of DE3 dominates during October–April, with maximum meridional winds near the equator of order 8 ms−1. D0 exists during nearly all months and is nonsymmetric about the equator with maximum northward wind amplitudes in the Southern Hemisphere of order 7–10 ms−1. DW2 closely resembles the first symmetric propagating mode from classical tidal theory, with maximum northward wind amplitudes of order 10–12 ms−1 during September through February. The combination of DE3, D0, and DW2 with DW1 gives rise to significant longitude variations in the diurnal tide between ±40° latitude. Forcing in the Global Scale Wave Model (GSWM) is calibrated according to the above observations, thus enabling global estimates of nonmigrating tidal temperatures and other fields. For instance, it is estimated that the temperature and eastward wind perturbations associated with DE3 may be as large as 20K and 35 ms−1 at 145 km and 115 km, respectively, over the equatorial region during July.
Improving burning efficiency estimates through satellite assessment of fuel moisture content

[1] The assessment of burning efficiency (BE) is a critical parameter for estimating gas emissions derived from biomass burning. Several authors have proven a strong dependence of BE on moisture conditions of the fuel. This paper presents an empirical study where the relationships between fuel moisture content (FMC) and satellite-derived variables are evidenced. The study was conducted in Mediterranean ecosystems, using both high- and low-resolution satellite images (Landsat-TM, SPOT-Vegetation and NOAA-advanced very high resolution radiometer). First, theoretical relationships between FMC and reflected or emitted radiance are discussed. Second, multitemporal trends of vegetation indices and surface temperatures are compared with field measurements of FMC for Mediterranean grasslands and shrublands. Pearson r correlation coefficients were computed for a 4-year series of field measurements of FMC and satellite images. Pearson r values show a good correlation between FMC and shortwave infrared (SWIR; 1.6–2 μm) reflectance, for both grasslands and shrublands, although the relations improve when near-infrared (NIR) and SWIR reflectances are combined. “Traditional” spectral vegetation indices (based on the red and NIR reflectances) only work reasonably well with grasslands but not with shrublands. For shrublands a synthetic index mixing vegetation indices and surface temperature improves determination coefficients to estimate FMC. Finally, on the basis of these findings, multivariate fittings were computed and validated using AVHRR images. The assessment sample also provided high determination coefficients (r2 > 0.75) in estimating FMC, both for the study site and other control sites.