Miracle-dz/UniFAR-FTUs huggingface dataset:
Skill, Correction, and Downscaling of GCM-Simulated Precipitation

AbstractThe ability of general circulation models (GCMs) to correctly simulate precipitation is usually assessed by comparing simulated mean precipitation with observed climatologies. However, to what extent the skill in simulating average precipitation indicates how well the models represent temporal changes is unclear. A direct assessment of the latter is hampered by the fact that freely evolving climate simulations for past periods are not set up to reproduce the specific evolution of internal atmospheric variability. Therefore, model-to-real-world comparisons of time series of daily, monthly, or annual precipitation are not meaningful. Here, for the first time, the authors quantify GCM skill in simulating precipitation variability using simulations in which the temporal evolution of the large-scale atmospheric state closely matches that of the real world. This is achieved by nudging the atmospheric states in the ECHAM5 GCM, but crucially not the precipitation field itself, toward the 40-yr European Ce.
Decadal changes in the South Pacific western boundary current system revealed in observations and ocean state estimates

Observations and ocean state estimates are used to investigate the nature and mechanism of decadal variability in the East Australian Current (EAC) system and South Pacific subtropical gyre. A 62 year record on the Tasmanian continental shelf shows decadal variations of temperature and salinity, as well as a long-term trend, which has been related to wind-driven variations in the poleward extension of the EAC. Repeat expendable bathythermograph lines spanning the last 15 years suggest that low-frequency variations in the transport of the EAC extension and Tasman Front are anticorrelated, but the time series are too short to draw firm conclusions. Here we use two ocean state estimates spanning the past 50 years to diagnose the physical mechanisms and spatial structure of the decadal variability of the South Pacific subtropical gyre. The observations and state estimates paint a consistent picture of the decadal variability of the gyre and EAC system. Strengthening of the basin-wide wind stress curl drives a southward expansion of the subtropical gyre. As the gyre shifts south, the EAC extension pathway is favored at the expense of the Tasman Front, resulting in the observed anticorrelation of the these two major currents. The results suggest that the subtropical gyre and western boundary current respond to decadal variability in basin-scale wind stress curl, consistent with Island Rule dynamics; that strong decadal variability of the South Pacific gyre complicates efforts to infer trends from short-term records; and that wind stress curl changes over the South Pacific basin drive changes in the EAC system that are likely to have implications for marine ecosystems and regional climate.
Basal slip and mechanical anisotropy of biotite

The basal slip systems of biotite and their mechanical expressions have been investigated by shortening single crystals oriented to maximize and minimize shear stresses on (001). Samples loaded at 45° to (001) exhibit gentle external rotations associated with dislocation glide. High-angle kink bands in these samples, unlike those developed in micas loaded parallel to (001), are limited to sample corners. Samples shortened perpendicular to (001) show no evidence of nonbasal slip and fail by fracture over all conditions tested. The mechanical response of biotite shortened at 45° to (001) is nearly perfectly elastic-plastic; stress-strain curves are characterized by a steep elastic slope, a sharply defined yield point, and continued deformation at low (mostly 1%. Stresses measured beyond the yield point are insensitive to confining pressure over the range 200 to 500 MPa and exhibit weak dependencies upon strain rate and temperature. Assuming an exponential relationship between differential stress σd and strain rate e˙ of the form e˙=Cexp(ασd)exp(−Q/RT), the data collected over strain rates and temperatures of 10−7 to 10−4 s−1 and 20° to 400°C, respectively, are best fit by an exponential constant α of 0.41±0.08 MPa-1 and an activation energy Q of 82±13 kJ/mol. A power law fits the data equally well with n = 18±4 and Q = 51±9 kJ/mol. Samples oriented favorably for slip in directions [100] and [110] are measurably weaker than those shortened at 45° to [010] and [310], consistent with the reported Burgers vectors 〈100〉, 1/2 〈110〉, and 1/2 〈110〉. The anisotropy of biotite is further revealed by contrasting these plastic strengths with results of samples deformed parallel and perpendicular to (001). Previous studies have shown that biotite loaded in the (001) plane is strong prior to the nucleation of kink bands. The strength of biotite shortened perpendicular to (001) exceeds that measured parallel to (001) and is pressure dependent. Application of the results to deformation within the continental crust suggests that biotite oriented favorably for slip is much weaker than most other silicates over a wide range of geologic conditions. Its presence within foliated rocks and shear zones may limit locally the stresses that can be supported.
Effect of tidal flat on the thermal effluent dispersion from a power plant

[1] The effect of a tidal flat on the dispersion of thermal effluent from the nuclear power plant at YongGwang (5.8 × 106 kW) along the west coast of Korea was investigated using intensive field observations and three-dimensional numerical simulations. The calculated sea surface temperature distribution reproduces well the observed one with a root mean square error of 0.53°C. A water column on the tidal flat area received a heat influx of 168 W m−2 on 17 April 2003 and transported the received heat to the adjacent coastal water at low water. The total heat supply from the tidal flat area to the coastal water was 6.6 × 1010 W, and was larger by about 1 order of magnitude than that from the power plant of 7.0 × 109 W on 17 April 2003, which was a fine day at spring tide. This fact shows that the effect of the tidal flat on the thermal effluent from the power plant is very large.
Strain modelling, seismic anisotropy and coupling at strike-slip boundaries: applications in New Zealand and the San Andreas fault

Abstract Despite similar surface transform faulting behaviour, observed shear-wave splitting patterns in the California and New Zealand plate boundary regions are markedly different. To better understand the origin of the seismic anisotropy in these regions we model mantle flow and strain for a variety of strike-slip plate boundary scenarios. Simple relations between the flow or strain and elastic anisotropy are assumed to determine the integrated splitting in shear particle motion along teleseismic paths. Strain-controlled models fit the observations in New Zealand and California better than simplified flow-controlled models. Fast shear polarizations are progressively rotated toward the shear plane over time, and even a constant-viscosity model provides a good fit to the fast directions in New Zealand and southern California. The constant viscosity implies strong coupling between the surface and the deeper mantle. To fit the lack of decrease in delay times with distance from the fault, the relationship between delay time and strain must saturate at small strains. If this is the case, then strain in southern New Zealand and southern California may be small, equivalent to that achieved along an infinite fault by about 3–10 Ma of their present motion. Stratified viscosity allows more rapid rotation of fast directions toward fault-parallel than occurs in isoviscous models, and can explain the nearly fault-parallel fast directions in the central South Island. Different aspects of the northern California results are fitted with different models, but a rapid change in viscosity with depth is needed to produce the full effects of the behaviour previously modelled as two layers of anisotropy suggesting vertical decoupling.
A NEW WIDE‐GAUGE SAUROPOD TRACK SITE FROM THE LATE CRETACEOUS OF MENDOZA, NEUQUÉN BASIN, ARGENTINA

Abstract: Agua del Choique is a new Late Cretaceous sauropod track site from Mendoza Province, Neuquén Basin, Argentina. It is situated in the Loncoche Formation, late Campanian – early Maastrichthian in age, and is one of the youngest sauropod tracks site recorded in the world. Agua del Choique represents a lake setting and river‐dominated delta deposits, and comprises at least 160 well‐preserved tracks, located on a calcareous sandstone bed. A new ichnotaxon, Titanopodus mendozensis ichnogen. et ichnosp. nov., is erected for the footprints of this track site. Titanopodus mendozensis exhibits the following association of features: (1) wide‐gauge trackway (manus and pes trackway ratios of 18–22 and 26–31 per cent respectively), (2) pronounced heteropody (manus‐pes area ratio of 1:3), (3) outer limits of trackway defined, in some cases, by the manus tracks, and (4) manus impression with an asymmetrical crescent contour and acuminate external border. Titanopodus mendozensis is an excellent case study of the wide‐gauge style of locomotion produced by Late Cretaceous derived titanosaurs that have no impression of manual phalanges. These features, and the fossil record from the Loncoche Formation, suggest that the trackmakers were, probably, middle size saltasaurine or aeolosaurine titanosaurs (14–16 m long).
Frequency of cool summers in interior North America over the past three centuries

An innovative technique utilizes a tree‐ring marker to investigate long‐term changes in the frequency of cool summers in Interior North America (INA), a region that currently suffers important gaps in knowledge concerning annual to secular temperature changes. Using multivariate adaptive regression splines (MARS), we established a threshold for the formation of climatically‐induced light rings recorded in Pinus banksiana trees from INA. Then, we used the MARS model to reconstruct negative departures in summer maximum temperatures (April–September) from 1717 to 2007. The estimates explain 45% of the variance in instrumental temperature data. The reconstruction indicates the presence of significant multidecadal changes in the frequency of cool summers, with maximums in 1780, 1900 and 1960 and minimums in 1740, 1860, 1920 and 2000. No evidence of secular changes was found.
Seismicity and geometry of the south Chilean subduction zone (41.5°S–43.5°S): Implications for controlling parameters

In 2005 an amphibious seismic network was deployed on the Chilean forearc between 41.75°S and 43.25°S. 364 local events were observed in a 11‐month period. A subset of the P and S arrival times were inverted for hypocentral coordinates, 1‐D velocity structure and station delays. Main seismic activity occurred predominantly in a belt parallel to the coast of Chiloé Island in a depth range of 12–30 km presumably related to the plate interface. The 30° inclination of the shallow part of the Wadati‐Benioff zone is similar to observations further north indicating that oceanic plate age is not controlling the subduction angle of the shallower part for the Chilean subduction zone. The down‐dip termination of abundant intermediate depth seismicity at approximately 70 km depth seems to be related to the young age (and high temperature) of the oceanic plate. Crustal seismicity is associated with the Liquiñe‐Ofqui fault zone and active volcanoes.
Analysis of the correlations between atmospheric boundary‐layer and free‐tropospheric temperatures in the tropics

We investigate the vertical correlations between temperature variations at 925 hPa, in the atmospheric boundary layer, and temperature variations in the free troposphere and lower stratosphere in the Tropics in daily and monthly averaged satellite and radiosonde measurements and in six General Circulation Models (GCMs). The results show generally positive correlations between the boundary layer temperatures and temperatures in the rest of the troposphere, with negative correlations occurring around the tropopause and in the lower stratosphere. In typically non‐convective regions, the variations at the surface show little connection to mid and upper tropospheric temperature variations. In the convective Western Pacific, the correlations are low in the mid troposphere and much larger around 200 hPa. GCMs generally capture the temperature correlations, although as a group they tend to overpredict the coupling between the boundary layer and the rest of the troposphere. The basic correlation patterns of monthly temperature are found similar to the daily results.
Ensemble hydrological prediction‐based real‐time optimization of a multiobjective reservoir during flood season in a semiarid basin with global numerical weather predictions

Future streamflow uncertainties hinder reservoir real‐time operation, but the ensemble prediction technique is effective for reducing the uncertainties. This study aims to combine ensemble hydrological predictions with real‐time multiobjective reservoir optimization during flood season. The ensemble prediction‐based reservoir optimization system (EPROS) takes advantage of 8 day lead time global numerical weather predictions (NWPs) by the Japan Meteorological Agency (JMA). Thirty‐member ensemble streamflows are generated through running the water and energy budget‐based distributed hydrological model fed with 30‐member perturbed quantitative precipitation forecasts (QPFs) and deterministic NWPs. The QPF perturbation amplitudes are calculated from the QPF intensity and location errors during previous 8 day periods. The reservoir objective function is established to minimize the maximum reservoir water level (reservoir and upstream safety), the downstream flood peak (downstream safety), and the difference between simulated reservoir end water level and target level (water use). The system is evaluated on the Fengman reservoir basin (semiarid), which often suffers from extreme floods in summer and serious droughts in spring. The results show the ensemble QPFs generated by EPROS are comparable to those for JMA by using probability‐based measures. The streamflow forecast error is significantly reduced by employing the ensemble prediction approach. The system has demonstrated high efficiency in optimizing reservoir objectives for both normal and critical flood events. Fifty‐member ensembles generate a wider streamflow and reservoir release range than 10‐member ensembles, but the ensemble mean end water levels and releases are comparable. The system is easy to operate and thereby feasible for practical operations in various reservoir basins.
Gravity data as a tool for detecting faults: In-depth enhancement of subtle Almada's basement faults, Brazil

We demonstrate the potential of gravity data to detect and to locate in-depth subtle normal faults in the basement relief of a sedimentary basin. This demonstration is accomplished by inverting the gravity data with the constraint that the estimated basement relief presents local abrupt faults and is smooth elsewhere. We inverted the gravity data from the onshore Almada Basin in northeastern Brazil, and we mapped several normal faults whose locations and plane geometries were already known from seismic imaging. The inversion methoddelineatedwellboththediscontinuitieswithsmallor largeslipsandasequenceofstepfaults.Usingsyntheticdata, weperformedasystematicsearchofnormalfaultslipsversus fault displacement depths to map the fault-detectable region inthisspace.Thismappinghelpstoassesstheabilityofgravityinversiontodetectnormalfaults. Mappingshowsthatnormalfaultswithsmall0.5 km,mediumabout1 km,and large about 2 km vertical slips can be detected if the maximummidpointdepthsofthefaultplanesaresmallerthan1.8, 3.8,and6.8 km,respectively.
Seabed erosion on the Lomonosov Ridge, central Arctic Ocean: A tale of deep draft icebergs in the Eurasia Basin and the influence of Atlantic water inflow on iceberg motion?

[1] The submarine Lomonosov Ridge, which bisects the Arctic Ocean, is covered by ∼450 m of hemipelagic sediments. High-resolution chirp sonar and side-scan data have documented erosion of a section of the ridge. Here we present multichannel seismic and chirp sonar data which show removal of unconsolidated sediments along the Eurasia Basin side of the Lomonosov Ridge, where the central ridge is shallower than 1000 m. The incomplete erosion of the hemipelagic drape and probable topographic control of ice motion suggest that the deepest draft glacier ice, which reached the central Arctic Ocean from the Eurasia Basin, was in the form of armadas of large icebergs embedded in sea ice rather than a single, continuous floating ice shelf. Massive, rapid discharge of glacier ice was probably required to produce the deepest draft (>800 m) icebergs. Eastward and northward drift trajectories from a likely iceberg source area on the Kara-Barents Sea margin would reflect the relative strength of Atlantic inflow through the Fram Strait. However, only icebergs with drafts exceeding bathymetric thresholds on the Lomonosov Ridge would leave an erosive imprint on the seabed. Advection of Atlantic water may have been relatively strong at times of discharge from the Saalian ice sheet. Icebergs exiting the Arctic Ocean caused massive erosion and redeposition of the hemipelagic sediments on top of Yermak Plateau.
Computer techniques applied to formation evaluation. [Edwards Limestone near San Antonio]

Well logs from a test hole drilled in the Edwards Limestone near San Antonio, Texas, were evaluated using various computer programs to examine formation characteristics. The hole was cored from 600 feet to a total depth of 1160 feet and eleven separate logs were run on the cored interval. Numerous core samples were analyzed for mineralogy, density, porosity, sonic velocity, and permeability. These data provided an unusual opportunity to determine the reliability of computer codes used in formation evaluation from geophysical logs. Computer results were obtained on mineralogy using a method of linear programming on selected logs and were found to compare quite favorably with the x-ray analysis of the core. With these computed results, a thermal conductivity log was generated which was combined with a temperature gradient log to produce a heat flow log. Regions of internal water circulation are clearly defined in the heat flow log and coincide with zones of high permeability determined from core analysis and pump tests. Programs were applied which calculate a lithology corrected porosity, matrix density, matrix velocity, sonic porosity, secondary (fracture and vugular) porosity, and apparent water resistivity from logs. The algorithms for these codes are discussed and the resulting logs aremore » presented and compared with pictures of the core and the televiewer log. « less
Methods for in-field user calibration of an inertial measurement unit without external equipment

This paper presents methods to calibrate and compensate for non-zero biases, non-unit scale factors, axis misalignments and cross-axis sensitivities of both the tri-axial accelerometer and gyroscopic setups in a micro-electro-mechanical systems (MEMS) based inertial measurement unit (IMU). These methods depend on the Earth's gravity as a stable physical calibration standard. Specifically, the calibration of gyroscopes is significantly improved by comparing the outputs of the accelerometer and the IMU orientation integration algorithm, after arbitrary motions. The derived property and proposed cost function allow the gyroscopes to be calibrated without external equipment, such as a turntable, or requiring precise maneuvers. Both factors allow the IMU to be easily calibrated by the user in the field so that it can function as an accurate orientation sensor. A custom-made prototype IMU is used to demonstrate the effectiveness of the proposed methods, with data that are carefully obtained using prescribed motions, as well as those less rigorously collected from the IMU when it is mounted on the head of a user or held in hands with brief random movements. With calibration, the observed average static angular error is less than a quarter of a degree and the dynamic angular error is reduced by a factor of 2 to 5.
Convection in three dimensions with surface plates: Generation of toroidal flow

This work presents numerical calculations of mantle convection that incorporate some of the basic observational constraints imposed by plate tectonics. The model is three-dimensional and includes surface plates; it allows plate velocity to change dynamically according to the forces which result from convection. We show that plates are an effective means of introducing a toroidal component into the flow field. After initial transients the plate motion is nearly parallel to transform faults and in the direction that tends to minimizes the toroidal flow field. The toroidal field decays with depth from its value at the surface; the poloidal field is relatively constant throughout the layer but falls off slightly at the top and bottom boundaries. Layered viscosity increasing with depth causes the toroidal field to decay more rapidly, effectively confining it to the upper, low-viscosity layer. The effect of viscosity layering on the poloidal field is relatively small, which we attribute to its generation by temperature variations distributed throughout the system. The generation of toroidal flow by surface plates would seem to account for the observed nearly equal energy of toroidal and poloidal fields of plate motions on the Earth. A low-viscosity region in the upper mantle will cause the toroidal flow to decay significantly before reaching the lower mantle. The resulting concentration of toroidal flow in the upper mantle may result in more thorough mixing there and account for some of the geochemical and isotopic differences proposed to exist between the upper and lower mantles.
A preliminary semiempirical thermosphere model of Mars: DTM‐Mars

[1] A semiempirical thermosphere model of Mars has been constructed based on the DTM algorithm that was developed for the terrestrial thermosphere. DTM-Mars reproduces the observed densities with a 1-σ model uncertainty of approximately 35% outside dust season. During dust storms the uncertainty increases by approximately a factor two. The data used in this study have been derived from the Mars Global Surveyor accelerometer observations as well as from analysis of precise orbit determination results. The temperature modeling is based on the Mars-GRAM 2000 [Justus and James, 2000] and the MTGCM [Bougher et al., 2000] models, while the CO2, O, and He constituent modeling has been achieved through the adjustment of model coefficients to density data. DTM-Mars is preliminary because the geographical and solar activity coverage of the assimilated density data currently available is not representative of all atmospheric conditions. For example, the effect of dust storms on the thermospheric density is only represented by a temperature increase on a planetary scale, because the data did not allow the determination of a semidiurnal variation caused by local effects in the lower atmosphere. The model accuracy will be improved in the future by assimilating density data taken under different atmospheric conditions, for example, from the Mars Odyssey mission, once these become available.