Miracle-dz/UniFAR-FTUs huggingface dataset:
Time variation and asymmetry in the statistics of geomagnetic reversal sequences

Time-varying statistics of geomagnetic reversal sequences are examined to test the hypothesis that reversals are generated by a gamma renewal process. Although gross statistical properties of the observations support this model, the statistics of normal polarity intervals are found to differ significantly from those of reversed polarity intervals. This asymmetry, which is not predicted by theoretical dynamo or reversal mechanisms, can be related to the relative stability of normal and reversed states. The reversed state is found to be less stable in the period immediately following a reversal. On the basis of these results the simplest stochastic model describing reversals would be an alternating renewal process with a time-varying mean and gamma-distributed polarity intervals.
Long‐Term High‐Resolution Radar Rainfall Fields for Urban Hydrology

Accurate records of high‐resolution rainfall fields are essential in urban hydrology, and are lacking in many areas. We develop a high‐resolution (15 min, 1 km2) radar rainfall data set for Charlotte, North Carolina during the 2001‐2010 period using the Hydro‐NEXRAD system with radar reflectivity from the National Weather Service Weather Surveillance Radar 1988 Doppler weather radar located in Greer, South Carolina. A dense network of 71 rain gages is used for estimating and correcting radar rainfall biases. Radar rainfall estimates with daily mean field bias (MFB) correction accurately capture the spatial and temporal structure of extreme rainfall, but bias correction at finer timescales can improve cold‐season and tropical cyclone rainfall estimates. Approximately 25 rain gages are sufficient to estimate daily MFB over an area of at least 2,500 km2, suggesting that robust bias correction is feasible in many urban areas. Conditional (rain‐rate dependent) bias can be removed, but at the expense of other performance criteria such as mean square error. Hydro‐NEXRAD radar rainfall estimates are also compared with the coarser resolution (hourly, 16 km2) Stage IV operational rainfall product. Stage IV is adequate for flood water balance studies but is insufficient for applications such as urban flood modeling, in which the temporal and spatial scales of relevant hydrologic processes are short. We recommend the increased use of high‐resolution radar rainfall fields in urban hydrology.
Behaviour of fire weather indices in the 2009–10 New Zealand wildland fire season

The Weather Research and Forecasting mesoscale atmospheric model was used to investigate fire weather conditions during the 2009–10 New Zealand wildland fire season. The analysis considered New Zealand's version of the Fire Weather Index used in the Canadian Forest Fire Danger Rating System, the Haines Index (HI) and the Continuous Haines Index (CHI). This represents the first investigation in New Zealand of the HI and CHI, which rate the potential for extreme fire behaviour or large fire growth based on the lower tropospheric atmospheric stability and humidity. The wildland fire activity during the 2009–10 fire season was typical of New Zealand, and there was considerable spatial and temporal variability in the fire weather conditions. The most frequent severe fire weather conditions as quantified by the fire weather indices occurred to the east of the dividing mountain ranges in both the North Island and South Island, and were associated with the hot, dry and windy north-westerly foehn winds that commonly affect New Zealand. The 36 wildland fires greater in area than 5 ha during the 2009–10 fire season occurred under a range of fire weather conditions, and no correlation was found between the wildland fire size and each individual weather variable.
The sequence of events surrounding Termination II and their implications for the cause of glacial‐interglacial CO2 changes

Events surrounding Termination II, as preserved in the Vostok ice core, provide a number of clues about the mechanisms controlling glacial to interglacial climate change. Antarctic temperature and the atmosphere's CO2 content increased together over a period of ∼8000 years. This increase is bounded by a drop in dust flux at its onset and by a drop in the δ18O of trapped air at its finish. A similar lag between dust flux and foraminiferal δ18O is seen in a Southern Ocean marine record, suggesting that the δ18O in air trapped in Vostok ice is a valid proxy for ice volume. The synchronous change of atmospheric CO2 and southern hemisphere temperature thus preceded the melting of the northern hemisphere ice sheets. This observation, coupled with the fact that nutrient reorganization in the North Atlantic occurs with or after the sea level rise, eliminates many scenarios proposed to explain the CO2 rise, including those which rely on sea level change, conveyor-related nutrient redistribution, or North Atlantic cooling. Southern Ocean scenarios become the front runners, but the most popular mechanism, iron fertilization, has two problems in explaining the CO2 rise before Termination II. First, much of the dust demise occurs prior to the change in CO2, so if iron is the villain, a threshold value of its supply must be called upon above which productivity does not continue to increase. Second, the CO2 rise continues for some 4–5 kyr after the dust flux has fallen to close to zero. These problems may be solved if the increased iron supply in dust caused higher rates of nitrogen fixation during the glacial periods. In this case the residence time of oceanic nitrate of a few thousand years would enable decreasing productivity to be a global rather than a local phenomenon and would explain the slow rampup of atmospheric CO2.
Incorporating model uncertainty into attribution of observed temperature change

Optimal detection analyses have been used to determine the causes of past global warming, leading to the conclusion by the Third Assessment Report of the IPCC that “most of the observed warming over the last 50 years is likely to have been due to the increase in greenhouse gas concentrations”. To date however, these analyses have not taken full account of uncertainty in the modelled patterns of climate response due to differences in basic model formulation. To address this current “perfect model” assumption, we extend the optimal detection method to include, simultaneously, output from more than one GCM by introducing inter‐model variance as an extra uncertainty. Applying the new analysis to three climate models we find that the effects of both anthropogenic and natural factors are detected. We find that greenhouse gas forcing would very likely have resulted in greater warming than observed during the past half century if there had not been an offsetting cooling from aerosols and other forcings.
Long-term changes of euphausiids in shelf and oceanic habitats southwest, south and southeast of Iceland

TERESA SILVA1,2*, ASTTHOR GISLASON1, PRISCILLA LICANDRO3, GUDRUN MARTEINSDOTTIR2, ANA SOFIA A. FERREIRA4, KRISTINN GUDMUNDSSON1 AND OLAFUR S. ASTTHORSSON1 1 MARINE RESEARCH INSTITUTE, SKULAGATA 4, REYKJAVIK 121, ICELAND, INSTITUTE OF BIOLOGY, UNIVERSITY OF ICELAND, STURLUGATA 7, REYKJAVIK 101, ICELAND, SAHFOS, SIR ALISTER HARDY FOUNDATION FOR OCEAN SCIENCE, THE LABORATORY, CITADEL HILL, PLYMOUTH PL1 2PB, UK AND NATIONAL INSTITUTE
VISCOUS PROPERTY OF LOOSE SAND IN TRIAXIAL COMPRESSION, EXTENSION AND CYCLIC LOADING

ABSTRACT The viscous property of sand under triaxial compression (TC), triaxial extension (TE) and cyclic triaxial loading conditions was evaluated by using reconstituted loose samples of three types of relatively fine uniform and relatively angular sand (Silica No. 8, Toyoura and Hostun). The viscous property was quantified mainly by changing stepwise the axial strain rate many times and partially by performing drained sustained loading, both during otherwise monotonic loading (ML) at a constant strain rate. Such a peculiar feature of viscous property as that the viscous stress increment decays with an increase in the irreversible strain during ML at a constant strain rate (i.e., the so-called TESRA viscosity), which has been observed with Toyoura and Hostun sands in previous studies, was observed also with Silica No. 8 sand. The magnitude of viscous property is represented by the rate-sensitivity coefficient, β, defined as the slope of the Δ R / R − log { ( γ . ir ) after / ( γ . ir ) before } relation, where Δ R is a sudden change in the principal stress ratio, R=σ1′/σ3′, caused by a step change in the irreversible shear strain rate from ( γ . ir ) before to ( γ . ir ) after at a given R value during otherwise ML. The following was found. The same definition for β is relevant to drained TC and TE tests. In drained cyclic triaxial loading, the β value is obtained from the above-shown equation after re-defining the sign of Δ R and proportionally scaling the value of R. With the respective type of sand, the β values under these different loading conditions are very similar. The effect of overconsolidation on the β value is insignificant. The β values of these three types of sand are similar to each other and also to those of other ordinary types of sand and gravel having largely different particle sizes. The decay rate of viscous stress increment with an increase in the irreversible shear strain, which is another factor of the viscous property, is rather similar among the three types of sand, while the decay rate is slightly lower in ML TC than in ML TE. The effect of overconsolidation on the decay rate is insignificant.
Modeling particles and pelagic organisms in Chesapeake Bay: Convergent features control plankton distributions

A two-dimensional Lagrangian particle trajectory model is described and used to study how surface currents transport particles and, by analogy, plankton in Chesapeake Bay, United States. It is shown that persistent patches of high particle concentration develop in well-defined regions along the eastern shore and in the lower reaches of some western shore tributaries due to a combination of passive accumulation of particles in areas where the flushing rate is low and convergence. In the model the highest particle concentrations in the Chesapeake consistently develop in the lower bay (latitude 37.1°–37.7° N) in two specific regions near the shore of Cape Charles where convergence and downwelling occur. It is shown that one of these is associated with a strong and persistent, residual cyclonic eddy located over an abrupt change in bottom topography. Recent bay wide field surveys reveal that various planktonic groups, including phytoplankton, zooplankton, and bay anchovy eggs and larvae, have maximum abundances in the vicinity of this eddy. It is argued that these convergent areas are important features that have a strong influence on plankton distributions and that they provide consistently high food concentrations for higher trophic levels.
Improved measurement of fission-track annealing in apatite using c-axis projection

Abstract Apatite fission-track length data are used extensively for thermal history inversion. However, several studies have documented instances of poor reproducibility of length data. We address this problem by using c-axis projection to normalize track lengths for crystallographic angle in the extensive laboratory annealing data set acquired by Barbarand et al. (2003a, 2003b). A new simplification reduces the c-axis projection model from six to four fitted parameters. Normalizing for track angle using c-axis projection improves every aspect of length measurement reproducibility examined. It accelerates convergence of mean length in single analyses; increases consistency among replicate measurements by a single analyst; enhances consistency of measurements of the same mounts by different analysts; and improves the match between analyses conducted with and without Cf-irradiation. C-axis projection is also shown to enhance the thermal sensitivity of length data. Based on these results, we assert that c-axis projection is a good means of compensating for observer bias, although it does not overcome differences caused by experimental error.
Global Precipitation Estimates from Cross-Track Passive Microwave Observations Using a Physically Based Retrieval Scheme

AbstractThe estimation of precipitation across the globe from satellite sensors provides a key resource in the observation and understanding of our climate system. Estimates from all pertinent satellite observations are critical in providing the necessary temporal sampling. However, consistency in these estimates from instruments with different frequencies and resolutions is critical. This paper details the physically based retrieval scheme to estimate precipitation from cross-track (XT) passive microwave (PM) sensors on board the constellation satellites of the Global Precipitation Measurement (GPM) mission. Here the Goddard profiling algorithm (GPROF), a physically based Bayesian scheme developed for conically scanning (CS) sensors, is adapted for use with XT PM sensors. The present XT GPROF scheme utilizes a model-generated database to overcome issues encountered with an observational database as used by the CS scheme. The model database ensures greater consistency across meteorological regimes and sur.
An Analysis of the DIF Sources of ABIDE Mathematics Self-Efficacy Scale by means of a Latent Class Approach

This study aims to identify the sources of Differential Item Functioning (DIF) using the Mixture Ordinal Logistic Regression (Mixture OLR) method, a contemporary approach for detecting DIF. To analyze mathematics self-efficacy, data from a scale comprising 9 items were obtained from 5000 8th-grade students as part of the ABIDE-2016 project. The study compared the presence and extent of DIF by gender using two methods and examined the sources of DIF for items displaying DIF with Mixture OLR. The OLR analysis revealed that five items exhibited DIF at level A, but no DIF was observed with Mixture OLR. Furthermore, it was found that the magnitude of DIF (B) for an item showing DIF at level A changed due to Mixture OLR. The results indicate that the homogeneity of the data affects both the number of items displaying DIF and the magnitude of DIF. Three items did not exhibit significant DIF according to both methods. One significant finding in the study highlights the moderating effect of latent class on item 8, where DIF was observed. However, the source of DIF was not related to gender but rather stemmed from different ecological variables. An analysis of latent class characteristics revealed that students with significant DIF effects had lower absenteeism and fewer siblings. Additionally, students in this class had greater access to books at home and participated in more out-of-school mathematics courses. Surprisingly, these students were found to engage less in social activities. Various factors can influence how students respond to test items, potentially leading to DIF. These factors may include cultural background, gender, social environment, school, teacher, family interest/attitude toward the child, and home climate. Therefore, when developing and administering tests, it is crucial to test for data homogeneity and consider the impact of these variables, in addition to gender, to identify any sources of DIF in test items.
Total soil organic matter and its labile pools following mulga (Acacia aneura) clearing for pasture development and cropping 1. Total and labile carbon

Mulga (Acacia aneura) woodlands and open forests occupy about 150 Mha in Australia, and originally occupied 11.2 Mha in Queensland. Substantial areas (1.3 Mha) of the mulga vegetation have been cleared in Queensland, mostly for pasture production, but some areas are also used for cereal cropping. Twenty years after mulga clearing we found a significant loss of total soil organic C (28–35% from the 0–0.05 m depth) and light fraction C (>50% from the 0–1 m depth) from soil under pasture and cropping at a site in southern Queensland. We report here the changes in soil N and labile N pools in a paired-site study following conversion of mulga to buffel pasture (Cenchrus ciliaris) and cereal (mostly wheat) cropping for more than 20 years. Conversion from mulga forest to pasture and cultivation resulted in greater losses of soil N than organic C in the top 0.1 m depths. As a result, C/N ratios in soil under both pasture and cropping were higher than soil under mulga, indicating a decline in soil organic matter quality after mulga clearing. Although land-use change had no significant effect on 15N natural abundance (δ15N) values of total soil N down to a depth of 1 m, δ15N values of wheat tops and roots indicated that the primary source of N under cropping was soil organic N, while that of buffel pasture was a mixed source of soil N and decomposed litter and root N. Light fraction N (<1.6 Mg/m3) declined by 60–70% throughout the 1 m soil profile under pasture and cropping, but it was 15N-enriched in these 2 land-use systems. The δ15N values of mulga phyllodes, twigs, and fine roots, indicated an input of atmospheric fixed N2 that was estimated to be about 25 kg N/ha.year. However, the source and magnitude of this N resource needs to be confirmed. Soil N losses were estimated to be 12 kg N/ha.year under pasture and 17 kg N/ha.year under cropping over a 20-year period. These findings raise the issue of the long-term sustainable use of cleared mulga areas for pasture and/or cropping. The labile C and N pools and N mineralised also declined, which would have an immediate adverse effect on soil fertility and plant productivity of cleared Mulga Lands, as well as reducing their potential as a soil sink for greenhouse gases.
Reconstruction and dynamics of the Late Wisconsin "Ontario" ice dome in the Finger Lakes region, New York

Distribution of drumlins on the Ontario Lowlands and the northern Appalachian Plateau of New York State are utilized in a glaciological model that estimates thicknesses of the Late Wisconsin Ice Sheet along five glacial flowlines over the central section of the Finger Lakes. Dynamics of the model are based upon a force balance approach that incorporates variable width of a flowband, bedslope, radius of curvature, and center of outflow location. Drumlin axes along five hydrostatic isograms were projected northward. Points of axes convergence define the center of outflow in the eastern Ontario Basin. Flowlines along the axial trace of the major Seneca and Cayuga Troughs and bordering interfluves were constructed southward to the Valley Heads Moraine System. Calculation of flowline geometry for any assumed basal shear stress requires neither information on ice temperature nor the flow law of ice. Ice thicknesses for each flow line were calculated for τ b values of . 5, 1.0, and 1.5 bar. Ice thicknesses at 1 bar range from a minimum of 1,932 m for the Seneca Trough flowline to a maximum of 2,093 m at the Keuka-Seneca interfluve flowline. Raising or lowering τ b by . 5 bar results in maximum thickness differences of +21% and -26%, respectively. Simulating ice recession, a series of ice-marginal, terminal positions were plotted for a basal shear stress of 1 bar. These predicted terminal positions agree well with locations of mapped moraine deposits. These probable values of basal shear stress support the presence of glacial flow representative of internal deformation rather than basal sliding. Although recent interpretations of the formation of the Finger Lakes focus on ice streams facilitated by large volumes of subglacial meltwater, our evidence discounts the presence of ice streams and supports the existence of outlet glaciers in the troughs of the Finger Lakes.
The distribution and behavior of Martian ground ice during past and present epochs

Mars undergoes significant oscillations in its orbit, which will have a pronounced effect on its climate and, in particular, on the behavior of subsurface water ice. We explore and map the behavior of ice in the Martian near-surface regolith over the past 1 m.y. using a diffusion and condensation model presented in an earlier paper, with two primary modifications to include orbitally induced variations in insolation and atmospheric water abundance. We find that the past behavior of ground ice differs significantly from that at the present epoch, primarily the result of high-amplitude oscillations in obliquity (presently 25°). In midlatitude and equatorial regions, ground ice will condense from atmospheric water during times of higher obliquity, filling the top few meters of the regolith with significant amounts of ice. At an obliquity of 32°, ground ice becomes stable globally. During times of lower obliquity, ground ice will sublime and diffuse back into the atmosphere, dessicating the regolith to a depth of about 1 to 2 m equatorward of 60° to 70° latitude. In the high-latitude regions these oscillations are considerably subdued. Below this depth of cyclic saturation and dessication a long-term stability of ice exists in some geographic regions. We present a map of the distribution of ice expected at the present epoch. Cyclic exchange of water between the global regolith and polar regions will have significant implications for surface geology and the polar layered deposits.
A new species of mosasaur (Squamata: Mosasauridae) from the Pierre Shale (lower Campanian) of Manitoba

Plioplatecarpus nichollsae, sp. nov., from the lower Campanian (Pembina Member, Pierre Shale Formation) is diagnosed by the following: a thickened ventral rim of the external naris, a short supratemporal fenestra, a frontal shield with well-developed posterolateral lappets that overlap the parietal dorsally, proximal rib shafts with an approximately circular (but not inflated) cross section, a scapula shaped as in other Plioplatecarpus species but approximately the same size (not larger) than the coracoid, and a moderately large parietal foramen that reaches the frontoparietal suture but does not invade the frontal. The last two characters require that the diagnosis of the genus Plioplatecarpus be emended. With other Plioplatecarpus species, P. nichollsae shares a robust humerus with a distal expansion at least as great as the total length of the bone, a rectangular preorbital frontal shield, a "peg and socket" postorbitofrontal-jugal articulation, a transversely directed ectopterygoid process of the pter.
Meteorological conditions in the Arctic Ocean in spring and summer 2007 as recorded on the drifting ice station Tara

Meteorological observations were made at the drifting ice station Tara in the central Arctic Ocean from 23 March to 19 September 2007, constituting a unique data set from the season preceding the record‐low sea ice extent. Comparisons of the Tara data with observations at the Russian drifting ice stations in 1937–1938 and 1950–1991 and at SHEBA in 1998 indicated that at Tara and SHEBA the atmospheric transmissivity for shortwave radiation was smaller than at the Russian stations, suggesting a higher cloud fraction or optical thickness. Compared to the mean conditions at the Russian stations, at Tara the melting season was twice as long and in April the 2‐m air temperature was 7.0°C higher, but in July the 2‐m temperature difference disappeared. The Tara tethersonde sounding data suggest that the air temperature at the altitudes of 200–1000 m was approximately 1°C higher than the mean of 1954–1985.