Miracle-dz/UniFAR-FTUs huggingface dataset:
Mathematical Modeling of Graded River Profiles

Numerical modeling of the longitudinal profiles of rivers at grade is accomplished using the basic equations of open-channel flow, sediment transport equations, and empirical relations for downstream variation in flow discharge, sediment discharge, sediment caliber, and channel width. Only in some cases are the computed stream profiles fit exactly by any one of the commonly supported mathematical function analogs to graded profile form-exponential, logarithmic, or power function, but in most cases any of these functions can provide a fit with a degree of error smaller than would be noted in treating field data. Profiles dominated by spatial change in fluid and sediment discharge are distinctly power functions, while profiles dominated by sediment size reduction are not necessarily exponential in form. Other important controls on profile shape are the degree of downstream width change in response to increasing discharge and the general range of sediment size. A dynamic model of a river's approach to grade indicates that disequilibrium river profiles closely approximate a graded profile shape even while the general slope is relatively high, and significant erosion remains to achieve equilibrium.
Trajectory sensitivity of the transient climate response to cumulative carbon emissions

The robustness of Transient Climate Response to cumulative Emissions (TCRE) is tested using an Earth System Model (Geophysical Fluid Dynamics Laboratory‐ESM2G) forced with seven different constant rates of carbon emissions (2 GtC/yr to 25 GtC/yr), including low emission rates that have been largely unexplored in previous studies. We find the range of TCRE resulting from varying emission pathways to be 0.76 to 1.04°C/TtC. This range, however, is small compared to the uncertainty resulting from varying model physics across the Fifth Coupled Model Intercomparison Project ensemble. TCRE has a complex relationship with emission rates; TCRE is largest for both low (2 GtC/yr) and high (25 GtC/yr) emissions and smallest for present‐day emissions (5–10 GtC/yr). Unforced climate variability hinders precise estimates of TCRE for periods shorter than 50 years for emission rates near or smaller than present day values. Even if carbon emissions would stop, the prior emissions pathways will affect the future climate responses.
Analysis of Rainfall Variables Trends and Potential Vegetation Responses in Sinaloa, México

Based on monthly data from 55 meteorological stations from the North Pacific Watershed, seven annual rainfall trends were estimated and analyzed using non-parametric tests. The estimated slopes were analyzed in a geographic context to determine a potential spatial arrangement. Finally a brief analysis of the potential vegetation response from the different physiographic regions and the implications in the productive analysis is discussed. The findings indicated divergent trends in all the proposed variables, in general increasing and drier trends were found. Latitude was the most relevant factor regarding trend behavior in geographic terms. The lack of awareness and apathy from the authorities in the region were found, plus the regional vulnerability may originate notorious and serious consequences if the proper measures are not taken into account.
Long recurrence interval of faulting beyond the 2005 Kashmir earthquake around the northwestern margin of the Indo-Asian collision zone

The 2005 Kashmir earthquake in Pakistan occurred on a previously mapped active fault around the northwest margin of the Indo-Asian collision zone. To address the quantitative contribution of the earthquake to plate convergence, we performed paleoseismological trench excavations at Nisar Camp site near Muzaffarabad across the middle section of the 2005 surface rupture. The fault strands exposed in the trench cut late Holocene fluvial deposits and record evidence of both the 2005 and a penultimate event, supported by the presence of colluvial deposits and a downdip increase in displacement along the fault strands. The 2005 event produced a net slip of 5.4 m, and the penultimate earthquake exhibits a similar amount of slip. Radiocarbon ages and historical accounts loosely constrain the timing of the penultimate event between 500 and 2200 yr B.P.; however, the exposed section encompasses ~4 k.y. of stratigraphy, suggesting an average interevent interval of ~2 k.y. for the 2005 type events. We thus conclude that the 2005 event did not occur on the plate boundary megathrusts, but on intraplate active faults within the Sub-Himalaya. Consequently, the accumulated elastic strain around the complex northwestern margin of the Indo-Asian collision zone has not been significantly released by the 2005 earthquake.
Energy Estimates and Cavity Interaction for a Critical‐Exponent Cavitation Model

We consider the minimization of $\int_{\Omega _\varepsilon } {|D{\bf u}|^p } d{\bf x}$ in a perforated domain $\Omega _\varepsilon : = \Omega \backslash \cup _{i = 1}^M B_\varepsilon ({\bf a}_i )$ of $\font\open=msbm10 at 10pt\def\R{\hbox{\open R}}\R^n$ among maps $\font\open=msbm10 at 10pt\def\R{\hbox{\open R}}{\bf u} \in W^{1,p} (\Omega _\varepsilon ,\R^n )$ that are incompressible (det $D{\bf u} \equiv 1$) and invertible, and satisfy a Dirichlet boundary condition u = g on ∂Ω. If the volume enclosed by g(∂Ω) is greater than |Ω|, any such deformation u is forced to map the small holes Bε(ai) onto macroscopically visible cavities (which do not disappear as ε → 0). We restrict our attention to the critical exponent p = n, where the energy required for cavitation is of the order of $\sum\nolimits_{i = 1}^M {v_i |\log \varepsilon |}$ and the model is suited, therefore, for an asymptotic analysis (v1,…, vM denote the volumes of the cavities). In the spirit of the analysis of vortices in Ginzburg‐Landau theory, we obtain estimates for the “renormalized” energy $${1 \over n}\int\limits_{\Omega _\varepsilon } {\left| {{{D{\bf u}} \over {\sqrt {n - 1} }}} \right|^p } {\rm d}{\bf x} - \sum\limits_i {v_i |\log \varepsilon |} ,$$ showing its dependence on the size and the shape of the cavities, on the initial distance between the cavitation points a1,…,aM, and on the distance from these points to the outer boundary ∂Ω. Based on those estimates we conclude, for the case of two cavities, that either the cavities prefer to be spherical in shape and well separated, or to be very close to each other and appear as a single equivalent round cavity. This is in agreement with existing numerical simulations and is reminiscent of the interaction between cavities in the mechanism of ductile fracture by void growth and coalescence. © 2012 Wiley Periodicals, Inc.
Improved long‐term mean annual rainfall fields for Colombia

With the aim of improving the long‐term mean annual surface water balance of Colombia, four new annual average precipitation fields are estimated at 4 km spatial resolution. To put in context, a concise literature review of rainfall in Colombia is presented. For estimation purposes, diverse multivariate geostatistical methods are implemented by combining information from 1180 raingauges covering the period 1950‐2005, and satellite data from the tropical rainfall measuring mission (TRMM) for the period 1999‐2005, used as a drift for the following geostatistical methods: (1) kriging with an external drift (KED), (2) standardized cokriging (SCK), (3) colocated cokriging (CCK), and (4) Markov regionalization CCK (CCKM). To ensure the reliability of the estimated precipitation fields, a detailed cross‐validation procedure is performed, including univariate and bivariate analyses of residuals, which allows us to conclude that the best estimated rainfall field is obtained with KED, and the worst with SCK. Visual analyses are also performed in the search for consistency of the resulting precipitation fields. Furthermore, local (at‐a‐pixel) uncertainty modelling analysis is performed using the indicator approach. Conditional cumulative distribution functions (CCDF) are estimated using indicator CCK with Bayes‐Markov hypothesis. Statistical descriptors for the pixel's CCDFs are estimated based on the resulting precipitation fields, including long‐term mean, conditional variance and the coefficient of variation. These improved precipitation fields along with their estimated uncertainties are available (http://cancerbero.unalmed.edu.co/∼hidrosig/index.php) for the scientific community and constitute useful basic information for diverse applications in water resources, agriculture, hydropower generation, human health, risks and disaster prevention, and many other applied sectors in Colombia. Copyright © 2010 Royal Meteorological Society
In situ measurements of saltwater flux through tidal passes of Lake Pontchartrain estuary by Hurricanes Gustav and Ike in September 2008

Storm surge induced saltwater flux through multiple inlets has never been documented. This article reports in situ measurements of saltwater flux through major tidal passes by two consecutive storm surges impacting Lake Pontchartrain estuary in Louisiana during the first two weeks in September 2008. The main peak of inward saltwater flux lasted for 1.9 days during the flood, followed by more than 8 days of outward salt flux. The salt flux rate reached close to 200 tons/sec through the northern channel and 16 tons/sec through the southern channel. Outward flux of salt during Gustav amounted to more than 16 million tons during the receding stage, more than twice of that measured for the flux into the lake. Apparently, overland inundation, which was not measured, caused this biased estimate of influx of salt. Hurricane Ike, however, did not cause such a dramatic difference in influx and outflux of salt.
Building Destruction from Waves and Surge on the Bolivar Peninsula during Hurricane Ike

The Bolivar Peninsula in Texas was severely impacted by Hurricane Ike with strong winds, large waves, widespread inundation, and severe damage. This paper examines the wave and surge climate on Bolivar during the storm and the consequent survival and destruction of buildings. Emphasis is placed on differences between buildings that survived (with varying degrees of damage) and buildings that were completely destroyed. Building elevations are found to be the primary indicator of survival for areas with large waves. Here, buildings that were sufficiently elevated above waves and surge suffered relatively little structural damage, while houses at lower elevations were impacted by large waves and generally completely destroyed. In many areas, the transition from destruction to survival was over a very small elevation range of around 0.5 m. In areas where waves were smaller, survival was possible at much lower elevations. Higher houses that were not inundated still survived, but well-built houses at lower elevations could also survive as the waves were not large enough to cause structural damage. However, the transition height where waves became damaging could not be determined from this study.
Pollution transport efficiency toward the Arctic: Sensitivity to aerosol scavenging and source regions

The processes driving current changes in Arctic atmospheric composition and climate are still uncertain. In particular the relative contributions of major source regions from the midlatitudes remain a matter of debate in the literature. The objectives of this study are to better quantify the relative contributions of different processes governing the transport of pollution from the midlatitudes to the Arctic and the relative contributions of different geopolitical source regions. We use a suite of observational data sets (including the Arctic Research of the Composition of the Troposphere from Aircraft and Satellites (ARCTAS) campaigns and the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) satellite instrument) to constrain a global aerosol simulation from the ECHAM5-HAMMOZ model. Preliminary comparison of model results with vertical profiles of sulfate and black carbon (BC) collected during the ARCTAS campaigns and with aerosol extinction time series retrieved from CALIOP indicates that the model underestimates export of aerosols from the planetary boundary layer to the free troposphere in the midlatitudes and long-range transport of aerosols from the midlatitudes toward the Arctic. In contrast, observed CO profiles are relatively well simulated, which points to a possible problem with wet scavenging. Decreasing the prescribed aerosol scavenging coefficients within the range of experimental data available in the literature significantly improves the agreement with observations. Sulfate and BC burdens in the Arctic increase by a factor 5-6. Annual global lifetimes of sulfate and BC increase from 3.1 to 4.6 days and from 4.4 to 5.9 days, respectively. Using the improved simulation, we find that 59% of sulfate in the Arctic troposphere comes from the oxidation of SO2 emitted in Siberia (19%), Europe (18%), Asia (13%), and North America (9%). Anthropogenic and biomass burning BC emitted in Siberia, Asia, Europe, and North America contributes 29, 27, 25, and 17%, respectively, to the Arctic BC burden. Emissions of aerosols (or precursors) from Siberia and Europe are more susceptible to be transported and subsequently deposited on the Arctic (about 7-12%) compared to those from North America and Asia (1-4%). Overall, the study shows that aerosol scavenging removal processes play a crucial role on the aerosol transport from the midlatitudes toward the Arctic and should be carefully characterized in aerosol models.
Geology of Deep Spring Valley, California

Deep Spring Valley is one of the most remarkable desert basins in California. Several thousand feet of pre-Cambrian strata and 10,000 feet of Lower Cambrian strata are wonderfully exposed around portions of the valley. A granite-monzonite series, probably of late Jurassic age, intrudes the strata on a large scale. Various conflicting ideas have been expressed in regard to the origin of the valleys of the Basin Range province. Deep Spring Valley very clearly owes its origin to faulting, the whole region being in fact a mosaic of normal fault blocks. Great fault facets are remarkably exhibited. The recency of the dislocation along the main fault is proved by many miles of sharply faulted alluvial cones; the occurrence of river beds on the top of a great fault block; and a field of very fresh lava which has been dislocated 1,500 feet, vertically. In relatively late Quaternary time a deep fresh-water lake occupied the valley.
Dinoflagellate cysts and mid-Oligocene chronostratigraphy in the central Mediterranean region

Two new dinoflagellate cyst zones are proposed, linking previously established zonal schemes for the Eocene–Oligocene and Oligocene–Miocene successions in the central Mediterranean region. The Hystrichokolpoma pusillum (Hpu) and Chiropteridium lobospinosum (Clo) interval zones are based on the Contessa Quarry and Monte Cagnero sections (central Italy), and are correlated with previously established magnetostratigraphical and biostratigraphical schemes. The base of the Chattian is considered to correlate with Chron Cl0n. In central Italy, the most distinct dinoflagellate cyst event associated with this chron is the first occurrence of Distatodinium biffii, marking the base of the Distatodinium biffii (Dbi) Zone. Indirect evidence also suggests that the first occurrence of Distatodinium biffii is above but close to the base of the Chattian Stage in its type area in northwest Germany, thus making it an important marker. Other possible markers for the base of the Chattian are the last occurrence of Areosphaeridium pectiniforme and the lowest acme of Chiropteridium spp. The latter may be related to the major mid-Oligocene sea-level fall (TA–TB Exxon supercycle boundary), also considered to represent the base of the Chattian and previously correlated with Chron Cl0n. However, in the Contessa Quarry section this dinoflagellate cyst event is associated with the older Chron C11.
Beach ridge systems – archives for Holocene coastal events?

Holocene coastal evolution has been extensively studied by workers from various earth science disciplines, particularly sedimentologists and geomorphologists. Some of these studies have focused on the history of regional sea-level changes in various ocean basins and the mechanisms – such as eustasy, glacio-isostasy, sediment compaction, neotectonics and climatic forces – involved in such changes. Although beach ridges have been used to identify steps in coastal evolution, only in a few cases have beach ridge systems been investigated with respect to event histories (for example, cyclones and tsunamis). Beach ridge systems, however, belong to the most promising geo-archives for the study of climate change and sea-level variations over the Holocene, as well as for deciphering event histories. This paper presents examples of some studies in this field, in relation to a global overview of beach ridge systems and their morphological characteristics.
Aeolian abrasion of quartz particles and the production of silt-size fragments: preliminary results

Summary Experimental abrasion of quartz sand in an air stream shows that particles with initially high angularity are progressively rounded by the chipping of edges and corners. Grains closely resemble dune sand grains from deserts with respect to rounding and microscopic surface textures after 48 hours of abrasion. Results show an initially high weight loss from the original grains (primarily by edge chipping), compared with subsequent abrasion. High percentages of coarse and medium silt are produced but there is a gradual increase in the percentage of fine silt as rounding increases and the quantity of fines generated declines. Silica extraction from the fines using water shows concentrations of several hundred ppm. Implications for loess production and silcrete formation are suggested.
Planktic foraminifera, particle flux and oceanic productivity off Pakistan, NE Arabian Sea: modern analogues and application to the palaeoclimatic record

Abstract We use the flux of bulk sediment (CaCO3, biogenic opal, organic carbon, lithogenic material), and of planktic foraminifera (PF) and other shell-bearing plankton from sediment trap EPT-2 off Pakistan to (1) constrain the seasonal pattern of regional productivity and (2) search for indications of the NE monsoon winter situation that may serve as a modern analogue to better reveal the seasonal climatic signals preserved in the sedimentary record of the Arabian Sea. Our trap data show a clear seasonality of fluxes that can also be traced in the composition of non-bioturbated (varved) summer and winter sediment laminae preserved within the oxygen minimum zone. In EPT-2, the flux of PF is low during summer, but during winter and late spring it is higher, as at trap station WAST, in the upwelling area of the western Arabian Sea. Globigerina bulloides, a PF species linked to summer upwelling and high productivity, is of minor importance off Pakistan. In contrast, Globigerina falconensis dominates in flux and relative abundance, and is indicative of winter mixing, when NE monsoonal winds cool the highly saline surface waters and break up stratification. An enhanced horizontal flux of suspended sediments stirred up on the shelf and upper slope is clearly shown by the peak in occurrence of small benthic foraminifera during winter. Altogether, our data suggest that the particle flux in the northeastern Arabian Sea is determined by local sediment resuspension and winter productivity rather than by summer monsoonal upwelling, representing a ‘non-upwelling’ environment, in contrast to the ‘summer upwelling’ regime off Oman, Somalia and southern India. We used this evidence to reconstruct the seasonal intensity of both monsoons for the past 25 ka: the SW and NE monsoon both were weak during the last glacial period. The NE monsoon peaked during the cool phases of the glacial to interglacial climatic transition (i.e. during the Younger Dryas (YD) and Heinrich Event H1). The SW monsoon was reinforced after the YD. Both monsoons were enhanced during early Holocene time, when summer insolation and hence atmospheric forcing was at a maximum.
A new model of volatile bubble growth in a magmatic system: Isobaric case

[1] The nucleation, growth, and, ultimately, coalescence of volatile bubbles in a silicate melt (magma chamber) play a crucial role in the processes leading to volcanic eruptions. A new diffusion-limited nonlinear growth and nucleation model of volatile bubbles in such a system is proposed here. In contrast to previously existing models, the present one treats the competitive effects of the other randomly located bubbles on the growth dynamics in presence of a hydrodynamic coupling with the melt advection field through its viscous resistance. I consider here cases where the fluid pressure is kept constant. Numerical results pertaining to a basaltic and a rhyolitic melt suggest that for small volatile supersaturations and for small times, bubble growth occurs essentially as in the single-bubble problem. However, for longer times, the influence of the other bubbles is important. I find that bubble growth rate decreases exponentially with time and propose an approximate expression for the decay rate. Finally, for larger volatile supersaturations, the bubble growth is subjected to transitions to and from an inflationary regime, whereby the bubble radius increases very rapidly during a small time interval.