Miracle-dz/UniFAR-FTUs huggingface dataset:
Role of the Indian Ocean in the Biennial Transition of the Indian Summer Monsoon

The biennial variability is a large component of year-to-year variations in the Indian summer monsoon (ISM). Previous studies have shown that El Nino–Southern Oscillation (ENSO) plays an important role in the biennial variability of the ISM. The present study investigates the role of the Indian Ocean in the biennial transition of the ISM when the Pacific ENSO is absent. The influence of the Indian and Pacific Oceans on the biennial transition between the ISM and the Australian summer monsoon (ASM) is also examined. Controlled numerical experiments with a coupled general circulation model (CGCM) are used to address the above two issues. The CGCM captures the in-phase ISM to ASM transition (i.e., a wet ISM followed by a wet ASM or a dry ISM followed by a dry ASM) and the out-of-phase ASM to ISM transition (i.e., a wet ASM followed by a dry ISM or a dry ASM followed by a wet ISM). These transitions are more frequent than the out-of-phase ISM to ASM transition and the in-phase ASM to ISM transition in the coupled model, consistent with observations. The results of controlled coupled model experiments indicate that both the Indian and Pacific Ocean air–sea coupling are important for properly simulating the biennial transition between the ISM and ASM in the CGCM. The biennial transition of the ISM can occur through local air–sea interactions in the north Indian Ocean when the Pacific ENSO is suppressed. The local sea surface temperature (SST) anomalies induce the Indian monsoon transition through low-level moisture convergence. Surface evaporation anomalies, which are largely controlled by surface wind speed changes, play an important role for SST changes. Different from local air–sea interaction mechanisms proposed in previous studies, the atmospheric feedback is not strong enough to reverse the SST anomalies immediately at the end of the monsoon season. Instead, the reversal of the SST anomalies is accomplished in the spring of the following year, which in turn leads to the Indian monsoon transition.
Neoproterozoic tectonic and climatic evolution recorded in the Gariep Belt, Namibia and South Africa

ABSTRACT The Pan‐African Gariep Belt in south‐western Namibia and westernmost South Africa provides an excellent window into the interplay between tectonic and climatic changes during the Neoproterozoic era. Recently acquired chemostratigraphic data from cap carbonate sequences above glaciogenic diamictite horizons, together with U–Pb zircon and Pb–Pb carbonate ages, indicate sedimentation in the Gariep Basin from continental break‐up around 770 Ma to basin closure and continent collision around 545 Ma. The basin is subdivided into an eastern failed rift graben and a western half graben that evolved into an oceanic basin between the Kalahari and the Rio de la Plata cratons. Three megasequences are distinguished in the external, para‐autochthonous part of the belt (Port Nolloth Zone): an early continental, predominantly siliciclastic, sag rift megasequence (M1), a passive continental margin, carbonate‐rich megasequence (M2), and a syn‐orogenic carbonate and flysch megasequence (M3). Two glaciogenic diamictite horizons at the end of M1 and M2 are recognized and they are correlated with the global ∼750 Ma Sturtian and ∼580 Ma Marinoan glaciations, respectively. While the former is restricted to proximal continental rift shoulders, the latter extends into the oceanic realm which marks the internal part of the belt (Marmora Terrane). Only the younger diamictite is associated with iron formation. The sequence of regressive and transgressive stages recorded by the sediment fill does not reflect simply the tectonic evolution from rifting to drifting and eventual basin closure, but is strongly controlled by severe climatically induced sea‐level changes that were either competing with or reinforcing tectonically induced sea‐level changes.
Changes in dissolved oxygen in the Southern Ocean with climate change

Climate models predict that increasing greenhouse gases in the atmosphere will change our climate. However, the range of observations available to assess these model predictions is limited. We have utilized an ocean biogeochemical model to project the impact of climate change on the oxygen cycle in the ocean and the air‐sea exchange of oxygen. With climate change, our model predicts an outgassing of oxygen from the ocean. In the model, the Southern Ocean is the region that displays the largest change in the air‐sea exchange of oxygen with climate change. The reduced oxygen uptake in the Southern Ocean is dominated by a reduction in convective mixing and in the subduction rate of bottom water which decreases the amount of dissolved oxygen in the Southern Ocean. Our model results suggest that dissolved oxygen is sensitive to changes in Southern Ocean circulation revealing the potential to use dissolved oxygen to test model predictions of climate change. From Southern Ocean observations collected 28 years a part we observed a decrease in dissolved oxygen that was consistent with model climate change simulation. This provides credibility to the climate model predictions. Additional analysis and observations of dissolved oxygen are needed to substantiate our climate model simulations.
The South America Monsoon Circulation and Its Relationship to Rainfall over West-Central Brazil

Abstract The mean atmospheric circulation for the rainy season over west-central Brazil (20°–10°S, 60°–50°W) is investigated for a 21-yr period (July 1979–June 2000). The NCEP–NCAR reanalysis, pentad outgoing longwave radiation (OLR), and daily gridded precipitation analyses from NCEP are used in this study. The analysis presented here provides an improved description of the mean annual cycle based on daily and pentad (5-day) rainfall and atmospheric circulation data. The pentad precipitation averaged for the study region shows a rapid increase during the spring months (September–November) and a rapid decrease in April. The rainiest period (more than 8 mm day−1) is from December to February. There are distinct wet (7 months) and dry (5 months) seasons, with approximately 90% of the total annual rainfall occurring during October–April. The rainy season begins following the period when temperature is at its seasonal maximum. The pre-rainy-season warmth acts to destabilize the atmosphere and to create a reve.
Contrasting Various Metrics for Measuring Tropical Cyclone Activity

Popular metrics used for measuring the tropical cyclone (TC) activity, including NTC (number of tropical cyclones), TCD (tropical cyclone days), ACE (accumulated cyclone energy), PDI (power dissipation index), along with two newly proposed indices: RACE (revised accumulated cyclone energy) and RPDI (revised power dissipation index), are compared using the JTWC (Joint Typhoon Warning Center) best-track data of TC over the western North Pacific basin. Our study shows that, while the above metrics have demonstrated various degrees of discrepancies, but in practical terms, they are all able to produce meaningful temporal and spatial changes in response to climate variability. Compared with the conventional ACE and PDI, RACE and RPDI seem to provide a more precise estimate of the total TC activity, especially in projecting the upswing trend of TC activity over the past few decades, simply because of a better approach in estimating TC wind energy. However, we would argue that there is still no need to find a ”universal” or ”best” metric for TC activity because different metrics are designed to stratify different aspects of TC activity, and whether the selected metric is appropriate or not should be determined solely by the purpose of study. Except for magnitude difference, the analysis results seem insensitive to the choice of the best-track datasets.
ROLE OF HYDROXYL ORIENTATION IN MICA ALTERATION

Phlogopite and biotite are generally more susceptible to alteration by ion exchange than muscovite. The key mechanism responsible for this difference is considered to be hydroxyl orientation. Single-crystal study with the infrared spectrophotometer established the orientation and bonding of the hydroxyl ions. The dipole moments of the hydroxyl ions in phlogopite, a trioctahedral mica, are perpendicular to the cleavage, whereas those in muscovite, a dioctahedral mica, are obliquely oriented. The hydroxyl ions in phlogopite absorb a higher frequency (3700 Cm −1 ) infrared than those in muscovite (3600 Cm −1 ). Biotite and iron-rich phlogopite generally show absorption at two frequencies, which indicates both trioctahedral and dioctahedral configurations. The inclined hydroxyl ions in dioctahedral mica place the potassium ions in a more negative environment than the perpendicular hydroxyl ions in trioctahedral mica. The more negative environment binds the potassium ions more securely in the lattice.
Ocean circulation beneath Filchner‐Ronne Ice Shelf from three‐dimensional model results

A high-resolution three-dimensional ocean circulation model is applied to the cavity beneath Filchner-Ronne Ice Shelf (FRIS). The model predicts predominantly barotropic currents which form a series of cyclonic gyres in the deep basins and anticyclonic circulations around the islands. The surface circulation can be such that the water moves in the direction of decreasing or increasing ice thicknesses, in the former case leading to freezing, while melting at the ice shelf base results in the latter case. The pattern of melting and freezing is consistent with known distributions of marine ice and melting areas beneath FRIS. An anticyclonic circulation around the Korff and Henry Ice Rises with melting west of Korff Ice Rise and freezing on the eastern side and north of Henry Ice Rise is the main source for an ice-pumping mechanism that produces the observed large marine ice body in the central Filchner-Ronne Ice Shelf. The estimates for net melting for realistic conditions at the open ocean boundary are 40-50 km 3 yr -1 , indicating that ice shelf-ocean interaction is an important contribution to the mass balance of the ice shelf.
Coherent composition of glacial dust on opposite sides of the East Antarctic Plateau inferred from the deep EPICA ice cores

The dust provenance identification through isotopic and geochemical tracers focused mostly on ice cores drilled in the Pacific‐Indian sector of Antarctica, where a common provenance of dust from Southern South America during glacial ages was demonstrated. Conversely, in other areas of the East Antarctic Plateau as Dronning Maud Land provenance was deduced indirectly from back trajectory analyses and soluble chemistry records. In this work, we present the first comparison of major elemental composition of dust archived in two ice cores from opposite sides of Antarctica, in the framework of the EPICA Project. Mineral particles extracted from the EDC and EDML cores date back to glacial MIS 2, 4 and 6, over the last 200 kyr. Results reveal a coherent geochemical dust composition at both locations, providing experimental evidence of a common provenance over the wide area of East Antarctica during glacials, and key analytical constrains for atmospheric general circulation models.
Tectonic cycles in the Strangways Metamorphic Complex, Arunta Inlier, central Australia: geochronological evidence for exhumation and basin formation between two high-grade metamorphic events*

Deformation, metamorphism and magmatism during the Strangways Orogeny in the eastern Arunta Inlier of central Australia appears to be a result of plate-margin-related tectonism along the southern margin of the North Australian Craton. SHRIMP zircon dating of basement and cover sequences in the Strangways Metamorphic Complex indicates that the Strangways Orogeny consisted of two distinct tectonothermal cycles between ca 1.79 and ca 1.71 Ga. Sedimentary protoliths of the Mt Bleechmore Granulite were deposited after ca 1.8 Ga and probably metamorphosed at ca 1.78 Ga (the Early Strangways Event). These rocks were subsequently exhumed and eroded, forming a basement on which the Ledan Package (Mendip Metamorphics, Ledan Schist and Utopia Quartzite) was deposited after ca 1.77 Ga. Metamorphic zircon overgrowths (1723 ± 9 Ma) and a pegmatite intrusion (1730 ± 4 Ma) in the Mendip Metamorphics record a second phase of deformation and metamorphism (the Late Strangways Event). The arc-like Huckitta and Inkamulla Granodiorites in the eastern Strangways Metamorphic Complex were intruded at 1762 ± 3 Ma and 1773 ± 4 Ma, respectively, suggesting that the Early Strangways Event was associated with subduction along the southern margin of the North Australian Craton. Exhumation and basin formation between the two periods of contraction was possibly a consequence of extension after the Early Strangways Event and related to A-type magmatism at ca 1.74 Ga in the eastern Strangways Metamorphic Complex. Metamorphic zircon overgrowths in the Huckitta Granodiorite have an age of 332 ± 3 Ma and record a phase of relatively high-grade metamorphism towards the end of the Alice Springs Orogeny.
Soil Aggregation and Fungal and Bacterial Biomass under Annual and Perennial Cropping Systems

Understanding the mechanisms controlling crop effects on soil aggregation is necessary to develop sustainable soil management practices. Changes in soil aggregation, carbohydrates, and fungal vs. bacterial biomass were monitored following a shift from fallow (bare soil) to various cropping systems. Faba bean (Vicia faba L.) and wheat (Triticum aestivum L.) were used as annual cropping systems, while alfalfa (Medicago saliva L.), timothy (Phleum pratense L.), bromegrass (Bromus inermis L.), and reed canarygrass (Phalaris arundinacea L.) were used as perennial cropping systems. Crops were established in spring 1989, on a silly clay loam (fine, mixed, frigid Typic Dystrochrept) and a clay loam (fine-loamy, mixed, frigid Typic Humaquept) near Quebec City (Canada). Alter three growing seasons, the mean-weight diameter of water-stable aggregates (MWD) was higher under reed canarygrass (2.26 mm in the clay loam and 2.45 mm in the silly clay loam) and timothy (2.13 and 2.26 mm) than under faba bean (1.92 and 1.89 mm) or wheat (2.06 and 1.57 mm). Intermediate values were found under alfalfa and bromegrass. Changes in MWD were not correlated with microbial biomass C. Acid-hydrolyzable carbohydrates correlated with MWD in the silly clay loam (r 2 = 0.42) but the relationship decreased with higher carbohydrate levels in the clay loam (r 2 = 0.05). Close correlations were found between MWD and both fungal glucosamine (r 2 = 0.68 *** , soils combined) and bacterial muramic acid (r 2 = 0.48 *** ). Changes in MWD were mostly reflected in aggregates >2 mm, and the close relationship with fungal glucosamine suggests that fungi played a dominant role in soil macroaggregation. Measurement of muramic acid and glucosamine is proposed as a potential approach to compare bacterial vs. fungal contributions to soil aggregation.
Ecosystem management for parks and wilderness.

The purpose of this book is to indicate why a new vision is necessary for park and wilderness management and to discuss strategies for cooperative management. It is not intended to define precisely what those goals should be. The workshop participants represented too narrow a group to set those goals even in a preliminary way, a fact recognized early in the workshop. However, this group was able to define a framework for future management to serve as a forum for park and wilderness ecosystem management. There will never be a single blueprint, a cookbook approach that will fit every park and wilderness situation. Unique legal, biological, and social situations guarantee that individualistic solutions be defined, and that those solutions remain flexible to incorporate new information and values within the intent of Congress. These themes comprise the common thread of the chapters to follow. The first and last chapters synthesize the workshop discussions. The intervening chapters are organized in a disciplinary fashion discussing legal issues, vegetation, wildlife, effects on terrestrial and aquatic resources from long-range air transport, perspectives on economics and human ecology, and finally three management perspectives. Each recognizes the problems of managing these park and wilderness ecosystems through past,more » outmoded paradigms, and the dangers of defining a rigid set of new paradigms. As a whole, the book provides a comprehensive view of our current problems and future opportunities for ecosystem management in parks and wilderness. « less
Note on the seasonal use of lowland and highland habitats by the West African Chimpanzee Pan troglodytes verus (Schwarz, 1934) (Primates: Hominidae): Implications for its conservation

The West African Chimpanzee Pan troglodytes verus is endangered. In order to gain insight into the survival potential of this subspecies in Senegal (West Africa), we investigated relationships between this primate and its habitat, particularly from a novel perspective: the influence of the topography on the seasonality of its distribution within its habitat. In Senegal chimpanzees are rarely seen in the wild, particularly outside of protected areas, which is where the present study was conducted on the basis of nest census findings (N=436). According to our observations between March 1998 and March 2000, we established that chimpanzees nested in the gallery forest during the dry season and higher areas (hills and plateaus, plateau edge gallery forests) during the rainy season. Valley flooding during the rainy season may be the major reason for chimpanzees to nest in the highlands. The results can help conservation managers to protect the species.
On the local meteorology at the marginal ice zone of the Bering Sea

In March 1981, detailed meteorological observations were made at the marginal ice zone in the Bering Sea during a period of northerly winds. A 20% increase in wind speed from 90 km inside the edge to 90 km over the ocean was observed. The temperature increased from −11°C to −5°C, and the boundary layer height over the ocean increased from 450 m to 600 m. Data support the concept of a diverging (accelerating) flow. A simple integrated slab model of the atmospheric boundary layer which includes the effects of clouds, surface heat flux, and radiative cooling is applied to the conditions of the marginal ice zone. The model shows that most of the observed variation in the marginal ice zone can be explained by drag variation over the ice and heat flux over the open ocean. Heat flux in the marginal ice zone and cloud processes affect the results only slightly.
Physical and optical properties of mineral dust aerosol during the Dust and Biomass-burning Experiment

[1] We present aircraft measurements of dust aerosol during the Dust and Biomass-burning Experiment (DABEX), a project affiliated with the African Monsoon Multidisciplinary Analysis. DABEX took place between 13 January and 3 February 2006 in Sahelian west Africa, with the aircraft based at Niamey, Niger. The data set is augmented with Aerosol Robotic Network (AERONET) data. A mineral dust layer below 1–2 km (sourced from the north) and an overlying biomass burning (BB) layer (sourced from anthropogenic fires to the south) was observed on all days, although variability was observed in both layers. There is evidence of ozone loss within the dust, but with CO levels between 140 and 170 ppbv some history of combustion has occurred. Size distribution of the dust is compared with that of the BB aerosol and with dust measured near Senegal, during the Dust Outflow and Deposition to the Ocean (DODO-1) experiment. For accurate representation of the optical properties, five log-normals to the size distribution across sizes 0.05–5 μm are required, although two log-normals are adequate. The single scattering albedo was almost purely scattering, with values of 0.99 ± 0.01. During the strongest dust events the dust contribution to the column optical depth was 75–80%, compared to a DABEX mean of 50%. The aircraft-derived optical depth varied between 0.19 and 1.07, with the dust-only contribution between 0.07 and 0.81. AERONET optical depth trends are in good agreement with aircraft during DABEX, albeit with a bias to higher aircraft values. Retrieved AERONET aerosol size distributions show variable agreement with the aircraft. Differences between Versions 1 and 2 of the AERONET algorithm are highlighted.
Smectite-illite-muscovite transformations, quartz dissolution, and Silica release in shales

Quantitative analysis of the smectite-to-illite and illite-to-muscovite transformations indicates that 17–28 wt. % SiO2 and 17–23 wt. % SiO2, respectively, are liberated during these reactions, assuming that Al is conserved. Dissolution of quartz silt in shales yields up to 6–9% SiO2 in the range up to 200°C and a further 10–15% SiO2 in the 200–500°C range. For muds altered to shales at 200°C, 14–20 wt. % silica is evolved. From 200 to 500°C, a further 18–28 wt. % silica is evolved. Additional small amounts of silica may be released in the alteration of feldspar to clay and by stylolitization of quartz silt. Thus, in the burial and temperature range of diagenesis into the epizone, major quantities of silica are released from clays and by quartz dissolution in shales. Within this range of alteration, concomitant decline of whole-rock Si/Al (SiO2/Al2O3) in the transformation of smectite to illite to muscovite suggests the liberated silica migrates from the source shale. As a result, the metamorphosed shales are more micaceous and less quartzose than their progenitor muds. In the diagenetic zone and anchizone, the evolved silica is probably a major source of quartz cement in sandstones. In the epizone, evolved silica is commonly present in quartz veins in the parent rocks. Fluid-inclusion temperatures in quartz overgrowths and fracture fillings in some sandstones suggest that some cements may have been derived from downdip basinal shales and pressure solution in sandstones.
Land use and water quality

: The interaction between land use and water quality is of great importance worldwide as agriculture has been proven to exert a huge pressure on the quality of groundwater and surface waters due to excess losses of nutrients (nitrogen and phosphorous) through leaching and erosion processes. These losses result in, inter alia, high nitrate concentrations in groundwater and eutrophication of rivers, lakes and coastal waters. Combatting especially non-point losses of nutrients has been a hot topic for river basin managers worldwide, and new important mitigation measures to reduce the input of nutrients into groundwater and surface waters at the pollution source have been developed and implemented in many countries. This Special Issue of the Land use and Water Quality conference series (LuWQ) includes a total of 11 papers covering topics such as: (i) nitrogen surplus; (ii) protection of groundwater from pollution; (iii) nutrient sources of pollution and dynamics in catchments and (iv) new technologies for monitoring, mapping and analysing water quality.