ENSO,the IOD and the intraseasonal prediction of heat extremes across Australia using POAMA-2

The simulation and prediction of extreme heat over Australia on intraseasonal timescales in association with the El Niño–Southern Oscillation (ENSO) and the Indian Ocean Dipole (IOD) is assessed using the Bureau of Meteorology’s Predictive Ocean Atmosphere Model for Australia (POAMA). The analysis is based on hindcasts over 1981–2010 and focuses on weeks 2 and 3 of the forecasts, i.e. beyond a typical weather forecast. POAMA simulates the observed increased probabilities of extreme heat during El Niño events, focussed over south eastern and southern Australia in SON and over northern Australia in DJF, and the decreased probabilities of extreme heat during La Niña events, although the magnitude of these relationships is smaller than observed. POAMA also captures the signal of increased probabilities of extreme heat during positive phases of the IOD across southern Australia in SON and over Western Australia in JJA, but again underestimates the strength of the relationship. Shortcomings in the simulation of extreme heat in association with ENSO and the IOD over southern Australia may be linked to deficiencies in the teleconnection with Indian Ocean SSTs. Forecast skill for intraseasonal episodes of extreme heat is assessed using the Symmetric Extremal Dependence Index. Skill is highest over northern Australia in MAM and JJA and over south-eastern and eastern Australia in JJA and SON, whereas skill is generally poor over south-west Western Australia. Results show there are windows of forecast opportunity related to the state of ENSO and the IOD, where the skill in predicting extreme temperatures over certain regions is increased.     

Long term shoreline oscillation and changes of Cauvery delta coastline inferred from satellite imageries

Coastal zone is highly volatile ecosystem which is always in adjustments. Loss of shore line will cause severe impact on human life and as well as their properties. Remote sensing is a reliable technique to study the historical shoreline changes. Therefore in this paper long term shoreline oscillations of Cauvery delta shorelines at Poompuhar, Tharangambadi and Nagapattinam were studied using satellite imageries and the same was physically observed at the above three locations with the help of reference pillars and compared mutually. It was observed that the shoreline at Poompuhar is under accretion at the rate of 1.79m/ year and other shoreline stretches at Tharangambadi and Nagapattinam were under erosion at 0.4888m/ year and 0.4985m/ year respectively. It was also observed that the remote sensing study qualitatively matches with the physical observation for all the three coastal stretches of the study area.     

Uvaichnites riojana: A new crane-like bird ichnotaxon from the lower Miocene of La Rioja (Ebro Basin,Spain)

A new bird ichnotaxon found in Cenicero (La Rioja, Ebro Basin, Spain) is described here. The footprints are preserved in sandstone beds in a central-distal alluvial fringe with a mud-dominated floodplain, located in the transition unit between the Nájera and Haro formations. This level is positioned between the Y and Z local Agenian biozones (lower Miocene). The footprints were preliminarily studied in another work and considered as an indeterminate ichnotaxon. Uvaichnites riojana ichnogen. nov. and ichnosp. nov. is a tridactyl footprint characterized by a prominent central pad, very large to enormous sized, with unjointed toes at the proximal end. These features differ from Aquatilavipes, Aviadactyla, Avipeda, Ludicharadripodiscus, Fuscinapeda, and Ornithotarnocia of the Avipedidae morphofamily. U. riojana is considered to be similar to common crane (Grus grus) footprints in the Gruidae family. There are a few references about this family in the Iberian Peninsula and Balearic Islands and this find could confirm the presence of Gruidae since at least the lower Miocene.     

The stability of road cut cliff face along SH-121: a case study

Rockfall is one of the major concerns along highways, settlements and forests around the globe. Amboli road cut hill is one such region which is highly vulnerable and suffers from recurrent rockfall mostly in the rainy season, which blocks the State Highway 121 for considerable period of time. The steep and highly jointed slope along the road makes the zone prone to failure due to rainwater action. This road experiences heavy traffic throughout the year as it is the only road connecting Goa to Satara and Kolhapur via Sawantwadi in Maharashtra State, India. Therefore, an attempt has been made in this study to understand the stability of the cliff face. A combination of field study and 2D computer simulation was performed to assess surface characteristics of the cliff face. Bounce height, translational kinetic energy, translational velocity and factor of safety for saturated condition have been estimated. The result of this study shows that the rock face is highly unstable taking into consideration the environmental condition and daily traffic. Proper preventive measures have also been suggested to arrest the movement of falling rocks before reaching the roads or valleys. It is a belief that if proper care is taken, then further uncertain rockfall hazards can be prevented.     

Cobalt zoning in microscopic pyrite from Kamoto,Republic of the Congo (Kinshasa)

The Kamoto deposit consists of two stratiform orebodies separated by a barren sedimentary unit. It is a copper and cobalt deposit, the main features of which are summarized in the first part of the paper. Above the upper orebody, dolostone beds are found, where pyrite is the only sulfide mineral. This pyrite was investigated with the help of a microprobe: all idiomorphic grains were found to be surrounded by a well-defined rim, where the cobalt content reaches 4%; framboidal grains were also found to be heterogeneous with respect to cobalt. The distribution of nickel and copper is described. These observations afford one more evidence that post-depositional events played an important role in the Mine Series of Katanga, especially with regard to heavy metals geochemistry.

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Resume Le gisement de Kamoto est constitué de deux corps minéralisés stratiformes séparés par une unité sédimentaire stérile. C'est un gisement de cuivre et de cobalt dont les principales caractéristiques sont brièvement résumées. Audessus du corps minéralisé supérieur, on trouve des couches de dolomie, où la pyrite est le seul sulfure présent. Cette pyrite a été étudiée à l'aide d'une microsonde: tous les grains idiomorphes y sont entourés d'une bordure bien nette, où la teneur en cobalt atteint 4%; les grains d'apparence framboïdale sont également hétérogènes au point de vue de leur teneur en cobalt. La distribution du nickel et du cuivre est décrite. Ces observations apportent um témoignage supplémentaire de l'importance des événements postérieurs au dépôt dans la «Série des Mines» katangaise, tout spécialement en ce qui concerne la géochimie des métaux lourds. Elles démontrent que le «système» constitué par la roche sédimentaire est resté ouvert pendant un certain temps après la sédimentation.

     

Mass Spectrometric Isotope Dilution Determination of Cadmium in Geochemical Reference Samples

Twenty seven geochemical reference samples have been analysed for cadmium using the stable isotope dilution technique. These include four USGS, one NBS, five CRPG, eleven ANRT and six NIMROC samples. Each sample has been analysed at least in duplicate.
The four USGS samples have previously been measured in this laboratory by Rosman and De Laeter, but the present results are believed to be more accurate than the earlier data. Our results for the other twenty three samples are much lower than most of the published data. There is also evidence of cadmium inhomogeneities in some of the samples.     

A comparison of channel-base currents and optical signals for rocket-triggered lightning strokes

A comparative analysis has been performed of the channel-base current and light waveforms for four rocket-triggered lightning strokes. It has been found that the current and light signals at the bottom of the channel exhibit a linear relationship (direct proportionality) in their rising portions. However, just after the peaks the linearity disappears, and the light signals usually decrease faster than the currents during the next several microseconds. Later, this trend is reversed and in some cases the light signals show another rising trend, even when the currents continue to decrease. The linear light/current relationship for the rising portions of the waveforms appears to be the same for different strokes. The findings support the idea of evaluating the variation of return stroke current along the lightning return stroke channel using light signals, provided that evaluation is limited to the rising portions of those signals and assuming that the light/current relationship observed at the bottom of the channel holds at other heights.     

Evaluation of the spatial changes in seagrass cover in the lagoons of Lakshadweep islands,India, using IRS LISS III satellite images

A study was conducted in Lakshadweep islands to determine the feasibility of using Indian Remote Sensing (IRS) satellites for detecting changes in the seagrass from other coastal features. IRS ID and IRS P6 LISS III having spatial resolution of 23.5 m with lower cost compared to all other contemporary satellites with the same spatial resolution have not been widely used for monitoring the changes in seagrass cover. In this context, the present study attempted to explore the effectiveness of LISS III data for mapping seagrasses and to inform the international community about the usefulness of these low-cost imageries for coastal resource monitoring. Supervised classification and change detection studies found a significant decrease in seagrass cover of 73.03 ha in the Lakshadweep group of islands. An overall accuracy of 67.5% was obtained for the change maps, and seagrass cover and its changes vary at different islands.     

Pravčice Rock Arch (Bohemian Switzerland National Park, Czech Republic) deterioration due to natural and anthropogenic weathering

The dominant factors affecting the development of weathering forms on the Prav?ice Rock Arch (PRA) (Bohemian Switzerland National Park, Czech Republic) are discussed, based on the in situ monitoring of weathering forms, as well as on laboratory studies of materials taken from this site. The in situ monitoring shows the progressive development of distinct weathering forms (delamination of case-hardened rock surfaces, cyclic efflorescence, and granular disintegration of exposed weakly cemented rock mass) in specific portions of the PRA, whose location is controlled by lithology, jointing/local hydrodynamics, and exposure to climatic factors. From the analysis of efflorescence, the dominance of sulphates is evident; particularly of gypsum and alums. However, the synergistic effects of the several salt species (that also include minor nitrates and chlorides) upon the mechanical disintegration of sandstone can be expected.