An atmospheric instability derived with MODIS profile using real-time direct broadcast data over the Indian region

In this study, assessing the atmospheric instability, a new index, named here as MODIS (Moderate Resolution Imaging Spectroradiometer) profile index (MPI), has been statistically computed using temperature and moisture profile data from the real-time direct broadcast receiving systems installed at three places of India Meteorological Department. The training dataset has been prepared using MODIS temperature and moisture profile from the Aqua and Terra satellites over the Indian region for clear and convective weather conditions during the period of March to June 2011. The MPI values are produced at 5?×?5?km pixel resolution when at least 6 out of 9 FOVs from MODIS granules are found cloud free. If more than 3 FOVs are cloudy, the MPI has not been computed. The formulation of MPI and its comparison have been examined with well-established traditionally used K index, Lifted Index and total totals index derived from radiosonde profiles of temperature, pressure and humidity. It has been observed that in most of the cases, MPI has well correlated with those derived from ground truth observations. Therefore, spatially interpolated MPI can be utilized as an indicator for regional and location-specific forecast over the areas where radiosonde data are not available. The results also indicated that MPI can be used as a sensitive measure in very early stages of instability developments such as thunderstorm and rainfall because no other single stability index can provide a distinct threshold value for these events. Therefore, a single MPI value at a certain threshold can be treated as a stability index instead of other available indices. It is also being proposed that the inclusion of MPI as a stability parameter in physical or numerical modeling can improve accurate local severe storm predictions as a useful predictor and can also be used as diagnostic tools. The MPI can make a useful simulation using entire temperature and moisture profile data for the assessment of instability significantly to severe weather forecasting since other instability indices are often derived from a fixed pressure level quantity of vertical profile parameters.     

Toxicity of Diluted Dyeing and Printing Industry Effluent to a Penaeid Prawn,Parapenaeopsis sculptilis (Heller)

Experiments were carried out on the toxicity of diluted dyeing and printing industry effluent to a penaeid prawn, Parapenaeopsis sculptilis (Heller). Effluent tolerance experiments showed that both juvenile and adult prawns were unable to withstand the increasing concentration of the effluent. Juveniles were more susceptible to effluent than adults. As a consequence of higher consumption of energy due to the disturbed metabolism a decrease in the metabolite content was observed, whereas the content of ions showed an irregular trend with all the concentrations. The behavioural study showed that before death both juvenile and adult prawns became inactive, followed by paralysis. The physico-chemical nature of the effluent showed high amounts of solids, BOD, COD, sodium, magnesium, calcium, chloride, ammonium nitrogen, sulphate and absence of DO, probably causing an osmotic imbalance in the prawn body which leads to early mortality. Even a 1% concentration of such an effluent of a physico-chemical nature was reported to be toxic to the prawns.     

Simultaneous microwave observations of solar flares at 6 and 20 cm wavelengths using the VLA

Using the Very Large Array, solar burst observations have been carried out simultaneously at 6 and 20 cm. Structural changes and preheating have been observed in the flaring regions on time scales of minutes to tens of minutes before the onset of the burst impulsive phase. The 6 cm burst sources are located close to the neutral line, or near the legs of a flaring loop. The 20 cm burst sources show complex and extended structures spatially separated from both the preburst emission and the gradual decay phase of the burst. We interpret the observations in terms of a two-component flare model (bulk heating as well as acceleration of particles) and derive the physical parameters of the burst sources.On leave of absence from Indian Institute of Astrophysics, Bangalore, India.     

Palaeoproterozoic metamorphism in the Jeori-Wangtu Gneissic Complex (JWGC), western Himalayas

The Jeori-Wangtu Gneissic Complex (JWGC) exposed as a tectonic window in the Lesser Himalayas represents one of the oldest Gneissic Complex of the Himalayas. Foliated granite and the metapelite constitute the dominant lithologies of the JWGC. The western margin of the JWGC is bounded by a brittle shear while in the east, the tectonic surface is a ductile shear zone.Kyanite schist, chloritoid schist, staurolite schist (St-1), garnet schist and staurolite schist (St-2) are present in a west to east sequence beginning from near to the Jhakhri thrust and up to the contact with the JWGC granite. Mica schist is intermittently present and is the dominant metapelite. Low to medium grade regional metamorphic conditions has been inferred for these rocks.Calc silicate enclaves within the JWGC granite preserve the contact metamorphic effects. These are reflected in development of narrow zones of disequilibrium assemblages of calcareous garnet (grs₅₃), clinopyroxene, K feldspar, calcic plagioclase (An₈₆), quartz, zoned sphene, zoned allanite, amphiboles, calcite and epidote.Recording of contact metamorphic assemblage of 1.80 Ga granite witin the enclave calc silicates and in the host metapelites over an earlier, relict low to medium grade assemblage indicates that the JWGC preserves palaeoproterozoic metamorphic imprints.     

http://www.sciencedirect.com/science/article/pii/S1674987110000356

We have analyzed the July 15,2009,Fiordland earthquake(M_w 7.8),which occurred in the southwestern part of the South Island of New Zealand.This thrust-related earthquake in the southern Fiordland subduction zone is the largest New Zealand earthquake in the past 80 years.We have constrained a rupture model for this earthquake using coseismic offsets derived from the continuous geodetic network(Global Positioning System) of the New Zealand Institute of Geological and Nuclear Sciences (GNS Science).Our anal...     

Positions of type II fundamental and harmonic sources in the 30–100 MHz range

Observations of a type II burst with fundamental and harmonic structure were made, with the Clark Lake Radio Observatory's E-W and N-S sweep frequency interferometers operating in the range 120–20 MHz with time and frequency resolution of 1 s and 100 kHz, respectively. The type II burst was preceded by a type III-type V, and the associated flare of importance SN was located at S 20 W 73. The interferometric data show that the fundamental and harmonic were coincident in position. Further, the type III positions as a function of frequency were practically the same as those of the type II burst. The implications of these results are discussed.     

Decameter storm radiation,II

The physical properties of six decametric storms, observed at Clark Lake Radio Observatory are studied. The height of the storm continuum sources was determined from the rotation rate. Assuming that the radiation originates at the plasma frequency we computed the gradient of electron density for the regions where the storms originate. The mean angular size of the decametric continuum sources is large; it increases with decreasing frequency. The storm continuum is found to be strongly directive toward the disk center. The east-west asymmetry, well observed at meter wavelengths is also observed at decameter wavelengths. The occurrence of two distinct classes of type III bursts in storms is discussed: ‘off-fringe’ and ‘onfringe’ type Ill's. The ‘off-fringe’ Ill's are found to be displaced in position from the continuum source ; on the other hand, the ‘on-fringe’ ones coincide in position with the continuum. These two kinds of bursts differ in other properties as well. A model of the storm region is proposed. The continuum radiation and the ‘on-fringe’ type III's are believed to originate above closed magnetic loops, in regions of diverging field lines; the ‘offfringe’ type Ill's are thought to be excited by energetic electron streams, having access to open magnetic field lines at the base of the loops.     

Non-radial magnetic field structures in the solar corona

We report on the structure and geometry of coronal magnetic fields inferred from the observations of meter-decimeter type III and moving type IV radio bursts, associated with a Hα flare. This is the first report of type III radio bursts from the Nançay radioheliograph after it acquired the two-dimensional multifrequency capability. Dispersion of the radio source positions with frequency suggests that open and closed field lines are considerably inclined to the radial direction which is consistent with the connectivity observed in the magnetogram. We suggest that multiple arch systems are involved in the type IV emission. From the polarization and dispersion characteristics of the type IV source, we infer that the emission is due to fundamental plasma emission.     

Slab detachment of subducted Indo-Australian plate beneath Sunda arc,Indonesia

Necking, tearing, slab detachment and subsequently slab loss complicate the subduction zone processes and slab architecture. Based on evidences which include patterns of seismicity, seismic tomography and geochemistry of arc volcanoes, we have identified a horizontal slab tear in the subducted Indo-Australian slab beneath the Sunda arc. It strongly reflects on trench migration, and causes along-strike variations in vertical motion and geochemically distinct subduction-related arc magmatism. We also propose a model for the geodynamic evolution of slab detachment.