Convective Cloud Detection and Tracking from Series of Infrared Images

The most significant part of prediction of precipitation is the detection and identification of convective (cumulonimbus) clouds, also the tracking of cloud movement is important for identification of location of precipitation. A very simple methodology for detecting convective clouds and then tracking its movement from a series of infrared (IR) images is proposed in this paper. IR image is segmented using k-means clustering algorithm, which has been implemented using Euclidean, Manhattan and Mahalanobis distances and the results have been compared. Cloud clusters have been identified from segmented image and subsequently the large clusters were extracted. Center of Mass (CoM) was calculated for each selected cloud cluster and its position after every 30 min was predicted and compared with the actual values. If the predicted position deviates, the proposed models automatically adjusts itself, and the next prediction becomes closer to original values of position.     

Thermal decomposition pattern and particle size estimation of iron minerals associated with the Cretaceous‐Tertiary boundary at Gubbio

Abstract— Mössbauer studies of the samples from the Cretaceous‐Tertiary (K‐T) boundary layer at Gubbio, Italy show that iron appears mainly in two phases, magnetically ordered hematite and a paramagnetic silicate phase. The average particle size of hematite is estimated to be in the range of 16 to 27 nm from transmission electron micrographs and lack of a Morin transition. The hyperfine magnetic field at the iron nucleus is observed to be somewhat less than that of bulk hematite, which may be explained by collective magnetic excitation. Stepwise heating up to 1000°C shows a decomposition pattern of the paramagnetic phase, which suggests it to be a tri‐octahedral layer silicate. The iron‐bearing phases found in the bulk sedimentary K‐T boundary material are different from those found in the spherules separated from this material indicating that the redox conditions changed rapidly after the impact, becoming more oxidizing during the period these bulk phases were formed.     

Insight to Ecosystem Based Approach (EBA) at Landscape Level Using a Geospatial Medium

Ecosystem based approach (EBA) for resource management is a concerted, environmentally tuned and an integrated framework that holistically addresses the ecological character of the natural resource, its societal benefit spectrum and its environmental functions. In this paper, the EBA concept is closely linked with the emerging concept of multiple use systems (MUS) while taking account of environmental, economic, and social factors that govern the ecosystems services and benefits. We elucidate a multi-scalar approach and multiple case studies to understand EBA particularly in context of a wetlandscape. At the global scale, Ramsar sites of international importance are geospatially analyzed with reference to their agro-ecology and biodiversity. At regional scale, the agrarian use of inland wetlands in India was re-evaluated taking account of database from a recent inland wetland inventory. At the local scale, drawing on the landscape characterization and the ecological economics for fresh water Lake Kolleru in India and the Muthurajawela Marsh-Negombo Lagoon coastal marsh in Sri Lanka, we illustrate some of the practical challenges in balancing wetland conservation, development needs and the overall well-being of local people. We also discuss how variability in the scale, geophysical characteristics of the site and the data availability confines the ability to simplify a single complete approach to address issues in complex ecosystem such as wetlands. All levels of the study are supported by a variety of earth observation data and the geographical information system (GIS) tools. The site level analysis also draws on socio-economic assessment tools.     

Rationale for measurement of midocean tsunami signature

Abstract

Arguments are presented to justify midocean tsunami measurements and related investigations aimed toward improvement of tsunami prediction and warning. It is postulated that midocean tsunami signatures be measured simultaneously at several locations and correlated with high‐accuracy onshore measurements.     

Astronomical and terrestrial causes of physical, chemical and biological changes at geological boundaries

The boundary horizons of the Cretaceous-Tertiary (Um Sohryngkew River section, Meghalaya and Anjar section, Kutch), the Permo-Triassic (Guling, Lalung, Ganmachidam and Attargoo sections, Spiti valley) and the Eocene-Oligocene (Tapti River section, Gujarat) have been identified in the sedimentary records of the Indian subcontinent. These sections have been studied for geochemical anomalies. The results are discussed in the framework of extra-terrestrial and terrestrial causes proposed to explain the physical, chemical and mineralogical observations at these boundaries. A critical analysis suggests that although the astronomical causes, particularly the bolide impacts, can easily explain the geochemical and physical changes, the terrestrial causes (volcanism) may have played a significant role in creating the biological stress observed in fossil records (mass extinction) at or near some of these boundaries.     

Cosmogenic radioisotopes in the Dhajala chondrite: implications to variations of cosmic ray fluxes in the interplanetary space

Activities of a suite of radioisotopes ranging in half-life from 5.6 days (⁵²Mn) to 3.7 m.y. (⁵³Mn) have been measured in the Dhajala chondrite. The results show that all the radioactivities are close to the expected levels except⁵⁴Mn and ²²Na. Their activities are higher than those based on the interplanetary fluxes at 1 A.U. near the ecliptic, expected immediately before the fall of Dhajala, corresponding to the time of solar minimum. Furthermore, activity ratios of ⁵⁴Mn/⁵³Mn and ²²Na/²⁶Al are higher by 30–50% than expected. The departure from the expected values is discussed in terms of spatial variations of cosmic rays based on the computed orbital parameters of the meteoroid. If the galactic cosmic ray fluxes in the equatorial region (±15°) are assumed to be the same as in the ecliptic plane then these results suggest higher fluxes by 33 ± 7% at heliographic latitudes 15–40°S, during solar minimum.     

Cosmic ray effects in the solar system objects

Long term characteristics of solar and galactic cosmic rays, as revealed by the study of their nuclear effects in lunar, meteoritic and terrestrial samples are summarised. The data so far available on radioisotopes, noble gases and tracks, though limited, are consistent with nearly constant fluxes and composition during different epochs over billions of years; one exception is¹⁴C activity in the earths atmosphere over the past few hundred years, suggesting a variation in the solar activity. Other small or brief variations, which cannot be ruled out as yet, require better estimation of depth and size dependence of nuclear effects in rocks before they can be attributed to cosmic rays.     

Late Quaternary geomorphic evolution of the lower Narmada valley, Western India: implications for neotectonic activity along the Narmada–Son Fault

Geomorphic data combined with stratigraphic studies provide significant information to constrain timing and amount of fault movement. The lower Narmada valley lies astride the Narmada–Son Fault (NSF), an important ENE–WSW-trending tectonic element responsible for the current intraplate seismicity being experienced in the central part of the Indian plate. Varying nature and degree of tectonic movements along the NSF during Late Pleistocene and Holocene have produced four geomorphic surfaces in the lower Narmada valley: the alluvial plain (S₁), ravine surface (S₂), a gravelly fan surface (S₃) and the valley fill terrace surface (S₄). Two major phases of tectonic movements in a compressive stress regime are recorded along the NSF: slow synsedimentary subsidence of the basin during Late Pleistocene due to differential movement, followed by inversion of the basin during the Holocene marked by differential uplift along the NSF. The study suggests that the inversion of the basin is in response to the significant increase in the intensity of compressive stresses in the Indian plate mainly during the Early Holocene. The present incisive drainage and recent seismic activity indicate that the compressive stresses continue to accumulate along the NSF due to continued northward movement of the Indian plate.     

Nighttime fluctuations (scintillations) in Faraday rotation angle of VHF signals from geostationary satellites

Faraday rotation angle records of VHP (137.35 MHz) signals from ATS-3 received at São José dos Campos (Magnetic dip-23.7°) exhibit nighttime fluctuations during equinoctial and summer months. These fluctuations have periodicities ranging from several seconds to about an hour. We investigate the relationship between these fluctuations and the F-layer irregularities.