Aerosol radiation cloud interactions over the tropical Indian Ocean prior to the onset of the summer monsoon

Prior to the summer monsoon, from December to April every year, the trade wind blowing from the northeast brings polluted continent air over the Arabian Sea and the tropical Indian Ocean. A variety of fine suspended particles, majority of them manmade, get accumulated over the ocean region till the summer monsoon sets in and cleans the atmosphere. Aerosols have long been recognized for their role in cloud development and rain formation. They act as condensation nuclei for the formation of raindrops and help precipitation. But, if they are present in large quantities they produce a narrow spectrum of small cloud droplets and do not allow the droplets to grow. These clouds do not precipitate and the rain formation is inhibited. The aerosol-cloud interaction could be playing a crucial role on the onset of monsoon over different regions and the spatial distribution of rain over India. Recent observations over the Arabian Sea and the tropical Indian Ocean, conducted as part of the Indian Ocean Experiment, have revealed the presence of large amount of aerosols over these regions. The aerosols brought from the Indian subcontinent and other surrounding regions have relatively high concentration of soot particles, which substantially reduce the amount of solar radiation reaching the ocean surface. Results on this direct effect of aerosols on the radiation budget as well as their impact on cloud properties are presented and discussed

Raman spectroscopy of intermediate valent (IV) systems: electron-phonon coupling and charge fluctuation

Raman scattering measurements on intermediate valent rare earth chalcogenides crystallizing in the NaCl structure are reviewed. The experimentally obtained Raman intensities are compared with the theoretically calculated intensities, using a lattice dynamical model in which the electron lattice interaction has been expressed in terms of local intraionic charge deformabilities, with monopolar (breathing Γ+ 1), dipolar (Γ- 15), and quadrupolar (Γ+ 12) symmetry. Phonon anomalies in SmS, Sm0·75 Y0·25S and YS are described and discussed. Finally, evidence for a new excitation involving 4f charge fluctuations is presented, which is observed as a dispersionless excitation in the acoustic-optic phonon gap in (IV) materials

A Study on Caring Perception of Informal Caregivers of Elders

The advancement in public health and medical technologies, during the twenty first century leads to increase the life expectancy, it leads to over population especially aging. Increasing number of elders has been increasing in the number of elders with disability; hence the elders require the palliative care assistance to fulfill their daily activities with the help of formal or informal caregivers. The informal caregivers of elders refers to non-paid individuals, who are primarily responsible for providing and/or coordinating care of the elders in their house, such as a spouse, offspring, other relative and non-relative, they act as anticipatory, preventive, supervisory, instrumental and protective roles. The rapid changes of familial system, the caregivers of elder were faced psycho-social, physical and financial problems. The researcher was motivated to undertake the level of caregiver caring perception of BPL (Below Poverty Line) informal care givers of elder at Coimbatore city with the objectives of to assess the personal background of the selected respondents and to find out the different levels of caregiver caring perception. The researcher adopted descriptive research design, census method of sampling and interview schedule is the tool for data collection in his study. The strong filial-piety norms, traditional values and community respect were influenced the positive thoughts as well as the financial problems, tedious caring job, difficulty in fulfilling the elders’ basic needs were negative thoughts of caring the informal caregivers of elders. Keywords: Informal caregiver, BPL (Below Poverty Line), Perception, Strong filial-piety norms, Community respec

Characterization of the domain chaos convection state by the largest Lyapunov exponent

Using numerical integrations of the Boussinesq equations in rotating cylindrical domains with realistic boundary conditions, we have computed the value of the largest Lyapunov exponent lambda1 for a variety of aspect ratios and driving strengths. We study in particular the domain chaos state, which bifurcates supercritically from the conducting fluid state and involves extended propagating fronts as well as point defects. We compare our results with those from Egolf et al., [Nature 404, 733 (2000)], who suggested that the value of lambda1 for the spiral defect chaos state of a convecting fluid was determined primarily by bursts of instability arising from short-lived, spatially localized dislocation nucleation events. We also show that the quantity lambda1 is not intensive for aspect ratios Gamma over the range 20<Gamma<40 and that the scaling exponent of lambda1 near onset is consistent with the value predicted by the amplitude equation formalism

Airborne lidar study of the vertical distribution of aerosols over Hyderabad, an urban site in central India, and its implication for radiative forcing calculations

Use of a compact, low power commercial lidar onboard a small aircraft for aerosol studies is demonstrated. A Micro Pulse Lidar fitted upside down in a Beech Superking aircraft is used to measure the vertical distribution of aerosols in and around Hyderabad, an urban location in the central India. Two sorties were made, one on 17 February 2004 evening hours and the other on 18 February 2004 morning hours for a total flight duration of four hours. Three different algorithms, proposed by Klett (1985), Stephens et al.&amp;nbsp;(2001) and Palm et al.&amp;nbsp;(2002) for deriving the aerosol extinction coefficient profile from lidar data are studied and is shown that the results obtained from the three methods compare within 2%. The result obtained from the airborne lidar is shown more useful to study the aerosol distribution in the free troposphere than that obtained by using the same lidar from ground. Using standard radiative transfer model the aerosol radiative forcing is calculated and is shown that knowledge on the vertical distribution of aerosols is very important to get more realistic values than using model vertical profiles of aerosols. We show that for the same aerosol optical depth, single scattering albedo and asymmetry parameter but for different vertical profiles of aerosol extinction the computed forcing values differ with increasing altitude and improper selection of the vertical profile can even flip the sign of the forcing at tropopause level

Absorbing aerosols: contribution of biomass burning and implications for radiative forcing

Absorbing aerosols supplements the global warming caused by greenhouse gases. However, unlike greenhouse gases, the effect of absorbing aerosol on climate is not known with certainty owing to paucity of data. Also, uncertainty exists in quantifying the contributing factors whether it is biomass or fossil fuel burning. Based on the observations of absorption coefficient at seven wavelengths and aerosol optical depth (AOD) at five wavelengths carried out at Gadanki (13.5&#176; N, 79.2&#176; E), a remote village in peninsular India, from April to November 2008, as part of the "Study of Atmospheric Forcing and Responses (SAFAR)" pilot campaign we discuss seasonal variation of black carbon (BC) concentration and aerosol optical depth. Also, using spectral information we estimate the fraction of fossil-fuel and nonfossil fuel contributions to absorption coefficient and contributions of soot (Black Carbon), non-soot fine mode aerosols and coarse mode aerosols to AOD. BC concentration is found to be around 1000 ng/m3 during monsoon months (JJAS) and around 4000 ng/m3 during pre and post monsoon months. Non-fossil fuel sources contribute nearly 20% to absorption coefficient at 880 nm, which increases to 40% during morning and evening hours. Average AOD is found to be 0.38&#177;0.15, with high values in May and low in September. Soot contributes nearly 10% to the AOD. This information is further used to estimate the clear sky aerosol direct radiative forcing. Top of the atmosphere aerosol radiative forcing varies between -4 to 0Wm-2, except for April when the forcing is positive. Surface level radiative forcing is between -10 to -20Wm-2. The net radiation absorbed within the atmosphere is in the range of 9 to 25Wm-2, of which soot contributes about 80 to 90%

Pressure-induced changes in the reflectivity of SmSe and some comments on Nd-substituted SmSe

Pressure induced changes in the reflectivity of SmSe have been investigated up to 70 kbar hydrostatic pressure, using the gasketted diamond anvil high‐pressure x‐ray apparatus in conjunction with an optical microspectroscopic system. The effect of Nd substitution on the lattice parameter, resistivity, and color of SmSe has also been studied. Reflectivity data for GdSe at ambient pressure have been obtained for comparison with the metallic phase of SmSe. With increasing pressure the color of the sample (as observed in reflected light) goes through a sequence of changes, from black, steel‐blue, deep purple, reddish purple, copperlike metallic color to bronze yellow at the highest pressure. From the reflectivity data, the static conductivity has been evaluated and is compared with the dc conductivity, previously measured on SmSe single crystals under hydrostatic pressure. Deviations from Drude theory indicate that the interband contribution to the dielectric constant plays an important role in determining the sequence of metallic colors observed in metallic rare‐earth monochalcogenides

Aerosol characteristics and aerosol radiative forcing over Maitri, Antarctica

During the 20th Indian Antarctic expedition conducted in January-February 2001, a detailed study on the aerosol spectral optical depth, mass concentration and size-distribution along with columnar ozone and watervapour concentrations was made from the Indian station, Maitri (70.77&#176; S, 11.73&#176; E). A low aerosol optical depth of about 0.03 at 400 nm wavelength and a dry aerosol mass concentration of about 7 &#181;g/m3 for the PM10 particles are found for this anthropogenically least-affected continent on the earth. The aerosol sizedistribution reveals that about 63% of the total aerosol mass comes from particles of size greater than 1 &#181;m, which are of mainly natural origin. Average columnar ozone and total precipitable water-vapour content during the observation period were found to be 271.6 DU and 0.147 cm respectively, and the observed day-to-day variations are explained using air back-trajectory analysis. Estimation of aerosol radiative forcing over Maitri reveals a positive forcing of 0.95 W/m2 at the top of the atmosphere and -0.83 W/m2 at the surface. Using model calculations, it is shown that these forcing values can have large annual variation both in magnitude and sign due to variation in the sun-earth geometry, typical of a polar region, even if we assume a constant aerosol amount throughout the year