Facility•Ahmedabad, Gujarat, India•
About: Physical Research Laboratory is a facility organization based out in Ahmedabad, Gujarat, India. It is known for research contribution in the topics: Neutrino & Monsoon. The organization has 2612 authors who have published 6379 publications receiving 122246 citations. The organization is also known as: PRL.
Papers published on a yearly basis
Scripps Institution of Oceanography1, Max Planck Society2, Council of Scientific and Industrial Research3, Leibniz Association4, Indiana University5, Georgia Institute of Technology6, University of California, San Diego7, University of Hawaii at Manoa8, Oregon State University9, National Center for Atmospheric Research10, Met Office11, Goddard Space Flight Center12, Desert Research Institute13, Physical Research Laboratory14, Florida State University15, Urbana University16, Lawrence Berkeley National Laboratory17, Climate Monitoring and Diagnostics Laboratory18, University of Cambridge19, University of Miami20, Pacific Northwest National Laboratory21, Université Paris-Saclay22, University of Alaska Fairbanks23, National Oceanic and Atmospheric Administration24, Complutense University of Madrid25
TL;DR: The Indian Ocean Experiment (INDOEX) documented this Indo-Asian haze at scales ranging from individual particles to its contribution to the regional climate forcing as discussed by the authors, and integrated the multiplatform observations (satellites, aircraft, ships, surface stations, and balloons) with one-and four-dimensional models to derive the regional aerosol forcing resulting from the direct, the semidirect and the two indirect effects.
Abstract: Every year, from December to April, anthropogenic haze spreads over most of the North Indian Ocean, and South and Southeast Asia. The Indian Ocean Experiment (INDOEX) documented this Indo-Asian haze at scales ranging from individual particles to its contribution to the regional climate forcing. This study integrates the multiplatform observations (satellites, aircraft, ships, surface stations, and balloons) with one- and four-dimensional models to derive the regional aerosol forcing resulting from the direct, the semidirect and the two indirect effects. The haze particles consisted of several inorganic and carbonaceous species, including absorbing black carbon clusters, fly ash, and mineral dust. The most striking result was the large loading of aerosols over most of the South Asian region and the North Indian Ocean. The January to March 1999 visible optical depths were about 0.5 over most of the continent and reached values as large as 0.2 over the equatorial Indian ocean due to long-range transport. The aerosol layer extended as high as 3 km. Black carbon contributed about 14% to the fine particle mass and 11% to the visible optical depth. The single-scattering albedo estimated by several independent methods was consistently around 0.9 both inland and over the open ocean. Anthropogenic sources contributed as much as 80% (±10%) to the aerosol loading and the optical depth. The in situ data, which clearly support the existence of the first indirect effect (increased aerosol concentration producing more cloud drops with smaller effective radii), are used to develop a composite indirect effect scheme. The Indo-Asian aerosols impact the radiative forcing through a complex set of heating (positive forcing) and cooling (negative forcing) processes. Clouds and black carbon emerge as the major players. The dominant factor, however, is the large negative forcing (-20±4 W m^(−2)) at the surface and the comparably large atmospheric heating. Regionally, the absorbing haze decreased the surface solar radiation by an amount comparable to 50% of the total ocean heat flux and nearly doubled the lower tropospheric solar heating. We demonstrate with a general circulation model how this additional heating significantly perturbs the tropical rainfall patterns and the hydrological cycle with implications to global climate.
TL;DR: A review of the use of 15N/14N ratios in investigating sources and mechanisms of pollution in the hydrosphere is given in this paper, where it is shown that these differences are largely the result of kinetic isotope fractionation associated with bacterially-mediated reactions.
Abstract: Pollution of the hydrosphere and atmosphere by compounds of nitrogen is a serious problem. This paper reviews the manner in which studies of natural abundance 15N/14N ratios may be employed in investigating the sources and mechanisms of pollution. Cultivation-induced mineralization of soil nitrogen, fertilizer, and animal or sewage wastes are the three main sources of nitrate pollution in the hydrosphere. In many cases these sources produce nitrate with distinguishable 15N/14N ratios, and on this basic isotopic data for nitrate have been successfully used for identifying the source of pollution in a wide variety of ground- and surface water environments. Distinction between continentally- and marine-derived organic nitrogen in ecologically sensitive coastal waters also appears possible. These differences in 15N/14N ratios, however, are largely the result of kinetic isotope fractionation associated with bacterially-mediated reactions. The unpredictable magnitude of this type of fractionation tends to restrict the use of nitrogen isotope data in the hydrosphere to semi-quantitative interpretations. Observations of the isotopic fractionation between nitrogen compounds in the atmosphere may provide valuable information on whether their physico-chemical reactions are controlled by kinetic or by equilibrium processes. The possibility of using 15N/14N data for distinguishing between anthropogenic and natural sources of NOx gases, potentially a very important application, is as yet unproven.
Max Planck Society1, Scripps Institution of Oceanography2, National Center for Atmospheric Research3, Georgia Institute of Technology4, University of Maryland, College Park5, Utrecht University6, University of Innsbruck7, National Oceanic and Atmospheric Administration8, Physical Research Laboratory9, National Physical Laboratory10, Lawrence Berkeley National Laboratory11, University of California, Riverside12, Stockholm University13
TL;DR: It is shown that agricultural burning and especially biofuel use enhance carbon monoxide concentrations and Fossil fuel combustion and biomass burning cause a high aerosol loading, which gives rise to extensive air quality degradation.
Abstract: The Indian Ocean Experiment (INDOEX) was an international, multiplatform field campaign to measure long-range transport of air pollution from South and Southeast Asia toward the Indian Ocean during the dry monsoon season in January to March 1999. Surprisingly high pollution levels were observed over the entire northern Indian Ocean toward the Intertropical Convergence Zone at about 6°S. We show that agricultural burning and especially biofuel use enhance carbon monoxide concentrations. Fossil fuel combustion and biomass burning cause a high aerosol loading. The growing pollution in this region gives rise to extensive air quality degradation with local, regional, and global implications, including a reduction of the oxidizing power of the atmosphere.
28 Oct 2017
TL;DR: In this article, the spectral density S y (f) of the function y(t) where the spectrum is considered to be one-sided on a per hertz basis is defined.
Abstract: Consider a signal generator whose instantaneous output voltage V(t) may be written as V(t) = [V 0 + ??(t)] sin [2??v 0 t + s(t)] where V 0 and v 0 are the nominal amplitude and frequency, respectively, of the output. Provided that ??(t) and ??(t) = (d??/(dt) are sufficiently small for all time t, one may define the fractional instantaneous frequency deviation from nominal by the relation y(t) - ??(t)/2??v o A proposed definition for the measure of frequency stability is the spectral density S y (f) of the function y(t) where the spectrum is considered to be one sided on a per hertz basis. An alternative definition for the measure of stability is the infinite time average of the sample variance of two adjacent averages of y(t); that is, if y k = 1/t ??? tk+r = y(t k ) y(t) dt where ?? is the averaging period, t k+1 = t k + T, k = 0, 1, 2 ..., t 0 is arbitrary, and T is the time interval between the beginnings of two successive measurements of average frequency; then the second measure of stability is ?? y 2(??) ??? (y k+1 - y k )2/2 where denotes infinite time average and where T = ??. In practice, data records are of finite length and the infinite time averages implied in the definitions are normally not available; thus estimates for the two measures must be used. Estimates of S y (f) would be obtained from suitable averages either in the time domain or the frequency domain.
Brown University1, Indian Space Research Organisation2, Physical Research Laboratory3, United States Geological Survey4, Jet Propulsion Laboratory5, Mount Holyoke College6, Johns Hopkins University Applied Physics Laboratory7, Goddard Space Flight Center8, College of Charleston9, Planetary Science Institute10, University of Maryland, College Park11, University of Tennessee12, DARPA13
TL;DR: Analysis of recent infrared mapping by Chandrayaan-1 and Deep Impact, and reexamining Cassini data obtained during its early flyby of the Moon, Pieters et al. reveal a noticeable absorption signal for H2O and OH across much of the surface, implying that solar wind is depositing and/or somehow forming water and OH in minerals near the lunar surface, and that this trapped water is dynamic.
Abstract: The search for water on the surface of the anhydrous Moon had remained an unfulfilled quest for 40 years. However, the Moon Mineralogy Mapper (M 3 ) on Chandrayaan-1 has recently detected absorption features near 2.8 to 3.0 micrometers on the surface of the Moon. For silicate bodies, such features are typically attributed to hydroxyl- and/or water-bearing materials. On the Moon, the feature is seen as a widely distributed absorption that appears strongest at cooler high latitudes and at several fresh feldspathic craters. The general lack of correlation of this feature in sunlit M 3 data with neutron spectrometer hydrogen abundance data suggests that the formation and retention of hydroxyl and water are ongoing surficial processes. Hydroxyl/water production processes may feed polar cold traps and make the lunar regolith a candidate source of volatiles for human exploration.
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|Pradip Kumar Sahu||78||378||20153|
|Girish S. Agarwal||69||718||20780|
|Bhupendra Nath Goswami||55||194||15937|
|Prabir K. Patra||46||178||8544|
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