Probabilistic assessment of projected climatological drought characteristics over the Southeast USA     

Subhasis Mitra  Puneet Srivastava  Jasmeet Lamba 《Climatic change》2018,147(3-4):601-615

The study makes a probabilistic assessment of drought risks due to climate change over the southeast USA based on 15 Global Circulation Model (GCM) simulations and two emission scenarios. The effects of climate change on drought characteristics such as drought intensity, frequency, areal extent, and duration are investigated using the seasonal and continuous standard precipitation index (SPI) and the standard evapotranspiration index (SPEI). The GCM data are divided into four time periods namely Historical (1961–1990), Near (2010–2039), Mid (2040–2069), and Late (2070–2099), and significant differences between historical and future time periods are quantified using the mapping model agreement technique. Further, the kernel density estimation approach is used to derive a novel probability-based severity-area-frequency (PBS) curve for the study domain. Analysis suggests that future increases in temperature and evapotranspiration will outstrip increases in precipitation and significantly affect future droughts over the study domain. Seasonal drought analysis suggest that the summer season will be impacted the most based on SPI and SPEI. Projections based on SPI follow precipitation patterns and fewer GCMs agree on SPI and the direction of change compared to the SPEI. Long-term and extreme drought events are projected to be affected more than short-term and moderate ones. Based on an analysis of PBS curves, especially based on SPEI, droughts are projected to become more severe in the future. The development of PBS curves is a novel feature in this study and will provide policymakers with important tools for analyzing future drought risks, vulnerabilities and help build drought resilience. The PBS curves can be replicated for studies around the world for drought assessment under climate change.  相似文献   

An investigation of long-term changes in rainfall over the equatorial Indian Ocean trough region during northern summer using multisatellite data     

Satya Prakash  C. Mahesh  V. Sathiyamoorthy  R. M. Gairola  A. K. Mitra 《Theoretical and Applied Climatology》2016,124(1-2):129-139

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Disappearance of the New Moore Island from the Southernmost Coastal Fringe of the Sundarban Delta - A Case Study     

Sugata Hazra  Anirban Mukhopadhyay  Samadrita Mukherjee  Anirban Akhand  Abhra Chanda  Debasish Mitra  Tuhin Ghosh 《Journal of the Indian Society of Remote Sensing》2016,44(3):479-484

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On the scavenging of organic gases by cloud and raindrops: I. A theoretical and experimental study of acetaldehyde absorption and desorption for water drops in air     

J. H. Topalian  S. Mitra  D. C. Montague  A. Quintanar  H. R. Pruppacher 《Journal of Atmospheric Chemistry》1983,1(3):325-334

Our previously developed theoretical models for describing the rate at which water-soluble atmospheric trace gases are scavenged by cloud and rindrops were evaluated for the case of acetaldehyde being absorbed and desorbed by water drops of radii between 250 to 2500 m radius. The experimental verification of our theoretical predictions was carried out in the UCLA 33 m high precipitation shaft in which falling water drops were allowed to come to terminal velocity before passing through a chamber of variable lengths filled with air containing acetaldehyde at various partial pressures. For all drop sizes studied, the experimental results and the theoretical predictions were in reasonable agreement.  相似文献   

Variation of Rayleigh wave group velocity dispersion and seismic heterogeneity of the Indian crust and uppermost mantle     

S. Mitra  K. Priestley  V. K. Gaur  S. S. Rai  J. Haines 《Geophysical Journal International》2006,164(1):88-98

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New Bathonian (Middle Jurassic) ammonite assemblages from Kutch, India     

Pinaki Roy  Subhendu Bardhan  Aparajita Mitra  Sudipta K. Jana 《Journal of Asian Earth Sciences》2007,30(5-6):629-651

The Bathonian ammonite assemblages have been previously poorly recorded in Kutch. The present study has unearthed a rich array of ammonite taxa ranging from the Middle to Upper Bathonian. While Oxycerites Rollier (1909) is a new record from Kutch, the oldest occurrence of Choffatia Siemiradzki (1898) has been found from the Middle Bathonian horizon. Oxycerites cf. orbis (Giebel) is a zonal index of the Late Bathonian in other areas and thus facilitates interprovincial correlation. Besides, palaeobiogeographic and stratigraphic distribution of many species have been modified based on new information. For example, macrocephalitin species, i.e., Kamptokephalites cf. etheridgei Spath (1928), Macrocephalites bifurcatus transient intermedius Spath (1928), M. cf. mantataranus Boehm (1912) were previously known from West Pacific, Indonesia have been now found in Kutch. Gracilisphinctes Buckman (1920) has been previously known to occur during the Middle Bathonian time, the present work extends its stratigraphic distribution up to the definite Upper Bathonian horizon. Procerites hians (Waagen) an endemic species in Kutch previously known from the Upper Bathonian beds, its stratigraphic range has been extended down to the Middle Bathonian.Detail taxonomy of the newly obtained taxa has been done and in many cases sexual dimorphism has been recognized.  相似文献   

Observations of trace gases and aerosols over the Indian Ocean during the monsoon transition period     

T. K. Manual  Ateef Khan  Y. Nazeer Ahammed  R. S. Tanwar  R. S. Parmar  K. S. Zalpuri  Prabhat K. Gupta  S. L. Jain  Risal Singh  A. P. Mitra  S. C. Garg  A. Suryanarayana  V. S. N. Murty  M. Dileep Kumar  Andrew J. Shepherd 《Journal of Earth System Science》2006,115(4):473-484

Characteristics of trace gases (O₃, CO, CO₂, CH₄ and N₂O) and aerosols (particle size of 2.5 micron) were studied over the Arabian Sea, equatorial Indian Ocean and southwest part of the Bay of Bengal during the monsoon transition period (October–November, 2004). Flow of pollutants is expected from south and southeast Asia during the monsoonal transition period due to the patterns of wind flow which are different from the monsoon period. This is the first detailed report on aerosols and trace gases during the sampled period as the earlier Bay of Bengal Experiment (BOBMEX), Arabian Sea Monsoon Experiment (ARMEX) and Indian Ocean Experiments (INDOEX) were during monsoon seasons. The significant observations during the transition period include: (i) low ozone concentration of the order of 5 ppbv around the equator, (ii) high concentrations of CO₂, CH₄ and N₂O and (iii) variations in PM2.5 of 5–20μg/m³.  相似文献   

A connectionist approach to SODAR pattern classification     

Choudhury  S. Mitra  S. 《Geoscience and Remote Sensing Letters, IEEE》2004,1(2):42-46

SODAR (or acoustic radar) systems are a useful tool to efficiently probe the lower planetary boundary layer (LPBL). The observations obtained by these systems can prove to be extremely useful if classified and interpreted correctly. The manual identification of different types of SODAR-recorded lower atmospheric microstructures is a laborious task and can be performed only by an expert having wide experience with the system and the variety of observations recorded by it. In this letter, we have developed a connectionist system to classify or identify SODAR patterns. The results demonstrate that the multilayer perceptron-based model is capable of successfully identifying the different SODAR patterns.  相似文献   

On a finiteSH type source in a layered half-space (II)     

M. Mitra 《Pure and Applied Geophysics》1970,80(1):147-151

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On the torsional vibration of a finite circular cylinder of non-homogeneous material by a particular type of twist on one of its plane ends     

A. K. Mitra  Purabi Mukherji 《Pure and Applied Geophysics》1972,95(1):75-79

Summary In the present note, the problem of torsional vibration of a finite circular cylinder of non-homogeneous material has been considered. The lateral surface of the cylinder is assumed to be free from shearing stress. One end of the cylinder is taken to be fixed while a circular region on the other end which is not fixed is acted over by a periodic shearing force.  相似文献