Browsing by Author "J. Sharma"

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Assessing the accuracy of different Z-R relationships for Doppler Weather Radar based rainfall estimation: A comparative study for the Delhi region
(Elsevier Ltd, 2025) J. Sharma; Arpita Rastogi; Shikha Verma; Gajendra Kumar; Arti K. Choudhary
Z-R relationships are the most used methods for calculating rainfall using radar reflectivity, which provide a relation between the radar reflectivity (Z) to rainfall rate (R). However, different Z-R relationships may yield varying rainfall estimates depending on regional climatic conditions and radar characteristics. This study presents a comparison of various Z-R relationships (Marshall-Palmer (Z = 200R1.6), WSR-88D (Z = 300R1.4), and Rosenfeld tropical (Z = 250R1.2)) for the Delhi radar station for 2019. The study was performed for four seasons (Winter, Pre-Monsoon, Monsoon, and Post-monsoon) as well as for different rainfall intensity (Light, Moderate, and Heavy rain). The accuracy of each relationship was evaluated using statistical variables such as correlation coefficient (R), RMSE, MAE, Bias and NSE. Results indicate significant variability in rainfall estimation across different relationships. The Marshall-Palmer encompasses the best correlation with rain gauge data during the monsoon and post-monsoon, whereas the Rosenfeld Tropical exhibits the strongest correlation for the winter and pre-monsoon. Additionally, Rosenfeld Tropical has a strong correlation for moderate and heavy rainfall intensity, whereas Marshall Palmer offers a satisfactory correlation for light rainfall intensity. However, Marshall-Palmer offers the best performance for the overall dataset with R = 0.623, RMSE of 13.44, and MAE = 10.07, as well as the lowest RMSE for all seasons and rainfall intensity. These findings highlight the significance of selecting a correct Z-R relationship for accurate rainfall estimation in diverse meteorological conditions, and underscore the need for localized calibration of Z-R parameters for enhanced forecasting accuracy in the Delhi region. © 2025 Elsevier Ltd.
Behaviour of a discontinuity at the wave-head propagating through a relaxing gas
(Springer-Verlag, 1982) J. Sharma; R. Shyam; V.D. Sharma
The rate of amplification of a discontinuity in the velocity gradient is evaluated at the wave-head in a spatially uniform but time evolving flow of a relaxing gas. The paper investigates the effects of relaxation (present in the flow) and the initial wave front curvature on the growth and decay behaviour of waves in the thermodynamical state of weak or strong equilibrium. © 1982 Springer-Verlag.
Development of a new vegetation modulated soil moisture index for the spatial disaggregation of SMAP soil moisture data product
(Elsevier Ltd, 2024) J. Sharma; R. Prasad; P.K. Srivastava; S.A. Yadav; S.K. Singh; B. Verma
Microwave remote sensing serves as a complementary tool for soil moisture mapping and monitoring in comparison to the optical and the infrared remote sensing. The key advantage of microwave remote sensing lies in its ability to estimate soil moisture irrespective of weather or atmospheric conditions. However, existing microwave passive soil moisture products are currently available only at a coarse spatial resolution, limiting their utility for various regional hydrological applications. Various studies have introduced different approaches to downscale these satellite soil moisture data products but the modulation of vegetation present on the soil surface is still a challenging task in the field of downscaling satellite soil moisture data products. Therefore, this study presents a novel vegetation modulated soil moisture index developed by incorporating the MODIS (MODerate resolution Imaging Spectroradiometer) NDVI (Normalized Difference Vegetation Index), and LST (Land Surface Temperature). This newly derived index is then used to downscale the coarse resolution SMAP (Soil Moisture Active Passive) soil moisture data product. The proposed downscaling method has been validated using ground - measured soil moisture and compared with conventional downscaling approaches. It is found that the newly developed method, which has a bias error of −0.004 m3/m3 an Unbiased Root Mean Square Error (ubRMSE) of 0.068 m3/m3 of the downscaled soil moisture and demonstrates more intricate spatial variations. © 2024 Elsevier Ltd
Fungal planet description sheets: 868-950
(Nationaal Herbarium Nederland, 2019) P.W. Crous; A.J. Carnegie; M.J. Wingfield; R. Sharma; G. Mughini; M.E. Noordeloos; A. Santini; Y.S. Shouche; J.D.P. Bezerra; B. Dima; V. Guarnaccia; I. Imrefi; Ž. Jurjević; D.G. Knapp; G.M. Kovács; D. Magistà; G. Perrone; T. Rämä; Y.A. Rebriev; R.G. Shivas; S.M. Singh; C.M. Souza-Motta; R. Thangavel; N.N. Adhapure; A.V. Alexandrova; A.C. Alfenas; R.F. Alfenas; P. Alvarado; A.L. Alves; D.A. Andrade; J.P. Andrade; R.N. Barbosa; A. Barili; C.W. Barnes; I.G. Baseia; J.-M. Bellanger; C. Berlanas; A.E. Bessette; A.R. Bessette; A.Yu. Biketova; F.S. Bomfim; T.E. Brandrud; K. Bransgrove; A.C.Q. Brito; J.F. Cano-Lira; T. Cantillo; A.D. Cavalcanti; R. Cheewangkoon; R.S. Chikowski; C. Conforto; T.R.L. Cordeiro; J.D. Craine; R. Cruz; U. Damm; R.J.V. De Oliveira; J.T. De Souza; H.G. De Souza; J.D.W. Dearnaley; R.A. Dimitrov; F. Dovana; A. Erhard; F. Esteve-Raventós; C.R. Félix; G. Ferisin; R.A. Fernandes; R.J. Ferreira; L.O. Ferro; C.N. Figueiredo; J.L. Frank; K.T.L.S. Freire; D. García; J. Gené; A. Gęsiorska; T.B. Gibertoni; R.A.G. Gondra; D.E. Gouliamova; D. Gramaje; F. Guard; L.F.P. Gusmão; S. Haitook; Y. Hirooka; J. Houbraken; V. Hubka; A. Inamdar; T. Iturriaga; I. Iturrieta-González; M. Jadan; N. Jiang; A. Justo; A.V. Kachalkin; V.I. Kapitonov; M. Karadelev; J. Karakehian; T. Kasuya; I. Kautmanová; J. Kruse; I. Kušan; T.A. Kuznetsova; M.F. Landell; K.-H. Larsson; H.B. Lee; D.X. Lima; C.R.S. Lira; A.R. Machado; H. Madrid; O.M.C. Magalhães; H. Majerova; E.F. Malysheva; R.R. Mapperson; P.A.S. Marbach; M.P. Martín; A. Martín-Sanz; N. Matočec; A.R. McTaggart; J.F. Mello; R.F.R. Melo; A. Mešić; S.J. Michereff; A.N. Miller; A. Minoshima; L. Molinero-Ruiz; O.V. Morozova; D. Mosoh; M. Nabe; R. Naik; K. Nara; S.S. Nascimento; R.P. Neves; I. Olariaga; R.L. Oliveira; T.G.L. Oliveira; T. Ono; M.E. Ordoñez; A.M. Ottoni; L.M. Paiva; F. Pancorbo; B. Pant; J. Pawłowska; S.W. Peterson; D.B. Raudabaugh; E. Rodríguez-Andrade; E. Rubio; K. Rusevska; A.L.C.M.A. Santiago; A.C.S. Santos; C. Santos; N.A. Sazanova; S. Shah; J. Sharma; B.D.B. Silva; J.L. Siquier; M.S. Sonawane; A.M. Stchigel; T. Svetasheva; N. Tamakeaw; M.T. Telleria; P.V. Tiago; C.M. Tian; Z. Tkalčec; M.A. Tomashevskaya; H.H. Truong; M.V. Vecherskii; C.M. Visagie; A. Vizzini; N. Yilmaz; I.V. Zmitrovich; E.A. Zvyagina; T. Boekhout; T. Kehlet; T. Læssøe; J.Z. Groenewald
Novel species of fungi described in this study include those from various countries as follows: Australia, Chaetomella pseudocircinoseta and Coniella pseudodiospyri on Eucalyptus microcorys leaves, Cladophialophora eucalypti, Teratosphaeria dunnii and Vermiculariopsiella dunnii on Eucalyptus dunnii leaves, Cylindrium grande and Hypsotheca eucalyptorum on Eucalyptus grandis leaves, Elsinoe salignae on Eucalyptus saligna leaves, Marasmius lebeliae on litter of regenerating subtropical rainforest, Phialoseptomonium eucalypti (incl. Phialoseptomonium gen. nov.) on Eucalyptus grandis camaldulensis leaves, Phlogicylindrium pawpawense on Eucalyptus tereticornis leaves, Phyllosticta longicauda as an endophyte from healthy Eustrephus latifolius leaves, Pseudosydowia eucalyptorum on Eucalyptus sp. leaves, Saitozyma wallum on Banksia aemula leaves, Teratosphaeria henryi on Corymbia henryi leaves. Brazil, Aspergillus bezerrae, Backusella azygospora, Mariannaea terricola and Talaromyces pernambucoensis from soil, Calonectria matogrossensis on Eucalyptus urophylla leaves, Calvatia brasiliensis on soil, Carcinomyces nordestinensis on Bromelia antiacantha leaves, Dendryphiella stromaticola on small branches of an unidentified plant, Nigrospora brasiliensis on Nopalea cochenillifera leaves, Penicillium alagoense as a leaf endophyte on a Miconia sp., Podosordaria nigrobrunnea on dung, Spegazzinia bromeliacearum as a leaf endophyte on Tilandsia catimbauensis, Xylobolus brasiliensis on decaying wood. Bulgaria, Kazachstania molopis from the gut of the beetle Molops piceus. Croatia, Mollisia endocrystallina from a fallen decorticated Picea abies tree trunk. Ecuador, Hygrocybe rodomaculata on soil. Hungary, Alfoldia vorosii (incl. Alfoldia gen. nov.) from Juniperus communis roots, Kiskunsagia ubrizsyi (incl. Kiskunsagia gen. nov.) from Fumana procumbens roots. India, Aureobasidium tremulum as laboratory contaminant, Leucosporidium himalayensis and Naganishia indica from windblown dust on glaciers. Italy, Neodevriesia cycadicola on Cycas sp. leaves, Pseudocercospora pseudomyrticola on Myrtus communis leaves, Ramularia pistaciae on Pistacia lentiscus leaves, Neognomoniopsis quercina (incl. Neognomoniopsis gen. nov.) on Quercus ilex leaves. Japan, Diaporthe fructicola on Passiflora edulis P. edulis f. flavicarpa fruit, Entoloma nipponicum on leaf litter in a mixed Cryptomeria japonica and Acer spp. forest. Macedonia, Astraeus macedonicus on soil. Malaysia, Fusicladium eucalyptigenum on Eucalyptus sp. twigs, Neoacrodontiella eucalypti (incl. Neoacrodontiella gen. nov.) on Eucalyptus urophylla leaves. Mozambique, Meliola gorongosensis on dead Philenoptera violacea leaflets. Nepal, Coniochaeta dendrobiicola from Dendriobium lognicornu roots. New Zealand, Neodevriesia sexualis and Thozetella neonivea on Archontophoenix cunninghamiana leaves. Norway, Calophoma sandfjordenica from a piece of board on a rocky shoreline, Clavaria parvispora on soil, Didymella finnmarkica from a piece of Pinus sylvestris driftwood. Poland, Sugiyamaella trypani from soil. Portugal, Colletotrichum feijoicola from Acca sellowiana. Russia, Crepidotus tobolensis on Populus tremula debris, Entoloma ekaterinae, Entoloma erhardii and Suillus gastroflavus on soil, Nakazawaea ambrosiae from the galleries of Ips typographus under the bark of Picea abies. Slovenia, Pluteus ludwigii on twigs of broadleaved trees. South Africa, Anungitiomyces stellenboschiensis (incl. Anungitiomyces gen. nov.) and Niesslia stellenboschiana on Eucalyptus sp. leaves, Beltraniella pseudoportoricensis on Podocarpus falcatus leaf litter, Corynespora encephalarti on Encephalartos sp. leaves, Cytospora pavettae on Pavetta revoluta leaves, Helminthosporium erythrinicola on Erythrina humeana leaves, Helminthosporium syzygii on a Syzygium sp. bark canker, Libertasomyces aloeticus on Aloe sp. leaves, Penicillium lunae from Musa sp. fruit, Phyllosticta lauridiae on Lauridia tetragona leaves, Pseudotruncatella bolusanthi (incl. Pseudotruncatellaceae fam. nov.) and Dactylella bolusanthi on Bolusanthus speciosus leaves. Spain, Apenidiella foetida on submerged plant debris, Inocybe grammatoides on Quercus ilex subsp. ilex forest humus, Ossicaulis salomii on soil, Phialemonium guarroi from soil. Thailand, Pantospora chromolaenae on Chromolaena odorata leaves. Ukraine, Cadophora helianthi from Helianthus annuus stems. USA, Boletus pseudopinophilus on soil under slash pine, Botryotrichum foricae, Penicillium americanum and Penicillium minnesotense from air. Vietnam, Lycoperdon vietnamense on soil. Morphological and culture characteristics are supported by DNA barcodes. © 2019 Naturalis Biodiversity Center & Westerdijk Fungal Biodiversity Institute.
Improved radar vegetation water content integration for SMAP soil moisture retrieval
(Elsevier B.V., 2025) J. Sharma; Rajendra B. Prasad; Prashant Kumar Srivastava; Shubham Kumar Singh; Suraj A. Yadav; Dharmendra Kumar Pandey
The Vegetation Water Content (VWC) serves as a crucial parameter within the framework of the Soil Moisture Active Passive (SMAP) satellite mission, particularly in its utilization for vegetation optical depth estimation in the Single Channel Algorithm (SCA) to determine soil moisture content. This study attempts to enhance the soil moisture estimation by estimating microwave VWC utilizing the Single Look Complex (SLC) format of dual-polarized Sentinel-1 data. This approach aims to refine the efficacy of the Single Channel Algorithm (SCA), thereby elevating the precision and reliability of soil moisture estimations. The Sentinel-1 datasets have been utilized to compute radar indices, particularly the Dual Polarimetric Radar Vegetation Index (DPRVI), Radar Vegetation Index (RVI), and Cross- and Co-Polarized Ratio (CCR). DPRVI reflects vegetation's growth and moisture properties, while RVI and CCR indicate vegetation water content and health status. The radar indices were employed within regression approaches such as random forest (RF), support vector regression (SVR), adaptive neuro-fuzzy inference system (ANFIS), and linear regression to estimate VWC. The performance of DPRVI was found better to capture aspects of vegetation dynamics and effectively estimates VWC values with a high correlation (R2) of 0.59. Furthermore, the DPRVI-estimated VWC values are integrated into the SCA, a renowned method for soil moisture retrieval. The results of SCA are compared to the ground-measured soil moisture along with the already available SMAP L2-enhanced passive soil moisture product. The soil moisture estimation via SCA integrated with the DPRVI-estimated VWC enhances the soil moisture estimations with an accuracy of (RMSE = 0.042 m3/m3 and ubRMSE = 0.039 m3/m3) compared to the SMAP L2 soil moisture. This integration allows for a more comprehensive understanding of soil-vegetation-atmosphere interactions and improves the accuracy of soil moisture assessments, critical for hydrological modeling, agricultural management, and environmental monitoring efforts. © 2024 Elsevier B.V.
On the breakdown of wave fronts of characteristics in an ideal dissociating gas
(1981) V.D. Sharma; J. Sharma; Radhe Shyam
Using the method of characteristics, the problem of breaking or non-breaking of waves is studied in a plane cylindrically or spherically symmetric flow of an ideal dissociating gas. It is investigated as to how the effects of dissociation and that of the wave front curvature influence the breaking or non-breaking of waves. In a symmetrical converging gas motion a remarkable difference between the behaviours of cylindrical and spherical waves is discovered. © 1981.