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In this paper, a statistical study on geoeffectiveness of CMEs integrated with DH-type II radio bursts, association of Dst with plasma and interplanetary field parameters (T,V,P,β,Bz,Bt,E) and their product function BzV for solar cycle 24... more
In this paper, a statistical study on geoeffectiveness of CMEs integrated with DH-type II radio bursts, association of Dst with plasma and interplanetary field parameters (T,V,P,β,Bz,Bt,E) and their product function BzV for solar cycle 24 is presented. We have selected 119 DH-CME events from March 2008 to December 2015. Based on minimum Dst index ≤−50 nT of geomagnetic storm, the events are assorted into two groups, specifically (i) Geoeffective events (ii) Non-geoeffective events. The geoeffective events are found to have high start frequency, low end frequency, broad bandwidth, long duration, slower drift rate than non-geoeffective events. CME speed and flare flux for geoeffective events are moderately correlated(r=0.50) which shows that flares may be related to geomagnetic storms through CMEs. Higher speed of CMEs associated with geoeffective events suggests that CME speed is an important parameter for geoeffectiveness. A large fraction of CME associated with DH-type-II radio b...
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Statistical analysis of rainfall pattern and its variability for 20 years (1990-2010) data is performed for two mountainous urban centres of Uttarakhand i.e. Almora (29.60 N, 79.670 E and altitude 1,204m asl) and Nainital (29.40 N, 79.470... more
Statistical analysis of rainfall pattern and its variability for 20 years (1990-2010) data is performed for two mountainous urban centres of Uttarakhand i.e. Almora (29.60 N, 79.670 E and altitude 1,204m asl) and Nainital (29.40 N, 79.470 E and altitude 2,020m asl). Non Parametric method of Principal Component Analysis (PCA) gives the correlation between different extreme rainfall indices. It is concluded that PCA suggest 90% of the variance in composite matrix of extreme rainfall indices.
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In the present paper, we have studied the statistical analysis between all India homogeneous rainfall (RF) with sunspot number (SN) during 1900-2014 (115-year period). We have calculated correlations coefficient of rainfall with sunspot... more
In the present paper, we have studied the statistical analysis between all India homogeneous rainfall (RF) with sunspot number (SN) during 1900-2014 (115-year period). We have calculated correlations coefficient of rainfall with sunspot number (SN) for annual and seasonal months: January, February (JF); March April May (MAM); June July August September (JJAS) and October November December (OND) and we have obtained high correlation ranging between 0.75 to 0.95. Our results show that rainfall is strongly influenced by sunspot number. Our study also indicates that occurrence of solar activity features play an important role for variability of rainfall.
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This paper presents a statistical study of different solar activity features (DSAF), viz. sunspot number (SN), solar active prominences (SAP), solar flares (SF) and solar proton events (SPE) with total column ozone (TCO) amount using 28... more
This paper presents a statistical study of different solar activity features (DSAF), viz. sunspot number (SN), solar active prominences (SAP), solar flares (SF) and solar proton events (SPE) with total column ozone (TCO) amount using 28 years (1986-2013) data. The ozone data has been taken for two hill stations of Uttarakhand, viz. Nainital (29º23'N, 79º27'E) and Mussoorie (30°27'N, 78°06'E). The study reveals a positive correlation between yearly averaged TCO and DSAF. The value of linear correlation coefficient (r) for TCO-Nainital with SN, SAP, SF and SPE is found to be 0.51, 0.30, 0.49, and 0.54, respectively and for TCO-Mussoorie with SN, SAP, SF, SPE is found to be 0.45, 0.27, 0.44, and 0.51, respectively. This supports the fact that solar activity features contribute to the production of ozone. Also the trend in TCO over both the stations annually, monthly and seasonally has been studied. A negative trend is observed indicating a decrease in the ozone concentr...
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Research Interests: Engineering, Mathematics, Statistics, Radiation, Solar radiation, and 10 moreRenewable and Sustainable Energy Systems, Correlation coefficient, Coefficient of Determination, Indexation, Empirical Model, Mean Absolute Percentage Error, Parametric Model, Empirical models, Mean Squared Error, and Root mean square error
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ABSTRACT The analysis of rainfall pattern and indices of extreme rainfall events is performed for two meteorological stations located in the Central Himalayan Region which is highly vulnerable to rain-induced hazards. The records of these... more
ABSTRACT The analysis of rainfall pattern and indices of extreme rainfall events is performed for two meteorological stations located in the Central Himalayan Region which is highly vulnerable to rain-induced hazards. The records of these rain-induced disasters suggest that such events are generally observed in later part of monsoon season, when soil is saturated after monsoon rains. An attempt is made here to test trends of 19 different extreme rainfall indices that have been widely used in the literature, using daily rainfall data for two urban centres (Nainital and Almora) over the period 1992–2005. We have used statistical tools such as Sen’s method and Mann–Kendall test for detection of trend in annual rainfall, monsoon rainfall, number of rainy days and 1-day extreme rainfall. Principal component analysis gives the correlation between different extreme rainfall indices. Time series of principal components are representing the trends of extreme indices, their variation and interrelation between different indices. The perception study conducted in the same sites indicates that extreme rainfall events and change in rainfall amount and timing are well perceived by the local people.
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ABSTRACT The present study is an attempt to analyse the precipitable water vapour (PWV) derived from Global Positioning System (GPS) and observed meteorological data over Almora, Central Himalayan Region. The PWV values derived using GPS... more
ABSTRACT The present study is an attempt to analyse the precipitable water vapour (PWV) derived from Global Positioning System (GPS) and observed meteorological data over Almora, Central Himalayan Region. The PWV values derived using GPS study is compared with the corresponding moderate resolution imaging spectro-radiometer (MODIS) data. The statistical analysis reveals a positive correlation between both methods. Moderate resolution imaging spectroradiometer near-infrared (MODIS NIR) clear column water vapour product shows a higher correlation (R 2 = 90–93 %) with GPS-derived precipitable water vapour on annual scale as compared to the seasonal scale (R 2 = 62–87 %). MODIS is found to be overestimating in NIR clear column where the magnitude of bias and RMSE show systematic changes from season to season. Monsoon is an important phenomenon in the Indian weather context and holds significant importance in Central Himalayan ecosystem. The monthly and seasonal variation in precipitable water vapour is related with monsoon onset in the region. Diurnal variations in precipitable water vapour are studied with other meteorological data over Almora during dry and wet season. The precipitable water vapour had minimum value in the morning, increases in the afternoon to evening and again decreases to the midnight in both the dry and wet seasons. These results suggest that diurnal variation of water vapour is caused by the transport of water vapour by thermally induced local circulation.
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Regular and systematic measurements of mesospheric temperatures have been carried out during March and April 2007 to determine planetary-scale wave activities in the tropical region, utilizing ground-based Rayleigh Light Detection and... more
Regular and systematic measurements of mesospheric temperatures have been carried out during March and April 2007 to determine planetary-scale wave activities in the tropical region, utilizing ground-based Rayleigh Light Detection and Ranging (LiDAR) and satellite-based Microwave Limb Sounder (MLS) data from Gadanki, India (13.5° N, 79.2° E) and MLS data over a site in North America (23.5° N, 100° W).
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First ground-based mesospheric temperature measurements from a central Himalayan station of India, Nainital (29.4°N and 79.5°E) have been carried out during January 2007 with the help of OH and O2 airglow monitoring during night-time. The... more
First ground-based mesospheric temperature measurements from a central Himalayan station of India, Nainital (29.4°N and 79.5°E) have been carried out during January 2007 with the help of OH and O2 airglow monitoring during night-time. The derived temperatures exhibit large amplitudes of ~3-6 h waves together with a longer period nocturnal tide-like feature with periodicity ~8-10 h. The observed temperatures are
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Using 30 years data (1986-2015) we have made an attempt to study the dependency of total column ozone (TCO) on solar activity features: solar flares (SF), solar active prominence (SAP) and sunspot numbers (SN) for two hill stations of... more
Using 30 years data (1986-2015) we have made an attempt to study the dependency of total column ozone (TCO) on solar activity features: solar flares (SF), solar active prominence (SAP) and sunspot numbers (SN) for two hill stations of Uttarakhand viz. Nainital (29.4 N.79.47E) and Mussorie (30.27 N 78.06 E) by Artificial neural network (ANN) technique. Our study supports the fact that solar activity features contribute to the production of ozone.