Faisal Afridi | University of Karachi (original) (raw)
Dr. Faisal Ahmed Khan Afridi achieved Ph.D degree in Space Science & Technology from the Institute of Space Science & Technology, University of Karachi, in 2020. His Ph.D topic was "Effects of Fluctuating Dynamics of Clouds on Satellite-Earth Links at Pakistan Atmospheric Region". He achieved first position in M.Phil./Ph.D (75%) & Ph.D (84%) coursework classes. He studied 12 Courses with 24 Credit Hours in M.Phil./Ph.D, while studied 6 Courses with 18 Credit Hours in Ph.D and 24 Credit Hours of Ph.D Dissertation. He obtained his M.Sc degree from the Department of Applied Physics, University of Karachi, Pakistan, in 1997 and B.Sc. (Physics, Mathematics & Statistics) degree from the Department of Physics, University of Karachi.
He is associated as Assistant Professor Visiting (Full Time), Lecturer (Visiting / Full Time) and Cooperative Teacher in the different Departments of various Universities with more than 10 years of experience in teaching at the University level & 6.5 years part time teaching in a Technical institute. He has about 03 years & 05 months of Management & Technical Job Experience, while about 9.5 years’ experience as a Chief Executive of his own business namely “Digital Information Systems” from 1998 to 2007.
He has published 19 Peer-reviewed Journal Papers and 2 Conference Papers. The total Score of his Published Papers in ISI / WoS recognized Journals is 8.631. He is supervising one M.Phil and one Ph.D student at Institute of Space Science & Technology, University of Karachi. He participated in more than 68 National / International Conferences, Seminars, Symposium, Workshops & Lectures. He has experienced of organizing 25 Conferences, Seminars, Symposium & Workshops and various Astronomical events at Karachi University Astronomical Observatory. He is the member / life member of 26 Professional Societies of National and International level. He achieved 9 different awards for organizing various Conferences, Workshops, Seminars & Astronomical events. He is elected several times as a Joint Secretary and Secretary (Sindh Chapter) of Pakistan Physical Society. He has total 24 Citations of his Publications and Reviewer in 4 National & International Journals & 01 International Conference. He has reviewed dozen papers for the Arabian Journal of Geosciences, Springer, New York, USA; Egyptian Journal of Remote Sensing & Space Sciences, Elsevier, Egypt; Journal of Basic & Applied Sciences, Karachi, Pakistan and Gobal Congress on Electrical Engineering, Valencia, Spain.
His major research interests include Atmospheric Physics, Satellite Communication, Radiowave Propagation, Ionosphere, Astrophysics, Climatology, Environment, Climate Change, Urban Heat Island, Flooding & Seismology. He taught different subjects such as Satellite Communication, Antenna & Radiowave Propagation, Aerospace Science & their Applications, Environmental Science, Fiber Optics Communication, Wireless Communication, Digital Communications, Electronic Communication, Data Communication & Networking, Analog Electronics, Digital Electronics, Microwave Electronics, Signal & Systems, Orbital Mechanics, Space Flight Dynamics and System Analysis & Design to the students of B.Sc. & M.Sc. classes of the Institute of Space Science & Technology, Department of Applied Physics, Department of Computer Science, University of Karachi and the Department of Physics, Federal Urdu University of Arts, Science & Technology, Karachi. He taught one course “Wireless & Cellular Communication” to M.Phil. students and 2 Courses “Satellite Communication Engineering” & “Environmental Physics” to Ph.D. students.
He achieved 29 Online “Certificates of Completion” related to the Research Publications from Elsevier Publishing Campus, Amsterdam, The Netherlands. He designed the new & re-designed the old curriculum of different courses at B.Sc., M.Sc., M.Phil. & Ph.D. levels in different Departments of various Universities. He supervised & coordinated 9 various Technical Field Trips & Pakistan Study Tour.
Supervisors: Prof. Dr. M. Ayub Khan Yousufzai
Address: Institute of Space Science & Technology, University of Karachi, Main University Road, Karachi-75270, Pakistan
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Faculty of Technical & Engineering, Islamic Azad University South Tehran Branch, Tehran, Iran
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Papers by Faisal Afridi
Proceedings of the Pakistan Academy of Sciences, Dec 5, 2013
This study presents a descriptive statistical analysis of cloud cover using monthly data for Sind... more This study presents a descriptive statistical analysis of cloud cover using monthly data for Sindh and Makran coasts recorded by the Pakistan Meteorological Department from 1980 to 2004. For Sindh coast, we are considered the data for Karachi and for Makran, we have taken the case of Quetta. For this purpose, Exploratory Data Analysis (EDA) approach was utilized. Through this approach, analysis of the data illustrated variability in the behavior of the cloud dynamics for both the regions. The degree of variation in the computed parametric values at Karachi region was remarkable as compared to the Quetta region. Interpretations of the temporal character depict that the fluctuations in the cloud concentration of Quetta region is different from Karachi due to coastal location.
Arabian Journal of Geosciences, 2021
This study dictates that the ionospheric plasma does play a pivoted role in propagating radio wav... more This study dictates that the ionospheric plasma does play a pivoted role in propagating radio waves reaching the ground after reflecting from the ionospheric layer such as F2 layer that is regarded the most prominent layer in our solar atmosphere. It is said that the formation of this region is due to the interference of solar extreme UV radiations and other natural agents that create free electrons in the ionosphere influencing the propagation of radio signals through the open space. Due to the action of solar activity, it varies diurnally, following the certain patterns. Ionospheric variation is considered as having a nonlinear character. The parametric estimation of observed data obtained from United Kingdom Solar System Data Centre and space agency SUPARCO of Pakistan during the period 2008–2017 which confirmed the variability of ionospheric F2 region and regularity of the daily observations. These results have established that the critical frequency of F2 layer departed significantly from a Gaussian distribution. This shows the unique characteristics of nonlinearity. In this communication, we have employed fractal dimension to verify the complex nature of the ionospheric region. Evidently, this approach measures the index of the complexity in the physical processes in the deep space such as the same phenomenon of the anomalous behavior of ionospheric layers for depicting the sophistication of the system. The consequence of the executive approaches reveals that the behavior of F2 layer is anti-persistent, and the probability of the existence of intricacy in this region is obvious. This kind of study usually assists the government and private organizations for maintaining entire records of ionospheric activities that are going on globally and regionally.
International Journal of Global Warming, 2021
Extreme rainfall plays a key role in hydrological designs, resources of water management, flood h... more Extreme rainfall plays a key role in hydrological designs, resources of water management, flood hazard and land sliding in mountainous regions. In hydrological analysis, it has been a topic of interest to establish a suitable probabilistic approach for extreme rainfall. Monthly extreme rainfall of five meteorological stations of Gilgit-Baltistan (GB) from 1971-2010 have been used. The percentile deviation and probabilistic models have been applied to calculate variation and return levels of seasonal extreme rainfall. The outcome of this study shows that the preferred stations of GB (Gilgit, Skardu, Bunji, Gupis and Astore) will receive rainfall greater than 107.76 mm, 140.64 mm, 69.23 mm, 85.34 mm and 153.44 mm, respectively for the incoming 50-year return period, which are more than the extreme rainfall of 2010. The analysis also predicts that on average, Gilgit-Baltistan will receive 111.28 mm return level against the 50 year return period in the summer season. These results are useful for agriculture, environmental researchers, planners and decision makers to get precautionary measures in Gilgit-Baltistan.
Journal of Mathematical and Fundamental Sciences, 2020
This paper presents an analysis of cosmic ray intensity in Pakistan air space using spatial inter... more This paper presents an analysis of cosmic ray intensity in Pakistan air space using spatial interpolation, comparing it with Chinese cosmic ray records from 1984 to 1993. The Exploratory Data Analytic (EDA) approach was applied to compare the cosmic ray fluctuations in both countries. The time series plot of the monthly cosmic rays showed relatively flatter counts in Pakistan than in China.
Journal of Applied and Emerging Sciences, Dec 2018
A low cost and indigenous experimental training, testing and process optimization setup of the he... more A low cost and indigenous experimental training, testing and process optimization setup of the heat pumping system is designed, developed and fabricated for the engineering students. The setup can be an effort to provide an indigenous option and import substitution for the local industries and academic institutions. The system uses difluoro-monochloromethane (CHCIF2) for the heat transport mechanism which has a heat of vaporization (∆Hvap) of 233.95 kJ/kg at the boiling point of-40 o C. The control compression and expansion of the gas is performed by using the electro-mechanical controls and semi-hermetic compressor. The whole experimental setup is installed on the bench top table with vertical installation in open-air inside the laboratory. The change in pressure and temperature values at various stages of the setup is monitored by sensors, gauges, and visual displays. Physical states of the transport medium, i.e. liquid, vapors and super vapors are monitored by installing the transparent glass windows in the passage of transport medium. Hands-on experiments and procedures can be run on this setup in order to acquire deeper knowledge about design and process optimization of thermodynamical parameters, such as coefficient of performance (COP), Carnot cycle, dynamics of pressure-temperature imbalance during operating cycles and phase transformation of the transport medium under several operating conditions and parameters.
Arabian Journal of Geosciences, Oct 1, 2019
The stratospheric ozone behavior is of great importance for the shelter of life on the earth’s bi... more The stratospheric ozone behavior is of great importance for the shelter of life on the earth’s biosphere from harmful UV radiation. A wavelet technique and explorative analysis are applied on ozone monthly time series data set from 1970 to 2013 for the stratospheric region of Pakistan. Such analysis was performed in order to fully characterize the distinct time-frequency ozone variability. Moreover, in the analysis of ozone irregularity, the main frequency constituents in the data set are estimated by the global wavelet scale. The results obtained in this investigation confirmed particular patterns that could be used to describe the regional condition of ozone. The wavelet approach illustrates a strong power spectrum along with the 2–16-month cycle, indicating an annual oscillation of 12 months for whole data set, which is investigated by the peak of the integration of time average of power over time that also reveals powerful annual pulses. The low variance period results in a band emphasized the presence of variation for seasonal interval of stratospheric ozone for each month starting from January to December. The main objective of this paper is to study the dynamics of ozone concentration at the atmospheric region of Pakistan. It also aims to examine the role of the particular ozone concentration patterns indicating inter-annual irregularity of Ozone status.
Journal of National Science of Foundation in Srilanka, 2018
For many decades ionospheric researchers investigated the variations in the ionosphere due to sol... more For many decades ionospheric researchers investigated the variations in the ionosphere due to solar activity. The suggested relevant models are based on single-station data, considering regional and global geographic conditions. The present study investigated the impact of the solar cycles 21st (1976 to 1986) and 23rd (1996 to 2008) on the ionospheric F2 layer’s critical frequency (f0F2) at mid-latitude over the Wakkanai region (45.39o N, 141.68o E), Japan. The statistical analyses showed that monthly median f0F2 has a significant non-linear association with high sunspot numbers (SSN) over Wakkanai, which represents a saturation effect depending on the time of the day in different months and on the magnitude of the solar cycle. Polynomial empirical models of f0F2 based on parameters such as SSN and geomagnetic index Ap were examined. Considering the rate of change in solar activity factor much improved the accuracy of our empirical model and also reduces the hysteresis effect. The most appropriate empirical model for single-station diurnal models of f0F2 was developed using Fourier series. Diurnal models incorporate Japanese standard time, months and sunspot numbers. The computed f0F2 models were compared with the IRI-2012 model’s predicted f0F2 values, which demonstrated the better accuracy of the Fourier model compared to the global IRI model. The models obtained in this study are useful for researchers and organizations working in the field of sunspot performance relating to the dynamics of the ionosphere.
Journal of Atmospheric and Solar-Terrestrial Physics, 2018
This study investigates the nonlinear dynamics of the stratospheric ozone layer at Pakistan atmos... more This study investigates the nonlinear dynamics of the stratospheric ozone layer at Pakistan atmospheric region. Ozone considered now the most important issue in the world because of its diverse effects on earth biosphere, including human health, ecosystem, marine life, agriculture yield and climate change. Therefore, this paper deals with total monthly time series data of stratospheric ozone over the Pakistan atmospheric region from 1970 to 2013. Two approaches, basic statistical analysis and Fractal dimension (D) have adapted to study the nature of nonlinear dynamics of stratospheric ozone level. Results obtained from this research have shown that the Hurst exponent values of both methods of fractal dimension revealed an anti-persistent behavior (negatively correlated), i.e. decreasing trend for all lags and Rescaled range analysis is more appropriate as compared to Detrended fluctuation analysis. For seasonal time series all month follows an anti-persistent behavior except in the month of November which shown persistence behavior i.e. time series is an independent and increasing trend. The normality test statistics also confirmed the nonlinear behavior of ozone and the rejection of hypothesis indicates the strong evidence of the complexity of data. This study will be useful to the researchers working in the same field in the future to verify the complex nature of stratospheric ozone.
Proceedings of the Pakistan Academy of Sciences, Dec 25, 2017
This study focused on the concept of fractal structure in plasma turbulence. This phenomenon is a... more This study focused on the concept of fractal structure in plasma turbulence. This phenomenon is a multifaceted action of charged particles and electromagnetic field and is an unstable state of fluid. Therefore, it occurs as a consequence of the collective character of mutual interactions of charged particles in the plasma. Using the rescaled range analysis approach, we estimated the fractal dimension of plasma turbulence data at the Pakistan atmospheric region to the observed dynamical behavior. The estimated value of fractal dimension of plasma turbulence was approximately 1.8; the plasma turbulence being greater than 1.5, the behavior was anti-persistent, i.e., indicating a deceasing trend in plasma turbulence. This study revealed that the nature of plasma turbulence was randomness and intermittence. In summary, it was observed that fractal analysis is helpful to examine the persistent, anti-persistent and Brownian nature for long-range behavior of chaotic systems.
Journal of Basic and Applied Sciences, Dec 28, 2017
Earthquake recurrence is depicted on the basis of the time following subsequent seasons at the co... more Earthquake recurrence is depicted on the basis of the time following subsequent seasons at the coastal regions of Pakistan. Recurrence time for intricate shock waves is simulated by using earth positions at equinoxes and perihelion-aphelion positions of the earth from the Sun. In connection to the spatial and temporal behavior of earth, the external geomagnetic variation is significant not only influenced by the distances between the Sun and earth and annual revolving period of earth around the Sun at heliocentric path but also affected by a lunar revolving period on an elliptical path around the earth. The Apparent path of the Sun during the year where earth is the center of the celestial sphere and relative to earth, the Sun appears on ecliptic sphere which intersects the celestial equator in two points known as the vernal equinox of 21 st march and autumn equinox of 21 st September. The perihelion position on earth is nearest to the Sun and aphelion is the furthest position of the earth from the Sun, these are empirically distributed on the basis of mutual interaction. The seasonal effects are recognized by the wavelet characterization on maximum amplitudes of shock waves with reference to vernal – autumn equinoxes of distributed perihelion-aphelion periods. The seasonal period of geomagnetic seismicity is a manifestation of the mean time between earthquakes within a specified region where many faults are activated. The cyclic nature of earthquakes and geomagnetic influences on seismic waves by stress-strain tectonic process and releasing energy for the relaxation mechanism are experienced in nature, therefore the issues relevant to their aphelion – perihelion periodicities, influential conditions of geomagnetic instability and their coupling for shock waves propagation are tackled by the wavelet applications.
Journal of Basic & Applied Sciences, 2017
In this research article, the authors have implemented the Exploratory Data Analysis (EDA) techni... more In this research article, the authors have implemented the Exploratory Data Analysis (EDA) techniques to examine the deviation of the monthly median noon and midnight values of the critical frequency of F2 layer ionosphere (i.e. f0F2) at the Wakkanai station (45.39°N, 141.68°E), Japan, during sunspot cycle 21 st (1976-1986) and 23 rd (1996-2008). Primarily, univariate analysis has been done, which shows the variations in f0F2 at different local times, seasons and in the range of sunspot numbers (SSN), in which winter and semi-annual anomalies are detected in the months of December and March respectively. Secondly, the regression analysis is being used as a bivariate data analysis. The results proved a significantly nonlinear relationship exists between f0F2 and SSN. In both solar cycles, saturation effects are seen in the month of March during the noontime period and immensely in June during the midnight time. The behavior of the ionosphere has been studied for different latitudes, seasonal effects and sunspot dynamic conditions, in which this paper plays an essential role in it.
Journal of Geospace Science, Sep 2015
In this paper the impact of the sunspot cycle, its influence on the composition of F2 layer of io... more In this paper the impact of the sunspot cycle, its influence on the composition of F2 layer of ionosphere at day and night time over the mid-latitude region has been investigated for Wakkanai (45.39ºN, 141.68ºE) Japan. To carry out the study, we have considered the 21 st solar cycle (1976-1986) and 23 rd solar cycle (1996-2008). The trends of critical frequency (foF2) for a different local time, months and solar cycles have been analyzed which illustrated the dynamics of the F2 layer. The sunspot cycle extensively effect the foF2 for any local time and month, while the seasonal trend, showed the foF2 non-dependence on solar zenith angle in which the seasonal and semiannual anomalies were pragmatic in the months of December and March respectively. However, the tendency of diurnal foF2 is usually high in the daytime and low at night time, although the Mid-latitude Summer Nighttime Anomaly (MSNA) has been experiential in the diurnal cycle of foF2 in the month of June. This communication augments the knowledge and will provide guideline to researchers working in the field of solar activity varying the dynamics of the ionosphere correlating fluctuating sunspot numbers.
Journal of Information & Communication Technology, Sep 2014
In this study, the physical behavior of the ionospheric layer in Pakistan's atmospheric region, t... more In this study, the physical behavior of the ionospheric layer in Pakistan's atmospheric region, the Exploratory Data Analysis (EDA) is performed. Using these analyses, probabilistic and mean deviation models are developed to study the skip distance for radio-wave propagation of Ionospheric F2 layer for the Pakistan atmospheric region.These models provided a full description of the essential processes. The Time plot shows the seasonality behavior of the skip distance for radio-wave propagation. The frequency distribution plot of skip distance for radio wave propagation shows the normality of the data. The information attained from these forecasts by analyzing these models, can be further worked with very likely parameters and variables in the physical system to get a favorable performance. Such an approach is well explained within the possibility of computational analysis. The models presented in this paper along with their physical interpretations are helpful for public and private sector organizations.
Proc. 13th International Conference on Statistical Sciences, May 2015
This paper presents the study of wavelet analysis of ionospheric dynamics that has been illustrat... more This paper presents the study of wavelet analysis of ionospheric dynamics that has been illustrated for electron concentration, refractive index and skip distance for radio
wave propagation of the ionospheric F2 layer at Pakistan Air Space. As we that the wavelet is a short term Fourier Transform convolved with data, gives some frequency
information at a location, the skip distance is defined as the shortest distance from a transmitter, measured along the surface of the earth. The range of the skip distance depends on the frequency of the wave, the angle of incidence and the degree of ionization. We proposed to study the effectiveness of ionospheric dynamics and
parametric estimation by developing a quantitative treatment for data covering a specific period during the years 1989-1990. The data sets are recorded on daily basis using Digisonde, DGS-256 installed at Space and Atmospheric Sciences (SPAS) division, SUPARCO, Karachi, Pakistan. The aim here is to examine the periodicity in the electron concentration, refractive index and skip distance signals.
We have looked upon an idea to find hidden periodicities and a discontinuity analyzed by Fast Fourier Transformation (FFT) and wavelet technique in one dimension. Haar5-8
levels for approximation and details. This approach is implemented to theorize the physical process of the electronic communication terms such as skip distance Fluctuations, refractive index and electron concentration. This study appraises the importance of this methodology
for ionospheric research that is being carried out here in Pakistan.
Journal of Basic & Applied Sciences, Mar 5, 2015
Radioactive measurements in the decay process of any radioactive sample can be predicted by radio... more Radioactive measurements in the decay process of any radioactive sample can be predicted by radioactive-decay law. This predication is based over its average behavior. In actual practice, the radioactive measurements show fluctuations about the average value. For any radioactive sample, there is an exact number which disintegrates in any given unit of time fluctuates around the average value. In counting applications, it is important to estimate this fluctuation because it indicates the repeatability of results of a measurement. This will identify it by using periodogram analysis that depicts the periodicity in the radioactive decay of the given sample of Americium-241. Statistical distributions that the given sample followed with goodness-of-fit tests are examined. Maximum-Likelihood Estimator (MLE) has been used to find the population parameters. The randomness in radioactive decay has been verified by non-parametric method. These statistical analyses are based over the amount of internal fluctuation in the given radioactive source that is consistent with the predictions obtained. These measurements are obtained by measuring the decay of 300 counts per 10 sec. of Americium-241 using a Geiger Muller (GM) Counter in the teaching laboratory, at the Department of Physics, University of Karachi, Karachi, Pakistan.
Proceedings of 12th International Conference on Statistical Sciences, May 2014
In this communication, we have presented the empirical assessment of the effects of atmospheric r... more In this communication, we have presented the empirical assessment of the effects of atmospheric relative humidity on cloud cover at the Quetta region, Pakistan using dataset on a monthly basis from 1980 to 2009. Relative humidity is an important variable in the study of the atmospheric dynamics and ecosystem. Clouds are also one of the most significant constituents of our atmosphere. Clouds deliver water from the atmosphere to the Earth’s surface as rain or snow and are thus a key step in the hydrologic cycle.
To study the behavior and association of relative humidity on cloud cover at the Quetta region, we have adopted approaches such as Exploratory Data Analysis (EDA). It has been observed that the relative humidity has a significant and positive correlation on cloud cover at the Quetta region. In order to strengthen our claim, we have compared the data sets of relative humidity with cloud cover at the Quetta region and analyzed both the data sets that exhibit positive correlation along with the interpretations.
Journal of Information & Communication Technology, Mar 2013
The signal power is radiated into a substantial angular region of atmosphere by the transmitting ... more The signal power is radiated into a substantial angular region of atmosphere by the transmitting antenna and only a small fraction is intercepted by the receiving antenna. The proper knowledge of antenna is essential for the communication scientists to evaluate the performance of a communication system. The satellite communication experts need to be able to launch radio quanta over a very limited range of frequencies and hence quantum energies. In some cases they wish to launch the quanta particularly in a certain direction, towards a known location where they are to be received. They do all these things by means of a structure called an antenna.
Antennas are devices used either for the emission or for the reception of radio quanta. An emitting antenna is a device supplied by an electric power generated at a certain frequency and radiation of waves in space. According to several different physical mechanisms observed for the propagation of radio waves that are given below: free space propagation or line of sight propagation, reflection, transmission, diffraction, scattering and wave guiding.
In this communication, the types of satellite antennas for emitting and receiving power have been discussed that depend on their intended use as well as on the frequency and they include (i) Horn antennas (ii) paraboloid reflector etc. Some parametric characteristics such as (i) radiation patterns (ii) the power gain (iii) the directivity (iv) the beam width (v) the aperture (vi) the polarization (vii) their impedance with their model equations are also mentioned. The modeling of beam widths with aperture ratio effects and fluctuations have been illustrated.
Proceedings of the Pakistan Academy of Sciences, Dec 5, 2013
This study presents a descriptive statistical analysis of cloud cover using monthly data for Sind... more This study presents a descriptive statistical analysis of cloud cover using monthly data for Sindh and Makran coasts recorded by the Pakistan Meteorological Department from 1980 to 2004. For Sindh coast, we are considered the data for Karachi and for Makran, we have taken the case of Quetta. For this purpose, Exploratory Data Analysis (EDA) approach was utilized. Through this approach,
analysis of the data illustrated variability in the behavior of the cloud dynamics for both the regions. The degree of variation in the computed parametric values at Karachi region was remarkable as compared to the Quetta region. Interpretations of the temporal character depict that the fluctuations in the cloud concentration of Quetta region is different from Karachi due to coastal location.
Journal of Basic & Applied Sciences, Nov 21, 2013
The stratosphere is one of the constituents of thermal structure of the atmosphere. The maximum c... more The stratosphere is one of the constituents of thermal structure of the atmosphere. The maximum concentration of ozone is found at the stratospheric region where it is interacted by many species including chemical and physical processes. Atmosphere as a whole is an open system that is regarded as a non linear system and that seems to be complex. Therefore, a non-linear trend is plausible to explain phenomenon of ozone layer depletion (OLD).
In this manuscript we have paid our attention in the analysis of the major portion of historic data on stratospheric O3 based on ground-based measurements by the Dobson Spectrophotometer. In this communication we have estimated parameters for describing non-linearity in the process using polynomial trend functions and predicted values are calculated for the period from 1960 to 1999. Future values for ozone depths are computed till 2006 and compared with the minor portion of the data set.
Proceedings of the Pakistan Academy of Sciences, Jun 2013
The aim of this study was to assess the seasonal variability in virtual height of ionospheric F2 ... more The aim of this study was to assess the seasonal variability in virtual height of ionospheric F2 layer for Pakistan’s atmospheric region (PAR). In this communication virtual height variations have been analyzed by the descriptive statistical techniques. These methodologies comprise an autoregressive strategy, linear
regression and polynomial regression. The relevance of these models has been illuminated using predicted values of different parameters under the seasonal variation of ionospheric F2 layer in virtual height that affect the radio wave propagation through the ionosphere. These techniques are implemented to theorize the
physical process of varying the virtual heights that leads this study towards formulating the variations due to interaction of radio wave propagation with this ionospheric layer.
Proceedings of the Pakistan Academy of Sciences, Dec 5, 2013
This study presents a descriptive statistical analysis of cloud cover using monthly data for Sind... more This study presents a descriptive statistical analysis of cloud cover using monthly data for Sindh and Makran coasts recorded by the Pakistan Meteorological Department from 1980 to 2004. For Sindh coast, we are considered the data for Karachi and for Makran, we have taken the case of Quetta. For this purpose, Exploratory Data Analysis (EDA) approach was utilized. Through this approach, analysis of the data illustrated variability in the behavior of the cloud dynamics for both the regions. The degree of variation in the computed parametric values at Karachi region was remarkable as compared to the Quetta region. Interpretations of the temporal character depict that the fluctuations in the cloud concentration of Quetta region is different from Karachi due to coastal location.
Arabian Journal of Geosciences, 2021
This study dictates that the ionospheric plasma does play a pivoted role in propagating radio wav... more This study dictates that the ionospheric plasma does play a pivoted role in propagating radio waves reaching the ground after reflecting from the ionospheric layer such as F2 layer that is regarded the most prominent layer in our solar atmosphere. It is said that the formation of this region is due to the interference of solar extreme UV radiations and other natural agents that create free electrons in the ionosphere influencing the propagation of radio signals through the open space. Due to the action of solar activity, it varies diurnally, following the certain patterns. Ionospheric variation is considered as having a nonlinear character. The parametric estimation of observed data obtained from United Kingdom Solar System Data Centre and space agency SUPARCO of Pakistan during the period 2008–2017 which confirmed the variability of ionospheric F2 region and regularity of the daily observations. These results have established that the critical frequency of F2 layer departed significantly from a Gaussian distribution. This shows the unique characteristics of nonlinearity. In this communication, we have employed fractal dimension to verify the complex nature of the ionospheric region. Evidently, this approach measures the index of the complexity in the physical processes in the deep space such as the same phenomenon of the anomalous behavior of ionospheric layers for depicting the sophistication of the system. The consequence of the executive approaches reveals that the behavior of F2 layer is anti-persistent, and the probability of the existence of intricacy in this region is obvious. This kind of study usually assists the government and private organizations for maintaining entire records of ionospheric activities that are going on globally and regionally.
International Journal of Global Warming, 2021
Extreme rainfall plays a key role in hydrological designs, resources of water management, flood h... more Extreme rainfall plays a key role in hydrological designs, resources of water management, flood hazard and land sliding in mountainous regions. In hydrological analysis, it has been a topic of interest to establish a suitable probabilistic approach for extreme rainfall. Monthly extreme rainfall of five meteorological stations of Gilgit-Baltistan (GB) from 1971-2010 have been used. The percentile deviation and probabilistic models have been applied to calculate variation and return levels of seasonal extreme rainfall. The outcome of this study shows that the preferred stations of GB (Gilgit, Skardu, Bunji, Gupis and Astore) will receive rainfall greater than 107.76 mm, 140.64 mm, 69.23 mm, 85.34 mm and 153.44 mm, respectively for the incoming 50-year return period, which are more than the extreme rainfall of 2010. The analysis also predicts that on average, Gilgit-Baltistan will receive 111.28 mm return level against the 50 year return period in the summer season. These results are useful for agriculture, environmental researchers, planners and decision makers to get precautionary measures in Gilgit-Baltistan.
Journal of Mathematical and Fundamental Sciences, 2020
This paper presents an analysis of cosmic ray intensity in Pakistan air space using spatial inter... more This paper presents an analysis of cosmic ray intensity in Pakistan air space using spatial interpolation, comparing it with Chinese cosmic ray records from 1984 to 1993. The Exploratory Data Analytic (EDA) approach was applied to compare the cosmic ray fluctuations in both countries. The time series plot of the monthly cosmic rays showed relatively flatter counts in Pakistan than in China.
Journal of Applied and Emerging Sciences, Dec 2018
A low cost and indigenous experimental training, testing and process optimization setup of the he... more A low cost and indigenous experimental training, testing and process optimization setup of the heat pumping system is designed, developed and fabricated for the engineering students. The setup can be an effort to provide an indigenous option and import substitution for the local industries and academic institutions. The system uses difluoro-monochloromethane (CHCIF2) for the heat transport mechanism which has a heat of vaporization (∆Hvap) of 233.95 kJ/kg at the boiling point of-40 o C. The control compression and expansion of the gas is performed by using the electro-mechanical controls and semi-hermetic compressor. The whole experimental setup is installed on the bench top table with vertical installation in open-air inside the laboratory. The change in pressure and temperature values at various stages of the setup is monitored by sensors, gauges, and visual displays. Physical states of the transport medium, i.e. liquid, vapors and super vapors are monitored by installing the transparent glass windows in the passage of transport medium. Hands-on experiments and procedures can be run on this setup in order to acquire deeper knowledge about design and process optimization of thermodynamical parameters, such as coefficient of performance (COP), Carnot cycle, dynamics of pressure-temperature imbalance during operating cycles and phase transformation of the transport medium under several operating conditions and parameters.
Arabian Journal of Geosciences, Oct 1, 2019
The stratospheric ozone behavior is of great importance for the shelter of life on the earth’s bi... more The stratospheric ozone behavior is of great importance for the shelter of life on the earth’s biosphere from harmful UV radiation. A wavelet technique and explorative analysis are applied on ozone monthly time series data set from 1970 to 2013 for the stratospheric region of Pakistan. Such analysis was performed in order to fully characterize the distinct time-frequency ozone variability. Moreover, in the analysis of ozone irregularity, the main frequency constituents in the data set are estimated by the global wavelet scale. The results obtained in this investigation confirmed particular patterns that could be used to describe the regional condition of ozone. The wavelet approach illustrates a strong power spectrum along with the 2–16-month cycle, indicating an annual oscillation of 12 months for whole data set, which is investigated by the peak of the integration of time average of power over time that also reveals powerful annual pulses. The low variance period results in a band emphasized the presence of variation for seasonal interval of stratospheric ozone for each month starting from January to December. The main objective of this paper is to study the dynamics of ozone concentration at the atmospheric region of Pakistan. It also aims to examine the role of the particular ozone concentration patterns indicating inter-annual irregularity of Ozone status.
Journal of National Science of Foundation in Srilanka, 2018
For many decades ionospheric researchers investigated the variations in the ionosphere due to sol... more For many decades ionospheric researchers investigated the variations in the ionosphere due to solar activity. The suggested relevant models are based on single-station data, considering regional and global geographic conditions. The present study investigated the impact of the solar cycles 21st (1976 to 1986) and 23rd (1996 to 2008) on the ionospheric F2 layer’s critical frequency (f0F2) at mid-latitude over the Wakkanai region (45.39o N, 141.68o E), Japan. The statistical analyses showed that monthly median f0F2 has a significant non-linear association with high sunspot numbers (SSN) over Wakkanai, which represents a saturation effect depending on the time of the day in different months and on the magnitude of the solar cycle. Polynomial empirical models of f0F2 based on parameters such as SSN and geomagnetic index Ap were examined. Considering the rate of change in solar activity factor much improved the accuracy of our empirical model and also reduces the hysteresis effect. The most appropriate empirical model for single-station diurnal models of f0F2 was developed using Fourier series. Diurnal models incorporate Japanese standard time, months and sunspot numbers. The computed f0F2 models were compared with the IRI-2012 model’s predicted f0F2 values, which demonstrated the better accuracy of the Fourier model compared to the global IRI model. The models obtained in this study are useful for researchers and organizations working in the field of sunspot performance relating to the dynamics of the ionosphere.
Journal of Atmospheric and Solar-Terrestrial Physics, 2018
This study investigates the nonlinear dynamics of the stratospheric ozone layer at Pakistan atmos... more This study investigates the nonlinear dynamics of the stratospheric ozone layer at Pakistan atmospheric region. Ozone considered now the most important issue in the world because of its diverse effects on earth biosphere, including human health, ecosystem, marine life, agriculture yield and climate change. Therefore, this paper deals with total monthly time series data of stratospheric ozone over the Pakistan atmospheric region from 1970 to 2013. Two approaches, basic statistical analysis and Fractal dimension (D) have adapted to study the nature of nonlinear dynamics of stratospheric ozone level. Results obtained from this research have shown that the Hurst exponent values of both methods of fractal dimension revealed an anti-persistent behavior (negatively correlated), i.e. decreasing trend for all lags and Rescaled range analysis is more appropriate as compared to Detrended fluctuation analysis. For seasonal time series all month follows an anti-persistent behavior except in the month of November which shown persistence behavior i.e. time series is an independent and increasing trend. The normality test statistics also confirmed the nonlinear behavior of ozone and the rejection of hypothesis indicates the strong evidence of the complexity of data. This study will be useful to the researchers working in the same field in the future to verify the complex nature of stratospheric ozone.
Proceedings of the Pakistan Academy of Sciences, Dec 25, 2017
This study focused on the concept of fractal structure in plasma turbulence. This phenomenon is a... more This study focused on the concept of fractal structure in plasma turbulence. This phenomenon is a multifaceted action of charged particles and electromagnetic field and is an unstable state of fluid. Therefore, it occurs as a consequence of the collective character of mutual interactions of charged particles in the plasma. Using the rescaled range analysis approach, we estimated the fractal dimension of plasma turbulence data at the Pakistan atmospheric region to the observed dynamical behavior. The estimated value of fractal dimension of plasma turbulence was approximately 1.8; the plasma turbulence being greater than 1.5, the behavior was anti-persistent, i.e., indicating a deceasing trend in plasma turbulence. This study revealed that the nature of plasma turbulence was randomness and intermittence. In summary, it was observed that fractal analysis is helpful to examine the persistent, anti-persistent and Brownian nature for long-range behavior of chaotic systems.
Journal of Basic and Applied Sciences, Dec 28, 2017
Earthquake recurrence is depicted on the basis of the time following subsequent seasons at the co... more Earthquake recurrence is depicted on the basis of the time following subsequent seasons at the coastal regions of Pakistan. Recurrence time for intricate shock waves is simulated by using earth positions at equinoxes and perihelion-aphelion positions of the earth from the Sun. In connection to the spatial and temporal behavior of earth, the external geomagnetic variation is significant not only influenced by the distances between the Sun and earth and annual revolving period of earth around the Sun at heliocentric path but also affected by a lunar revolving period on an elliptical path around the earth. The Apparent path of the Sun during the year where earth is the center of the celestial sphere and relative to earth, the Sun appears on ecliptic sphere which intersects the celestial equator in two points known as the vernal equinox of 21 st march and autumn equinox of 21 st September. The perihelion position on earth is nearest to the Sun and aphelion is the furthest position of the earth from the Sun, these are empirically distributed on the basis of mutual interaction. The seasonal effects are recognized by the wavelet characterization on maximum amplitudes of shock waves with reference to vernal – autumn equinoxes of distributed perihelion-aphelion periods. The seasonal period of geomagnetic seismicity is a manifestation of the mean time between earthquakes within a specified region where many faults are activated. The cyclic nature of earthquakes and geomagnetic influences on seismic waves by stress-strain tectonic process and releasing energy for the relaxation mechanism are experienced in nature, therefore the issues relevant to their aphelion – perihelion periodicities, influential conditions of geomagnetic instability and their coupling for shock waves propagation are tackled by the wavelet applications.
Journal of Basic & Applied Sciences, 2017
In this research article, the authors have implemented the Exploratory Data Analysis (EDA) techni... more In this research article, the authors have implemented the Exploratory Data Analysis (EDA) techniques to examine the deviation of the monthly median noon and midnight values of the critical frequency of F2 layer ionosphere (i.e. f0F2) at the Wakkanai station (45.39°N, 141.68°E), Japan, during sunspot cycle 21 st (1976-1986) and 23 rd (1996-2008). Primarily, univariate analysis has been done, which shows the variations in f0F2 at different local times, seasons and in the range of sunspot numbers (SSN), in which winter and semi-annual anomalies are detected in the months of December and March respectively. Secondly, the regression analysis is being used as a bivariate data analysis. The results proved a significantly nonlinear relationship exists between f0F2 and SSN. In both solar cycles, saturation effects are seen in the month of March during the noontime period and immensely in June during the midnight time. The behavior of the ionosphere has been studied for different latitudes, seasonal effects and sunspot dynamic conditions, in which this paper plays an essential role in it.
Journal of Geospace Science, Sep 2015
In this paper the impact of the sunspot cycle, its influence on the composition of F2 layer of io... more In this paper the impact of the sunspot cycle, its influence on the composition of F2 layer of ionosphere at day and night time over the mid-latitude region has been investigated for Wakkanai (45.39ºN, 141.68ºE) Japan. To carry out the study, we have considered the 21 st solar cycle (1976-1986) and 23 rd solar cycle (1996-2008). The trends of critical frequency (foF2) for a different local time, months and solar cycles have been analyzed which illustrated the dynamics of the F2 layer. The sunspot cycle extensively effect the foF2 for any local time and month, while the seasonal trend, showed the foF2 non-dependence on solar zenith angle in which the seasonal and semiannual anomalies were pragmatic in the months of December and March respectively. However, the tendency of diurnal foF2 is usually high in the daytime and low at night time, although the Mid-latitude Summer Nighttime Anomaly (MSNA) has been experiential in the diurnal cycle of foF2 in the month of June. This communication augments the knowledge and will provide guideline to researchers working in the field of solar activity varying the dynamics of the ionosphere correlating fluctuating sunspot numbers.
Journal of Information & Communication Technology, Sep 2014
In this study, the physical behavior of the ionospheric layer in Pakistan's atmospheric region, t... more In this study, the physical behavior of the ionospheric layer in Pakistan's atmospheric region, the Exploratory Data Analysis (EDA) is performed. Using these analyses, probabilistic and mean deviation models are developed to study the skip distance for radio-wave propagation of Ionospheric F2 layer for the Pakistan atmospheric region.These models provided a full description of the essential processes. The Time plot shows the seasonality behavior of the skip distance for radio-wave propagation. The frequency distribution plot of skip distance for radio wave propagation shows the normality of the data. The information attained from these forecasts by analyzing these models, can be further worked with very likely parameters and variables in the physical system to get a favorable performance. Such an approach is well explained within the possibility of computational analysis. The models presented in this paper along with their physical interpretations are helpful for public and private sector organizations.
Proc. 13th International Conference on Statistical Sciences, May 2015
This paper presents the study of wavelet analysis of ionospheric dynamics that has been illustrat... more This paper presents the study of wavelet analysis of ionospheric dynamics that has been illustrated for electron concentration, refractive index and skip distance for radio
wave propagation of the ionospheric F2 layer at Pakistan Air Space. As we that the wavelet is a short term Fourier Transform convolved with data, gives some frequency
information at a location, the skip distance is defined as the shortest distance from a transmitter, measured along the surface of the earth. The range of the skip distance depends on the frequency of the wave, the angle of incidence and the degree of ionization. We proposed to study the effectiveness of ionospheric dynamics and
parametric estimation by developing a quantitative treatment for data covering a specific period during the years 1989-1990. The data sets are recorded on daily basis using Digisonde, DGS-256 installed at Space and Atmospheric Sciences (SPAS) division, SUPARCO, Karachi, Pakistan. The aim here is to examine the periodicity in the electron concentration, refractive index and skip distance signals.
We have looked upon an idea to find hidden periodicities and a discontinuity analyzed by Fast Fourier Transformation (FFT) and wavelet technique in one dimension. Haar5-8
levels for approximation and details. This approach is implemented to theorize the physical process of the electronic communication terms such as skip distance Fluctuations, refractive index and electron concentration. This study appraises the importance of this methodology
for ionospheric research that is being carried out here in Pakistan.
Journal of Basic & Applied Sciences, Mar 5, 2015
Radioactive measurements in the decay process of any radioactive sample can be predicted by radio... more Radioactive measurements in the decay process of any radioactive sample can be predicted by radioactive-decay law. This predication is based over its average behavior. In actual practice, the radioactive measurements show fluctuations about the average value. For any radioactive sample, there is an exact number which disintegrates in any given unit of time fluctuates around the average value. In counting applications, it is important to estimate this fluctuation because it indicates the repeatability of results of a measurement. This will identify it by using periodogram analysis that depicts the periodicity in the radioactive decay of the given sample of Americium-241. Statistical distributions that the given sample followed with goodness-of-fit tests are examined. Maximum-Likelihood Estimator (MLE) has been used to find the population parameters. The randomness in radioactive decay has been verified by non-parametric method. These statistical analyses are based over the amount of internal fluctuation in the given radioactive source that is consistent with the predictions obtained. These measurements are obtained by measuring the decay of 300 counts per 10 sec. of Americium-241 using a Geiger Muller (GM) Counter in the teaching laboratory, at the Department of Physics, University of Karachi, Karachi, Pakistan.
Proceedings of 12th International Conference on Statistical Sciences, May 2014
In this communication, we have presented the empirical assessment of the effects of atmospheric r... more In this communication, we have presented the empirical assessment of the effects of atmospheric relative humidity on cloud cover at the Quetta region, Pakistan using dataset on a monthly basis from 1980 to 2009. Relative humidity is an important variable in the study of the atmospheric dynamics and ecosystem. Clouds are also one of the most significant constituents of our atmosphere. Clouds deliver water from the atmosphere to the Earth’s surface as rain or snow and are thus a key step in the hydrologic cycle.
To study the behavior and association of relative humidity on cloud cover at the Quetta region, we have adopted approaches such as Exploratory Data Analysis (EDA). It has been observed that the relative humidity has a significant and positive correlation on cloud cover at the Quetta region. In order to strengthen our claim, we have compared the data sets of relative humidity with cloud cover at the Quetta region and analyzed both the data sets that exhibit positive correlation along with the interpretations.
Journal of Information & Communication Technology, Mar 2013
The signal power is radiated into a substantial angular region of atmosphere by the transmitting ... more The signal power is radiated into a substantial angular region of atmosphere by the transmitting antenna and only a small fraction is intercepted by the receiving antenna. The proper knowledge of antenna is essential for the communication scientists to evaluate the performance of a communication system. The satellite communication experts need to be able to launch radio quanta over a very limited range of frequencies and hence quantum energies. In some cases they wish to launch the quanta particularly in a certain direction, towards a known location where they are to be received. They do all these things by means of a structure called an antenna.
Antennas are devices used either for the emission or for the reception of radio quanta. An emitting antenna is a device supplied by an electric power generated at a certain frequency and radiation of waves in space. According to several different physical mechanisms observed for the propagation of radio waves that are given below: free space propagation or line of sight propagation, reflection, transmission, diffraction, scattering and wave guiding.
In this communication, the types of satellite antennas for emitting and receiving power have been discussed that depend on their intended use as well as on the frequency and they include (i) Horn antennas (ii) paraboloid reflector etc. Some parametric characteristics such as (i) radiation patterns (ii) the power gain (iii) the directivity (iv) the beam width (v) the aperture (vi) the polarization (vii) their impedance with their model equations are also mentioned. The modeling of beam widths with aperture ratio effects and fluctuations have been illustrated.
Proceedings of the Pakistan Academy of Sciences, Dec 5, 2013
This study presents a descriptive statistical analysis of cloud cover using monthly data for Sind... more This study presents a descriptive statistical analysis of cloud cover using monthly data for Sindh and Makran coasts recorded by the Pakistan Meteorological Department from 1980 to 2004. For Sindh coast, we are considered the data for Karachi and for Makran, we have taken the case of Quetta. For this purpose, Exploratory Data Analysis (EDA) approach was utilized. Through this approach,
analysis of the data illustrated variability in the behavior of the cloud dynamics for both the regions. The degree of variation in the computed parametric values at Karachi region was remarkable as compared to the Quetta region. Interpretations of the temporal character depict that the fluctuations in the cloud concentration of Quetta region is different from Karachi due to coastal location.
Journal of Basic & Applied Sciences, Nov 21, 2013
The stratosphere is one of the constituents of thermal structure of the atmosphere. The maximum c... more The stratosphere is one of the constituents of thermal structure of the atmosphere. The maximum concentration of ozone is found at the stratospheric region where it is interacted by many species including chemical and physical processes. Atmosphere as a whole is an open system that is regarded as a non linear system and that seems to be complex. Therefore, a non-linear trend is plausible to explain phenomenon of ozone layer depletion (OLD).
In this manuscript we have paid our attention in the analysis of the major portion of historic data on stratospheric O3 based on ground-based measurements by the Dobson Spectrophotometer. In this communication we have estimated parameters for describing non-linearity in the process using polynomial trend functions and predicted values are calculated for the period from 1960 to 1999. Future values for ozone depths are computed till 2006 and compared with the minor portion of the data set.
Proceedings of the Pakistan Academy of Sciences, Jun 2013
The aim of this study was to assess the seasonal variability in virtual height of ionospheric F2 ... more The aim of this study was to assess the seasonal variability in virtual height of ionospheric F2 layer for Pakistan’s atmospheric region (PAR). In this communication virtual height variations have been analyzed by the descriptive statistical techniques. These methodologies comprise an autoregressive strategy, linear
regression and polynomial regression. The relevance of these models has been illuminated using predicted values of different parameters under the seasonal variation of ionospheric F2 layer in virtual height that affect the radio wave propagation through the ionosphere. These techniques are implemented to theorize the
physical process of varying the virtual heights that leads this study towards formulating the variations due to interaction of radio wave propagation with this ionospheric layer.
Supervising a 6-Credit Hours Final Year Thesis related to Cloud Attenuation in Satellite Communic... more Supervising a 6-Credit Hours Final Year Thesis related to Cloud Attenuation in Satellite Communication to the student of M.Sc. (Final) year of Institute of Space Science & Technology, University of Karachi, January, 2023.