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Investigating the Aerosol Optical Depth and Angstrom Exponent and Their Relationships with Meteorological Parameters Over Lahore in Pakistan
摘要： In the present work, AERONET (AErosol RObotic NETwork) data of 2006–2014 have been used to analyze the variations in aerosol optical depth (AOD) at 500 nm and Angstrom exponent (440/870) (AE). In order to have an in-depth knowledge of aerosol variability, we have analyzed the association of aerosol properties with the meteorological parameters such as temperature, mean sea level pressure, rainfall, dew point, and dust storm frequency. Long-term observations of MODIS-AOD are also validated with AERONET-AOD over Lahore. The peak monthly mean value of AOD is found in July (1.00 ± 0.34) with the corresponding AE value of 0.85 ± 0.29 pointing toward the fact that desert/soil dust aerosols dominated the atmosphere of Lahore. The lowest value of AOD is found in February (0.47 ± 0.26) with the corresponding AE value of 1.22 ± 0.29 representing the presence of urban/industrial aerosols in the atmosphere over Lahore. The monthly mean AE value is found to be maximum in January (1.36 ± 0.15), whereas lowest value of AE is found in June (0.55 ± 0.25). AOD shows positive correlations with temperature, dew point, relative humidity, visibility, rain and dust storm frequency, and negative with mean sea level pressure and wind speed. AE exhibits positive correlations with relative humidity and mean sea level pressure, while with temperature, dew point, visibility, rain and dust storm frequency, it shows negative correlations.
关键词： Aerosol optical depth,Angstrom exponent,Meteorological parameters,Lahore
更新于2025-09-23 15:23:52
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Free Space Optical Communication (System Design, Modeling, Characterization and Dealing with Turbulence) || 2. Real-time measurement of meteorological parameters for estimating low altitude atmospheric turbulence strength (C2 n)
摘要： The major factor that limits the performance of Free Space Optical Communication (FSOC) is atmospheric turbulence which fluctuates over time in accordance with the variations in local meteorological parameters. Estimating the atmospheric turbulence strength (C2n) from measurement data is significant for finding the data rate the system is capable of operating at under different outdoor local environmental conditions. Hence, a low cost customized system for continuously measuring local meteorological data is developed and presented in this chapter. A field test scintillometer setup is established for a link range of 0.5 km at an altitude of 15.25 m. Specialized sensors are interfaced to the digital architectures to acquire the real-time data corresponding to atmospheric changes. The accuracy and performance of the measurement system are tested against standard instruments and the maximum correlation coefficients of 99.92 %, 99.63 %, 99.73 %, and 99.88 % are achieved for wind speed, temperature, relative humidity and pressure respectively. Atmospheric turbulence strength is estimated for the diurnal period using measured meteorological data. The validations of the estimated results with the scintillometer measurement are also analyzed. The weather profile and corresponding C2n variations at our test field for different seasons over a one year period are presented and the results are analyzed.
关键词： atmospheric turbulence,meteorological parameters,scintillometer,PAMELA model,Free Space Optical Communication (FSOC)
更新于2025-09-12 10:27:22
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Assessment of 50?kWp rooftop solar photovoltaic plant at The ICFAI University, Jaipur: A case study
摘要： Currently, India is espousing nonconventional energy sources at an express rate owing to concerns about climate change, emission of harmful greenhouse gases (GHG), and exhausting conventional energy sources. The solar photovoltaic (SPV) plants are, hence, expected to play a noteworthy role to meet energy security and sustainability goals. Contemporary studies reveal substantial ecological concerns associated with installing the ground mounted SPV plants in urban locations. Further observations depict that aforementioned plants need additional land, transmission, and distribution infrastructures. Consequently, rooftop SPV plants are the best solution to produce energy in urban locations, owing to the availability of a large number of empty rooftop spaces with least capacity expenditure. The present article discusses the techno-economic and ecological aspects of a 50 kWp rooftop SPV plant installed at ICFAI University, Jaipur. The plant has produced around 64.149 MWh in the year 2017. The technical assessment focuses on the effects of the meteorological parameters upon energy generation factors. The annual average final yield, reference yield, capacity utilization factor, and performance ratio found to be 106.9 kWh/kWp/month, 149.7 kWh/kWp/month, 14.64 and 70%, respectively. The economic parameters like net present value, internal rate of return, profitability index, and payback period are computed with 0–50% subsidy rates, which supports the financial viability of the plant. The plant contributed significantly to reducing GHG emissions by mitigating 102 t CO2, 128 kg SO2, 268 kg NOx, and 7,033 kg ash in the year 2017 as evident from the ecological investigation.
关键词： rooftop solar photovoltaic plant,GHG emissions,meteorological parameters,pay back period,capacity utilization factor,performance ratio
更新于2025-09-11 14:15:04
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From Remotely-Sensed Data of Norwegian Boreal Forests to Fast and Flexible Models for Estimating Surface Albedo
摘要： The importance to consider changes in surface albedo and go beyond simple carbon accounting when assessing climate change impacts of forestry and land use activities is increasingly recognized. However, representation of albedo changes in climate models is complex and highly parameterized, thereby limiting their applications in climate impact studies. The availability of simple yet reliable albedo models can enhance consideration of albedo changes in land use studies. We propose a set of simpli?ed models for estimating surface albedo in a boreal forest. We process and harmonize datasets of remotely-sensed albedo estimates, forest structure parameters, and meteorological records for different forest locations in Norway. By combining linear unmixing with nonlinear programming, we simultaneously produce albedo estimates at the same resolution of the land cover dataset (16 m, notably higher than satellite retrievals) and a variety of ?exible models for albedo predictions. We test different combinations of functional forms, variables, and constraints, including variants speci?c for snow-free conditions. We ?nd that models capture the seasonal pattern of surface albedo and the interactive effect of forest structures and meteorological parameters, and many of them show good statistical scores. The cross-validation exercise shows that the models derived from one area perform reasonably well when applied to other forested areas in Norway, regardless of the temporal and spatial scales. By incorporating changes in forest structure and climate conditions as explicit variables, these models are simple to be used in different applications aiming at estimating albedo changes from forest management and climate change.
关键词： meteorological parameters,forest management,surface albedo,boreal forests,climate impact assessment
更新于2025-09-09 09:28:46