references.bib

% Encoding: UTF-8

@Article{long_automated_2008,
  author   = {Long, C. N. and Shi, Y.},
  title    = {An {Automated} {Quality} {Assessment} and {Control} {Algorithm} for {Surface} {Radiation} {Measurements}},
  journal  = {The Open Atmospheric Science Journal},
  year     = {2008},
  pages    = {23--37},
  abstract = {We present an automated algorithm for testing surface broadband radiation measurements to detect erroneous data. The methodology has been developed using data from the US Department of Energy Atmospheric Radiation Meas- urement (ARM) Program. The testing includes physically possible limits as determined by the World Meteorological Or- ganization (WMO) Baseline Surface Radiation Network, as well as user configurable limits based on climatological analysis of data collected at the measurement site. The algorithm can be run in near real time, or more typically on a daily basis. Additionally, longer monthly or yearly runs can be used to assess more subtle tendencies and problems in the data through evaluation of daily summaries of quality flagging.},
  file     = {An Automated Quality Assessment and Control Algorithm for Surface Radiation Measurements_Long2008.pdf:/home/athan/LIBRARY/Atmospheric_Environmental_Physics/Articles/Quality Control Procedures/An Automated Quality Assessment and Control Algorithm for Surface Radiation Measurements_Long2008.pdf:application/pdf},
  keywords = {Data quality, QCrad implementation},
}

@Report{Reno2012,
  author           = {Reno, Matthew J. and Hansen, Clifford W. and Stein, Joshua S.},
  date             = {2012-03-01},
  title            = {Global horizontal irradiance clear sky models: implementation and analysis},
  doi              = {10/gq5npv},
  number           = {SAND2012-2389, 1039404},
  pages            = {SAND2012--2389, 1039404},
  url              = {https://www.osti.gov/servlets/purl/1039404/},
  urldate          = {2022-10-30},
  abstract         = {Clear sky models estimate the terrestrial solar radiation under a cloudless sky as a function of the solar elevation angle, site altitude, aerosol concentration, water vapor, and various atmospheric conditions. This report provides an overview of a number of global horizontal irradiance (GHI) clear sky models from very simple to complex. Validation of clear-sky models requires comparison of model results to measured irradiance during clear-sky periods. To facilitate validation, we present a new algorithm for automatically identifying clear-sky periods in a time series of GHI measurements. We evaluate the performance of selected clear-sky models using measured data from 30 different sites, totaling about 300 site-years of data. We analyze the variation of these errors across time and location. In terms of error averaged over all locations and times, we found that complex models that correctly account for all the atmospheric parameters are slightly more accurate than other models, but, primarily at low elevations, comparable accuracy can be obtained from some simpler models. However, simpler models often exhibit errors that vary with time of day and season, whereas the errors for complex models vary less over time.},
  file             = {Stein et al. - 2012 - Global horizontal irradiance clear sky models  im.pdf:Clear Sky Models/Global Horizontal Irradiance Clear Sky Models_ Implementation and Analysis_Reno2012.pdf:},
  groups           = {Clear Sky Models},
  langid           = {english},
  modificationdate = {2022-10-30T11:32:10},
  shorttitle       = {Global horizontal irradiance clear sky models},
}



@TechReport{Long2006,
  author      = {C. N. Long and Y. Shi},
  title       = {The QCRad Value Added Product: Surface Radiation Measurement Quality Control Testing, Including Climatology Configurable Limits},
  institution = {Office of Science, Office of Biological and Environmental Research, U.S. Department of Energy},
  year        = {2006},
  number      = {DOE/SC-ARM/TR-074},
  month       = {September},
  abstract    = {This document describes the QCRad methodology, which uses climatological analyses of the surface
radiation measurements to define reasonable limits for testing the data for unusual data values. The main
assumption is that the majority of the climatological data are “good” data, which for field sites operated
with care such as those of the Atmospheric Radiation Measurement (ARM) Program is a reasonable
assumption. Data that fall outside the normal range of occurrences are labeled either “indeterminate”
(meaning that the measurements are possible, but rarely occurring, and thus the values cannot be
identified as good) or “bad” depending on how far outside the normal range the particular data reside.
The methodology not only sets fairly standard maximum and minimum value limits, but also compares
what we have learned about the behavior of these instruments in the field to other value-added products
(VAPs), such as the Diffuse infrared (IR) Loss Correction VAP (Younkin and Long 2004) and the Best
Estimate Flux VAP (Shi and Long 2002).
},
  file        = {The QCRad Value Added Product - Surface Radiation Measurement Quality Control Testing, Including Climatology Configurable_Long2006.pdf:/home/athan/LIBRARY/Atmospheric_Environmental_Physics/Technical Reports/Data Processing/The QCRad Value Added Product - Surface Radiation Measurement Quality Control Testing, Including Climatology Configurable_Long2006.pdf:PDF},
}

@Article{Long2000,
  author    = {Charles N. Long and Thomas P. Ackerman},
  title     = {{Identification of clear skies from broadband pyranometer measurements and calculation of downwelling shortwave cloud effects}},
  journal   = {Journal of Geophysical Research},
  year      = {2000},
  volume    = {105},
  number    = {D12},
  pages     = {15609--15626},
  issn      = {01480227},
  doi       = {10.1029/2000JD900077},
  url       = {http://doi.wiley.com/10.1029/2000JD900077},
  abstract  = {We present an automated method to identify periods of clear skies for a 160° field of view using only 1-min measurements of surface downwelling total and diffuse shortwave irradiance. The clear-sky detection method is verified using Whole Sky Imager and lidar data, observer reports, and model comparisons. Identified clear-sky irradiance measurements are then used to empirically fit clear-sky irradiance functions using the cosine of the solar zenith angle as the independent variable. These fitted functions produce continuous estimates of clear-sky total, diffuse, and direct component shortwave irradiances. While this method ignores diurnal changes in such variables as column water vapor and aerosol amounts and changes between clear-sky days, it is shown that the resultant clear-sky irradiance estimates have RMS uncertainty comparable to the uncertainty of the measuring instruments themselves. The estimated clear-sky irradiances are used to estimate the effect of clouds on the downwelling shortwave irradiance as a difference between the measured and clear-sky amounts. We show that the cloud effect calculations from this method appear to decrease the uncertainty due to systematic pyranometer offsets and cosine response errors. Thus any data set that includes downwelling diffuse and total shortwave measurements can be processed to identify clear-sky periods and produce estimates of clear-sky irradiance and cloud effects.},
  file      = {Identification of clear skies from broadband pyranometer measurements and calculation of downwelling shortwave cloud effects_Long2000.pdf:/home/athan/LIBRARY/Atmospheric_Environmental_Physics/Articles/Clear sky detection/Identification of clear skies from broadband pyranometer measurements and calculation of downwelling shortwave cloud effects_Long2000.pdf:PDF},
  isbn      = {0148-0227},
  keywords  = {Clear sky detection,Global model,Global radiation},
  publisher = {Wiley Online Library},
}

@Article{Reno2016,
  author    = {Matthew J. Reno and Clifford W. Hansen},
  title     = {{Identification of periods of clear sky irradiance in time series of GHI measurements}},
  journal   = {Renewable Energy},
  year      = {2016},
  volume    = {90},
  pages     = {520--531},
  issn      = {18790682},
  doi       = {10.1016/j.renene.2015.12.031},
  url       = {http://dx.doi.org/10.1016/j.renene.2015.12.031},
  abstract  = {We present a simple algorithm for identifying periods of time with broadband global horizontal irradiance (GHI) similar to that occurring during clear sky conditions from a time series of GHI measurements. Other available methods to identify these periods do so by identifying periods with clear sky conditions using additional measurements, such as direct or diffuse irradiance. Our algorithm compares characteristics of the time series of measured GHI with the output of a clear sky model without requiring additional measurements. We validate our algorithm using data from several locations by comparing our results with those obtained from a clear sky detection algorithm, and with satellite and ground-based sky imagery.},
  file      = {Identification of periods of clear sky irradiance in time series of GHI measurements_Reno22.pdf:/home/athan/LIBRARY/Atmospheric_Environmental_Physics/Articles/Clear sky detection/Identification of periods of clear sky irradiance in time series of GHI measurements_Reno22.pdf:PDF},
  keywords  = {Clear sky,Clear sky detection,Global horizontal irradiance,Global model,Global radiation,Solar resource},
  publisher = {Elsevier},
}

@Article{Inman2016,
  author       = {Rich H. Inman and Yinghao Chu and Carlos F. M. Coimbra},
  title        = {{Cloud enhancement of global horizontal irradiance in California and Hawaii}},
  volume       = {130},
  pages        = {128--138},
  issn         = {0038-092X},
  abstract     = {Clouds significantly attenuate ground-level solar irradiance causing substantial reduction in photovoltaic power output capacity. However, partly cloudy skies may lead to temporary enhancement of local Global Horizontal Irradiance (GHI) above the clear-sky ceiling and, at times, the extraterrestrial irradiance. Such enhancements are referred to here as Cloud Enhancement Events (CEEs). In this work we study these CEEs and assess quantitatively the occurrence of resulting coherent Ramp Rates (RRs). We analyze a full year of ground irradiance data recorded at the University of California, Merced, as well as nearly five months of irradiance data recorded at the University of California, San Diego, and Ewa Beach, Hawaii. Our analysis shows that approximately 4% of all the data points qualify as potential CEEs, which corresponds to nearly 3.5 full-days of such events per year if considered sequentially. The surplus irradiance enhancements range from 18 W m-2 day-1 to 73 W m-2 day-1. The maximum recorded GHI of ∼1400 W m-2 occurred in San Diego on May 25, 2012, which was nearly 43% higher than the modeled clear-sky ceiling. Wavelet decomposition coupled with fluctuation power index analysis shed light on the time-scales on which cloud induced variability and CEEs operate. Results suggest that while cloud-fields tend to induce variability most strongly at the 30 min time-scale, they have the potential to cause CEEs that induce variability on time-scales of several minutes. This analysis clearly demonstrates that CEEs are an indicator for periods of high variability and therefore provide useful information for solar forecasting and integration.},
  date         = {2016},
  doi          = {10.1016/j.solener.2016.02.011},
  file         = {Cloud enhancement of global horizontal irradiance in California and Hawaii_Inman2016.pdf:Cloud enhancement of global horizontal irradiance in California and Hawaii_Inman2016.pdf:PDF},
  groups       = {Clound Enhancment},
  journaltitle = {Solar Energy},
  keywords     = {Cloud enhancement,Global horizontal irradiance,Ramp rate,Wavelet},
  owner        = {AN},
  publisher    = {Elsevier Ltd},
  timestamp    = {2022-10-16},
}

@Article{Gueymard2017,
  author       = {Christian A. Gueymard},
  title        = {{Cloud and albedo enhancement impacts on solar irradiance using high-frequency measurements from thermopile and photodiode radiometers. Part 1: Impacts on global horizontal irradiance}},
  volume       = {153},
  pages        = {755--765},
  issn         = {0038-092X},
  abstract     = {Using many years of high-quality measurements from a variety of radiometers at both 1-min and 1-s resolution, this study provides a detailed analysis of cloud enhancement (CE) and albedo enhancement (AE) effects on solar irradiance. This first part focuses on global horizontal irradiance. Various possible definitions of the CE phenomenon are extracted from the literature and discussed, in the context of PV applications most importantly. Based on 10 years of 1-min measurements of all shortwave irradiance components at a high-elevation site (1829 m) on the foothills of the Rocky Mountains in Colorado, a frequency analysis of extreme events triggered by enhancement effects is carried out, using three different criteria to delineate enhancement effects: global horizontal irradiance (GHI) above 1 sun, and clearness index (KT) above either 0.8 or 1.0. This analysis shows that the annual frequency of these extreme events is extremely variable, and also largely dependent on the type of instrumentation (thermopile vs. photodiode). Although the scattering of light off cumulus-type cloud edges is directly associated with CE effects, three different types of CE phenomenon are proposed, which depend on the relative mix of diffuse and direct irradiance prior and during an episode, and on the magnitude of the regional albedo. The maximum observed global irradiance varies between 1546 and 1891 W m−2 at this site, depending on type of instrument and temporal resolution. The latter value (≈1.9 suns), obtained with a photodiode sensor at 1-s resolution, corresponds to KT = 1.62 and appears to constitute a new GHI world record. It results from the combination of CE and AE effects, the latter being caused by strong backscattering, itself triggered by a fresh snow cover over the region. If the magnitude and frequency of enhancement events are critical to detect rapid transients that can be harmful to PV installations, it is suggested to rely on photodiode sensors at 1-s resolution or better.},
  date         = {2017},
  doi          = {10.1016/j.solener.2017.05.004},
  file         = {Cloud and albedo enhancement impacts on solar irradiance using high frequency measurements from thermopile_Gueymard2017.pdf:Cloud and albedo enhancement impacts on solar irradiance using high frequency measurements from thermopile_Gueymard2017.pdf:PDF},
  groups       = {Clound Enhancment},
  journaltitle = {Solar Energy},
  keywords     = {Albedo,Cloud enhancement,Global horizontal irradiance,Pyranometry},
  owner        = {AN},
  publisher    = {Elsevier Ltd},
  timestamp    = {2022-10-16},
}

@Article{Vamvakas2020,
  author    = {Vamvakas, Ioannis and Salamalikis, Vasileios and Kazantzidis, Andreas},
  title     = {{Evaluation of enhancement events of global horizontal irradiance due to clouds at Patras, South-West Greece}},
  journal   = {Renewable Energy},
  year      = {2020},
  volume    = {151},
  number    = {xxxx},
  pages     = {764--771},
  issn      = {18790682},
  doi       = {10.1016/j.renene.2019.11.069},
  url       = {https://doi.org/10.1016/j.renene.2019.11.069},
  abstract  = {Cloudiness is the dominant factor that affects the transfer of solar irradiance through the atmosphere. Especially the type of clouds, their high spatial and temporal variability, velocity and position relatively to the Sun, could cause events ranging from total reduction to substantial enhancements of surface solar irradiance. In study, the enhancements of Global Horizontal Irradiance (GHI) at South Greece for 2 years are examined. We use 1–min averages of GHI, sunshine duration and synchronized estimations of cloud coverage and type from a digital imaging system. A radiative transfer model is used to estimate GHI under clear skies. For solar zenith angles lower than 80°, 4% of total GHI measurements are considered as enhancements. It is shown that the effect of thick clouds on the GHI enhancements is significantly higher when compared to the thin ones. We also examine cases that correspond to instantaneous clearness index values higher than 1 (Kt > 1): 228 extreme enhancement events are found including 5 cases with GHI values higher than 1367 W/m2 and a maximum value of 1420 W/m2. These results suggest that such events are common and should be included in the design and simulation of the performance of solar energy systems.},
  file      = {:/home/athan/LIBRARY/Atmospheric_Environmental_Physics/Didaktoriko/Vamvakas 2019 - Evaluation of enhancement events of global horizontal irradiance due to clouds at Patras South-West Greece.pdf:PDF},
  keywords  = {Clearness index,Clouds,Enhancement,Global horizontal irradiance,Sunshine duration},
  publisher = {Elsevier Ltd},
  timestamp = {2022-10-07},
}

@Comment{jabref-meta: databaseType:biblatex;}