Measuring Global Irradiance

2017 ◽  
pp. 119-176
Keyword(s):  
Global Irradiance

The influence of small cloud covers on the global irradiance at sea

1976 ◽  
Vol 81 (3) ◽  
pp. 395-398 ◽  
Author(s):  
Jack A. C. Kaiser ◽  
Robert H. Hill
Keyword(s):  
Global Irradiance ◽  
Small Cloud

scholarly journals Albedo and estimates of net radiation for green beans under polyethylene cover and field conditions

1999 ◽  
Vol 34 (10) ◽  
pp. 1763-1774 ◽  
Author(s):  
José Leonaldo de Souza ◽  
João Francisco Escobedo ◽  
Maria Terezinha Trovareli Tornero
Keyword(s):  
Solar Irradiance ◽  
Field Conditions ◽  
Net Radiation ◽  
Phaseolus Vulgaris L ◽  
Green Beans ◽  
Phenological Stages ◽  
Independent Variables ◽  
Clear Sky ◽  
Solar Elevation ◽  
Global Irradiance

This paper describes the albedo (r) and estimates of net radiation and global solar irradiance for green beans crop (Phaseolus vulgaris L.), cultivated in greenhouse with cover of polyethylene and field conditions, in Botucatu, SP, Brazil (22º 54' S; 48º 27' W; 850 m). The solar global irradiance (Rg) and solar reflected radiation (Rr) were used to estimate the albedo through the ratio between Rr and Rg. The diurnal curves of albedo were obtained for days with clear sky and partially cloudy conditions, for different phenological stages of the crop. The albedo ranged with the solar elevation, the environment and the phenological stages. The cloudiness range have almost no influence on the albedo diurnal amount. The estimation of radiation were made by linear regression, using the global solar irradiance (Rg) and net short-waves radiation (Rc) as independent variables. All estimates of radiation showed better adjustment for specific phenological periods compared to the entire crop growing cycle. The net radiation in the greenhouse has been estimated by the global solar irradiance measured at field conditions.

scholarly journals Long-Term Patterns and Trends of Shortwave Global Irradiance over the Euro-Mediterranean Region

Atmosphere ◽  
2021 ◽  
Vol 12 (11) ◽  
pp. 1431
Author(s):  
Elissavet Galanaki ◽  
George Emmanouil ◽  
Konstantinos Lagouvardos ◽  
Vassiliki Kotroni
Keyword(s):  
Mediterranean Region ◽  
Spatiotemporal Variability ◽  
Reanalysis Dataset ◽  
Global Irradiance ◽  
Seasonal Basis ◽  
Region 10 ◽  
Annual Scale ◽  
Good Agreement

The spatiotemporal patterns and trends of shortwave global irradiance (SWGI) are a crucial factor affecting not only the climate but also sectors of the economy. In this work, the ERA5-Land reanalysis dataset is employed and evaluated against in situ measurements from a dense network of surface stations operated by the National Observatory of Athens over Greece, revealing a good agreement between the two datasets. Then, the spatiotemporal variability of SWGI is investigated over the Euro-Mediterranean region (10° W–42° E and 30° N–52° N) for a 40-year period (1981–2020). SWGI exhibits a smooth latitudinal variability from north to south of −5.4 W/m2/degree on an annual scale, while it varies significantly on a seasonal basis and is almost four times lower in the winter than in the summer. The SWGI trend during the analyzed period was found to be positive and statistically significant at the 95% confidence level. Spring and summer are the periods where positive and the strongest rates of SWGI trends are evident, while in the winter and autumn, negative or neutral trends were found. The increasing SWGI trend shows a slowdown during the beginning of the 2000s in all seasons, except autumn. The SWGI trend decreases by about −0.06 W/m2/decade every 100 m of elevation increase.

Validation of global irradiance derived from INSAT-3D over India

Solar Energy ◽  
2020 ◽  
Vol 202 ◽  
pp. 45-54
Author(s):  
Harsh G. Kamath ◽  
J. Srinivasan
Keyword(s):  
Global Irradiance

scholarly journals Comparison of Pyranometric and Pyrheliometric Methods for the Determination of Sunshine Duration

2007 ◽  
Vol 24 (5) ◽  
pp. 835-846 ◽  
Author(s):  
Yvonne B. L. Hinssen ◽  
Wouter H. Knap
Keyword(s):  
Solar Irradiance ◽  
Extreme Values ◽  
Sunshine Duration ◽  
Global Radiation ◽  
Surface Radiation ◽  
Global Irradiance ◽  
Correlation Algorithm ◽  
Mean Differences ◽  
Radiation Measurements

Abstract Two pyranometric methods for the determination of sunshine duration (SD) from global irradiance measurements are evaluated by means of summated sunshine seconds derived from pyrheliometric measurements in combination with the WMO threshold of 120 W m−2 for the direct solar irradiance. The evaluation is performed using direct and global radiation measurements made at the Cabauw Baseline Surface Radiation Network (BSRN) site in the Netherlands for the period March 2005–February 2006. The “Slob algorithm” uses 10-min mean and extreme values of the measured global irradiance and parameterized estimates of the direct and diffuse irradiance. The “correlation algorithm” directly relates SD to 10-min mean measurements of global irradiance. The cumulative pyrheliometric SD for the mentioned period is 1429 h. Relative to this value, the Slob algorithm and correlation algorithm give −72 h (−5%) and +8 h (+0.6%). On a daily mean basis, the values are −0.22 ± 0.05 h day−1 and 0.03 ± 0.03 h day−1, respectively. By means of tuning the irradiance parameterizations of the Slob algorithm, the yearly cumulative and daily mean differences can be reduced to +7 h (+0.5%) and 0.02 ± 0.04 h day−1, respectively. It is concluded that, by use of either algorithm, it is possible to estimate daily sums of SD from 10-min mean measurements of global irradiance with a typical uncertainty of 0.5–0.7 h day−1. For yearly sums, the uncertainty typically amounts to 0.5%.

scholarly journals Improved Synthesis of Global Irradiance with One-Minute Resolution for PV System Simulations

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Martin Hofmann ◽  
Stefan Riechelmann ◽  
Cristian Crisosto ◽  
Riyad Mubarak ◽  
Gunther Seckmeyer
Keyword(s):  
Time Series ◽  
High Resolution ◽  
Transition Probability ◽  
Weather Condition ◽  
Weather Conditions ◽  
Pv System ◽  
High Resolution Data ◽  
Frequency Distributions ◽  
Global Irradiance ◽  
Mean Square Errors

High resolution global irradiance time series are needed for accurate simulations of photovoltaic (PV) systems, since the typical volatile PV power output induced by fast irradiance changes cannot be simulated properly with commonly available hourly averages of global irradiance. We present a two-step algorithm that is capable of synthesizing one-minute global irradiance time series based on hourly averaged datasets. The algorithm is initialized by deriving characteristic transition probability matrices (TPM) for different weather conditions (cloudless, broken clouds and overcast) from a large number of high resolution measurements. Once initialized, the algorithm is location-independent and capable of synthesizing one-minute values based on hourly averaged global irradiance of any desired location. The one-minute time series are derived by discrete-time Markov chains based on a TPM that matches the weather condition of the input dataset. One-minute time series generated with the presented algorithm are compared with measured high resolution data and show a better agreement compared to two existing synthesizing algorithms in terms of temporal variability and characteristic frequency distributions of global irradiance and clearness index values. A comparison based on measurements performed in Lindenberg, Germany, and Carpentras, France, shows a reduction of the frequency distribution root mean square errors of more than 60% compared to the two existing synthesizing algorithms.

Solar irradiance, air pollution and temperature changes in the Arctic

1995 ◽  
Vol 352 (1699) ◽  
pp. 247-258 ◽  
Keyword(s):  
Air Pollution ◽  
Spatial Distribution ◽  
Solar Irradiance ◽  
Early Spring ◽  
Surface Radiation ◽  
The Arctic ◽  
Radiation Balance ◽  
Temperature Changes ◽  
Global Irradiance ◽  
Arctic Haze

A highly significant decrease in the annual sums of global irradiance reaching the surface of the Arctic, averaging 0.36 W m -2 per year, was derived from an analysis of 389 complete years of measurement, beginning in 1950, at 22 pyranometer stations within the Arctic Circle. The smaller data base of radiation balance measurements available showed a much smaller and statistically non-significant change. Reductions in global irradiance were most frequent in the early spring months and in the western sectors of the Arctic, coinciding with the seasonal and spatial distribution of the incursions of polluted air which give rise to the Arctic Haze. Irradiance measured in Antarctica during the same period showed a similar and more widespread decline despite the lower concentrations of pollutants. A marked increase in the surface radiation balance was recorded. Possible reasons for these interpolar anomalies and their consequences for temperature change are discussed.

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