Estimation of net radiation for a coniferous forest, and the effects of logging on net radiation and the reflection coefficient

1978 ◽  
Vol 8 (4) ◽  
pp. 450-455 ◽  
Author(s):  
J. H. McCaughey
Keyword(s):  
Reflection Coefficient ◽  
Solar Radiation ◽  
Coniferous Forest ◽  
Field Studies ◽  
Global Solar Radiation ◽  
Balsam Fir ◽  
Net Radiation ◽  
Linear Regression Equation ◽  
Simple Linear Regression ◽  
Clear Cut

The results of field studies on the radiation climate at Montmorency, Quebec, are presented. These studies were conducted in the summers of 1975 and 1976, and two sites were used. The first site, used in both years, was forested with 50- to 60-year-old balsam fir (Abiesbalsamea L. Mill.). The second site, originally forested with balsam fir, was clear-cut in the fall of 1975. The daily mean reflection coefficient for solar radiation of the forest is 7% (sample of 264 hourly values). In contrast, the clear-cut site has a daily mean reflection coefficient of 18% (sample of 171 hourly values). There is no evidence of a systematic variation of hourly reflection coefficients with solar zenith angle for either site. The effect of logging on net radiation is characterized by a sample of 21 days in 1976 when hourly values of net radiation were available for both sites. Typically, during the night, the magnitude of net radiation on the forested site is less than that on the clear-cut site, and during the day, the net radiation on the clear-cut site is less than that on the forested site. In terms of daily totals, the effect of logging is to reduce net radiation by 10%.A simple linear regression equation for the calculation of net radiation for the forested site is presented. Global solar radiation (hourly values) is used as the predictor. The parameters of the model are similar to other equations for similar surfaces.

ESTIMATION OF NET AND SOLAR RADIATION

1971 ◽  
Vol 51 (1) ◽  
pp. 35-39 ◽  
Author(s):  
I. S. SELIRIO ◽  
D. M. BROWN ◽  
K. M. KING
Keyword(s):  
Regression Analysis ◽  
Solar Radiation ◽  
Global Solar Radiation ◽  
Daily Basis ◽  
Net Radiation ◽  
Climatological Station ◽  
The Relationship ◽  
Good Agreement

Relationships between net radiation (QN) and global solar radiation (QS) and between the ratios of QS and solar radiation at the top of the atmosphere (QS/QA) and duration of bright sunshine and daylength (n/N) were determined by regression analysis at Guelph, Ontario, Canada. The data used were recorded at the Guelph O.A.C. climatological station from March, 1964 to February, 1969. Results showed that during the spring, summer, and autumn seasons, QS alone can be used to estimate QN satisfactorily. Daily values of QN are about 50% of QS. The relationship derived for estimating QS from duration of bright sunshine (n) showed good agreement with findings of previous workers. QS varies between 20 and 80% of QA for overcast to cloudless days. The relationships derived in this study can be used to estimate net and solar radiation on a daily basis when these measurements are unavailable.

scholarly journals Radiation balance of coffee hedgerows

2008 ◽  
Vol 12 (3) ◽  
pp. 274-281 ◽  
Author(s):  
Luiz R. Angelocci ◽  
Fábio R. Marin ◽  
Felipe G. Pilau ◽  
Evandro Z. Righi ◽  
José L. Favarin
Keyword(s):  
Solar Radiation ◽  
Cover Crops ◽  
Ground Cover ◽  
Global Solar Radiation ◽  
Important Variable ◽  
Field Conditions ◽  
Radiation Balance ◽  
Net Radiation ◽  
Energy Exchanges ◽  
Good Agreement

The radiation balance of hedgerows is an important variable in studies of mass and energy exchanges between parcial ground cover crops and the atmosphere. This paper describes a device with eight net radiometers encompassing the plants of a hedgerow. The radiometers were moved along a length of hedgerow, in a continuous and reversible movement. The canopy net radiation in this length (Rnc) was found by integration of the measurements over the notional cylinder formed. The device showed good performance and provided reliable measurements of Rnc of coffee hedgerows, showing itselfto be an useful technique of measurement in field conditions. Good correlations between Rnc and global solar radiation, turfgrass and coffee crop net radiation were found in 15-min, daytime and 24-hr periods, allowing the possibility of estimating Rnc from these simple measurements. Beer’s law was also used to have an independent estimation of Rnc. A good agreement was found between values of Rnc estimated by this law of attenuation and those integrated by the device in periods of 15 min, with overestimation of 10%, whereas for values integrated over daytime periods the agreement was not satisfactory.

scholarly journals Detrended Multiple Cross-Correlation Coefficient applied to solar radiation, air temperature and relative humidity

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Andrea de Almeida Brito ◽  
Heráclio Alves de Araújo ◽  
Gilney Figueira Zebende
Keyword(s):  
Relative Humidity ◽  
Solar Radiation ◽  
Solar Energy ◽  
Correlation Coefficient ◽  
Air Temperature ◽  
Cross Correlation ◽  
Global Solar Radiation ◽  
Meteorological Variables ◽  
Hourly Data ◽  
Cross Correlations

AbstractDue to the importance of generating energy sustainably, with the Sun being a large solar power plant for the Earth, we study the cross-correlations between the main meteorological variables (global solar radiation, air temperature, and relative air humidity) from a global cross-correlation perspective to efficiently capture solar energy. This is done initially between pairs of these variables, with the Detrended Cross-Correlation Coefficient, ρDCCA, and subsequently with the recently developed Multiple Detrended Cross-Correlation Coefficient, $${\boldsymbol{DM}}{{\boldsymbol{C}}}_{{\bf{x}}}^{{\bf{2}}}$$DMCx2. We use the hourly data from three meteorological stations of the Brazilian Institute of Meteorology located in the state of Bahia (Brazil). Initially, with the original data, we set up a color map for each variable to show the time dynamics. After, ρDCCA was calculated, thus obtaining a positive value between the global solar radiation and air temperature, and a negative value between the global solar radiation and air relative humidity, for all time scales. Finally, for the first time, was applied $${\boldsymbol{DM}}{{\boldsymbol{C}}}_{{\bf{x}}}^{{\bf{2}}}$$DMCx2 to analyze cross-correlations between three meteorological variables at the same time. On taking the global radiation as the dependent variable, and assuming that $${\boldsymbol{DM}}{{\boldsymbol{C}}}_{{\bf{x}}}^{{\bf{2}}}={\bf{1}}$$DMCx2=1 (which varies from 0 to 1) is the ideal value for the capture of solar energy, our analysis finds some patterns (differences) involving these meteorological stations with a high intensity of annual solar radiation.

scholarly journals Solar Climate Features Taking into Account the Morphometric Conditions of the Area and the Possibility of Using Them in Heliotherapy on the Example of the Cieplice and Kołobrzeg Health Resorts (Poland)

Atmosphere ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 383
Author(s):  
Dawid Szatten ◽  
Mirosław Więcław
Keyword(s):  
Solar Radiation ◽  
Land Cover ◽  
Human Activity ◽  
Sunshine Duration ◽  
Quantitative Relationship ◽  
Global Solar Radiation ◽  
Main Element ◽  
Entropy Model ◽  
Health Treatment ◽  
Health Resorts

Global solar radiation is an important atmospheric stimulus affecting the human body and has been used in heliotherapy for years. In addition to environmental factors, the effectiveness of global solar radiation is increasingly influenced by human activity. This research was based on the use of heliographic and actinometric data (1996–2015) and the model distribution of global solar radiation to determine the possibility of heliotherapy with the example of two health resorts: Cieplice and Kołobrzeg (Poland). The solar features of health resorts (sunshine duration and global solar radiation) were characterized, and they were correlated with the spatial distribution of global solar radiation data obtained with the use of remote sensing techniques (System for Automated Geoscientific Analyzes-SAGA), including COoRdination and INformation on the Environment (CORINE) land cover (CLC) data. Using the maximum entropy model (MaxEnt), a qualitative and quantitative relationship between morphometric parameters and solar climate features was demonstrated for individual land cover types. Studies have shown that the period of late spring and summer, due to the climate’s solar features, is advisable for the use of heliotherapy. The human activity that determines the land cover is the main element influencing the spatial differentiation of the possibilities of using this form of health treatment. It also affects topographic indicators shown as significant in the MaxEnt predictive model. In general, areas with high openness were shown as predisposed for health treatment using global solar radiation, which is not consistent with areas commonly used for heliotherapy. The conducted research has shown the need for an interdisciplinary approach to the issue of heliotherapy, which will contribute to the optimization of the use of this form of health treatment from the perspective of climate change and human pressure.

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