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.

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 The Influence of Cloudiness and Synoptic Situations on the Solar Radiation Balance in the Area of Kaffiøyra (Nw Spitsbergen) in the Summer Seasons 2010 and 2011

2012 ◽  
Vol 5 (1) ◽  
pp. 77-95 ◽  
Author(s):  
Marek Kejna ◽  
Rajmund Przybylak ◽  
Andrzej Araźny
Keyword(s):  
Solar Radiation ◽  
Ground Cover ◽  
Global Solar Radiation ◽  
Atmospheric Radiation ◽  
Radiation Balance ◽  
Substantial Influence ◽  
Air Masses ◽  
The Individual

Abstract This article describes the influence of cloudiness and synoptic situations on individual components of the radiation balance such as: global solar radiation; surface-reflected radiation; longwave terrestrial and atmospheric radiation, and the long- and shortwave balance of two types of ground cover typical to Spitsbergen (the Kaffiøyra region), i.e. morainal and glacial. The research was carried out in the summer seasons of 2010 and 2011, using a Kipp & Zonen CNR4 net radiometer. A substantial influence of the presence of clouds on the individual components of the radiation balance was observed. The type of air masses related to specific synoptic situations was also found to affect the incoming and outgoing solar radiation, as well as its losses.

scholarly journals Structure of radiation balance in diverse types of relief

2015 ◽  
Vol 47 (4) ◽  
pp. 343-354 ◽  
Author(s):  
Zbigniew Caputa ◽  
Jakub Wojkowski
Keyword(s):  
Land Use ◽  
Solar Radiation ◽  
Small Area ◽  
Global Solar Radiation ◽  
Wave Radiation ◽  
Radiation Balance ◽  
Full Spectrum ◽  
Plant Groups ◽  
One Year ◽  
Radiation Conditions

Abstract Structure of radiation balance in diverse types of relief. The article presents the results of research on the structure of radiation balance in the full spectrum in diverse types of relief. The study was carried out on the Kraków-Częstochowa Upland (Poland). The varying terrain, its forms, expositions and slopes, large denivelations, and the varying land cover and land use make this small area very diverse as far as radiation conditions are concerned. On the basis of an actinometrical study the structure of radiation balance was assessed in two distinct morphologic terrain forms: the bottom of the valley and the plateau. It was proved that the global solar radiation (K↓) reaching the bottom of the valley in one year was on average 15% lower than the solar energy reaching the plateau. The all wave radiation balance (Q*) at the bottom of the valley was 16% less than on the plateau. The result of complex radiation conditions in the diversified relief was the occurrence of a mosaic of plant groups with distinct requirements.

scholarly journals Validation study of an overall radiation balance estimation method under Ponta Grossa (PR) Brazil weather conditions

2014 ◽  
Vol 34 (3) ◽  
pp. 461-472
Author(s):  
Gustavo C. Beruski ◽  
André B. Pereira
Keyword(s):  
Solar Radiation ◽  
Classical Method ◽  
Estimation Method ◽  
Farming Systems ◽  
Weather Conditions ◽  
Global Solar Radiation ◽  
Radiation Balance ◽  
State University ◽  
Statistical Parameters ◽  
Natural Processes

Radiation balance is the fraction of incident solar radiation upon earth surface which is available to be used in several natural processes, such as biological metabolism, water loss by vegetated surfaces, variation of temperature in farming systems and organic decomposition. The present study aimed to assess and validate the performance of two estimation models for Rn in Ponta Grossa city, Paraná State, Brazil. To this end, during the period of 04/01/2008 to 04/30/2011, from radiometric data collected by an automatic weather station set at the Experimental Station, of the State University of Ponta Grossa. We performed a linear regression study by confrontation between measurements made through radiometric balance and Rn estimates obtained from Brunt classical method, and the proposed method. Both models showed excellent performance and were confirmed by the statistical parameters applied. However, the alternative method has the advantage of requiring only global solar radiation values, temperature, and relative humidity.

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.

Preliminary Investigation of The Attenuation of Solar Radation in The Atmosphere Over Makurdi, Nigeria

2014 ◽  
Vol 4 (1) ◽  
pp. 392-396
Author(s):  
Bernadette Chidomnso Isikwue ◽  
Ada Amedu Aiji ◽  
Mathias Idugba Echi
Keyword(s):  
Solar Radiation ◽  
Air Force ◽  
Preliminary Investigation ◽  
Global Solar Radiation ◽  
Clearness Index ◽  
Geographic Latitude ◽  
A Value ◽  
Pattern Of Variation ◽  
Air Force Base ◽  
Good Agreement

The attenuation of solar radiation in the atmosphere over Makurdi (Latitude 7o 7’ N and longitude 8o 6’ E) was investigated by measurements of direct solar radiation (I) carried out using a digital sun photometer that measured in Wm- 2. The measurements were made at 9:00hrs, 12:00 hrs and 15: 00hrs daily for six months. Global solar radiation, (IG) was calculated for the six months using Gun Bellani measurements from Air Force Base, Makurdi. The diffuse component of solar radiation (ID) was evaluated and the extraterrestrial solar radiation (Io) was obtained by calculation using the equation of Duffie and Beckman (1983) and Liou (1980). The variation of attenuation with clearness index Ki was found. The attenuation in the atmosphere over Makurdi was found to be highest in the month of August with a value of 0.975 and lowest in December with a value of 0.427. There was good agreement in the pattern of variation of attenuation in Makurdi when compared with that of Ilorin that lies in the same geographic latitude.

scholarly journals Solar Radiation in the Arctic during the Early Twentieth-Century Warming (1921–50): Presenting a Compilation of Newly Available Data

2021 ◽  
Vol 34 (1) ◽  
pp. 21-37
Author(s):  
R. Przybylak ◽  
P. N. Svyashchennikov ◽  
J. Uscka-Kowalkowska ◽  
P. Wyszyński
Keyword(s):  
Twentieth Century ◽  
Solar Radiation ◽  
Solar Irradiance ◽  
Global Solar Radiation ◽  
Total Solar Irradiance ◽  
The Arctic ◽  
Data Series ◽  
Radiation Balance ◽  
Radiation Data ◽  
Early Twentieth Century

AbstractThe early twentieth-century warming (ETCW), defined as occurring within the period 1921–50, saw a clear increase in actinometric observations in the Arctic. Nevertheless, information on radiation balance and its components at that time is still very limited in availability, and therefore large discrepancies exist among estimates of total solar irradiance forcing. To eliminate these uncertainties, all available solar radiation data for the Arctic need to be collected and processed. Better knowledge about incoming solar radiation (direct, diffuse, and global) should allow for more reliable estimation of the magnitude of total solar irradiance forcing, which can help, in turn, to more precisely and correctly explain the reasons for the ETCW in the Arctic. The paper summarizes our research into the availability of solar radiation data for the Arctic. An important part of this work is its detailed inventory of data series (including metadata) for the period before the mid-twentieth century. Based on the most reliable data series, general solar conditions in the Arctic during the ETCW are described. The character of solar radiation changes between the ETCW and present times, in particular after 2000, is also analyzed. Average annual global solar radiation in the Russian Arctic during the ETCW was slightly greater than in the period 1964–90 (by about 1–2 W·m−2) and was markedly greater than in the period 2001–19 (by about 16 W·m−2). Our results also reveal that in the period 1920–2019 three phases of solar radiation changes can be distinguished: a brightening phase (1921–50), a stabilization phase (1951–93), and a dimming phase (after 2000).

scholarly journals Balanço de Radiação em Ecossistema de Caatinga Preservada Durante um Ano de Seca no Semiárido Pernambucano (Radiation Balance in Caatinga Ecosystem Preserved for a Year Drought in Semiarid Pernambucano)

2015 ◽  
Vol 8 (1) ◽  
pp. 041
Author(s):  
Luciana Sandra Bastos de Souza ◽  
Magna Soelma Beserra de Moura ◽  
Gilberto Chohaku Sediyama ◽  
Thieres George Freire da Silva
Keyword(s):  
Seasonal Variation ◽  
Solar Radiation ◽  
Photosynthetically Active Radiation ◽  
Climatic Conditions ◽  
Semiarid Region ◽  
Radiation Balance ◽  
Net Radiation ◽  
Active Radiation ◽  
Brazilian Semiarid ◽  
Semi Arid

O objetivo deste trabalho foi analisar as variações diárias e sazonais dos componentes do balanço de radiação e da radiação fotossinteticamente ativa para a caatinga preservada durante um ano seco no Semiárido pernambucano. O experimento foi conduzido durante o ano de 2012 em Petrolina, PE, localizado na região do Semiárido brasileiro. Para determinação dos componentes do balanço de radiação foi utilizado um saldo radiômetro modelo CNR1 instalado à 13,3 metros da superfície. Adicionalmente, analisou-se a interação entre a vegetação e a radiação por meio de sensores para o monitoramento da radiação fotossinteticamente ativa acima e em diferentes posições abaixo do dossel da caatinga. Estes dados foram utilizados no cálculo da fração da radiação fotossinteticamente ativa interceptada (fRFAi) e absorvida (fRFAa). Foi observada uma ampla variação sazonal da radiação solar global e do saldo de radiação que atingiram valores médios diários em torno de 23 MJ m-2 dia-1 e 15 MJ m-2 dia-1, respectivamente. Neste caso, observou-se que a magnitude dos valores dos componentes do balanço de radiação foi afetada principalmente em decorrência da nebulosidade e mudanças na vegetação que afetaram principalmente os níveis de emitância da superfície e sua reflexão. No que se refere às frações da radiação fotossinteticamente ativa interceptada e absorvida, observou-se que as mesmas apresentaram valores médios diários ao longo do ano bastante próximos, os quais foram iguais a 0,69 e 0,64, nesta ordem. Estes dados podem ser extremamente úteis para uma melhor compreensão da interação entre a caatinga e a atmosfera sob condições climáticas singulares, e portanto, serem utilizados na formulação de políticas climáticas.   A B S T R A C T The objective of this study was to analyze the daily and seasonal variations of the components of the radiation balance and photosynthetically active radiation for the Caatinga during a dry year in Pernambuco Semi-Arid. The experiment was conducted during the year 2012 in Petrolina, PE, located in the Brazilian semiarid region. To determine the components of the radiation balance we used a balance radiometer CNR1 model installed the 13.3 meters of surface. Additionally, we analyzed the interaction between vegetation and radiation using sensors to monitor the photosynthetically active radiation above and in different positions under the canopy of scrub. These data were used to calculate the fraction of intercepted photosynthetically active radiation (fRFAi) and absorbed (fRFAa). A wide seasonal variation of solar radiation and net radiation was observed that reached daily averages around 23 MJ m-2 d-1 and 15 MJ m-2 d-1, respectively. In this case, it was observed that the magnitude of the component values ​​of the radiation balance was mainly affected due to the cloudiness and changes in vegetation which mainly affected the levels of emittance and reflection surface. With regard to fractions of intercepted and absorbed photosynthetic active radiation, it was observed that they had daily average values ​​over the next years, which were equal to 0.69 and 0.64 in order. This data can be extremely useful for a better understanding of the interaction between the savanna and the atmosphere under natural climatic conditions. Keywords: radiation, net radiation, photosynthetically active radiation, Caatinga, dry.  

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