Il Nuovo Cimento C

, Volume 4, Issue 2, pp 113–122 | Cite as

Autocorrelation of daily global solar radiation

  • B. Bartoli
  • B. Coluzzi
  • V. Cuomo
  • M. Francesca
  • C. Serio
Article

Summary

We show that the time series of daily valuesK T (ratios of global solar radiation on a horizontal surface to extra atmospherical radiation) cannot be statistically distinguished from a 1st-order autoregressive stochastic process. The analysis of Italian meteorological data shows that the first autocorrelation coefficient is a random variable which is practically independent of locality; moreover, the distributions of the residues around the mean value are also independent of locality.

Keywords

Horizontal Surface Crotone Autocorrelation Coefficient Global Solar Radiation Station Latitude 

List of symbols

Fexp(t)

experimental global radiation on a horizontal surface on thet-th day of the month

Fext(t)

extra atmospherical radiation on a horizontal surface on thet-th day of the month

KT(t)

F exp (t)/F ext (t)

m

number of days per month

X

monthly average value of\(K_T :X = \sum\limits_{t = 1}^m {K_T (t)/m;} \)

u(t)

K T (t)−X

г

first autocorrelation coefficient

ϱ8(i)

estimation of г, calculated on thei-th month and relative to thes-th station

\(\bar \varrho _s :\)

average value of the monthly autocorrelation coefficients (relative to thes-th station)

Ws(i)

\(\hat \varrho _s (i) - \bar \varrho _s ;\)

\(\left\langle {\bar \varrho } \right\rangle :\)

average value of the monthly autocorrelation coefficients, all over Italy

Riassunto

Si dimonstra che la serie temporale dei valori giornalieriK T (rapporto tra la radiazione solare globale su superficie orizzontale e la radiazione extraatmosferica) non può essere statisticamente distinta da un processo stocastico autoregressivo di prim'ordine. L'analisi di dati meteorologici italiani mostra che il primo coefficiente di autocorrelazione è una variabile casuale che è praticamente indipendente dalla località; inoltre, anche le distribuzioni dei residui intorno al valore medio sono indipendenti dalla località.

Резюме

Мы показываем, что временные последовательности суточных значенийK T (отношения глобальной солнечной радиации на горизонтальной поверхности к внеатмосферной радиации) не могут быть статистически отличимЫ от авторегрессивного стохастического процесса первого порядка. Анализ метеорологических данных показывает, что первый автокорреляционный коэффициент представляет случайную перменную, которая практически не зависит от местоположения. Кроме того, распределения вычетов вокруг среднего значения также не зависят от местоположения.

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. (1).
    S. A. Klein, P. J. Cooper, T. L. Freeman, D. M., Beekman, W. A. Beckman andJ. A. Duffie:Sol. Energy,17, 29 (1975).CrossRefADSGoogle Scholar
  2. (2).
    V. Cuomo, M. Francesca andC. Serio:The reference year, inSolar Energy Availability, lecture notes of thePermanent School of Solar Energy Processes, SoGeSTA, Urbino, 1978, edited byV. Cena, cap. IV (Urbino, 1979).Google Scholar
  3. (3).
    B. Bartoli, S. Catalanotti, V. Cuomo, M. Francesca, C. Serio, V. Silvestrini andG. Troise:Nuovo Cimento C,2, 222 (1979).Google Scholar
  4. (4).
    G. Ambronsone:Energy delivered by solar collectors, inHeat Load Calculation and Economics: Optimization of the Building Envelope and of Solar Components, lecture notes of thePermanent School of Solar Energy Process, SoGeSTA, Urbino, 1978. cap. X, edited byV. Silvestrini (Napoli, 1979).Google Scholar
  5. (5).
    G. Ambrosone, A. Andretta, F. Bloisi, S. Catalanotti, V. Cuomo, V. Silvastrini andL. Vicari:Appl. Energy,7, 119 (1980).CrossRefADSGoogle Scholar
  6. (6).
    A. Andretta, G. Barone, L. Brunini, V. Cuomo, M. Francesca, P. Mattarelli andC. Serio:Appl. Energy.,7, 93 (1980).CrossRefADSGoogle Scholar
  7. (7).
    M. Kendall andA. Stuart:The Advanced Theory of Statistics (London, 1976).Google Scholar
  8. (8).
    H. Schaffé:The Analysis of Variance (New York, N. Y., (1959).Google Scholar
  9. (9).
    B. J. Brinkworth:Sol. Energy.,19, 343 (1977).CrossRefADSGoogle Scholar

Copyright information

© Società Italiana di Fisica 1981

Authors and Affiliations

  • B. Bartoli
    • 1
  • B. Coluzzi
    • 1
  • V. Cuomo
    • 1
  • M. Francesca
    • 1
  • C. Serio
    • 1
  1. 1.Istituto di Fisica della Facoltà di InegneriaNapoliItalia

Personalised recommendations