Calibration of Ångström-Prescott Equation to Estimate Daily Solar Radiation on Rio Grande do Norte State, Brazil

Medeiros, Felipe J. de; Silva, Claudio M. Santos e; Bezerra, Bergson G.

doi:10.1590/0102-77863230008

Acessibilidade / Reportar erro

Brasil

Revista Brasileira de Meteorologia

Español English

Brasil

Español English

sumário « anterior atual seguinte »

Sumário

Artigo • Rev. bras. meteorol. 32 (3) • Jul-Sep 2017 • https://doi.org/10.1590/0102-77863230008 copy

Calibration of Ångström-Prescott Equation to Estimate Daily Solar Radiation on Rio Grande do Norte State, Brazil

Calibração da Equação de Ångström-Prescott para Estimar a Radiação Solar Diária no Estado do Rio Grande do Norte, Brasil

Authorship SCIMAGO INSTITUTIONS RANKINGS

Abstract

Knowledge of solar radiation is required for many applications. However, this atmospheric variable is not measured with an adequate space resolution. In this sense, to sites where solar radiation data are not directly measure, estimative using Ångström-Prescott equation can be used in order to provide solar radiation data, with input of sunshine duration. Thus, the objective of present study was to calibrate the Ångström-Prescott equation for different sites in Rio Grande do Norte state, Brazil. The performance of the calibrated Ångström-Prescott equation was evaluated by comparing of daily global solar radiation observed in situ. The MBE (Mean Bias Error) was lower than 1.50 MJ m^-2 day^-1, the Pearson's correlation coefficient about 0.90 and Willmott's index of agreement higher than 0.90, which are considered satisfactory.

Keywords:
semiarid region; sunshine duration; Ångström-Prescott equation

Weather Station	Lat. (°S)	Lon. (°W)	Elev. (m)	Air Temp. (°C)	Prec. (mm)	Rel. Hum. (%)	Sunshine (h)	Climate
Natal	5.92	32.50	48.6	26.0	1465	77.3	2968.0	Humid
Macau	5.12	36.77	32.0	26.8	507	70.8	2686.0	Semi-Arid
Apodi	5.62	37.82	150.0	27.1	893	66.8	3041.1	Semi-Arid
Caicó	6.47	37.68	169.2	26.1	648	63.2	2700.0	Semi-Arid

Weather Station	Calibration Period	Calibrated Angström-Prescott equation	a + b	R²
Natal	DJF	H/H₀ = 0.31 + 0.38(n/N)	0.69	0.64
	MAM	H/H₀ = 0.27 + 0.45(n/N)	0.72	0.82
	JJA	H/H₀ = 0.29 + 0.42(n/N)	0.71	0.79
	SON	H/H₀ = 0.31 + 0.38(n/N)	0.69	0.61
	Annual	H/H₀ = 0.29 + 0.41(n/N)	0.70	0.75
Macau	DJF	H/H₀ = 0.41 + 0.26(n/N)	0.67	0.45
	MAM	H/H₀ = 0.38 + 0.32(n/N)	0.70	0.68
	JJA	H/H₀ = 0.39 + 0.31(n/N)	0.70	0.63
	SON	H/H₀ = 0.32 + 0.36(n/N)	0.68	0.46
	Annual	H/H₀ = 0.39 + 0.29(n/N)	0.68	0.58
Apodi	DJF	H/H₀ = 0.32 + 0.41(n/N)	0.73	0.78
	MAM	H/H₀ = 0.34 + 0.42(n/N)	0.76	0.71
	JJA	H/H₀ = 0.35 + 0.40(n/N)	0.75	0.72
	SON	H/H₀ = 0.36 + 0.38(n/N)	0.73	0.55
	Annual	H/H₀ = 0.34 + 0.41(n/N)	0.75	0.71
Caicó	DJF	H/H₀ = 0.35 + 0.39(n/N)	0.74	0.83
	MAM	H/H₀ = 0.38 + 0.37(n/N)	0.75	0.79
	JJA	H/H₀ = 0.37 + 0.39(n/N)	0.76	0.86
	SON	H/H₀ = 0.31 + 0.44(n/N)	0.75	0.79
	Annual	H/H₀ = 0.36 + 0.38(n/N)	0.74	0.82

Station	Calibration	RMSE (MJ m^-2 dia^-1)	r (-)	d (-)	MBE (MJ m^-2 dia^-1)	MPE (%)
Natal	Seasonal	1.01	0.95	0.97	-0.080	-0.22
	Annual	1.02	0.95	0.97	-0.093	-0.37
Macau	Seasonal	1.92	0.91	0.91	1.107	6.54
	Annual	1.94	0.89	0.91	1.040	6.21
Apodi	Seasonal	1.64	0.90	0.94	0.134	1.37
	Annual	1.64	0.90	0.95	0.300	2.01
Caicó	Seasonal	1.51	0.93	0.96	0.415	2.64
	Annual	1.49	0.96	0.96	0.420	1.75

Sociedade Brasileira de Meteorologia Rua. Do México - Centro - Rio de Janeiro - RJ - Brasil, +55(83)981340757 - São Paulo - SP - Brazil
E-mail: sbmet@sbmet.org.br

Acompanhe os números deste periódico no seu leitor de RSS

[1] Autor de correspondência: Bergson G. Bezerra, bergson.bezerra@gmail.com.