Broadband dependence of atmospheric transmissions in the UV and total solar radiation

Figures & data

Fig. 1. Annual cycles of the daily integrated SSR for the maximum possible clear-sky solar irradiance (reference value) and the all-sky average irradiance for (a) EUV, (b) TUV, and (c) GS total spectrum from March 2004 to February 2013. The solid and dashed lines show the envelope curves of the data maxima and the curves of the all-sky average values, respectively.

Table 1. Results of the harmonic analysis for the clear-sky model (Equation 3(3) $$y_t\mathrm{ }=\stackrel{\mathrm{-}}{y}+A\hspace{0.17em}\text{cos}\hspace{0.17em}(\frac{2\pi t}{n} – {\varphi }_1),$$(3) ).

SSR	Average $\left(\overline{y}\right)$	Amplitude (A)	Phase angle $({\mathrm{\varphi }}_1)$
			Degrees Radian
EUV (mW m^−2)	29.5	22.2	206 3.6
TUV (W$\mathrm{ }{\mathrm{m}}^{–2}$)	11.8	6.6	183 3.2
GS (W$\mathrm{ }{\mathrm{m}}^{–2}$)	248.5	118.6	172 3.0

Table 2. RAFs used in Equation (8)(8a) $${\text{SSR}}_{\mathrm{m}\_\text{corrected}}(i, \text{CC})={\text{SSR}}_m\times \left(1+\frac{\text{TCO}–\overline{\text{TCO}}}{\overline{\text{TCO}}}\times {\text{TCO}}_{\text{RAF}}+\frac{\text{AOD}–\overline{\text{AOD}}}{\overline{\text{AOD}}}\times {\text{AOD}}_{\text{RAF}}\right)$$(8a) (Kim et al. 2014).

SSR	CC	AOD	TCO
EUV (290–325 nm)	–0.12	–0.21	–1.16
TUV (290–363 nm)	–0.13	–0.21	–0.35
GS (305–2800 nm)	–0.25	–0.16	–0.23

Table 3. Annual mean correction ratios of the corrected SSR (EUV, TUV, and GS) to the measured SSR.

SSR	Cloud T	AOD T	Ozone T
EUV (290–325 nm)	0.992 (0.125)	1.014 (0.095)	0.998 (0.145)
TUV (290–363 nm)	0.990 (0.101)	1.012 (0.073)	0.999 (0.147)
GS (305–2800 nm)	0.992 (0.077)	1.022 (0.141)	1.013 (0.189)

Remarks: Figures in parentheses indicate standard deviation of the correction ratio.

Fig. 2. Annual cycles of monthly mean (a) SSI (GS, TUV, and EUV irradiances), number of data to the left vertical axis, and (b) CC, AOD (at 320.1 nm), TCO, and RH, over the period from March 2004 through February 2013.

Fig. 3. Annual cycles of (a) total, (b) cloud, (c) aerosol, and (d) ozone transmission in the EUV, TUV, and GS irradiances.

Table 4. EUV, TUV, and GS transmissions (%) grouped by CC amount, AOD, and TCO.

SSR	Group CC (tenths)
	<1	1–2	3–4	5–6	7–8	9–10
Number of data points	231	318	367	314	177	33
EUV	(87.4)	86.1	79.3	74.9	69.2	54.1
TUV	(86.8)	83.5	75.5	69.2	61.6	49.8
GS	(89.6)	83.7	73.8	64.5	56.0	43.4

SSR	Group AOD (320.1 nm)
	<0.5	0.5–0.8	0.9–1.2	1.3–1.6	1.7–2.0	2.1–2.4	2.5–4.0
Number of data points	184	377	342	259	149	67	62
EUV	(91.3)	87.6	81.2	75.9	68.4	66.7	56.7
TUV	(89.0)	84.2	76.8	71.0	65.1	63.2	53.6
GS	(91.6)	84.2	76.2	70.4	62.6	61.8	51.7

SSR	Group TCO (DU)
	<310	310–324	325–339	340–354	355–369	370–384	385–399	400 ≤
Number of data points	482	215	186	184	138	121	60	54
EUV	82.0	82.2	80.4	(80.8)	(78.5)	76.3	69.5	70.2
TUV	75.0	77.4	76.3	(77.8)	(77.8)	79.7	73.8	79.0
GS	71.7	75.9	75.9	(80.3)	(80.8)	83.4	75.3	82.5

Remarks: Figures in parentheses indicate nonsystematic wavelength dependence in atmospheric transmission.

Table 5. Annual averages and seasonal wavelength dependences in total, cloud, aerosol, and ozone transmission (%) increase and decrease with wavelength from EUV through the TUV and GS regions of the solar spectrum.

	Increase	Decrease
	March	July–January (August)	Annual
Total transmission (%)
EUV	69.5	80.4 (74.4)	77.6
TUV	72.6	74.7 (65.0)	73.6
GS	73.6	71.0 (57.0)	72.0
Cloud transmission (%)
EUV	72.5	81.3 (78.3)	78.4
TUV	72.8	75.6 (68.6)	73.9
GS	73.6	71.2 (58.8)	71.7
Aerosol transmission (%)
EUV	72.6	82.6 (80.8)	79.4
TUV	73.1	76.9 (71.0)	75.1
GS	74.2	73.6 (62.5)	74.1
Ozone transmission (%)
EUV	71.3	81.9 (79.3)	78.9
TUV	72.8	76.6 (70.1)	74.9
GS	74.1	73.4 (61.8)	74.1
Associated meteorological parameters
Cloud Cover (tenths)	4.7	4.2 (5.3)	4.2
Relative Humidity (%)	57.8	67.2 (75.6)	64.4
AOD (320.1 nm)	1.3	1.1 (1.3)	1.2
Total Ozone (DU)	371.4	311.1 (298.8)	329.5

Remarks: Transmissions in February, April, May, and June did not show systematic wavelength dependences except for the cloud transmission in February and June. Transmission in August is shown in parentheses.

Kim, W., Kim, J., Park, S. S. and Cho, H.-K., 2014. UV sensitivity to changes in ozone, aerosols, and clouds in Seoul, South Korea. J. Appl. Meteorol. Climatol. 53, 310–322. DOI:10.1175/JAMC-D-13-052.1.

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