Comparing MERRA surface global solar radiation and diffuse radiation against field observations in Shanghai. Reporter: Yue Kun

Transcription

1 Comparing MERRA surface global solar radiation and diffuse radiation against field observations in hanghai Reporter: Yue Kun 1

2 OUTLINE 1 Background and Objectives 2 Materials and Methods 3 Results and Discussions 4 ummary 2

3 Background and Objectives olar radiation at the Earth s surface (surface solar radiation, R) is the ultimate energy source for life on the planet. It must rely on reanalysis to get more continuous spatial and temporal radiation data. Reanalysis have positive biases with observations, to radiation data, the main causes of biases may be light cloud and aerosol. Reanalysis bias errors will affect the application. MERRA is one of reanalysis from NAA. Objective of this is to evaluation MERRA s global solar radiation and diffuse solar radiation against the observations in hanghai, and reduce the errors. 3

4 Materials and Methods Historical data: global solar radiation and diffuse solar radiation hanghai( E N) J/m 2 d MERRA: global solar radiation and diffuse solar radiation 1 4 J/m 2 d MODI data: The MODerate resolution Imaging pectrometer (MODI) instrument is one of the first passive satellite radiometers designed to retrieve aerosols over the land and ocean. The instrument oboard the Terra (EO- AM) in 1999,and aboard Aqua (EO-PM) satellites in 22. The daily level-2 data (Collection 5) at 55 nm from the Terra and Aqua MODI aerosol products (MOD4_L2, MYD4_L2) are applied in this study. Aerosol optical depth () is a measure of the opaqueness of air, and high values of indicate poor visibility. 4

5 Materials and Methods b k m m t e m t m b a k b [1.33cos(36 t / 365)]sin e sc d b Dm D m D D m bdm a b (1 b) m e a m e D (1 a b) Dm 5 [Gu et al.,1999] [Zhao et al.,213]

6 Diffuse Radiation(1 4 J/m 2 *d) Global olar Radiation(1 4 J/m 2 *d) Results and Discussions MERRA Year MERRA Year Daily global solar radiation and diffuse radiation 6

7 Diffuse Radiation(1 4 J/m 2 *d) Global olar Radiation(1 4 J/m 2 *d) Results and Discussions 25 MERRA Year 12 MERRA Year Monthly mean global solar radiation and diffuse radiation 7

8 Diffuse Radiation(1 4 J/m 2 *d) Global olar Radiation(1 4 J/m 2 *d) Results and Discussions MERRA y= *x R 2 =.4378 n=12 y= *x R 2 = n= y=2.416*x Year 8 7 R 2 = n=12 MERRA y=2.654*x R 2 =.1189 n= Year Annual mean global solar radiation and diffuse radiation 8

9 Global olar Radiation of MERRA(1 4 J/m 2 *d) Diffuse olar Radiation of MERRA(1 4 J/m 2 *d) Results and Discussions y=.3889*x R 2 =.3262 n=4655 P< P<.5 y=.7839*x R 2 =.6957 n= Global olar Radiation of (1 4 J/m 2 *d) Diffuse Radiation of (1 4 J/m 2 *d) Comparison of the daily global solar radiation and diffuse radiation 9

10 Model Bias Ratio Model Bias Ratio Relationship between daily clearness index() and daily global solar radiation s model bias ratio( diffuse radiation s model bias ratio) Model Bias Ratio Model Bias Ratio y=-.713*x R 2 =.1443 n= Observed Clearness Index y = 9.8*x 2-9.8*x R 2 =.1211 n=167 P<.1 D k t k t D -1 y=.92941*x R 2 = n= P< P< P< Observed Clearness Index -1.5 y= *x R 2 = n=

11 Global olar Radiation of MERRA(1 4 J/m 2 *d) Comparison of the daily global solar radiation Global olar Radiation of MERRA(1 4 J/m 2 *d) y=.8197*x R 2 =.699 n=167 before y=.86888*x R 2 = n=167 P<.1 P<.1 kt y=.8197*x R 2 =.699 n=167 before y=.75245*x R 2 = n=167 P< P<.1 after Global olar Radiation of (1 4 J/m 2 *d) after Global olar Radiation of (1 4 J/m 2 *d) 11

12 Diffuse Radiation of MERRA(1 4 J/m 2 *d) Diffuse Radiation of MERRA(1 4 J/m 2 *d) Comparison of the daily diffuse radiation y=.48482*x R 2 =.4751 n=167 P<.1 25 y=.48482*x R 2 =.4751 n=167 P<.1 5 before after 2 kt 5 before after P<.1 n=167 R 2 =.4793 y=.8225*x Diffuse olar Radiation of (1 4 J/m 2 *d) P<.1 n=167 R 2 = y=.98749*x Diffuse Radiation of (1 4 J/m 2 *d) 12

13 Global olar Radiation of MERRA(1 4 J/m 2 *d) Global olar Radiation of MERRA(1 4 J/m 2 *d) Comparison of the monthly mean global solar radiation 3 25 before 3 25 before P<.1 n=141 R 2 = y=.9285*x P<.1 n=141 R 2 = y=.9285*x after kt 25 after P< n=141 R 2 = y=.87958*x Global olar Radiation of (1 4 J/m 2 *d) 1 5 P<.1 n=141 R 2 = y=.81581*x Global olar Radiation of (1 4 J/m 2 *d) 13

14 Diffuse Radiation of MERRA(1 4 J/m 2 *d) Diffuse Radiation of MERRA(1 4 J/m 2 *d) Comparison of the monthly mean diffuse radiation y=.61362*x R 2 = n=141 P< y=.61362*x R 2 = n=141 P<.1 5 before y=.92234*x before y=1.756*x R 2 = n=141 P<.1 kt 15 1 R 2 = n=141 P<.1 5 after Diffuse Radiation of (1 4 J/m 2 *d) 5 after 1 2 Diffuse olar Radiation of (1 4 J/m 2 *d) 14

15 Global olar Radiation of MERRA(1 4 J/m 2 *d) Diffuse Radiation of MERRA(1 4 J/m 2 *d) Global olar Radiation of MERRA(1 4 J/m 2 *d) Diffuse Radiation of MERRA(1 4 J/m 2 *d) Comparison of the annual mean global solar radiation y=.58524*x R 2 = n= MERRA before MERRA after P<.1 y=.7419*x R 2 = n= P<.5 y=.29*x R 2 =.392 n=12 n=12 R 2 = MERRA before 6 16 MERRA after Global olar Radiation of (1 4 J/m 2 *d) y=.58524*x R 2 = n=12 k t k t D D 55 y=.22423*x Diffuse Radiation of (1 4 J/m 2 *d) MERRA before MERRA after R 2 = n=12 y=.45826*x MERRA before MERRA after P< Global olar Radiation of (1 4 J/m 2 *d) y=.22423*x R 2 = n=12 y=.64637*x R 2 =.7932 n=12 P< Diffuse Radiation of (1 4 J/m 2 *d) 15

16 Global olar Radiation(1 4 J/m 2 *d) Diffuse Radiation(1 4 J/m 2 *d) Global olar Radiation(1 4 J/m 2 *d) Diffuse Radiation(1 4 J/m 2 *d) Annual mean global solar radiation and diffuse radiation Year MERRA before MERRA after k t k t D MERRA before MERRA after Year MERRA before MERRA after D Year 5 4 MERRA before MERRA after

17 Global olar Radiation(1 4 J/m 2 *d) Diffuse Radiation(1 4 J/m 2 *d) Global olar Radiation(1 4 J/m 2 *d) Diffuse Radiation(1 4 J/m 2 *d) Monthly composite global solar radiation and diffuse radiation MERRA before MERRA after Feb Apr Jun Aug Oct Dec k t k t D MERRA before MERRA after Feb Apr Jun Aug Oct Dec 3 D MERRA before MERRA after Feb Apr Jun Aug Oct Dec MERRA before MERRA after 17 Feb Apr Jun Aug Oct Dec

18 Results and Discussions MERRA Corrected MERRA ME RME R 2 ME RME R 2 Kt Daily Monthly Annual Daily D Monthly D Annual D Daily Monthly Annual Daily D Monthly D Annual D

19 Global olar Radiation of MERRA(1 4 J/m 2 *d) Comparison of the monthly mean global solar radiation( diffuse radiation) without eliminating Diffuse Radiation of MERRA(1 4 J/m 2 *d) y=.78194*x R 2 =.8675 n= R 2 = n=153 y=.91314*x kt y=1.1264*x R 2 =.7641 n= R 2 =.6246 n=141 y=.9951*x Global olar Radiation of (1 4 J/m 2 *d) Diffuse Radiation of (1 4 J/m 2 *d) 19

20 ummary The results showed that the global solar radiation better with clearness index, and of the diffuse radiation with. Correction effect in longer time scale is better than shorter time scale. But data have more default, which will affect the. 2

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