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HelioClim-3 Uncertainty

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These statistics follow the benchmarking procedure recommended by the IEA-SHC 36 task (IEA Solar Heating and Cooling program). In particular, in the purpose to provide further standardization of international solar resource data sets to insure worldwide intercomparability and acceptance, several radiation databases were benchmarked, and several results are displayed in the following table. The hourly and daily horizontal radiation values of the HC3 database were benchmarked using 29 ground stations. The parameters resulting from this benchmark ware applied globally (no regionnally ) applied on to all the Meteosat area. See the list of the stations below.

Stations

List of the 29 stations
Africa De Aar (South-Africa)
Tamanrasset (Algeria)
Europe Agen (France)
Basel (Switzerland)
Bergen (Norway)
Carpentras (France)
Cabauw (Netherlands)
Camborne (Belgium)
Chemnitz (Germany)
Dresden site 1 (Germany)
Dresden site 2 (Germany)
Freiburg (Germany)
Freising (Germany)
Geneva Airport (Switzerland)
Geneva University (Switzerland)
Hamburg (Germany)
Ispra (Italy)
Kishinev (Moldavia)
Lerwick (Scotland)
Lugano (Switzerland)
Payerne (Switzerland)
Postdam (Germany)
Toravere (Estony)
Vaulx-en-Velin (France)
Weihenstephan (Germany)
Zinnwald (Germany)
Zurich ETH (Switzerland)
Zurich SMA (Switzerland)
Middle East Sede-Boqer (Israel)

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Major paper on the subject

Analysis of different comparison parameters applied to solar radiation data from satellite and German radiometric stations Solar Energy, Volume 83, Issue 1, January 2009, Pages 118-125 Bella Espinar, Lourdes Ramírez, Anja Drews, Hans Georg Beyer, Luis F. Zarzalejo, Jesús Polo, Luis Martín.

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Methodology and results of the comparison

Methodology: In this procedure, HC3 data over a horizontal plane are compared to ground measurements made on hourly basis or better. Only are kept instants for which the irradiance is greater than a given threshold, e.g., 10 W/m2. For each instant, we compute the difference HC3 minus ground observation. The time-series of differences is synthesized by several parameters such as the mean (bias), or the Root Mean Squared Error (RMSE). Relative quantities are computed by dividing the bias, respectively, the RMSE, by the mean value of the ground observations. The following table provides a summary for all stations. Values per station and each threshold are also available by clicking on the threshold.

Threshold (W/m²) Number samples Mean irradiance measured (W/m²) Bias (W/m²) Relative bias RMSE (W/m²) relative RMSE Correlation coefficient
0.1 211 796 302 -3 -1.1 % 69 22.9 % 0.9681
10 195 891 326 -4 -1.1 % 72 22.0 % 0.9649
50 167 819 376 -5 -1.4 % 77 20.4 % 0.9574
200 111 387 509 -10 -2.0 % 83 16.3 % 0.9351

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Threshold 0.1 W/m²

Stations Number samples Mean irradiance measured (W/m²) Bias (W/m²) Relative bias RMSE (W/m²) relative RMSE Correlation coefficient
Agen 19893 300 6 +2.0% 62 20.6% 0.9719
Basel 8682 263 1 +0.4% 80 30.6% 0.9471
Bergen 1289 190 32 +16.9% 100 52.4% 0.8892
Cabauw 285 130 -6 -4.8% 52 40.2% 0.9060
Camborne 12157 242 5 +2.3% 60 24.9% 0.9676
Carpentras 8897 355 2 +0.4% 65 18.4% 0.9746
Chemnitz 4311 252 -17 -6.9% 62 24.5% 0.9673
Deaar 3083 426 13 +3.1% 70 16.5% 0.9804
Dresden 3022 277 -14 -5.1% 64 23.2% 0.9645
Dresden2 4338 251 -20 -8.0% 90 35.9% 0.9288
Freiburg 1428 313 10 +3.1% 64 20.6% 0.9731
Freising 17309 270 -23 -8.4% 73 27.0% 0.9624
Geneva 8947 291 -8 -2.7% 60 20.7% 0.9754
Geneva2 13429 278 0 -0.1% 74 26.6% 0.9590
Hamburg 3032 250 0 -0.1% 62 24.6% 0.9615
Ispra 9009 278 -8 -2.9% 56 20.2% 0.9774
Kishinev 4443 281 7 +2.5% 67 23.9% 0.9687
Lerwick 11233 188 11 +5.9% 73 38.6% 0.9346
Lugano 8889 290 -3 -0.9% 60 20.8% 0.9745
Payerne 7600 386 -29 -7.4% 83 21.4% 0.9561
Postdam 3051 266 10 +3.7% 69 25.9% 0.9546
Sede_Boqer 8661 531 -29 -5.5% 69 13.1% 0.9781
Tamanrasset 10425 614 8 +1.2% 68 11.0% 0.9771
Toravere 12756 229 1 +0.5% 75 32.9% 0.9435
Vaulx 2578 318 7 +2.2% 72 22.8% 0.9647
Weihenstephan 1464 291 -31 -10.8% 81 27.7% 0.9542
Zinnwald 4011 249 -1 -0.5% 74 29.5% 0.9498
Zurich 8981 250 -2 -1.0% 65 26.0% 0.9655
Zurich2 8593 260 1 +0.5% 68 26.3% 0.9626

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Threshold 10 W/m²

Stations Number samples Mean irradiance measured (W/m²) Bias (W/m²) Relative bias RMSE (W/m²) relative RMSE Correlation coefficient
Agen 18636 320 6 +2.0% 64 20.0% 0.9692
Basel 8011 285 0 +0.1% 84 29.3% 0.9422
Bergen 1147 213 35 +16.6% 106 49.5% 0.8744
Cabauw 244 151 -8 -5.2% 56 37.3% 0.8849
Camborne 10844 270 6 +2.2% 64 23.6% 0.9629
Carpentras 8330 379 1 +0.4% 68 17.8% 0.9718
Chemnitz 4107 264 -18 -6.9% 63 23.9% 0.9656
Deaar 2846 461 14 +3.0% 73 15.8% 0.9776
Dresden 2878 291 -15 -5.1% 66 22.7% 0.9622
Dresden2 4085 267 -21 -8.1% 93 34.9% 0.9243
Freiburg 1293 345 11 +3.1% 68 19.6% 0.9690
Freising 15449 302 -26 -8.5% 77 25.5% 0.9574
Geneva 8160 318 -9 -2.8% 63 19.8% 0.9725
Geneva2 12246 305 -1 -0.2% 78 25.4% 0.9541
Hamburg 2834 267 0 -0.1% 64 23.8% 0.9579
Ispra 8114 309 -9 -3.0% 59 19.2% 0.9746
Kishinev 4025 310 8 +2.5% 70 22.7% 0.9646
Lerwick 9846 214 12 +5.8% 78 36.2% 0.9249
Lugano 8078 318 -3 -1.0% 63 19.8% 0.9713
Payerne 7565 388 -29 -7.4% 83 21.3% 0.9558
Postdam 2887 281 10 +3.6% 71 25.3% 0.9507
Sede_Boqer 8657 532 -29 -5.5% 69 13.1% 0.9781
Tamanrasset 10422 614 8 +1.2% 68 11.0% 0.9770
Toravere 11453 254 1 +0.6% 79 31.2% 0.9361
Vaulx 2411 339 7 +2.2% 75 22.0% 0.9610
Weihenstephan 1410 302 -33 -10.8% 82 27.2% 0.9523
Zinnwald 3857 259 -1 -0.6% 75 29.0% 0.9476
Zurich 8091 276 -3 -1.0% 68 24.7% 0.9613
Zurich2 7965 280 1 +0.4% 71 25.3% 0.9594

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Threshold 50 W/m²

Stations Number samples Mean irradiance measured (W/m²) Bias (W/m²) Relative bias (%) RMSE (W/m²) relative RMSE Correlation coefficient
Agen 16 294 363 6 1.7% 68 18.7% 0.9629
Basel 6 661 337 -3 -1.0% 89 26.5% 0.9304
Bergen 901 264 38 14.3% 115 43.7% 0.8401
Cabauw 187 189 -16 -8.4% 62 32.6% 0.8461
Camborne 9 075 318 6 +1.9% 69 21.7% 0.9541
Carpentras 7 342 426 0 +0.0% 71 16.6% 0.9661
Chemnitz 3 391 314 -22 -7.1% 69 21.9% 0.9587
Deaar 2 459 529 15 +2.9% 77 14.5% 0.9706
Dresden 2 456 336 -16 -4.9% 71 21.2% 0.9530
Dresden2 3 346 319 -26 -8.1% 102 32.0% 0.9060
Freiburg 1 127 392 11 +2.9% 72 18.3% 0.9614
Freising 13 075 352 -31 -8.7% 83 23.6% 0.9487
Geneva 6 930 370 -11 -3.0% 68 18.3% 0.9659
Geneva2 10 313 357 -3 -0.8% 84 23.4% 0.9430
Hamburg 2 386 312 0 -0.0% 69 22.0% 0.9465
Ispra 6 707 368 -12 -3.1% 64 17.5% 0.9678
Kishinev 3 397 362 8 +2.2% 76 20.9% 0.9560
Lerwick 7 727 265 14 +5.5% 86 32.6% 0.9022
Lugano 6 709 378 -7 -1.9% 67 17.9% 0.9641
Payerne 7 053 414 -31 -7.5% 86 20.7% 0.9502
Postdam 2 485 322 11 +3.5% 76 23.5% 0.9385
Sede_Boqer 8 507 540 -30 -5.5% 70 12.9% 0.9773
Tamanrasset 10 343 618 8 +1.2% 68 11.0% 0.9764
Toravere 9 371 305 1 +0.3% 87 28.5% 0.9189
Vaulx 2 068 391 8 +2.0% 80 20.4% 0.9500
Weihenstephan 1 207 349 38 -10.8% 88 25.2% 0.9433
Zinnwald 3 184 308 -3 -0.9% 82 26.5% 0.9355
Zurich 6 640 331 -4 -1.3% 74 22.5% 0.9519
Zurich2 6 478 338 0 -0.1% 77 22.8% 0.9491

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Threshold 200 W/m²

Stations Number samples Mean irradiance measured (W/m²) Bias (W/m²) Relative bias RMSE (W/m²) relative RMSE Correlation coefficient
Agen 10722 491 4 +0.8% 74 15.0% 0.9388
Basel 4081 478 -17 -3.5% 96 20.2% 0.8990
Bergen 457 411 13 +3.2% 114 27.8% 0.7854
Cabauw 73 307 -48 -15.5% 76 24.8% 0.7511
Camborne 5426 454 2 +0.5% 73 16.1% 0.9296
Carpentras 5425 537 -5 -0.9% 72 13.3% 0.9536
Chemnitz 1969 459 -29 -6.3% 80 17.5% 0.9294
Deaar 1967 631 13 +2.1% 72 11.4% 0.9639
Dresden 1559 462 -17 -3.7% 80 17.4% 0.9123
Dresden2 1977 463 -36 -7.9% 115 24.9% 0.8466
Freiburg 791 509 11 +2.2% 79 15.4% 0.9328
Freising 8341 487 -41 -8.4% 96 19.8% 0.9142
Geneva 4517 507 -18 -3.5% 76 15.0% 0.9422
Geneva2 6609 493 -11 -2.2% 93 18.9% 0.9074
Hamburg 1447 439 -4 -1.0% 74 16.9% 0.9102
Ispra 4493 492 -12 -2.4% 71 14.5% 0.9460
Kishinev 2196 498 7 +1.4% 78 15.8% 0.9327
Lerwick 4007 403 9 +2.3% 92 22.8% 0.8496
Lugano 4591 500 -17 -3.4% 71 14.3% 0.9471
Payerne 5309 510 -36 -7.1% 94 18.5% 0.9246
Postdam 1544 446 9 +2.1% 79 17.8% 0.8969
Sede_Boqer 7043 628 -31 -4.9% 72 11.5% 0.9663
Tamanrasset 9178 682 9 +1.3% 70 10.3% 0.9660
Toravere 5609 432 0 -0.1% 93 21.6% 0.8725
Vaulx 1443 509 7 +1.3% 85 16.8% 0.9169
Weihenstephan 778 476 -47 -9.9% 102 21.3% 0.9085
Zinnwald 1830 454 -10 -2.2% 90 19.8% 0.9006
Zurich 4034 472 -8 -1.7% 86 18.2% 0.9171
Zurich2 3971 479 -5 -1.0% 89 18.5% 0.9110

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