Abstract:
This is Version 1.0 of a satellite-derived surface solar energy data
set formulated for the Renewable Energy Industry. It contains 52
monthly-averaged parameters, specified by the DOE National Renewable
Energy Laboratory, which are useful in the application of solar energy
technologies. The Surface Solar Energy (SSE) data set was created by
the NASA Langley Research Center and Analytical Services
... and
Materials, Inc. under sponsorship of the NASA Mission to Planet Earth
program.
This SSE data set is a synthesis of the World Climate Research
Program/Surface Radiation Budget (WCRP/SRB) shortwave data set
(Version 1.1), ISCCP-C1 (International Satellite Cloud Climatology
Project) 3-hourly satellite data, and ISCCP-C2 monthly mean cloud
fraction data. ISCCP provides global coverage of satellite data on an
equal-area grid (6596 cells). Each cell represents an area equal to
that of a 2.5 degree latitude/longitude cell at the equator
(approximately 280 square km). Comparison with data from
approximately 500 ground sites suggest that the satellite-derived
values are generally within 10 percent of surface measured values for
most regions of the world. However, there are two notable exceptions.
1. These Version 1.0 values may be as much as 30 percent high in
regions of large-scale biomass burning in those months when total
precipitation is less than 24mm. These regions are mostly in Africa
and South America; however, other parts of the world may be affected
to a lesser degree. The error is caused by the fact that the Version
1.1 WCRP/SRB data set did not account for high levels of smoke in the
atmospheric aerosols. The full extent of biomass burning and its
effect on surface solar energy is not yet known by the scientific
community. Efforts are underway at NASA Langley Research Center to
correct this problem. It is planned that a Version 2.0 SSE global data
set will be available during 1998 which accounts for the majority of
the effects of biomass burning.
2. These Version 1.0 values may be as much as 40 percent low over bare
snow or ice surfaces. The problem is caused by the fact that the ISCCP
C2 data cannot separate clouds from bare snow or ice because of the
satellite channels that were used in that product. Comparisons with
ground site data suggest that errors are within 10 percent for those
snow regions with significant vegetation or topography to cause dark
contrast or shadows. Again, it is expected that the future version of
this SSE data set will contain more accurate values over snow and ice.
The following parameters will be included for each cell for each of the 12
months. The values for each month will be either the average, minimum, or
maximum over the existing SRB data set 4-year period (3 years for January
and February). The convention that is used is the following: total
irradiance = direct irradiance + diffuse irradiance.
1. CELL NUMBER, [1 - 6596]. UNITS - dimensionless
2. CELL CENTER, LATITUDE [+90N, -90S]. UNITS - decimal degrees
3. CELL CENTER, LONGITUDE [0E - 360E]. UNITS - decimal degrees
4. CELL BOUNDARIES, LATITUDE [+90N, -90S]. UNITS - decimal degrees
5. CELL BOUNDARIES, LONGITUDE [0E - 360E]. UNITS - decimal degrees
6. AVERAGE TOP-OF-ATMOSPHERE DOWN. UNITS - kwhm-2 per 24h day
7. AVERAGE TOTAL HORIZONTAL-SURFACE DOWN. UNITS - kwhm-2 per 24h day
8. MINIMUM TOTAL HORIZONTAL-SURFACE DOWN. UNITS - kwhm-2 per 24h day
9. MAXIMUM TOTAL HORIZONTAL-SURFACE DOWN. UNITS - kwhm-2 per 24h day
10. AVERAGE AEROSOL OPTICAL DEPTH. UNITS - dimensionless
11. AVERAGE TOTAL COLUMN PRECIPITABLE WATER. UNITS - cm
12. AVERAGE NEAR SURFACE PRECIPITABLE WATER. UNITS - cm
13. AVERAGE NEAR SURFACE AIR TEMPERATURE. UNITS - deg k
14. AVERAGE DAYLIGHT CLOUD FRACTION. UNITS - dimensionless
15. AVERAGE DAYLIGHT CLOUD OPTICAL DEPTH. UNITS - dimensionless
16. AVERAGE TOTAL HORIZONTAL-SURFACE DOWN @ 0 Z. UNITS - wm-2
17. AVERAGE TOTAL HORIZONTAL-SURFACE DOWN @ 3 Z. UNITS - wm-2
18. AVERAGE TOTAL HORIZONTAL-SURFACE DOWN @ 6 Z. UNITS - wm-2
19. AVERAGE TOTAL HORIZONTAL-SURFACE DOWN @ 9 Z. UNITS - wm-2
20. AVERAGE TOTAL HORIZONTAL-SURFACE DOWN @ 12 Z. UNITS - wm-2
21. AVERAGE TOTAL HORIZONTAL-SURFACE DOWN @ 15 Z. UNITS - wm-2
22. AVERAGE TOTAL HORIZONTAL-SURFACE DOWN @ 18 Z. UNITS - wm-2
23. AVERAGE TOTAL HORIZONTAL-SURFACE DOWN @ 21 Z. UNITS - wm-2
24. AVERAGE SOLAR ZENITH ANGLE COSINE @ 0 Z. UNITS - dimensionless
25. AVERAGE SOLAR ZENITH ANGLE COSINE @ 3 Z. UNITS - dimensionless
26. AVERAGE SOLAR ZENITH ANGLE COSINE @ 6 Z. UNITS - dimensionless
27. AVERAGE SOLAR ZENITH ANGLE COSINE @ 9 Z. UNITS - dimensionless
28. AVERAGE SOLAR ZENITH ANGLE COSINE @ 12 Z. UNITS - dimensionless
29. AVERAGE SOLAR ZENITH ANGLE COSINE @ 15 Z. UNITS - dimensionless
30. AVERAGE SOLAR ZENITH ANGLE COSINE @ 18 Z. UNITS - dimensionless
31. AVERAGE SOLAR ZENITH ANGLE COSINE @ 21 Z. UNITS - dimensionless
32. AVERAGE DAYLIGHT CLOUD FRACTION @ 0 Z. UNITS - dimensionless
33. AVERAGE DAYLIGHT CLOUD FRACTION @ 3 Z. UNITS - dimensionless
34. AVERAGE DAYLIGHT CLOUD FRACTION @ 6 Z. UNITS - dimensionless
35. AVERAGE DAYLIGHT CLOUD FRACTION @ 9 Z. UNITS - dimensionless
36. AVERAGE DAYLIGHT CLOUD FRACTION @ 12 Z. UNITS - dimensionless
37. AVERAGE DAYLIGHT CLOUD FRACTION @ 15 Z. UNITS - dimensionless
38. AVERAGE DAYLIGHT CLOUD FRACTION @ 18 Z. UNITS - dimensionless
39. AVERAGE DAYLIGHT CLOUD FRACTION @ 21 Z. UNITS - dimensionless
40. AVERAGE DAYLIGHT CLOUD OPTICAL DEPTH @ 0 Z. UNITS - dimensionless
41. AVERAGE DAYLIGHT CLOUD OPTICAL DEPTH @ 3 Z. UNITS - dimensionless
42. AVERAGE DAYLIGHT CLOUD OPTICAL DEPTH @ 6 Z. UNITS - dimensionless
43. AVERAGE DAYLIGHT CLOUD OPTICAL DEPTH @ 9 Z. UNITS - dimensionless
44. AVERAGE DAYLIGHT CLOUD OPTICAL DEPTH @ 12 Z. UNITS - dimensionless
45. AVERAGE DAYLIGHT CLOUD OPTICAL DEPTH @ 15 Z. UNITS - dimensionless
46. AVERAGE DAYLIGHT CLOUD OPTICAL DEPTH @ 18 Z. UNITS - dimensionless
47. AVERAGE DAYLIGHT CLOUD OPTICAL DEPTH @ 21 Z. UNITS - dimensionless
48. MINIMUM TOTAL HORIZONTAL-SURFACE DOWN OVER ONE 24H DAY. UNITS - kwh/m**2
49. MINIMUM TOTAL HORIZONTAL-SURFACE DOWN OVER 3 DAYS. UNITS - kwh/m**2
50. MINIMUM TOTAL HORIZONTAL-SURFACE DOWN OVER 7 DAYS. UNITS - kwh/m**2
51. MINIMUM TOTAL HORIZONTAL-SURFACE DOWN OVER 14 DAYS. UNITS - kwh/m**2
52. MINIMUM TOTAL HORIZONTAL-SURFACE DOWN OVER 21 DAYS. UNITS - kwh/m**2
53. MAXIMUM TOTAL HORIZONTAL-SURFACE DOWN OVER ONE 24H DAY. UNITS - kwh/m**2
54. MAXIMUM TOTAL HORIZONTAL-SURFACE DOWN OVER 3 DAYS. UNITS - kwh/m**2
55. MAXIMUM TOTAL HORIZONTAL-SURFACE DOWN OVER 7 DAYS. UNITS - kwh/m**2
56. MAXIMUM TOTAL HORIZONTAL-SURFACE DOWN OVER 14 DAYS. UNITS - kwh/m**2
57. MAXIMUM TOTAL HORIZONTAL-SURFACE DOWN OVER 21 DAYS. UNITS - kwh/m**2