For some meteorological applications, knowledge of incoming solar radiation at surface level (Sin) is very important. Conventional measurements of this flux by individual sensors are representative of small areas only. On the other hand, meteorological satellites allow a regular cover of the entire globe, providing estimates of radiative fluxes over wide areas, within the spatial resolution of the sensor (a few km). In addition, reanalysis products provide alternative Sin estimates that must be adequately validated. This work compares four long-term Sin databases for South America: three reanalysis products (NCEP/NCAR, ERA-40 e Eta/CPTEC) and the database produced by the algorithm GL1.2, which estimates Sin from a set of GOES images. The results indicate that the monthly fields of the NCEP/NCAR and the ERA-40 and the GOES-based estimates are very similar for all studied regions. On the other hand, Eta/CPTEC reanalysis presents much higher radiation values, for both the long-term annual and monthly means over South America.
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机译：对于某些气象应用，了解表面水平（Sin）的太阳辐射非常重要。单个传感器对该通量的常规测量仅代表小区域。另一方面，气象卫星可以对整个地球进行定期覆盖，从而在传感器的空间分辨率（几公里）内提供大范围辐射通量的估计值。此外，再分析产品提供了必须充分验证的备选Sin估计值。这项工作比较了南美的四个长期Sin数据库：三个重新分析产品（NCEP / NCAR，ERA-40 e Eta / CPTEC）和算法GL1.2生成的数据库，该算法从一组GOES图像中估算Sin。结果表明，所有研究区域的NCEP / NCAR和ERA-40以及基于GOES的估计的月度字段都非常相似。另一方面，Eta / CPTEC再分析的辐射值要高得多，对于南美的长期年均和月均均值。
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