Yates H W
Appl Opt. 1977 Feb 1;16(2):297-9. doi: 10.1364/AO.16.000297.
The net radiation balance of the earth is important globally for synoptic scale models and long-term climatic trends. It is important at the mesoscale level because it is a strong driving force on local meteorological phenomena. Both synoptic and mesoscale measurements are possible only from earth orbiting spacecraft, and serious efforts have been made to implement them. They have not achieved sufficient accuracy, precision, and stability to be really meaningful meteorologically. Measuring a small difference between two large numbers-the input to the earth and the earth radiation to space-is quite difficult and compounded by the spectral differences between the two. The instrumental considerations to achieving improvements in net radiation balance are discussed. The ratio of input to outflow, like albedo, is a dimensionless number which is amenable to measurement without recourse to calibrated instruments. If the solar constant is indeed reasonably constant, this ratio, which is more easily measured than an absolute value of either quantity, will be acceptable. Instrument stability, both spectral and absolute, as well as calibration methods and accuracy will be discussed with specific emphasis on estimating how and to what degree they can be improved.
地球的净辐射平衡在全球范围内对于天气尺度模型和长期气候趋势都很重要。在中尺度层面它也很重要，因为它是局部气象现象的强大驱动力。天气尺度和中尺度测量只有通过地球轨道航天器才能进行，并且已经做出了认真的努力来实施这些测量。然而，它们尚未达到足够的精度、准确性和稳定性，从而无法在气象学上真正具有意义。测量两个大数之间的微小差异——进入地球的辐射和地球向太空的辐射——非常困难，而且两者之间的光谱差异使情况更加复杂。本文讨论了实现净辐射平衡改进的仪器方面的考虑因素。输入与流出的比率，如反照率，是一个无量纲数，无需借助校准仪器即可进行测量。如果太阳常数确实相当恒定，那么这个比率比这两个量的绝对值更容易测量，将是可以接受的。将讨论仪器的稳定性，包括光谱稳定性和绝对稳定性，以及校准方法和准确性，并特别强调估计如何以及在何种程度上可以改进它们。
