一个相当好用的matlab函数，由美国国家可再生能源实验室科研人员设计，可以计算太阳的直射维度和方位角。只要输入时间、观测地点即可。 -This algorithm is based on numerical approximation of the exact equations.

　The authors of the original paper state that this algorithm should be

　precise at+/- 0.0003 degrees. I have compared it to NOAA solar table

　(http://www.srrb.noaa.gov/highlights/sunrise/azel.html) and to USNO solar

　table (http://aa.usno.navy.mil/data/docs/AltAz.html) and found very good

　correspondance (up to the precision of those tables), except for large

　zenith angle, where the refraction by the atmosphere is significant

　(difference of about 1 degree). Note that in this code the correction

　for refraction in the atmosphere as been implemented for a temperature

　of 10C (283 kelvins) and a pressure of 1010 mbar. See the subfunction

un_topocentric_zenith_angle_calculation� for a possible modification

　to explicitely model the effect of temperature and pressure as describe

　in Reda & Andreas (2003).