极轨气象卫星高光谱红外探测仪简介
An Introduction to Hyper-spectral Infrared Sounders Onboard Polar-orbiting Meteorological Satellites
中文摘要：
极轨（polar-orbiting）气象卫星在离地球高度约800km的极地轨道上运行，每天可绕地球14圈，每绕地球一圈需100多分钟。极轨卫星由南到北的地迹线与赤道的交点称为降交点，由北到南的地迹线与赤道的交点称为升交点。极轨卫星不同轨道的地迹线过赤道的经度由于地球自转而不同，但它们经过赤道的地方时间是相同的。一颗极轨气象卫星每天可覆盖全球两次，提供多光谱范围的微波、红外、可见光等全球资料。这与静止（geostationary）卫星不同。静止卫星观测虽然在时间上是连续的，但观测的空间范围和光谱范围有限[1]。极轨气象卫星资料在数值天气预报、气候研究及气象产品反演等领域都有重要应用价值。
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Abstract：
Polar-orbiting meteorological satellites circulate above the Earth at about 800-km altitude, completing 14 orbits daily. A single orbit takes about 100 minutes. Each polar-orbiting satellite provides observations on the so-called descending (ascending) node when moving from north (south) to south (north). The local time for all the descending nodes to cross the equator remains constant for a fixed polar-orbiting satellite, although their longitudes are different. The same is true of ascending nodes. Different from a geostationary satellite that provides temporally continuous observations within a limited spatial and spectral domain[1], a polar-orbiting meteorological satellite can provide global coverage in multiple visible, infrared and microwave bands twice daily. Observations from polar-orbiting meteorological satellites have played important roles in numerical weather prediction (NWP), climate study and product retrieval of meteorological variables.