The atmospheric transmittance properties for three near-infrared channels of POM02 skyradiometer at the wavelengths of 1020 nm

1627 nm

and 2200 nm

were studied by using a combined atmospheric radiative transfer model （CART）. Results showed that

the extinctions at the bands of 1020 nm

1627 nm

which are located in atmospheric window channel

obeyed the Beer-Lambert law. For the 2200 nm channel located in an absorption band

the absorption exhibited an exponential distribution. Then these channels of POM02 skyradiometer were calibrated with traditional Langley method and modified Langley method

respectively. Two calibration methods were applied for four clear days. It proved that the accuracy of derived transmittance has been improved by 3.8% using modified Langley method to 2200 nm channel.