Fig. 1. Schematic of Acquisition of H2O cross section. (a) Water vapor absorption cross-section in Hitran database; (b) water vapor absorption cross-section with Viogt linetype change; (c) instrument function of spectrometer; (d) effective absorption cross-section of H2O at wavelength band 1590~1620 nm

Fig. 2. Relationship curve between X(H2O) and L with water vaporr eaching saturated absorption, T=296 K and P=101.325 kPa

Fig. 3. Effect of temperature on water vapor absorption

Fig. 4. Instrument devices. (a) Systematic experimental device diagram; (b) distribution of indoor and outdoor devices

Fig. 5. Absorption cross-section curves of water vapor and CO2 under three different conditions

Fig. 6. Example of H2O retrieve by IR-DOAS

Fig. 7. Comparison of retrieval results between IR-DOAS and CE-318

Fig. 8. Linear correlation of observation data between IR-DOAS and CE-318

Fig. 9. Curves of S (H2O) and 1/sinα

Fig. 10. Distribution of S (H2O) in various azimuth directions

Table 1. Corresponding temperature and pressure at different altitudes