The Malkmus band model has been widely used in remote sensing and climate studies. However, its accuracy is not high. To solve this problem, a modified Malkmus band model was proposed by introducing a correction item....The Malkmus band model has been widely used in remote sensing and climate studies. However, its accuracy is not high. To solve this problem, a modified Malkmus band model was proposed by introducing a correction item. The HITRAN (High-resolution TRANsmission) 2008 database and the atmospheric models provided by the Air Force Geophysics Laboratory (AFGL) were used to calculate the molecular transmittances. By fitting the calculated transmittances to those by MODTRAN (MODerate resolution atmospheric TRANsmission) package with the least-squares method, the fitting coefficients of the correction item were obtained under different atmosphere models. The experimental results show that the root mean square errors (RMSE) of the modified model are significantly less than that of the traditional Malkmus band model by 1-2 orders of magnitude. In addition, the modified method is suitable for different atmospheric models and molecules.展开更多
A parameterized transmittance model （PTR） for ozone and water vapor monochromatic transmittance calculation in the solar-to-near-infrared spectrum 0.3-4 pm with a spectral resolution of 5 cm-1 was developed based on...A parameterized transmittance model （PTR） for ozone and water vapor monochromatic transmittance calculation in the solar-to-near-infrared spectrum 0.3-4 pm with a spectral resolution of 5 cm-1 was developed based on the transmittance data calculated by Moderate-resolution Transmittance model （MOD- TRAN）. Polynomial equations were derived to represent the transmittance as functions of path length and airmass for every wavelength based on the least-squares method. Comparisons between the transmittances calculated using PTR and MODTRAN were made, using the results of MODTRAN as a reference. Rela- tive root-mean-square error （RMSre） was 0.823% for ozone transmittance. RMSre values were 8.84~ and 3.48~ for water vapor transmittance ranges of 1-1 x 10-is and 1-1x 10-3, respectively. In addition, the Stratospheric Aerosol and Gas Experiment II （SAGEII） ozone profiles and University of Wyoming （UWYO） water vapor profiles were applied to validate the applicability of PTR model. RMSre was 0.437~ for ozone transmittance. RMSre values were 8.89~ and 2.43% for water vapor transmittance ranges of 1-1~10-is and 1-1~ 10-6, respectively. Furthermore, the optical depth profiles calculated using the PTR model were compared to the results of MODTRAN. Absolute RMS errors （RMSab） for ozone optical depths were within 0.0055 and 0.0523 for water vapor at all of the tested altitudes. Finally, the comparison between the solar heating rate calculated from the transmittance of PTR and Line-by-Line radiative transfer model （LBLRTM） was performed, showing a maximum deviation of 0.238 K d-1 （6% of the corresponding solar heating rate calculated using LBLRTM）. In the troposphere all of the deviations were within 0.08 K d-1. The computational speed of PTR model is nearly two orders of magnitude faster than that of MODTRAN.展开更多
基金Projects(U1231105,41404013)supported by the National Natural Science Foundation of ChinaProject(2012AA121301)supported by the National Hi-tech Research and Development Program of China
文摘The Malkmus band model has been widely used in remote sensing and climate studies. However, its accuracy is not high. To solve this problem, a modified Malkmus band model was proposed by introducing a correction item. The HITRAN (High-resolution TRANsmission) 2008 database and the atmospheric models provided by the Air Force Geophysics Laboratory (AFGL) were used to calculate the molecular transmittances. By fitting the calculated transmittances to those by MODTRAN (MODerate resolution atmospheric TRANsmission) package with the least-squares method, the fitting coefficients of the correction item were obtained under different atmosphere models. The experimental results show that the root mean square errors (RMSE) of the modified model are significantly less than that of the traditional Malkmus band model by 1-2 orders of magnitude. In addition, the modified method is suitable for different atmospheric models and molecules.
基金supported by the National Basic Research Program of China (Grant No.2011CB403401)the National Natural Sciences Foundation of China (Grant No. 41175029)
文摘A parameterized transmittance model （PTR） for ozone and water vapor monochromatic transmittance calculation in the solar-to-near-infrared spectrum 0.3-4 pm with a spectral resolution of 5 cm-1 was developed based on the transmittance data calculated by Moderate-resolution Transmittance model （MOD- TRAN）. Polynomial equations were derived to represent the transmittance as functions of path length and airmass for every wavelength based on the least-squares method. Comparisons between the transmittances calculated using PTR and MODTRAN were made, using the results of MODTRAN as a reference. Rela- tive root-mean-square error （RMSre） was 0.823% for ozone transmittance. RMSre values were 8.84~ and 3.48~ for water vapor transmittance ranges of 1-1 x 10-is and 1-1x 10-3, respectively. In addition, the Stratospheric Aerosol and Gas Experiment II （SAGEII） ozone profiles and University of Wyoming （UWYO） water vapor profiles were applied to validate the applicability of PTR model. RMSre was 0.437~ for ozone transmittance. RMSre values were 8.89~ and 2.43% for water vapor transmittance ranges of 1-1~10-is and 1-1~ 10-6, respectively. Furthermore, the optical depth profiles calculated using the PTR model were compared to the results of MODTRAN. Absolute RMS errors （RMSab） for ozone optical depths were within 0.0055 and 0.0523 for water vapor at all of the tested altitudes. Finally, the comparison between the solar heating rate calculated from the transmittance of PTR and Line-by-Line radiative transfer model （LBLRTM） was performed, showing a maximum deviation of 0.238 K d-1 （6% of the corresponding solar heating rate calculated using LBLRTM）. In the troposphere all of the deviations were within 0.08 K d-1. The computational speed of PTR model is nearly two orders of magnitude faster than that of MODTRAN.
