Method for inverting aerosol components using LiDAR ratio and depolarization ratio

A method for inverting aerosol components using a LiDAR ratio and a depolarization ratio by a NIES Miescattering LiDAR system, comprising the steps of:

• S1) detecting scattering of incident light and obtaining a LiDAR signal using a polarizer of the NIES Miescattering LiDAR system;
• S2) separating the LiDAR signal into a vertical polarization component to a horizontal polarization component by the polarizer, identifying sand dust, a spherical aerosol and a mixture of the sand dust and the spherical aerosol based on the depolarization ratio, the depolarization ratio being a ratio of a vertical polarization component to a horizontal polarization component of the LiDAR signal;
• S3) calculating a proportion of the sand dust in the mixture of the sand dust and the spherical aerosol;
• and
• S4) identifying soot and a water-soluble aerosol in the spherical aerosol based on a LiDAR ratio, wherein
• step S4 comprises:
• S41) establishing a lookup table 1 for the extinction coefficient σ with respect to an extinction coefficient σws of a water-soluble aerosol and an extinction coefficient σst of soot, and establishing an additional lookup table 2 with respect to a case that the extinction coefficient is greater than 1;
• S42) combining the lookup table for the extinction coefficient with the LiDAR ratio to establish a lookup table for a backscattering coefficient β:
• β
• =
• σ
• w
• ⁢
• s
• S
• 1
• +
• σ
• s
• ⁢
• t
• S
• 2
• S43) if 0<σsphere≤1, traversing the lookup table 1, or if 1<σsphere≤3, traversing the lookup table 2, wherein σsphere is an extinction coefficient for the spherical aerosol, σsphere is the backscattering coefficient;
• and retrieving an array of extinction coefficients from the lookup table whose errors relative to observed values meet a standard:
• ❘
• "\[LeftBracketingBar]"
• σ
• sphere
• -
• σ
• σ
• sphere
• ❘
• "\[RightBracketingBar]"
• <
• 0.01
• ❘
• "\[LeftBracketingBar]"
• β
• sphere
• -
• β
• β
• sphere
• ❘
• "\[RightBracketingBar]"
• <
• 0.01
• and
• S45) if the lookup table does not match the observed values, selecting as an optimal solution a solution ensuring a minimum deviation between an observed value and a theoretical value, that is, a solution meeting the following condition:
• min
• (
• ❘
• "\[LeftBracketingBar]"
• σ
• sphere
• -
• σ
• σ
• sphere
• ❘
• "\[RightBracketingBar]"
• 2
• +
• ❘
• "\[LeftBracketingBar]"
• β
• sphere
• -
• β
• β
• sphere
• ❘
• "\[RightBracketingBar]"
• 2
• )
• .