Three-dimensional variational assimilation method for aerosol extinction coefficient based on IMPROVE equation

Abstract

A three-dimensional variational assimilation method for an aerosol extinction coefficient based on an IMPROVE equation comprises the following steps: according to a three-dimensional variational theory and the IMPROVE equation, a computer program for solving a three-dimensional variational target functional is written and called an assimilation system; H is called as an observation operator and isan M*N-dimensional matrix, wherein M is equal to the length of y, N is equal to the length of x, and a result Hx obtained after x is multiplied by H leftwards is a vector with the same length as y; the function of H further comprises interpolating the values of grid points to observation positions of non-grid points; R is an observation error covariance and is an M*M-dimensional matrix; and T represents the transposition of the vector. Hx calculation is realized according to the IMPROVE equation, and assuming that the observation position of y is just at a regular grid point of a mode, calculation of Hx does not involve an interpolation process.

Description

technical field [0001] The invention relates to a method belonging to the field of data assimilation of change parameters of atmospheric aerosol, and is mainly applied to the data assimilation of aerosol extinction coefficient and air quality forecast research. In particular, it refers to the three-dimensional variational assimilation method of the aerosol extinction coefficient. Background technique [0002] The data assimilation of aerosol extinction coefficient is to use the aerosol extinction coefficient data detected by lidar or satellite on the basis of the background field (or called the first guess field, generally the three-dimensional grid field predicted by the numerical model). , to generate a three-dimensional analysis field that is closer to the real field and more accurate in aerosol mass concentration. For data that reflect the optical properties of aerosols, such as extinction coefficients, one of the difficulties in assimilation is the realization of the c...

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Problems solved by technology

There are certain shortcomings in the two methods. The calculation of the meter scattering formula is too complicated and sensitive to the calculation parameters; the regression equation cannot reflect the contribution of different aerosol species to the extinction coefficient, and it is difficult to reflect the conversion relationship because it is only based on statistical data. The physical basis that should be in the system, the scope of applicable time and space is also more limited

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