Studies On The Method Of Stereoscopic Calculation In The Cloud Top Height And Cloud Motion Wind Based On ASTERr Image

Cloud plays a significant regulatory role in the earth atmosphere energy balance of payments, and it’s an important factor to affect weather changes. Real-time and accurate determination of cloud top height, high-altitude westerly flow where the cloud is, is of great significance to some fields, like meteorological research, climate prediction and so on. This article innovatively combines the digital photogrammetric theory and remote sensing technology together, and introduces it to the study of cloud top height and cloud motion wind inversion, and by using single-star multi-angle3N,3B images of polar-orbiting Terra-ASTER, instead of conventional stationary meteorological satellite binary images, it achieves a conversion of resolution from low to high. On this basis, this paper has focused on the efficient matching of ASTER high-resolution images, and has reached high-precision and high-density matching effect to high resolution, texture detail and high brightness cloud areas, and then provides data support to the follow-up study. Subsequently, based on the line array imaging characteristics of ASTER multi-angle images, and considering the impact of cloud move to the cloud height resolving, it builds a cloud top height resolving model and cloud motion wind inversion method for the ASTER images, and then by joining the match results, cloud top height and westerly flow which impacts cloud move can be solved. In order to ensure the correctness and reliability of cloud height model and cloud motion wind method, the article has also conducted a comparision and validation analysis between resolving results and the cloud products and radiosonde data. This study is an exploration to precise and fine cloud and wind information, and it provides a reliable basis for effectively using satellite data in numerical weather forcast, meteorological observations and climate prediction. The major work of this paper is as follows:(1) Aimed at the characteristics of high-resolution, texture detail changes obviously, highlighted grayscale and matching difficultly of ASTER stereopair cloud area, this article firstly reduces the detail contrast gap between the image pair by narrowing image resolution, and then through image enhancement algorithms, including piecewise linear enhancement and Gaussian low-pass filtering enhancement algorithms, enhancing image detail, highlighting their contrast and weakening grayscale brightness, and then its’ using the innovative enhancement combination matching method, effectively improves the matching density and accuracy, and provides data guarantee for subsequent cloud top height resolving and cloud motion wind inversion.(2) This aitical basing on remote sensing technology and digital photogrammetry theory, combining the line array imaging characteristics of ASTER images, and considering the impact of cloud move to the cloud height resolving, establishes a cloud top height resolving model for the ASTER images. After getting cloud top height without wind and with wind by this model, the paper respectively uses three methods, as inspection of the control point on the model system error, inspection of the MISR cloud height products on cloud top height without wind resolving results, and joint inspection of FY cloud classification products and CloudSat products on cloud top height with wind resolving results, to test the model results. The comparative results have shown that, the proposed model has high reliability, and the calculated results have achieved a good feasibility and credibility.(3) According to the theory of cloud motion wind, this article conducts the cloud motion wind inversion experiment, which uses the same data and same experimental area with the cloud height solving, and then respectively conducts interaction test of the model calculating horizontal wind and cloud motion wind, and test of China27years monthly average wind speed radiosonde data on the model calculating horizontal wind and cloud motion wind. The test results show that, whether on distribution range or distribution trend of wind speed and wind direction, each method remains basically the same, which proves the feasibility and credibility of the proposed cloud motion wind inversion method and the part of ASTER cloud top height resolving model solving high-altitude wind speed, and also indirectly proves the reliability of the model resolving cloud top height with wind.