A tangent height retrieved by UV narrow bands (THRUNB) method is proposed to correct the tangent height from SCIAMACHY limb instrument to solve the tangent height offset caused by misalignment and other reasons in the pointing process of limb UV-VIS scattering detection instrument.In this method, a narrow band (300—305 nm) and a new engineering tangent height sequence (43, 46, 49, 52, and 55 km) are proposed to maintain measurement vectors that are more sensitive and with less dimension by analyzing the influence of the limb radiance profile shape and engineering pointing information of multiple UV bands on the tangent height correction. At the same time, the optimal estimation algorithm combined with SCIATRAN model is used to retrieve the tangent height deviation from the limb radiance.The experimental results show that the average accuracy of tangent height correction by the THRUNB method is improved by 45%, and the running time of the algorithm is reduced by 20%, compared with TRUE (tangent height retrieved by UV-B exploitation) method. Compared with SCIAMACHY L1B tangent height data provided by ESA, the average deviation of tangent height is less than 150 m. Compared with the SCIAMACHY v3.5 ozone profile product provided by University of Bremen, the average relative error of the retrieved ozone profile with tangent height correction is less than 10% in the range of 13—38 km, and the average relative error without tangent height correction is as high as 22% in the same range. At the same time, the effects of atmospheric pressure, temperature, and ozone profile on tangent height retrieved are investigated. The experimental results show that the influence of pressure and ozone on TH retrieval is positively correlated, whereas the temperature is negatively correlated. The ozone profile has the greatest influence on TH retrieval, followed by pressure and temperature.The THRUNB method can effectively reduce the tangent height offset caused by the instrument pointing information error. The accuracy of the retrieved atmospheric trace gas profile can be improved by correcting tangent height. The effective ozone and neutral density profiles are very important for tangent height correction.

limb radiance;tangent height;Correction;knee method;ozone profile;atmospheric remote sensing