基于敦煌定标场，以Terra/MODIS为基准传感器，通过限制成像角度（小于20°）、成像时刻（小于2 h）、云量和成像质量等约束，筛选出2008年9月—2021年12月147组有效交叉定标影像对，利用6SV v2.1模型进行辐射传输计算得到二者之间的光谱匹配因子，最终实现对环境一号卫星A星（HJ-1A）CCD1传感器的长时间序列交叉定标。结果表明：1）计算得到的交叉定标系数与官方公布的场地定标系数高度一致，交叉定标系数与官方定标系数之间的平均相对差异小于2.25%，定标结果的不确定度在5.34%以内；2）长时间序列交叉定标结果表明，HJ-1A/CCD1传感器发射1 a后，其增益状态于2009年10月20日进行了调整，导致交叉定标系数在发射后的第409天发生突变，增益调整后整体辐射性能较为平稳；3）2009年10月—2021年12月期间，HJ-1A/CCD1传感器的辐射性能呈波动缓慢下降趋势，年衰减率小于3.10%。本文方法可以有效地提高HJ-1A/CCD1传感器的辐射定标频次和定标精度，实现对HJ-1A/CCD1传感器全生命周期辐射性能的监测。

Huanjing-1A （HJ-1A） CCD1 has four reflected solar bands in visible and near-infrared bands. The on-orbit absolute radiometric calibration frequency of HJ-1A/CCD1 is limited to the annual site calibration. Cross calibration， as a supplement means of site calibration， can achieve high-frequency on-orbit absolute radiometric calibration. In this paper， we select Terra/MODIS as the reference sensor to perform long time series cross calibration on HJ-1A/CCD1 based on Dunhuang calibration site. By limiting conditions such as the imaging angle difference （less than 20°）， the imaging time difference （less than 2 hours）， cloud cover， and imaging quality between HJ-1A/CCD1 and Terra/MODIS， a total of 147 effective cross calibration image pairs were screened out from September 2008 to December 2021. Then the 6SV v2.1 radiative transfer model was used to calculate the spectral band adjustment factor， and ultimately achieving long time series cross calibration of HJ-1A/CCD1. The results show that： 1） The cross-calibration coefficients calculated in this article are highly consistent with the officially published calibration coefficients， with an average relative difference of less than 2.25%. The calibration uncertainty is within 5.34%. 2） The long time series cross calibration results showed that after one year on-orbit operation， the gain status of HJ-1A/CCD1 was adjusted on October 20， 2009， resulting in a sudden change in the cross-calibration coefficients on the 409th day after launch. After the adjustment， the overall radiometric performance was relatively stable. 3） The radiometric performance of HJ-1A/CCD1 showed a slow and fluctuating downward trend from October 2009 to December 2021， with an annual attenuation rate of less than 3.10%. The method proposed in this paper can effectively improve the radiometric calibration frequency and accuracy， and can be used for radiometric performance monitoring over the whole life cycle of HJ-1A/CCD1.