# Antarctic Surface Ice Velocity Retrieval from MODIS-Based Mosaic of Antarctica (MOA)
## 6 Conclusions  
This research demonstrates that MOA datasets are capable of generating the flow pattern of Antarctic ice streams, especially in tremendous ice shelves whose flow speed is relatively high enough to be detected by the tracking algorithm while preserving its surface morphology. In general, the accuracy is acceptable with the RMSE less then 60 m\(\cdot\)a\({}^{-1}\) if appropriate parameters are provided. The magnitude of the \(X\) and \(Y\) components in whole drainages as well as the local orientation variation agree well both with the surface texture of ice sheets in the original images and with the a priori authoritative MEaSUREs velocity dataset. However, for small-scale drainages with high spatial and temporal flow variability, such as that at the Pine Island Glacier or the Thwaites Glacier in the Amundsen sector, the signal can barely be interpreted correctly. In addition, the heterogeneity of the melting pattern in the summer from each other limits the tracking ability as well. Considering the inherent noise in the primitive output, the post-processing correction is indispensable for accuracy control. The strategy of the SNR thresholding, the Butterworth smoothing filter, and the iterative triple standard deviation truncation was proven effective and efficient in weeding out outliers, although more robust physical assimilation is worth further studying. The final velocity result shows that in spite of the coarse spatial resolution compared with the Landsat series, the MOA dataset with rapid revisiting and time consistency shows good performance in terms of the retrieval of ice surface velocity of ice streams and ice shelves. [PERSON] designed the experiments, processed and analyzed the data, and wrote the manuscript; [PERSON], [PERSON], and [PERSON] discussed the results; [PERSON] investigated the results and revised the manuscript; [PERSON] investigated the results, revised the manuscript, and supervised this study. This work was supported by the National Key Research and Development Program of China (Grant No. 2016 YFA0600103), the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No. XDA19070202), the National Natural Science Foundation of China (Grant No. 41406211, 41676176 and 41676182), and the Fundamental Research Funds for the Central Universities in China. We greatly thank NSIDC for providing MOA ([[https://nsidc.org/data/moa/](https://nsidc.org/data/moa/)]([https://nsidc.org/data/moa/](https://nsidc.org/data/moa/))) and MEaSUREs Ice Velocity ([[http://nsidc.org/data/nsidc-0484](http://nsidc.org/data/nsidc-0484)]([http://nsidc.org/data/nsidc-0484](http://nsidc.org/data/nsidc-0484))) datasets, NASA for providing Antarctic Drainage System file ([[https://icesat4.gsfc.nasa.gov/cryo_data/ant_grm_drainage_systems.php](https://icesat4.gsfc.nasa.gov/cryo_data/ant_grm_drainage_systems.php)]([https://icesat4.gsfc.nasa.gov/cryo_data/ant_grm_drainage_systems.php](https://icesat4.gsfc.nasa.gov/cryo_data/ant_grm_drainage_systems.php))), SCAR ADD for providing Landsat-8 rock outcrop ([[http://add.antarctica.ac.uk/repository](http://add.antarctica.ac.uk/repository)]([http://add.antarctica.ac.uk/repository](http://add.antarctica.ac.uk/repository))), Leprince for providing COSI-Corr software([[http://www.tectonics.caltech.edu/slip_history/spot_coseis/download_software.html](http://www.tectonics.caltech.edu/slip_history/spot_coseis/download_software.html)]([http://www.tectonics.caltech.edu/slip_history/spot_coseis/download_software.html](http://www.tectonics.caltech.edu/slip_history/spot_coseis/download_software.html))) and Mauroalberti's QGIS plugin VectorFieldCalc for use in constructing the streamline ([[https://plugins.qgis.org/plugins/VectorFieldCalc/](https://plugins.qgis.org/plugins/VectorFieldCalc/)]([https://plugins.qgis.org/plugins/VectorFieldCalc/](https://plugins.qgis.org/plugins/VectorFieldCalc/))). We greatly appreciate the anonymous reviewers for their constructive comments, and [PERSON] for the English language improvement.