Estimating spatial distribution of daily snow depth with kriging methods: combination of MODIS snow cover area data and ground-based observations
C. L. Huang1,2, H. W. Wang1,2, and J. L. Hou1,21Key Laboratory of Remote Sensing of Gansu Province, Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Sciences, Lanzhou, China 2Heihe Remote Sensing Experimental Research Station, Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Sciences, Lanzhou, Gansu, 730000, China
Received: 10 Aug 2015 – Accepted for review: 01 Sep 2015 – Discussion started: 22 Sep 2015
Abstract. Accurately measuring the spatial distribution of the snow depth is difficult because stations are sparse, particularly in western China. In this study, we develop a novel scheme that produces a reasonable spatial distribution of the daily snow depth using kriging interpolation methods. These methods combine the effects of elevation with information from Moderate Resolution Imaging Spectroradiometer (MODIS) snow cover area (SCA) products. The scheme uses snow-free pixels in MODIS SCA images with clouds removed to identify virtual stations, or areas with zero snow depth, to compensate for the scarcity and uneven distribution of stations. Four types of kriging methods are tested: ordinary kriging (OK), universal kriging (UK), ordinary co-kriging (OCK), and universal co-kriging (UCK). These methods are applied to daily snow depth observations at 50 meteorological stations in northern Xinjiang Province, China. The results show that the spatial distribution of snow depth can be accurately reconstructed using these kriging methods. The added virtual stations improve the distribution of the snow depth and reduce the smoothing effects of the kriging process. The best performance is achieved by the OK method in cases with shallow snow cover and by the UCK method when snow cover is widespread.
Huang, C. L., Wang, H. W., and Hou, J. L.: Estimating spatial distribution of daily snow depth with kriging methods: combination of MODIS snow cover area data and ground-based observations, The Cryosphere Discuss., 9, 4997-5020, doi:10.5194/tcd-9-4997-2015, 2015.