By Erika Simon


The Cryosphere model Comparison tool (CmCt) GRACE Mascon Module compares user uploaded ice sheet models to the GRACE Mascon product derived by NASA GSFC.

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Version 1.4 - published on 12 Feb 2021

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This Jupyter notebooks is a module of the Cryosphere model Comparison tool (CmCt). The tool is used to compare ice sheet model data from the GRACE (Gravity Recovery and Climate Experiment) satellite from the GRACE mission.

The GRACE satellite records time series of ice sheet mass change. GRACE, launched in 2002 and retired in September 2017, is a dual-satellite mission with the primary objective of measuring the gravity field of the Earth as it changes over space and time (Wahr et. Al., 1998). It does this by very accurately measuring the distance between the two satellites (to within a few micrometers), which are flying one behind the other in the same orbit, about 200 km apart and 400-500 km above Earth’s surface. Precisely measuring how the Earth’s gravity tugs each of the satellites differently allows for the calculation of changes in Earth’s gravitational potential field. GRACE has many limitations. One of the most important is that GRACE provides data with relatively low spatial resolution. The major difficulty when comparing GRACE to ice sheet model output is scaling the two datasets to comparable spatial resolution.

The CmCt GRACE Mascon tool uses the GRACE Mascon solution that was processed at NASA GSFC. The CmCt provides processing of the model to create the same mascon space as the NASA GSFC GRACE Mascon product than average the data over within the mascon space to provide a direct qualitative comparison.

The tool first processes the NASA GSFC GRACE product and then specifies the mascon space. Then averages over the observational data within the specifies mascon space. The CmCt takes the uploaded ice sheet model and converts it to the same mascon space as the observational data. Once the data is in the mascon space it averages over the data within the same space. The CmCt creates the GRACE mascon plot, the original plot of the submitted model, and the Model mascon plot hat is directly comparable with the GRACE Mascon product. The user can download these plots and/or add to the script for further analysis. We would like to acknowledge and thank to Michael Croteau and Bryant Loomis at NASA GSFC for providing the GRACE Mascon data product and contributing to the code.


Scott B. Luthcke et al. (2013). Antarctica, Greenland and Gulf of Alaska land-ice evolution from an iterated GRACE global mascon solution, Journal of Glaciology, Vol. 59, No. 216, 2013 doi:10.3189/2013JoG12J147

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Researchers should cite this work as follows:

  • Erika Simon (2021), "CmCt GRACE MASCON Tool,"

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