**Appendix A**

**Figure A1.** Monthly mean TWSC from different GRACE solutions and products in the exorheic catchments of China from 2003–2015. (**a**)–(**i**) corresponding to the nine exorheic catchments in China.

**Figure A2.** Annual ET based on different GRACE solutions and products in the exorheic catchments of China from 2003 to 2015. (**a**)–(**i**) corresponding to the nine exorheic catchments in China.

**Figure A3.** Annual precipitation from CMDC, and the forcing data of two versions of GLDAS and GLEAM from 2003–2015. (**a**)–(**i**) corresponding to the nine exorheic catchments in China.

**Figure A4.** Annual runoff from RSBC, GLDAS–1 Noah LSM and GLDAS–2.1 Noah LSM for 2003–2015. (**a**)–(**i**) corresponding to the nine exorheic catchments in China.

**Table A1.** The root mean square errors (RMSEs) between monthly mean ETWB and other ET estimations from 2003–2015 (unit: mm/month).



**Table A2.** The RMSEs between annual ETWB and other ET estimations from 2003–2015 (unit: mm/yr).

**Table A3.** The RMSEs between mean annual ETWB and ETGLDAS–1 (expressed as RMSE(ET)). The RMSEs between annual ETWB minus PCMDC and annual ETGLDAS–1 minus PGLDAS–1 (expressed as RMSE(ET–P)). The RMSEs between annual ETWB minus QRSBC and annual ETGLDAS–1 minus QGLDAS–1 (expressed as RMSE(ET–Q)). The RMSEs between annual ETWB subtracting the result of PCMDC minus QRSBC and annual ETGLDAS–1 subtracting the result of PGLDAS–1 minus QGLDAS–1 from 2003–2015 (expressed as RMSE(ET–(P–Q))). The proportion of RMSE changed of RMSE(ET–P) as opposed to RMSE (ET), RMSE(ET–Q) as opposed to RMSE (ET) and RMSE(ET–(P–Q)) as opposed to RMSE (ET).


**Table A4.** The RMSEs between mean annual ETWB and ETGLDAS–2.1 (expressed as RMSE(ET)). The RMSEs between annual ETWB minus PCMDC and annual ETGLDAS–2.1 minus PGLDAS–2.1 (expressed as RMSE(ET–P)). The RMSEs between annual ETWB minus QRSBC and annual ETGLDAS–2.1 minus QGLDAS–2.1 (expressed as RMSE(ET–Q)). The RMSEs between annual ETWB subtracting the result of PCMDC minus QRSBC and annual ETGLDAS–2.1 subtracting the result of PGLDAS–2.1 minus QGLDAS–2.1 from 2003–2015 (expressed as RMSE(ET–(P–Q))). The proportion of RMSE changed of RMSE(ET–P) as opposed to RMSE (ET), RMSE(ET–Q) as opposed to RMSE (ET) and RMSE(ET–(P–Q)) as opposed to RMSE (ET).



**Table A5.** The RMSEs between mean annual ETWB and ETGLEAM (expressed as RMSE(ET)), RMSEs between annual ETWB minus PCMDC and annual ETGLEAM minus PMSWEP from 2003–2015 (expressed as RMSE(ET–P)).
