Soil Moisture Assimilation Using a Modified Ensemble Transform Kalman Filter Based on Station Observations in the Hai River Basin

Figure 7

The Chi-square statistic (see (20)) at the assimilation time from June 1 2010 to August 31 2010 for the four assimilation schemes. The black line: ETKF; the red line: ETKF-Inf (); the green line: WCETKF; the blue line: WCETKF-Inf ().