HOW IS THE SOIL MOISTURE INITIALIZED?
The soil moisture and soil temperature fields in the 4-layer (NOAH) land-surface model (LSM) used by the operational mesoscale Eta model are continuously cycled without soil moisture nudging (e.g. to some climatology). These fields used now in the Eta are the sole product of model physics and internal Eta Data Assimilation System (EDAS) surface forcing (e.g. precipitation and surface radiation). The continuously cycled soil moisture in the coupled Eta/EDAS is obviously sensitive to whatever systematic biases exist in the coupled EDAS accumulated precipitation patterns. As such we monitor the monthly performance of the low-level (2-meter) air temperature and relative humidity forecasts by the operational mesoscale Eta model to assess the performance of the NOAH LSM (check out these monthly water budget plots and see our verification web site.) To date, however, while there are some modest seasonal biases that vary by region within the Eta model domain, no strong signals of undue soil mo
