Role of Soil moisture in the Predictability of Summer Rainfall over West Africa and South Asian Monsoon rainfall.

Soil moisture plays a key role in the water and energy cycle through the evaporation andrainfall over land. In complex topography regions such as South Asia and West Africa therole of the soil moisture in modulating local rainfall becomes more vital, which is analyzed inthe current study for the summer (June-September; JJAS) season. We obtained soil moistureGlobal Land Data Assimilation System (GLDAS) dataset for the period 2000-17, which ishigh resolution (0.25 deg) at global grids. We noticed that the MAY soil moisture variabilityin the tropical western African region is important for the successive JJAS rainfalllocally and as well as remotely for the South Asian region. The linear relationshipbetween one-month lead (MAY) soil moisture and JJAS rainfall shows that dryconditions may prevail in the western Africa for dry Soil moisture conditions andsimilar is notice remotely for the South Asian region. The relationship of SMAIand monsoon rainfall becomes more significant if we remove El Niño SouthernOscillation (ENSO) affect from SMAI. The mechanism and physical links between theantecedent soil moisture and successive rainfall are illustrated using Moist Static Energy(MSE). MSE and soil moisture have the similar anomaly composites for May andJune-September as dry and wet. Other than MSE the Potential Evapotranspiration (PET)is in good agreement in terms of anomaly with soil moisture anomaly both forWest Africa and South Asia. We also used REGgional Climate Model (RegCM)for a case study of 2007 flood case happened West Africa by using 10-ensemblemembers based on time lag approach. We found that that May soil initialization isimportant for the improvement of the extreme events. Please fill in your abstract text. [ABSTRACT FROM AUTHOR]