Potential predictability of Eurasian spring snow water equivalent in IAP AGCM4 hindcasts

ABSTRACT The potential predictability and skill of Eurasian spring snow water equivalent (SWE) are explored by using a suite of ensemble hindcast experiments with the fourth-generation IAP AGCM (IAP AGCM4) and observations for the period 1982–2012. IAP AGCM4 is generally capable of reproducing the spatial distribution of Eurasian spring SWE; nevertheless, the model overestimates the SWE over Eurasia, possibly because of positive precipitation biases in wintertime. IAP AGCM4 can successfully capture the long-term trend and leading pattern of Eurasian spring SWE. Additionally, the spring SWE anomalies are generally predictable in many regions over Eurasia, especially at high latitudes; moreover, IAP AGCM4 exhibits a remarkable prediction skill for spring SWE anomalies over Eurasia in many years during 1982 to 2012. In order to reveal the relative impacts of SST anomalies and atmospheric initial conditions on the seasonal predictability of Eurasian spring SWE, two additional sets of experiments are carried out. Overall, atmospheric initial anomalies have a dominant role, though the impact of SSTs is not negligible. This study highlights the importance of atmospheric initialization in seasonal climate forecasts of spring SWE anomalies, especially at high latitudes. GRAPHICAL ABSTRAC