[1] Interannual sea surface temperature (SST) anomalies in the South China Sea (SCS) are largely influenced by El Niño through El Niño-driven atmospheric and oceanic changes. This paper discovers a new observed feature of the SCS SST anomalies: a double-peak evolution following an El Niño event. The first and second peaks occur around February and August, respectively, in the subsequent year of the El Niño year (denoted by February [+1] and August [+1]). During and after the mature phase of El Niño, a change of atmospheric circulation alters the local SCS near-surface air temperature, humidity, cloudiness, and monsoon wind. These factors influence surface heat fluxes and oceanic flows over the SCS that can either warm or cool the SCS depending upon stages of SST anomaly evolution. The shortwave radiation and latent heat flux anomalies are major contributions to the first peak of the SCS SST anomalies, although the geostrophic heat advections warm the western boundary region of the SCS. After the first peak of February [+1], both the Ekman and geostrophic heat advections, assisted with a reduction of the net heat flux anomalies, cool the SCS SST anomalies. In August [+1], the mean meridional geostrophic heat advection makes the SCS SST anomalies peak again. Then, the latent heat flux anomalies (mainly attributed to anomalous air-sea difference in specific humidity) and the mean zonal geostrophic heat advection take over for the cooling of the SCS after the second peak.

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As a promising candidate for low‐cost and environmentally friendly thin‐film photovoltaics, the emerging kesterite‐based Cu2ZnSn(S,Se)4 (CZTSSe) solar cells have experienced rapid advances over the past decade. However, the record efficiency of CZTSSe solar cells (12.6%) is still significantly lower than those of its predecessors Cu(In,Ga)Se2 (CIGS) and CdTe thin‐film solar cells. This record has remained for several years. The main obstacle for this stagnation is unanimously attributed to the large open‐circuit voltage (V OC) deficit. In addition to cation disordering and the associated band tailing, unpassivated interface defects and undesirable energy band alignment are two other culprits that account for the large V OC deficit in kesterite solar cells. To capture the great potential of kesterite solar cells as prospective earth‐abundant photovoltaic technology, current research focuses on cation substitution for CZTSSe‐based materials. The aim here is to examine recent efforts to overcome the V OC limit of kesterite solar cells by cation substitution and to further illuminate several emerging prospective strategies, including: i) suppressing the cation disordering by distant isoelectronic cation substitution, ii) optimizing the junction band alignment and constructing a graded bandgap in absorber, and iii) engineering the interface defects and enhancing the junction band bending.