RESUMEN
Ensemble Kalman filter-based targeted observation is one of the best methods for determining the optimal observational array for oceanic buoy deployment. This study proposes a new algorithm suitable for a 'cross-region and cross-variable' approach by introducing a projection operator into the optimization process. A targeted observational analysis was conducted for El Niño-Southern Oscillation (ENSO) events in the tropical western Pacific for the Tropical Pacific Observation System (TPOS) 2020. The prediction target was at the Niño 3.4 region and the first 10 optimal observational sites detected reduced initial uncertainties by 70%, with the best observational array located where the Rossby wave signal dominates. At the vertical level, the most significant contribution was derived from observations near the thermocline. This study provides insights into understanding ENSO-related variability and offers a practical approach to designing an optimal mooring array. It serves as a scientific guidance for designing a TPOS observation network.
RESUMEN
Spherical polymer brushes, poly(acrylic acid) (PAA)-grafted polystyrene nanoparticle (PAA@PS), are employed as the macro-crosslinker to prepare PAA hydrogels. Benefitting from the innumerable hydrogen bonds between highly entangled PAA chains both in bulk and on the polymer brush, the PAA/PAA@PS hydrogels combine desirable stretchability, toughness, and notch-insensitivity. The uniaxial tensile tests show a very high fracture elongation up to 9.1 × 103 % while the fracture toughness reaches 3.0 MJ m-3 and the maximum swelling ratio of the hydrogel can be 2.0 × 103 as well. After being loaded with silver nanoparticles, the PAA/PAA@PS hydrogels are employed as a recyclable catalyst successfully.