We present two methods to refine the assimilation of satellite sea surface temperatures (SSTs) into a regional ocean model. First, we correct the SSTs for biases and show that this correction reduces the model SST errors. Then, we implement a special observation operator that handles the spatial resolution mismatch between coarse passive microwave SSTs and the high-resolution model. We find that excluding this operator spatially smooths the modeled SST, whereas its inclusion prevents this.