H300 based PDO index (HPDO) is defined as the projections of monthly mean H300 anomalies from NCEP GODAS onto their first EOF vector in the North Pacific (20ºN-60ºN). The 30-yr period from 1981-2010 is used to derived the climatology and the EOF analysis.
Compared to the conventional SST-based PDO (SPDO), HPDO provides a natural way to highlight the slower frequency variability in the SPDO and encapsulates an integrated view of temperature variability associated with the PDO in the upper ocean.
