Uncovering an Anthropogenic Sea Level Rise Signal in the Pacific Ocean
Event: 2014 Ocean Surface Topography Science Team Meeting
Session: Science Results from Satellite Altimetry: Regional and basin-scale processes and sea level rise
Presentation type: Type Oral
Internal climate variability across a range of scales is known to contribute to regional sea level trends, which can be much larger than the global mean sea level trend in many parts of the globe. Over decadal timescales, this internal variability obscures the long-term sea level change, making it difficult to assess the effect of anthropogenic warming on sea level. Here, an attempt is made to uncover the sea level rise pattern in the tropical Pacific Ocean associated with anthropogenic warming. More specifically, the sea level variability associated with the Pacific Decadal Oscillation (PDO) is estimated and removed from the regional sea level trends computed from satellite altimetry measurements over the past two decades. The resulting pattern of regional sea level rise uncovered in the tropical Pacific Ocean is explained in part by warming in the tropical Indian Ocean, which has been attributed to anthropogenic warming. This study represents one of the first attempts at linking the sea level trend pattern observed by satellite altimetry to anthropogenic forcing. The prevailing thought in literature has been that once the PDO shifts and changes phases, the sea level rise in the western tropical Pacific will ease and future decades will hold much more manageable levels of sea level change for the region. While this appears to be the case for areas near Indonesia, in the light of the results presented here, the high rate of sea level rise near the Philippines and northeastern Australia should not be similarly expected to abate over the next couple of decades.