Tag Archives: Pacific Ocean

Record warm waters off California coast

“California has seen a range of natural extremes this summer, from heat waves to wildfires. The state can now add to the list record-warm ocean temperatures. On August 1, 2018, researchers from the Scripps Institution of Oceanography observed water temperatures of 25.9 degrees Celsius (78.6 degrees Fahrenheit) along the coast at La Jolla, exceeding the previous record of 25.8°C (78.4°F) set in 1931.” click here

Ocean cycles synchronous with global temperature fluctuations

“Now isn’t it a bit odd that the authors made absolutely no mention of the ocean cycles in the abstract? As our regular readers know, the ocean cycles run surprisingly synchronous with the fluctuations in global temperatures, i.e. the key factors here are the AMO and PDO.” click here

South Pacific island shorelines expand

“the dramatic impacts of climate change felt on coastlines and people across the Pacific are still anecdotal” see discussion here

Michino Hisabayashi, John Rogan & Arthur Elmes. Quantifying shoreline change in Funafuti Atoll, Tuvalu using a time series of Quickbird, Worldview and Landsat data Journal GIScience & Remote Sensing Volume 55, 2018 Issue 3

Funafuti Atoll, Tuvalu is located in the southwestern Pacific Ocean, which has experienced some of the highest rates of global sea-level rise over the past 60 years. Atoll islands are low-lying accumulations of reef-derived sediment that provide the only habitable land in Tuvalu, and are considered vulnerable to the myriad possible impacts of climate change, especially sea-level rise. This study examines the shoreline change of twenty-eight islands in Funafuti Atoll between 2005 and 2015 using 0.65 m QuickBird, 0.46 m WorldView-2, and 0.31 m WorldView-3 imagery using an image segmentation and decision tree classification. Shoreline change estimates are compared to previous study that used a visual interpretation approach. The feasibility of estimating island area with Landsat-8 Operational Land Imager (OLI) data is explored using CLASlite software. Results indicate a 0.13% (0.35 ha) decrease in net island area over the study time period, with 13 islands decreasing in area and 15 islands increasing in area. Substantial decreases in island area occurred on the islands of Fuagea, Tefala and Vasafua, which coincides with the timing of Cyclone Pam in March, 2015. Comparison between the WorldView-2 shoreline maps and those created from Landstat-8 indicate that the estimates tend to be in higher agreement for islands that have an area > 0.5 ha, a compact shape, and no built structures. Ten islands had > 90% agreement, with percent disagreements ranging from 2.78 to 100%. The methods and results of this study speak to the potential of automated EoV shoreline monitoring through segmentation and classification tree approach, which would reduce down data processing and analysis time. With the growing constellation of high and medium spatial resolution satellite-based sensors and the development of semi or fully automated image processing technology, it is now possible to remotely assess the short and medium-term shoreline dynamics on dynamic atolls. Landsat estimates were reasonably matched to those derived from fine resolution imagery, with some caveats about island size and shape.