Comparison of Deepglider and RAPID-MOCHA Moored Array Observations

GSTDTAP

项目编号	1458174
	Comparison of Deepglider and RAPID-MOCHA Moored Array Observations
	Charles Eriksen
主持机构	University of Washington
项目开始年	2015
	2015-03-01
项目结束日期	2018-02-28
资助机构	US-NSF
项目类别	Standard Grant
项目经费	1085725(USD)
国家	美国
语种	英语
英文摘要	The Atlantic Meridional Overturning Circulation (AMOC) is a principal element of the global climate system. At 26.5 degrees North latitude, the AMOC is responsible for carrying about sixty percent of the net poleward heat flux carried by the oceans and about thirty percent of the total heat flux carried by the atmosphere and ocean together, integrated zonally around the globe. Through sea surface temperature modulation, the AMOC is linked to climate signals on interannual to multi-decadal time scales that can have extensive societal impact. Climate models predict substantial weakening of the AMOC over the next century, a change with potentially wide ramifications. For the past decade, U.S. and U.K. scientists have maintained a transatlantic heavily instrumented moored array to observe fluctuations in the AMOC and its heat flux. Variability on time scales longer than ten days is dominated by geostrophic current fluctuations inferred from transatlantic dynamic height differences and boundary current fluctuations. While effective, the moored array is costly to maintain. This project is an attempt to assess the effectiveness of very long-range full ocean depth underwater gliders in measuring aspects of the AMOC side-by-side the moored array. These autonomous vehicles, named Deepgliders, collect sea-surface to sea-floor profiles of temperature, salinity, and dissolved oxygen along slanting trajectories through the ocean in near-real time. They also return estimates of the full-depth average current. Successful application of Deepgliders to the 26.5 degrees North latitude line will motivate applying the technique to other transects of interest (such as in the North Atlantic subpolar gyre and the South Atlantic subtropical gyre), to address the challenges of repeat hydrography globally, and reduce the overall cost of such programs in order that such ocean climate projects can be afforded as a whole by funding agencies. These together will lead to deeper understanding of earth?s climate. The overall goal of the project is to learn how to assist the sustainable continuation of AMOC monitoring through coming decades. Learning to measure the AMOC using Deepgliders will help sustain operation of the current array at 26.5 degrees North for the many decades required to resolve interannual and multi-decadal variability. Only by operating for several decades will the signals associated with natural climate variability and anthropogenic climate change be evident and potentially distinguishable. A Deepglider is designed to make about 250 dives to as deep as 6000 m in missions lasting as long as 18 months while traveling as much as 10,000 km through the ocean on a single set of lithium batteries. It samples temperature, salinity, and dissolved oxygen along saw tooth paths through the ocean and communicates them to shore each time it reaches the sea surface via satellite telemetry. Two-way communication allows commands to be transmitted to Deepgliders so that its autonomous behavior can be controlled remotely from a pilot anywhere with an internet connection. As a pilot experiment, four one-year Deepglider missions are planned over a 2-year period overlapping moored deployments. Two of these will concentrate on maintaining position close to a RAPID-MOCHA mooring just offshore Abaco, Bahamas to resolve the principal variability in dynamic height for use in estimating the interior ocean contribution to AMOC variability. Two more will repeat a short section intended to capture temporal and spatial variations in Antilles and Deep Western Boundary Current flow. Deepglider and moored measurements will be compared to assess relative efficacy.
来源学科分类	Geosciences - Ocean Sciences
文献类型	项目
条目标识符	http://119.78.100.173/C666/handle/2XK7JSWQ/67679
专题	环境与发展全球科技态势
推荐引用方式 GB/T 7714	Charles Eriksen.Comparison of Deepglider and RAPID-MOCHA Moored Array Observations.2015.