Energy Consumption Modeling and Sensitivity Analysis for Deep-Argo Otarriinae Profiling Float

Deep-Argo Otarriinae profiling float is a new type of Argo profiling float that has a maximum diving depth of more than 4,000 m. It can collect ocean scientific data all-weather and uninterruptedly, which provides reliable data support for the global ocean scientific research. The working time of Deep-Argo profiling float is an important indicator of its practicality and economy, and it is clear that the energy consumption is a key factor in determining its working time. In this paper, the single profile energy consumption model with 19 parameters of Deep-Argo Otarriinae is established and the main effect indices and total effect indices of the energy consumption parameters to energy consumption are calculated using Sobol’ sensitivity analysis method, aiming to find the parameters that have the greatest impact on energy consumption. The results show that the gliding angle, the diving depth, and the gliding speed have a significant impact on energy consumption of Deep-Argo Otarriinae. The results of simulation have a good match with the actual application and have certain reference significance for the determination of the design parameters and the selection of the navigation parameters. This paper also provides a new idea of multiparameter energy consumption modeling for underwater equipment using buoyancy regulation.

Thermobaricity in the Transition Zones between Alpha and Beta Oceans

The role of the ocean in Earth’s climate is fundamentally influenced by the locally dominant stratifying property (heat or salt), which in turn can be used to categorize the ocean into three classes: alpha, beta, and transition zone oceans. Alpha and beta oceans are regions where the stratification is permanently set by heat and salt, respectively. Transition zone oceans exist between alpha and beta oceans and are regions where the stratification is seasonally or intermittently set by heat or salt. Despite their large ranges of temperature and salinity, transition zone oceans are the most weakly stratified regions of the upper oceans, making them ideal locations for thermobaric effects arising from the nonlinear equation of state of seawater. Here a novel definition and quantification of alpha, beta, and transition zone oceans is presented and used to analyze 4 years (2010–13) of hydrographic data developed from the Argo profiling float array. Two types of thermobaric instabilities are defined and identified in the hydrographic data. The first type arises from the vertical relocation of individual water parcels. The second type is novel and relates to the effect of pressure on the stratification through the pressure dependence of the thermal expansion coefficient; water that is stably stratified for one pressure is not necessarily stable for other pressures. The upper 1500 m of the global ocean is composed of 67% alpha, 15% beta, and 17% transition zone oceans, with 5.7% identified as thermobarically unstable. Over 63% of these thermobarically unstable waters exist in transition zone oceans, suggesting that these are important locations for efficient vertical transport of water-mass properties.