Drift Area Research Articles

Unilateral dynamic balance assessment: The test-retest reliability of the OptoJump next drift protocol

BackgroundThe OptoJump Next Drift Protocol is a test designed to assess unilateral dynamic balance. Participants are required to perform a series of unilateral jumps from which left/right and forward/back displacement (Drift) is calculated. ObjectivesThis investigation set out to establish the test-retest reliability of the OptoJump Next Drift Protocol. MethodTwenty-six participants performed the OptoJump Next Drift Protocol on two separate occasions. Drift Area and Drift Area as a percentage of total available jump area were calculated for each leg. ResultsInterclass Correlation Coefficients (ICC) indicated poor reliability for Drift Area and Drift Area as a percentage of total available jump area (right leg r = .44; left leg r = −0.20). However, 95% Limits of Agreement (LoA) suggested a stronger relationship. For Drift Area, between trial Mean Difference for the right leg was 50.87 cm2 (95% LoA = −227.57 – 328.87) and for the left leg it was 54.08 cm2 (95% LoA = −333.62 – 441.79). For Drift Area as a percentage of total available jump area, Mean Difference for the right leg was 0.56% (95% LoA = −2.44 – 3.65) and for left 0.60% (95% LoA = - 3.76–4.89). ConclusionsBased on the 95% LoA data, the authors suggest that the OptoJump Next Drift Protocol does offer an acceptable level of reliability.

Numerical analysis of an ultralow switching loss IGBT with super junction and blocking junction

In order to reduce the switching loss (ESW) and enhance the breakdown voltage (BV), in this paper, an insulated gate bipolar transistor with an internal blocking junction and super junction (SJBJ-IGBT) is proposed and investigated. By inserting P-pillar and N-pillar on both sides of the drift region, a drift area with auxiliary depletion function can be formed. The junction of the primary blocking layer (JPB) is located internally in the device’s drift region. The JPB is reverse biased and withstand the main E-field during device turn-off. Meanwhile, the JPB is surrounded by P-pillar and N-pillar, reducing the E-field(E-field) peak value of device, and making E-field distribution more uniform. Furthermore, during device turn-on, the reduction of the effective area of drift region makes it easier for the JPB side of the P-drift region to accumulate excess holes. So that the SJBJ-IGBT is easier to turn-on. The snapback phenomenon of SJBJ-IGBT is eliminated. Simulation results demonstrate that, under the same forward conduction voltage (VON) condition, the proposed device exhibits a significantly lower turn-on energy loss (EON) compared to the traditional super junction(SJ-IGBT), and is 44.5% lower than that of IPBJ-IGBT, while their turn-off energy losses (EOFF) are almost equivalent.Besides, the optimized E-field distribution in the SJBJ-IGBT shows 13.2% improvement of BV. Researching results can provide important reference for reducing the ESW of IGBT.

PROBABILISTIC APPROACH FOR PREDICTING THE DRIFT OF BODIES BY TSUNAMIS

The Great East Japan Earthquake of 2011 triggered a massive tsunami, and most of the dead and missing were killed by the tsunami. About 12 years after the disaster, search activities for missing persons are still ongoing. So far, the drift behavior of drifting debris (Nistor et al., 2017) has been studied. However, the human body's drift behavior and area due to tsunamis have not been studied. It is important to establish a prediction method for the drift behavior of the human body in order to quickly rescue people who are drowned by tsunamis. On the other hand, according to Mateus et al.(2020), probabilistic and statistical approaches are important. Therefore, in this study, it is clarified that the drifting behavior of the human body based on the results of the interview survey in Otsuchi Town, Iwate Prefecture, and performs reproduction calculations to verify the validity of the method and to examine the influence of the initial configuration of the drifting position of the human body.

Breakdown characteristics of trench edge terminated SiC Schottky diode

The demand for high power density and well working in harsh environment is fulfilled with wide bandgap devices. Industrial sector depends on the development and production high-frequency and high-voltage devices. In this work, the breakdown voltage of SiC-based Schottky diode increases by using trench egde termination method and the trench is filled with dielectric material SiO 2 . Owing to good thermal and electrical properties, SiC is considered as the best semiconductor for the devices which demand for high power, high temperature and high frequency. SiC has a low resistance for the drift area even when it is designed to handle high voltage, which is its key benefit for power device applications. Simulation of the device can be done by the Silvaco TCAD software to observe the electrical and physical behaviour of unterminated as well as terminated device. Estimated breakdown voltage of the device when it is unterminated is 140 V. By using trench termination, electric field at the edge spreads away and the observed breakdown voltage was increased to 800 V. With the potential to decrease device size and raise blocking voltage to an optimal level, trench termination technology has proven appealing for high-voltage power device design.

Modulation of Pacific Sea Surface Temperature on Two Types of Tropical Cyclone Tracks Affecting Northeast China

In this study, the northward-moving tropical cyclones (TCs) that influence Northeast China (NEC) in July–September are identified based on the distance between the TC center and the boundaries of NEC. Then, based on a machine learning algorithm named hierarchical agglomerative clustering, the tracks of northward-moving TCs that influence NEC are classified into the eastern-track type and the turning type. In NEC, the precipitation induced by eastern-track type TCs gradually decreases from east to west, and the precipitation induced by turning-type TCs gradually decreases from south to north. For eastern-track type TCs, negative Niño3 sea surface temperature (SST) anomalies in preceding January–March can induce cyclonic circulation anomalies and positive vorticity anomalies over the Philippine Sea during subsequent July–September, which favors the genesis of TCs. Moreover, the westerly anomaly in the subtropical western north Pacific and the strengthening of cyclonic steering flow over the Philippines jointly steer the TCs to move northward along the northerly airflow on the west of the western Pacific subtropical high, which favors the genesis of eastern-track type TCs. For turning-type TCs, the positive SST anomalies in the West Wind Drift area during preceding May–July cause positive vorticity anomalies from the northern Philippines to Taiwan from July to September. The cyclonic steering flow over the Philippines and the anticyclonic steering flow over the Sea of Japan lead the TCs to move northwestwards and then turn to northeast, which is conducive to the genesis of turning type northward-moving TCs. Finally, the results of numerical experiments have confirmed these findings.

Contourite systems around the northern exit from the Vema Channel

Several drifts of different types and sizes are identified near the northern exit of the Vema Channel, within the projects Neogene-Quaternary contourites of the Central and South Atlantic and Lateral sedimentation in the deep ocean (on the examples from the Central and South-Western Atlantic). Herein, we discuss new results of a multidisciplinary study of sixteen sediment cores and high-resolution sub-bottom (seismoacoustic) profiles, to address the impact of Lower Circumpolar Deep Water (LCDW) and Antarctic Bottom Water (AABW) passing through the Vema gateway on contourite accumulation and erosion. To the west of the northern exit from the Vema Channel, an anticyclonic gyre of LCDW is instrumental in the development of contourite drifts and sediment waves. The contourite origin of generally silty terrigenous sediments in the Santa Catarina Plateau – São Paulo Plateau area is ascertained by both morpho-seismic and sedimentary characteristics. Sedimentary features include: a lack of primary sedimentary structures and pervasive bioturbation; sharp erosional contacts, local hiatuses and stiff mud horizons; some sandy/silty layers and indistinct bedding; mostly fine grain-size, very poor sorting and distinctive bi-gradational sequences; a high degree of correlation between the content of sortable silt (SS) in the total < 63 μm size fraction and SS mean sizes in all eight cores studied. Biostratigraphy, oxygen isotope records and ten new accelerator mass-spectrometry (AMS) 14C dates reveal the mid to late Quaternary age of this mainly terrigenous contourite depositional system (CDS).By contrast, the dominantly calcareous Ioffe Drift, overlying the Florianopolis Fracture Zone (FFZ) ridge to the northeast of the Vema Channel, is far from any source of terrigenous material, and accumulated in an area of low biological productivity. The overall asymmetric geometry, mainly lenticular, upward-convex seismic units separated by erosional unconformities, reflection truncation, small-scale moats dissecting the drift surface collectively indicate its contourite origin. The interpretation of the drift as the CDS is supported by sediment characteristics including common hiatuses corresponding in some cases to erosional contacts, pervasive bioturbation, generally poor sediment sorting, and more or less well-developed bi-gradational sequences. The erosion and deposition in the drift area are mostly controlled by the main LCDW branch following northeastward along the FFZ. Extensive erosion by bottom currents has created numerous hiatuses and markedly reduced the thickness of drift's sediments. The stratigraphic record from the Ioffe Drift sediment cores reveals an Upper Pliocene – Quaternary succession. The results of detailed analyses of six cores from the Ioffe Drift area, compared with two cores and the upper part of DSDP Site 516 from the Rio Grande Rise, notably the use of a SS analogue, provide new information on calcareous biogenic contourites deposited in the pelagic realm of the South Atlantic.

Dynamic Response of an Offshore Floating Wind Turbine at Accidental Limit States—Mooring Failure Event

This paper investigates the dynamic response of a fully nonlinear model of a DeepCWind floating offshore wind turbine (FOWT) after one of its three-catenary mooring systems is broken. The drift area of the platform, pitch motion of the wind turbine, and tension on the two ends of the mooring line are the main dynamic response foci; in addition, a single mathematical formula is provided in this study to predict the maximum drift in surge direction. After the platform reaches the new equilibrium position maintained by the remaining two mooring lines, the tower pitch exceeds 20 degrees. The tension change is closely related to the drift motion, necessitating an increase in the minimum breaking load (MBL) of the mooring line components. The mathematical forecast of the maximum surge shows good agreement with the numerical results, even with different water depths

Cross Product and Partitioned Filtering-Based Graham Convex Hull for Buoy Drifting Area Demarcating

An improved Graham scan convex hull algorithm is designed using the convex hull region shrinkage algorithm and the sample selection decision algorithm. In the sorting of Graham scan convex hull algorithm, the cross-multiplication method is used instead of the operation of finding the polar angle, which avoids the high computational complexity of finding the inverse trigonometric function. When the polar angles are the same, that is, the two points are collinear, the points close to each other are deleted directly. Select the maximal horizontal ordinate point, minimal horizontal ordinate point, maximal longitudinal coordinate point, and minimal longitudinal coordinate point. Connect these points and obtain lines. The whole plane is divided into different regions. The points that are not on the convex hull are deleted, and the redundant points are removed. This can speed up the calculation of approximate convex hull boundary and shorten the time of convex hull calculation. The proposed algorithm is used for buoy drifting area demarcating. The offsets of the geometric center of the high-frequency position point and the distance from geometric center of high-frequency position of buoy to sinking stone are calculated. The experimental results show that the new algorithm can effectively accelerate the convex hull calculation. We use the convex hull process to compute the area of the drifting buoy position and discover that the drift area of the port hand buoy is similar. The drift area of the port hand buoys is similar. The drift area of the port hand buoy is greater than that of the port hand buoy.

Drift Evaluation of a Quadrotor Unmanned Aerial Vehicle (UAV) Sprayer: Effect of Liquid Pressure and Wind Speed on Drift Potential Based on Wind Tunnel Test

Background: Unmanned Aerial Vehicles (UAVs) applied to agricultural plant protection is widely used, and the field of operation is expanding due to their high efficiency and pesticide application reduction. However, the work on pesticide drift lags behind the development of the UAV spraying device. Methods: We compared the spray drift potential at four liquid pressures of 2, 3, 4, and 5 bar ejected from the hydraulic nozzles mounted on a UAV test platform exposed to different wind speeds of 2, 4, and 6 m/s produced by a wind tunnel. The combination of the wind tunnel and the UAV test platform was used to obtain strict test conditions. The droplet size distribution under spray drift pressures was measured by a laser diffraction instrument. Results: Increasing the pressure leads to smaller droplet volume diameters and produced fine droplets of less than 100 µm. The deposition in the drift area was elevated at most of the sampling locations by setting higher pressure and faster wind speed. The deposition ratios were all higher than the flow ratios under three wind speeds after the adjustment of pressures. For most samples within a short drift distance (2–8 m), the drift with the rotor motor off was more than an order of magnitude higher than that with the rotor motor on at a pressure of 3 bar. Conclusions: In this study, the wind speed and liquid pressure all had a significant effect on the UAV spray drift, and the rotor wind significantly inhibited a large number of droplets from drifting further.

An Acoustic Survey of Beaked Whales and Kogia spp. in the Mariana Archipelago Using Drifting Recorders

The distribution, abundance, and habitat of cryptic cetacean species such as beaked whales and dwarf/pygmy sperm whales (Kogiaspp.) are challenging to study due to their long dive times and/or very limited surface behavior. Even less is known in minimally studied and remote regions, including the Mariana Archipelago and parts of the broader western Pacific. In 2018, we deployed a network of eight Drifting Acoustic Spar Buoy Recorders (DASBRs) on the west side of the Mariana Archipelago with the goal of examining the distribution and habitat of beaked whales andKogiaspp. in this region using passive acoustic monitoring. Concurrently, conductivity-temperature-depth (CTD) data were collected within the drift area and combined with satellite oceanographic data to build Ensemble Random Forest Models to identify specific oceanographic features that determine the distribution of these species. DASBRs deployed at locations ranging from 13°N to 18°N generally drifted from east to west between the Mariana Archipelago and the West Mariana Ridge. Spectral and temporal characteristics of echolocation signals were used to identify the presence of beaked whales andKogiaspp. species. This dataset contained frequency modulated (FM) pulses characteristic of Longman’s (Indopacetus pacificus), Cuvier’s (Ziphius cavirostris), and Blainville’s (Mesoplodon densirostris) beaked whales, as well as the unidentified beaked whale FM pulse known as the “BWC,” along with narrow-band high frequency clicks fromKogiaspp. The detection rate was substantially higher for all species on the five tracks in the region north of 15.5°N than for those drifts occurring farther south. Species distribution models suggest that differences in the oceanographic characteristics between the northern and southern regions may impact foraging opportunities, possibly explaining the specific ecological niche for these species within this water mass. This is the first study of the distribution of cryptic cetacean species within the wider Mariana Archipelago region. We demonstrate that autonomous drifting acoustic recorders, combined with environmental sampling and remote satellite data are a powerful tool for studying the habitat dependent distribution of cryptic cetacean species.

Swimbladder filling in herring larvae: effects of food oil on the water surface

ABSTRACT There has been a recent interest in exploring the possibility of oil and gas production in the Lofoten-Vesterålen area along the Norwegian coast. Since this is an important drift area for offspring of several important commercial fish species, such an activity could potentially have adverse effects on fish early life survival. A potential surface oil spill could coincide in time with swimbladder filling in herring larvae originating from major spawning grounds in Møre, upstream of Lofoten-Vesterålen. A laboratory experiment was carried out to determine possible effects on growth and survival of herring larvae by adding an oil slick to the water surface. The presence of food oil on the water surface over a two-week period significantly affected swimbladder filling in two-month-old herring larvae (18% vs 85% filled in exposed vs control group larvae). However, overall larval size-at-age and survival were not affected by the prevention of swimbladder filling per se, neither did otolith microstructure analysis indicate any short-term reductions in growth. Overall survival during the three-month experiment was high and averaged 74%. The relative condition of food oil-exposed larvae was higher than among control group larvae. Analysis of the larval samples and food oil documented the incorporation of specific fatty acids (e.g. 18:1 n-9, 18:2 n-6) from the food oil into the larvae. Since an oil slick represents a physical barrier and a source of bioaccumulation, further experiments should be undertaken to evaluate the toxic effects of incorporated mineral oil compounds during swimbladder filling in herring larvae.

An Optimized Structure of Split-Gate Resurf Stepped Oxide UMOSFET

In this paper, a split-gate resurf stepped oxide with double floating electrodes (DFSGRSO) U-shape metal oxide semiconductor field-effect transistor (UMOSFET) is proposed. The floating electrodes are symmetrically distributed on both sides of the source electrode in the trench. The performance of the DFSGRSO UMOSFET with different size of floating electrodes is simulated and analyzed. The simulation results reveal that the floating electrodes can modulate the distribution of the electric field in the drift area, improving the performance of the device significantly. The breakdown voltage (BV) and figure of merit (FOM) of the DFSGRSO UMOSFET at optimal parameters are 23.6% and 53.1% higher than that of the conventional structure. In addition, the regulatory mechanism of the floating electrodes is analyzed. The electric field moves from the bottom of the trench to the middle of the drift area, which brings a new electric field peak. Therefore, the distribution of the electric field is more uniform for the DFSGRSO UMOSFET compared with the conventional structure.

Geochemical signatures of intense episodic anaerobic oxidation of methane in near-surface sediments of a recently discovered cold seep (Kveithola trough, NW Barents Sea)

At cold seep environments, the detection of large 34S enrichments within bulk sulphide minerals has been frequently used as a proxy to infer the vertical migrations of the sulphate-methane transition zone (SMTZ). Processes related to the oxidative part of the sulphur cycle can alter the original stable sulphur isotope composition (δ34S) of the solid sulphur phases, in particular at the sediment-water interface. Identification of paleo and present positions of methane fronts in the sedimentary records requires the use of multiple geochemical proxies. Authigenic enrichment of Mo has been demonstrated to represent a valid and durable tracer of the past SMTZ depth fluctuations and of the intensities of the related methane seepages. This study is based on two closely-spaced short cores collected from the Main Drift of the Kveithola trough, a glacially-carved depression located in northwestern Barents Sea. Active fluid seepage has been recently reported in this area and a gas flare was specifically observed in proximity of the sampling sites where the cores object of our study were retrieved. In order to collect evidences of the possible occurrence of anaerobic oxidation of methane (AOM) at the sediment-water interface of the investigated area and infer the entity of the associated methane flux, we combined the analyses of reduced sulphur species δ34S, total organic carbon and redox-sensitive elements. The negative δ34S values within the extracted solid sulphur phases (up to −49.1‰ for pyritic sulphur) show that organoclastic sulphate reduction (OSR) coupled with disproportionation of sulphur intermediates are the only active processes in the near-surface sediments. However, moderate to strong enrichments of Mo detected in the relatively organic carbon poor intervals of both cores and the lack of concurrent enrichments of Co, Cu, Ni, V and Zn, usually associated to OSR-dominated environment, suggested that the sulphidic conditions favouring the Mo enrichments were produced by AOM. Therefore, we infer that high methane flux events characterized the drift area of the Kveithola, occasionally moving upward the SMTZ and thus inducing intense AOM in proximity of the sediment-water interface of this part of the trough. Our results confirmed the validity of sedimentary Mo as an indicator of the occurrence and intensity of past methane seepages.

Design and Attainment Assessment of Different Protocols for Smart Industry to Observe and Control Gas Leakage Employing WSN

Harmful gases leaking from the equipment that are installed in the industries cause huge loss of lives of the workers as well as people living nearby the industries. The main causes for the gas leakage are poorly maintained machines, leaky storage tanks. So, focusing on the concentration of harmful toxic gases, a virtual analysis has done using QualNet 6.1. Different numbers of nodes have dropped randomly in different terrain areas. Three protocols LRWPAN, LRWPAND, LRWPANDMC have been used to virtually analyze the gas leakage scenario. These sensors detect the gases when the leakage is near about or more than the limit. At each time some nodes will be in sleep mode and others will be in active mode, this mechanism will increase the lifetime of the battery, as changing battery frequently will not be possible especially in remote areas. The crucial profit of this paper is to show the network performance which is simulated with a sink node receiving packets for different time duration and at different frequencies. The idea is to find out the optimal and efficient network for fast information flow with 50, 100, 300 nodes. The terrain area of the network is 100×50 m2, 100×100 m2, 500×500 m2 with the communication range of 10 m. The routing protocols implemented are Low-Rate Personal Area Network (LRPAN), Low-Rate Personal Area Network with Drift (LRPAND) and Low-Rate Personal Area Network with Drift and Multi-Channel. This paper has evaluated and analyzed the influence of packet flow at the different frequencies of 2.425, 2.450, 2.475 and 2.480 GHz. It is analyzed that performance of each protocol has varied significantly for different number of nodes. The performance of the network is improved by the different frequencies instead of 2.4 GHZ frequency. The parameters average end to end delay (seconds), jitter (seconds), throughput (bits per second) and network lifetime (hours) for different protocols such as LRPAN, LRPAND and LRPANDMC for different numbers of nodes 50, 100 and 300 are evaluated and compared. The optimum results are obtained by the LRPANDMC in the simulation process. Evaluation and analysis of the influence of different protocols on different number of nodes for different parameters has been done to determine most effective protocol. This type of network can be used in oil and gas industries, petroleum industries at remote areas where there are high chances of gas leakage incidents. The aim is to provide information in real-time scenario virtually.

Research on imaging system and spatial performance of a pulse-dilation framing camera with larger drift area

An imaging system of pulse-dilation framing camera with a larger drift area is proposed, the magnetic field is calculated and the electronic trajectories is traced, the influence of larger drift area on spatial performance is analyzed, the lager detection area and high spatial resolution of framing camera with larger drift area is discussed. The research results show that the better spatial performance of framing camera with larger drift area is feasibility. When the accelerating energy is 2 keV, the sub-picoseconds pulse-dilation framing camera with Φ90 mm of detection area and 423 μm of spatial resolution is achieved, the femtoseconds ones with Φ40 mm of detection area and 448 μm of spatial resolution is obtained. This work provides a theoretical possibility for achieving higher spatial performance of sub-picoseconds/femtoseconds framing camera with larger drift area.

Investigating the temporal performance of a pulse-dilation framing camera with larger drift area

A pulse-dilation framing camera with a larger drift area is proposed, the influence of drift area on temporal performance of camera is analyzed, the femtosecond (fs) level of temporal resolution of camera is discussed. The research results show that the total temporal resolution of camera consisted of technical and physical temporal resolution, although the two types of temporal resolution exhibit an opposite tendency as the drift area is increased, the total temporal resolution can be achieved to femtosecond level by optimizing the accelerating potential and drift area. When the accelerating potential is set as −2 kV, the total temporal resolution is achieved to 939 fs using 1.0 m of drift area. This work provides theoretical basis for the feasibility of realizing a femtosecond framing camera.

Povezanost varijabilnosti položaja stopala nedominantne noge sa ubrzanjem i agilnošću rukometaša

The horizontal acceleration and agility are both an essential part of sports performance in handball. The foot placement variability has been shown to vary between differences in speed and direction of running. However, no studies have considered the connection between the foot placement variability, forward acceleration and agility performance. In the present study, a proposed repetitive single leg countermovement drift test was analyzed as a measure of the foot placement variability and correlated with forward sprinting and agility performance in handball players. Twenty-three male handball players performed a series of 10 consecutive single leg countermovement jumps, 10 m forward acceleration sprint, a handball adapted T-agility test and a single leg countermovement jump test. Correlations between the drift area, T-agility test duration, acceleration performance are measured as well as the time used to accelerate at a 5 m and 10 m distance and the height of the single leg countermovement jump. The drift area for the non-dominant leg had high and significant negative correlations with the first 5 m of forward acceleration sprinting and a positive correlation with the T-agility test to the non-dominant side. The countermovement jump height had no significant correlation to any other parameters. This data indicates that the foot placement variability of the jumps performed on the non-dominant leg could be an indicator of the ability to control stability during short forward acceleration sprints and a quick change of direction. On the contrary, these correlations disappeared when the direction change was performed under reaction time conditions.

Analysis of spherical and comatic aberrations in a pulse-dilation framing camera

A pulse-dilation framing camera is a two-dimensional ultrafast diagnostic tool that is used to research spatiotemporal evolution of plasmas through pinhole array images in inertial confinement fusion experiments. This imaging technique uses a pulse dilated with magnetic focusing imaging. Aberrations exist in the images due to the influence of long drift area and magnetic focusing on photoelectron motion. These aberrations were simulated and measured in this study in order to further understand aberrations in a pulse-dilation framing camera. The results show that the spherical and comatic aberrations primarily affect the imaging quality during imaging of camera. The spherical aberration produces diffuse spots and reduces the spatial resolution for any point on the object (i.e., regardless of whether or not it lies on the optical axis). Meanwhile comatic aberration especially obvious occurs for off-axis points on the object. These results raise an important question regarding the development of larger object planes and multiple frames of cameras that remains to be resolved.

An Evolutionary Algorithm for Optimal Multi-Direction Search Route in Search and Rescue Operation

Enhancing the effectiveness of search and rescue operation at sea is the utmost importance. Once the search area has been identified, the success of search and rescue operations depends on search and rescue vessel swept the probability area of the distress object with the minimum search time, this is an important element to the success of search and rescue operation as it minimizes the risk and the cost for search and rescue team. However, determining the optimal search route to find the distress object is extremely complex because weather conditions, winds, waves, and currents always change constantly, whereas the condition of the search and rescue vessel also changes. The present article proposes the use of a bacterial foraging optimization algorithm and applies it to finding the optimal multi-direction search route for search and rescue vessel. The cost function takes into the consideration of the total search time as well as the probability of quick find of the object in distress. In this paper, the Monte Carlo simulation method is used to predict the most probable drift area of the distress object, and then a swarm of 10 bacteria is deployed for searching the optimal SAR route. It can be seen from the calculation result that the bacteria swarm has concentrated rather well after just several generations. The optimal search path is reasonable for the dominant weather conditions and is accordance with the popular code of practice.

Estimation of Oceanic Heat Flux Under Sea Ice in the Arctic Ocean

Oceanic heat flux (Fw) is the vertical heat flux that is transmitted to the base of sea ice. It is the main source of sea ice bottom melting. The residual method was adopted to study oceanic heat flux under sea ice. The data acquired by 28 ice mass balance buoys (IMBs) deployed over the period of 2004 to 2013 in the Arctic Ocean were used. Fw values presented striking seasonal and spatial variations. The average summer Fw values for the Canada Basin, Transpolar Drift, and Multiyear Ice area were 16.8, 7.7, and 5.9 Wm−2, respectively. The mean summer Fw for the whole Arctic was 10.1 Wm−2, which was equivalent to a bottom melt of 0.4m. Fw showed an autumn peak in November in the presence of the near-surface temperature maximum (NSTM). The average Fw for October to December was 3.7Wm−2. And the average Fw for January to March was 1.0Wm−2, which was approximately one third of the average Fw in the presence of NSTM. The summer Fw was almost wholly attributed to the incident solar radiation that enters the upper ocean through leads and the open water. Fw calculated through the residual method using IMB data was compared with that calculated through the parameterization method using Autonomous Ocean Flux Buoy data. The results revealed that the Fw provided by the two methods were consistent when the sea ice concentration exceeded 70% and mixing layer temperature departure from freezing point was less than 0.15℃. Otherwise, the Fw yielded by the residual method was approximately one third smaller than that provided by the parameterization method.