The concentration of chlorophyll-a in ocean surface waters is a good indicator of primary productivity. As part of a national-scale analysis of ecosystem processes influencing marine biodiversity, daily MODIS images were processed using NASA's SeaDAS software to generate chlorophyll-a monthly data for the period 2009-2011. Results show that Australian oceans have relatively low surface chlorophyll-a concentrations (average 0.2 mg/m3), with concentrations greater than 0.7 mg/m3 considered to indicate 'high' productivity. On this basis, productivity hotspots are mapped for locations that have 'high' productivity greater than 75% of the time (i.e. 9 out of 12 months). As expected, most productivity hotspots are confined to inner shelf and coastal areas, especially embayments. Key areas include the Great Barrier Reef, Gulf of Carpentaria, Van Diemen Gulf, Joseph Bonaparte Gulf, Kimberley coast, Exmouth Gulf and Shark Bay. Seasonally, the period February to June has larger areas of 'high' productivity. Annually, areas of hotspots decrease from 2009 to 2011. Among the 59 existing and proposed Commonwealth Marine Reserves (CMR), nine have hotspots occupying more than 1% of their area; a result consistent with their largely offshore location. In contrast, 47 out of 128 state/territory Marine Protected Areas (MPAs) which lie in inshore waters have more than 1% of area identified as hotspots. In total, chlorophyll-a hotspots occur in more than 20% (by area) of the state/territory MPAs, compared to less than 0.4% of CMRs. Ongoing analysis will relate these patterns to oceanographic models and biodiversity patterns at regional scales, with a focus on northern Australia.

The dominant ocean current off the Western Australian (WA) coast is the Leeuwin Current (LC) [1]. It is a warm, poleward flowing surface current up to 300 metres in depth and exhibits significant seasonal differences in intensity, ranging from strong during the austral winter and weak during the austral summer [2-3]. At a regional scale, the LC is significant because it directly influences the temperature and nutrient dynamics of the WA ocean ecosystem [3]. As a result, it has been shown that the LC affects the production of phytoplankton [4-5], the recruitment of western rock lobster [6], and the distribution of fishes and algae [7]. The LC can be observed from Sea Surface Temperature (SST) satellite-derived images. However, delineating an accurate map showing the extent and spatial structure of the LC from a SST image remains a challenge. And given the large area covered by the LC, an automatic approach is desirable. This study aims to test an object-based image processing technique from time-series MODIS SST data for the above purpose. SeaDas image processing software was used to process MODIS images from daily raw data to Level 3 products. The monthly SST4 layers between June 2009 and May 2010 were the inputs for this study. The SST layer shown in Figure 1a clearly indicates a warmer (than off-shore) southward flowing current (LC) that extends from Exmouth, passing Cape Leeuwin, into the Great Australian Bight. Previously, relative temperature differences have been employed to identify LC structure from SST images [8]. An off-shore SST profile crossing the LC (Figures 1a & b) shows that the LC, indicated by warmer temperatures, occupies a zone approximately between 10 km and 90 km from the coast, with a core current between 35 km and 70 km. This study utilised two characteristics of MODIS-derived sea surface temperatures to identify the extents of the LC. The first characteristic is that the LC is warmer than surrounding waters. The second characteristic is the connectivity between the core LC current and the eddies. According to the first characteristic, the SST images were treated as elevation surfaces where the LC occupies slope and ridge positions. Topographic Position Index (TPI) was then derived from these SST layers to identify topographic positions [9]. As shown in Figure 1c, the LC approximately corresponds with areas of large positive TPI values. In the next step, the multi-resolution algorithm in eCognition Developer was employed to segment the SST and TPI layers of each month into objects. The objects were classified into a pseudo LC class if their mean TPI values are greater than 0.25 of the global standard deviation value. The second characteristic of the LC was then used to remove false positive objects. To do that, a small number of objects at known LC locations were selected as 'seeds'. In a looping process, any objects that connect with these seeds were classified as true LC class. The extents of the LC for the 12 months analysed here areshown in Figure 2. The LC during austral winter is clearly stronger (e.g., larger in extent) than during austral summer, which confirms the findings of other studies [2-3]. The LC during the summer time is patchier, which required more seeds (8-14) than during the winter time (less than 5 seeds). The core summer current is also slightly further away from the coast. In addition, eddies are clearly visible in most months. In summary, the proposed object-based approach was semi-automatic and effective in delineating the extents of the LC although there is a degree of subjectivity in the selection of accurate seeds. The weak summer current, however poses some difficulty for the approach and future work is aimed at improving the modelling accuracy.

The high frequency (10 min) and resolution (~2km) of Himawari-8 data provides an enormous opportunity for the monitoring and investigation of highly dynamic oceanographic phenomena. This presentation aims to demonstrate the value of himawari-8 SST data for studies of the Bonney Coast upwelling, East Australian Current (EAC) and Madden-Julian Oscillation (MJO) diurnal SST (dSST) variations. During the 2016–17 summer, we identified three distinct upwelling events along the Bonney Coast. Each event surpassed its predecessor in area of influence, minimum temperature and duration. The EAC’s mapped between July 2015 and Sept 2017 showed clear seasonal and intra-seasonal variations. During summer, the EAC and its extension frequently encroached into the coastal areas of northern NSW and eastern Tasmania. A composite analysis based on MJO phases during the summer seasons of 2015–16 and 2016–17 showed that the dSST typically peaked during phases 2 and 3 off the northwest shelf, prior to the onset of the active phases of MJO (phase 4). The analysis indicated that dSST is negatively correlated with the surface wind speed but positively correlated with short-wave latent heat flux. In future, these monitoring and analytical capabilities can be effectively implemented in Geoscience Australia’s Digital Earth Australia platform. Abstract submitted/presented to 2019 Australian Marine science Association AMSA Conference (https://www.amsa.asn.au/2019-fremantle)

Geoscience Australia (GA) conducted a marine survey (GA0345/GA0346/TAN1411) of the north-eastern Browse Basin (Caswell Sub-basin) between 9 October and 9 November 2014 to acquire seabed and shallow geological information to support an assessment of the CO2 storage potential of the basin. The survey, undertaken as part of the Department of Industry and Science's National CO2 Infrastructure Plan (NCIP), aimed to identify and characterise indicators of natural hydrocarbon or fluid seepage that may indicate compromised seal integrity in the region. The survey was conducted in three legs aboard the New Zealand research vessel RV Tangaroa, and included scientists and technical staff from GA, the NZ National Institute of Water and Atmospheric Research Ltd. (NIWA) and Fugro Survey Pty Ltd. Shipboard data (survey ID GA0345) collected included multibeam sonar bathymetry and backscatter over 12 areas (A1, A2, A3, A4, A6b, A7, A8, B1, C1, C2b, F1, M1) totalling 455 km2 in water depths ranging from 90 - 430 m, and 611 km of sub-bottom profile lines. Seabed samples were collected from 48 stations and included 99 Smith-McIntyre grabs and 41 piston cores. An Autonomous Underwater Vehicle (AUV) (survey ID GA0346) collected higher-resolution multibeam sonar bathymetry and backscatter data, totalling 7.7 km2, along with 71 line km of side scan sonar, underwater camera and sub-bottom profile data. Twenty two Remotely Operated Vehicle (ROV) missions collected 31 hours of underwater video, 657 still images, eight grabs and one core. Following shipboard multibeam mapping, higher-resolution multibeam data were acquired in targeted areas (prior to instrument failure) using a Kongsberg Simrad EM2000 system mounted to Fugro's Echo Surveyor V (ES-5) AUV. This instrument had a depth rating of 3000 m, and surveyed the seafloor according to a pre-programmed mission plan. The AUV was fitted with a camera and light system designed to produce images of equal width and height (in the context of this survey, the images comprised 8 m by 8 m of seafloor). The equipment consisted of a light sensitive NEO 11 Megapixel 35 mm monochrome CCD (4008 x 2672) camera and two LED panels, each comprising 360 LEDs. High-resolution multibeam bathymetric data was collected together with side scan sonar and sub bottom profile data at an elevation of 30 m above the seafloor, and at line spacing's of 100 m. Overlapping high-resolution still photographs (captured every second) were then acquired on the survey lines at an elevation of 8 m above the seafloor. The AUV was equipped with an advanced real-time Aided Inertial Navigation System, which calculated the position, velocity and altitude of the vehicle and a HiPAP 500 USBL system was used to acoustically position the AUV. This catalogue entry refers to the five backscatter patches (A3 Patch 1, A3 Patch 2, A4 Patch 1, A4 Patch 2, A4 Patch 3) mapped using a Kongsberg Simrad EM2000 system mounted to Fugro's Echo Surveyor V (ES-5) AUV.

Geoscience Australia (GA) conducted a marine survey (GA0345/GA0346/TAN1411) of the north-eastern Browse Basin (Caswell Sub-basin) between 9 October and 9 November 2014 to acquire seabed and shallow geological information to support an assessment of the CO2 storage potential of the basin. The survey, undertaken as part of the Department of Industry and Science's National CO2 Infrastructure Plan (NCIP), aimed to identify and characterise indicators of natural hydrocarbon or fluid seepage that may indicate compromised seal integrity in the region. The survey was conducted in three legs aboard the New Zealand research vessel RV Tangaroa, and included scientists and technical staff from GA, the NZ National Institute of Water and Atmospheric Research Ltd. (NIWA) and Fugro Survey Pty Ltd. Shipboard data (survey ID GA0345) collected included multibeam sonar bathymetry and backscatter over 12 areas (A1, A2, A3, A4, A6b, A7, A8, B1, C1, C2b, F1, M1) totalling 455 km2 in water depths ranging from 90 - 430 m, and 611 km of sub-bottom profile lines. Seabed samples were collected from 48 stations and included 99 Smith-McIntyre grabs and 41 piston cores. An Autonomous Underwater Vehicle (AUV) (survey ID GA0346) collected higher-resolution multibeam sonar bathymetry and backscatter data, totalling 7.7 km2, along with 71 line km of side scan sonar, underwater camera and sub-bottom profile data. Twenty two Remotely Operated Vehicle (ROV) missions collected 31 hours of underwater video, 657 still images, eight grabs and one core. Shipboard and AUV multibeam bathymetry and sub-bottom profiler data indicated the presence of recently active faults in the area, some with significant seafloor surface expression (i.e. fault scarps with up to 40m offset). Some of these faults were visually inspected by the ROV which also confirmed the presence of diverse biological communities. Possible indications of shallow gas were observed on sub-bottom profiles, including amplitude anomalies, cross-cutting reflectors and zones of signal starvation. Water column observations including sidescan sonar, single-beam and multibeam echosounders, underwater video and photography did not conclusively identify hydrocarbon or other fluid seepage. Strong currents encountered during parts of the survey may have interfered with the direct detection of seeps in the water column. While no active signs of seepage were observed, the geochemical and biological sampling undertaken will aid in baseline environmental investigations for this region. The data collected during the survey are available for free download from the Geoscience Australia website.

Geoscience Australia (GA) conducted a marine survey (GA0345/GA0346/TAN1411) of the north-eastern Browse Basin (Caswell Sub-basin) between 9 October and 9 November 2014 to acquire seabed and shallow geological information to support an assessment of the CO2 storage potential of the basin. The survey, undertaken as part of the Department of Industry and Science's National CO2 Infrastructure Plan (NCIP), aimed to identify and characterise indicators of natural hydrocarbon or fluid seepage that may indicate compromised seal integrity in the region. The survey was conducted in three legs aboard the New Zealand research vessel RV Tangaroa, and included scientists and technical staff from GA, the NZ National Institute of Water and Atmospheric Research Ltd. (NIWA) and Fugro Survey Pty Ltd. Shipboard data (survey ID GA0345) collected included multibeam sonar bathymetry and backscatter over 12 areas (A1, A2, A3, A4, A6b, A7, A8, B1, C1, C2b, F1, M1) totalling 455 km2 in water depths ranging from 90 - 430 m, and 611 km of sub-bottom profile lines. Seabed samples were collected from 48 stations and included 99 Smith-McIntyre grabs and 41 piston cores. An Autonomous Underwater Vehicle (AUV) (survey ID GA0346) collected higher-resolution multibeam sonar bathymetry and backscatter data, totalling 7.7 km2, along with 71 line km of side scan sonar, underwater camera and sub-bottom profile data. Twenty two Remotely Operated Vehicle (ROV) missions collected 31 hours of underwater video, 657 still images, eight grabs and one core. This data package brings together a suite of datasets and documents which describe the seabed environments and shallow geology of the Caswell Sub-basin, Browse Basin, Western Australia.

Geoscience Australia (GA) conducted a marine survey (GA0345/GA0346/TAN1411) of the north-eastern Browse Basin (Caswell Sub-basin) between 9 October and 9 November 2014 to acquire seabed and shallow geological information to support an assessment of the CO2 storage potential of the basin. The survey, undertaken as part of the Department of Industry and Science's National CO2 Infrastructure Plan (NCIP), aimed to identify and characterise indicators of natural hydrocarbon or fluid seepage that may indicate compromised seal integrity in the region. The survey was conducted in three legs aboard the New Zealand research vessel RV Tangaroa, and included scientists and technical staff from GA, the NZ National Institute of Water and Atmospheric Research Ltd. (NIWA) and Fugro Survey Pty Ltd. Shipboard data (survey ID GA0345) collected included multibeam sonar bathymetry and backscatter over 12 areas (A1, A2, A3, A4, A6b, A7, A8, B1, C1, C2b, F1, M1) totalling 455 km2 in water depths ranging from 90 - 430 m, and 611 km of sub-bottom profile lines. Seabed samples were collected from 48 stations and included 99 Smith-McIntyre grabs and 41 piston cores. An Autonomous Underwater Vehicle (AUV) (survey ID GA0346) collected higher-resolution multibeam sonar bathymetry and backscatter data, totalling 7.7 km2, along with 71 line km of side scan sonar, underwater camera and sub-bottom profile data. Twenty two Remotely Operated Vehicle (ROV) missions collected 31 hours of underwater video, 657 still images, eight grabs and one core. This catalogue entry refers to the ship-based Sub-Bottom Profiler (SBP) SEGY-format line data (ie survey GA-0345) acquired within the survey areas.

Geoscience Australia (GA) conducted a marine survey (GA0345/GA0346/TAN1411) of the north-eastern Browse Basin (Caswell Sub-basin) between 9 October and 9 November 2014 to acquire seabed and shallow geological information to support an assessment of the CO2 storage potential of the basin. The survey, undertaken as part of the Department of Industry and Science's National CO2 Infrastructure Plan (NCIP), aimed to identify and characterise indicators of natural hydrocarbon or fluid seepage that may indicate compromised seal integrity in the region. The survey was conducted in three legs aboard the New Zealand research vessel RV Tangaroa, and included scientists and technical staff from GA, the NZ National Institute of Water and Atmospheric Research Ltd. (NIWA) and Fugro Survey Pty Ltd. Shipboard data (survey ID GA0345) collected included multibeam sonar bathymetry and backscatter over 12 areas (A1, A2, A3, A4, A6b, A7, A8, B1, C1, C2b, F1, M1) totalling 455 km2 in water depths ranging from 90 - 430 m, and 611 km of sub-bottom profile lines. Seabed samples were collected from 48 stations and included 99 Smith-McIntyre grabs and 41 piston cores. An Autonomous Underwater Vehicle (AUV) (survey ID GA0346) collected higher-resolution multibeam sonar bathymetry and backscatter data, totalling 7.7 km2, along with 71 line km of side scan sonar, underwater camera and sub-bottom profile data. Twenty two Remotely Operated Vehicle (ROV) missions collected 31 hours of underwater video, 657 still images, eight grabs and one core. This catalogue entry refers to standard Geotek multi-sensor core logger data from piston cores collected on the survey. Please follow link to manual for further information.

Geoscience Australia (GA) conducted a marine survey (GA0345/GA0346/TAN1411) of the north-eastern Browse Basin (Caswell Sub-basin) between 9 October and 9 November 2014 to acquire seabed and shallow geological information to support an assessment of the CO2 storage potential of the basin. The survey, undertaken as part of the Department of Industry and Science's National CO2 Infrastructure Plan (NCIP), aimed to identify and characterise indicators of natural hydrocarbon or fluid seepage that may indicate compromised seal integrity in the region. The survey was conducted in three legs aboard the New Zealand research vessel RV Tangaroa, and included scientists and technical staff from GA, the NZ National Institute of Water and Atmospheric Research Ltd. (NIWA) and Fugro Survey Pty Ltd. Shipboard data (survey ID GA0345) collected included multibeam sonar bathymetry and backscatter over 12 areas (A1, A2, A3, A4, A6b, A7, A8, B1, C1, C2b, F1, M1) totalling 455 km2 in water depths ranging from 90 - 430 m, and 611 km of sub-bottom profile lines. Seabed samples were collected from 48 stations and included 99 Smith-McIntyre grabs and 41 piston cores. An Autonomous Underwater Vehicle (AUV) (survey ID GA0346) collected higher-resolution multibeam sonar bathymetry and backscatter data, totalling 7.7 km2, along with 71 line km of side scan sonar, underwater camera and sub-bottom profile data. Twenty two Remotely Operated Vehicle (ROV) missions collected 31 hours of underwater video, 657 still images, eight grabs and one core. This catalogue entry refers to the sub-bottom profiler data acquired by the Fugro supplied AUV system (survey GA-0346).

The topographic Aspect grid represents the angle of aspect of the seabed in the Darwin Harbour survey area. The Aspect grid was created from the bathymetry grid of Darwin Harbour obtained from the survey onboard the Matthew Flinders. Please see the Metadata of the bathymetry grid for details (GeoCat: 74915).