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Multivariate networks are made up of nodes and their relationships (links), but also data about those nodes and links as attributes. Most real‐world networks are associated with several attributes, and many analysis tasks depend on analyzing both, relationships and attributes. Visualization of multivariate networks, however, is challenging, especially when both the topology of the network and the attributes need to be considered concurrently. In this state‐of‐the‐art report, we analyze current practices and classify techniques along four axes: layouts, view operations, layout operations, and data operations. We also provide an analysis of tasks specific to multivariate networks and give recommendations for which technique to use in which scenario. Finally, we survey application areas and evaluation methodologies.

The distribution of water masses and their circulation on the western Chukchi Sea shelf are investigated using shipboard data from the Russian-American Long Term Census of the Arctic (RUSALCA) program. Eleven hydrographic/velocity transects were occupied during September of that year, including a number of sections in the vicinity of Wrangel Island and Herald canyon, an area with historically few measurements. We focus on four water masses: Alaskan coastal water (ACW), summer Bering Sea water (BSW), Siberian coastal water (SCW), and remnant Pacific winter water (RWW). In some respects the spatial distributions of these water masses were similar to the patterns found in the historical World Ocean Database, but there were significant differences. Most notably, the ACW and BSW were transposed in Bering Strait, and the ACW was diverted from its normal coastal pathway northwestward through Herald Canyon. It is argued that this was the result of atmospheric forcing. September 2009 was characterized by an abnormally deep Aleutian Low and the presence of the Siberian High, which is normally absent this time of year. This resulted in strong northerly winds during the month, and mooring data from the RUSALCA program reveal that the ACW and BSW were transposed in Bering Strait for a significant portion of the month. Using an idealized numerical model we show that the Ekman response to the wind can cause such a transposition, and that the consequences of this will persist on the shelf long after the winds subside. This can explain the anomalous presence of ACW in Herald Canyon during the RUSALCA survey.

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Shipboard hydrographic and velocity sections are used to quantify aspects of the North Icelandic Jet (NIJ), which transports dense overflow water to Denmark Strait, and the North Icelandic Irminger Current (NIIC), which imports Atlantic water to the Iceland Sea. The mean transports of the two currents are comparable, in line with previous notions that there is a local overturning cell in the Iceland Sea that transforms the Atlantic water to dense overflow water. As the NIJ and NIIC flow along the north side of Iceland, they appear to share a common front when the bottom topography steers them close together, but even when they are separate there is a poleward flow inshore of the NIJ. The interannual variability in salinity of the inflowing NIIC is in phase with that of the outflowing NIJ. It is suggested, however, that the NIIC signal does not dictate that of the NIJ. Instead, the combination of liquid and solid freshwater flux from the east Greenland boundary can account for the observed net freshening of the NIIC to the NIJ for the densest half of the overturning circulation in the northwest Iceland Sea. This implies that the remaining overturning must occur in a different geographic area, consistent with earlier model results. The year-to-year variability in salinity of the NIJ can be explained by applying annual anomalies of evaporation minus precipitation over the Iceland Sea to a one-dimensional mixing model. These anomalies vary in phase with the wind stress curl over the North Atlantic subpolar gyre, which previous studies have shown drives the interannual variation in salinity of the inflowing NIIC.