SUMMARYThe first Provenance Challenge was set up in order to provide a forum for the community to understand the capabilities of different provenance systems and the expressiveness of their provenance representations. To this end, a functional magnetic resonance imaging workflow was defined, which participants had to either simulate or run in order to produce some provenance representation, from which a set of identified queries had to be implemented and executed. Sixteen teams responded to the challenge, and submitted their inputs. In this paper, we present the challenge workflow and queries, and summarize the participants' contributions.

Abstract. We propose a new method to improve the utility of three-dimensional ocean circulation models. The method uses climatological temperature and salinity data to adjust the momentum balance of the model, while leaving the tracer equations fully prognostic and unconstrained. The adjustment is accomplished by replacing density in the hydrostatic equation by a linear combination of model-computed and climatological density. The procedure is equivalent to adding a forcing term to the horizontal momentum equation through a modification of the model's horizontal pressure gradient term. The forcing term modifies the model-computed velocity field, which, in turn, affects the model-computed temperature and salinity fields through the advection term (there is no adjustment of the tracer equations carried by the model). Assuming the linear combination coefficient to be invariant in time and space, we suggest a statistical approach to estimating its optimal value. We apply this "semiprognostic" method to the northwest Atlantic. A primitive equation circulation model is initialized with January climatological temperature and salinity and is forced by monthly mean Comprehensive Ocean-Atmosphere Data Set surface wind stress and heat flux, by restoration of the surface salinity to monthly mean climatology, and by flows through the open boundaries. Both the model-computed tracer and velocity fields produced using the semiprognostic method show significant improvement over those produced by a purely prognostic calculation; drift of the tracer and velocity fields away from climatology is greatly reduced. Further, convective mixing is explicitly represented, thus improving the utility of results over those obtained from pure diagnostic calculations. The velocity fields obtained with the new approach are somewhat more realistic than those obtained from pure diagnostic calculations. The method reproduces many well-known circulation features in the region, including the Labrador Current, the Gulf Stream, and the North Atlantic Current. More significantly, the method reproduces reasonably well the seasonal evolution of temperature and salinity in the region despite the fact that the model's tracer fields are not constrained directly by the new method. This result suggests that the semiprognostic approach will be useful for examining the evolution of tracers that are not easily determined by observations.

In the study of fine art, provenance refers to the documented history of some art object. Given that documented history, the object attains an authority that allows scholars to appreciate its importance with respect to other works, whereas, in the absence of such history, the object may be treated with some skepticism. Our IT landscape is evolving as illustrated by applications that are open, composed dynamically, and that discover results and services on the fly. Against this challenging background, it is crucial for users to be able to have confidence in the results produced by such applications. If the provenance of data produced by computer systems could be determined as it can for some works of art, then users, in their daily applications, would be able to interpret and judge the quality of data better. We introduce a provenance lifecycle and advocate an open approach based on two key principles to support a notion of provenance in computer systems: documentation of execution and user-tailored provenance queries.

The Japanese eel larvae hatch near the West Mariana Ridge seamount chain and travel through the North Equatorial Current (NEC), the Kuroshio, and the Subtropical Countercurrent (STCC) region during their shoreward migration toward East Asia. The interannual variability of circulation over the subtropical and tropical regions of the western North Pacific Ocean is affected by the Philippines–Taiwan Oscillation (PTO). This study examines the effect of the PTO on the Japanese eel larval migration routes using a three-dimensional (3D) particle tracking method, including vertical and horizontal swimming behavior. The 3D circulation and hydrography used for particle tracking are from the ocean circulation reanalysis produced by the Japan Coastal Ocean Predictability Experiment 2 (JCOPE2). Our results demonstrate that bifurcation of the NEC and the strength and spatial variation of the Kuroshio affect the distribution and migration of eel larvae. During the positive phase of PTO, more virtual eels (“v-eels”) can enter the Kuroshio to reach the south coast of Japan and more v-eels reach the South China Sea through the Luzon Strait; the stronger and more offshore swing of the Kuroshio in the East China Sea leads to fewer eels entering the East China Sea and the onshore movement of the Kuroshio to the south of Japan brings the eels closer to the Japanese coast. Significant differences in eel migration routes and distributions regulated by ocean circulation in different PTO phases can also affect the otolith increment. The estimated otolith increment suggests that eel age tends to be underestimated after six months of simulation due to the cooler lower layer temperature. Underestimation is more significant in the positive PTO years due to the wide distribution in higher latitudes than in the negative PTO years.

[1] In the falls of both 1999 and 2000, waves with characteristics similar to tsunami hit the southeast coast of Newfoundland, Canada. The waves were large enough to cause local flooding, damage to docks, and other destruction. There is, however, no evidence of seismic events, underwater landslides, or slumping events on either occasion. Other explanations, such as storm surge, also appear unlikely, and local weather conditions at the coast were not exceptional at the time. On both occasions, tropical storms moved rapidly across the Grand Banks of Newfoundland from southwest to northeast, with a translation speed of %30 m s À1 . A significant, nonisostatic response to atmospheric pressure forcing can be expected over the shallow water of the banks since the translation speed of the storms is comparable to the local shallow water gravity wave speed. We speculate that the atmospheric pressure forcing associated with the storms generated a barotropic wake, and we use a numerical model to argue that as the storm moved back over the deep ocean, the wake was refracted and/or reflected by the variable bathymetry at the edge of the banks and that it was the refraction of the wake toward the coast that led to the unusual sea level events in southeastern Newfoundland. The numerical model results are in general agreement with the eye witness reports. The model-computed wave activity hits the southeast coast of Newfoundland at about the right time and in the right areas for both events, although for the 1999 event the model response is weaker than is observed at Port Rexton in Trinity Bay. The reason for the poorer model performance in the 1999 case is not known, although we do find that the model results are sensitive to uncertainty in the exact track taken by the storm across the banks. The model results demonstrate that the period and wavelength of the gravity waves comprising the wake are, in general, proportional to the length scale of the pressure forcing, an exception being the model response in Conception Bay, Newfoundland, where a resonant seiche response is found to dominate. Citation: Mercer, D., J. Sheng, R. J. Greatbatch, and J. Bobanović, Barotropic waves generated by storms moving rapidly over shallow water,