545 research outputs found
Body tides on an elliptical rotating earth
The complete tidal response of an elliptical, rotating, elastic Earth is found to contain small displacements which do not fit into the conventional Love number framework. Corresponding observable tidal quantities (gravity, tilt, strain, Eulerian potential, etc.) are modified by the addition of small latitude dependent terms
Dealing with complexity in education for sustainability - a shared journey for students and teachers in design education
Design graduates must be capable of responding meaningfully to an increasingly complex world. Student learning must provide a holistic and collaborative design practice that is both flexible and creative and authentically incorporates complexity. Within this context it is critical that sustainability, in its broadest definition, is embedded into the curriculum. This enables students to explore sustainability, grapple with issues concerning the interconnectedness of social, economic and environmental considerations in the local and global context, and to better understand the implications of their own actions in the real world. Appropriate teaching strategies are needed to support such learning
Three academics' narratives in transforming curriculum for education for sustainable development
The expectation is that higher education curricula which purports to incorporate education for sustainable development (ESD) supports university graduates in becoming more sustainable. It would then follow that if academics are to offer such curricula they need to be adequately equipped with the motivations, knowledge and skills to teach it. However, the extent to which ESD has resulted in genuine higher education curriculum change, and academic readiness for it, is debatable. As such, this article presents the academic experiences of three of the authors involved in a curriculum change process to embed ESD within a Bachelor of Arts (Textile Design) degree program. Individual post-project narratives of our experiences are summarised and thematically analysed. The analysis reveals these experiences as disorienting, yet subsequently transformative. The findings suggest promoting academics' transformative learning should be a focus of ESD curriculum change efforts. The findings support commitment to long-term, facilitated professional development to achieve transformative change; an often espoused, yet under-reported initiative
Будівельна лихоманка на Київських схилах
Forty marine-terminating glaciers have been surveyed daily since 2000 using cloud-free MODIS visible imagery (Box and Decker 2011; http://bprc. osu.edu/MODIS/). The net area change of the 40 glaciers during the period of observation has been -1775 km2, with the 18 northernmost (>72°N) glaciers alone contributing to half of the net area change. In 2012, the northernmost glaciers lost a collective area of 255 km2, or 86% of the total net area change of the 40 glaciers surveyed. The six glaciers with the largest net area loss in 2012 were Petermann (-141 km2), 79 glacier (-27 km2), Zachariae (-26 km2), Steenstrup (-19 km2), Steensby (-16 km2, the greatest retreat since observations began), and Jakobshavn (-13 km2). While the total area change was negative in 2012, the area of four of the forty glaciers did increase relative to the end of the 2011 melt season. The anomalous advance of these four glaciers is not easily explained, as the mechanisms controlling the behavior of individual glaciers are uncertain due to their often unique geographic!settings
Methods for removal of unwanted signals from gravity time-series : comparison using linear techniques complemented with analysis of system dynamics
We thanks the participants of the 35th General Assembly of the European Seismological Commission for comments on preliminary results. The authors are grateful to all IGETS contributors, particularly to the station operators and to ISDC/GFZ-Potsdam for providing the original gravity data used in this study. We also thank the developers of ATLANTIDA3.1 and UTide. Part of this work was performed using the ICSMB High Performance Computing Cluster, University of Aberdeen. We also thanks M. Thiel and A. Moura for reviewing a preliminary version and making comments on the methods section and M.A. Ara´ujo for comments on Lyapunov exponents. Funding: A. Valencio is supported by CNPq, Brazil [206246/2014-5]; and received a travel grant from the School of Natural and Computing Sciences, University of Aberdeen [PO2073498], for a presentation including preliminary results.Peer reviewedPostprintPublisher PD
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[Arctic] Greenland ice sheet [in “State of the Climate in 2012”]
Melting at the surface of the Greenland Ice Sheet set new records for extent and melt index (i.e., the number of days on which melting occurred multiplied by the area where melting was detected) for the period 1979–2012, according to passive microwave observations (e.g., Tedesco 2007, 2009; Mote and Anderson 1995). Melt extent reached ~97% of the ice sheet surface during a rare, ice-sheet-wide event on 11–12 July (Fig. 5.13a; Nghiem et al. 2012). This was almost four times greater than the average melt extent for 1981–2010. The 2012 standardized melting index (SMI, defined as the melting index minus its average and divided by its standard deviation) was +2.4, almost twice the previous record of about +1.3 set in 2010
Steric and mass-induced sea level variations in the Mediterranean Sea revisited
The total sea level variation (SLV) is the combination of steric and mass␣induced SLV, whose exact shares are key to understanding the oceanic response to climate system changes. Total SLV can be observed by radar altimetry satellites such as TOPEX/POSEIDON and Jason 1/2. The steric SLV can be computed through temperature and salinity profiles from in situ measurements or from ocean general circulation models (OGCM), which can assimilate the said observations. The mass-induced SLV can be estimated from its time-variable gravity (TVG) signals. We revisit this problem in the Mediterranean Sea estimating the observed, steric, and mass-induced SLV, for the latter we analyze the latest TVG data set from the GRACE (Gravity Recovery and Climate Experiment) satellite mission launched in 2002, which is 3.5 times longer than in previous studies, with the application of a two-stage anisotropic filter to reduce the noise in high-degree and -order spherical harmonic coefficients. We confirm that the intra-annual total SLV are only produced by water mass changes, a fact explained in the literature as a result of the wind field around the Gibraltar Strait. The steric SLV estimated from the residual of “altimetry minus GRACE” agrees in phase with that estimated from OGCMs and in situ measurements, although showing a higher amplitude. The net water fluxes through both the straits of Gibraltar and Sicily have also been estimated accordingly.This work was elaborated during the stay of the first author at the National Central University of Taiwan, thanks to a grant from the Generalitat Valenciana, Spain. Jean-Paul Boy is currently visiting NASA Goddard Space Flight Center, with a Marie Curie International Outgoing Fellowship (PIOF-GA-2008-221753). This work was partly funded by two Spanish projects from MICIN, ESP2006-11357, and AYA2009-07981 and one from Generalitat Valenciana (ACOMP2009/031)
Tidal friction in close-in satellites and exoplanets. The Darwin theory re-visited
This report is a review of Darwin's classical theory of bodily tides in which
we present the analytical expressions for the orbital and rotational evolution
of the bodies and for the energy dissipation rates due to their tidal
interaction. General formulas are given which do not depend on any assumption
linking the tidal lags to the frequencies of the corresponding tidal waves
(except that equal frequency harmonics are assumed to span equal lags).
Emphasis is given to the cases of companions having reached one of the two
possible final states: (1) the super-synchronous stationary rotation resulting
from the vanishing of the average tidal torque; (2) the capture into a 1:1
spin-orbit resonance (true synchronization). In these cases, the energy
dissipation is controlled by the tidal harmonic with period equal to the
orbital period (instead of the semi-diurnal tide) and the singularity due to
the vanishing of the geometric phase lag does not exist. It is also shown that
the true synchronization with non-zero eccentricity is only possible if an
extra torque exists opposite to the tidal torque. The theory is developed
assuming that this additional torque is produced by an equatorial permanent
asymmetry in the companion. The results are model-dependent and the theory is
developed only to the second degree in eccentricity and inclination
(obliquity). It can easily be extended to higher orders, but formal accuracy
will not be a real improvement as long as the physics of the processes leading
to tidal lags is not better known.Comment: 30 pages, 7 figures, corrected typo
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