Multi-Year Elevation Changes Near the West Margin of the Greenland Ice Sheet from Satellite Radar Altimetry

Mean changes in the surface elevation near the west margin of the Greenland ice sheet are measured using Seasat altimetry and altimetry from the Geosat Exact Repeat Mission (ERM). The Seasat data extend from early July through early October 1978. The ERM data extend from winter 1986-87 through fall 1988. Both seasonal and multi-year changes are measured using altimetry referenced to GEM T2 orbits. The possible effects of orbit error are minimized by adjusting the orbits into a common ocean surface. Seasonal mean changes in the surface height are recognizable during the Geosat ERM. The multi-year measurements indicate the surface was lower by 0.4 +/- 0.4 m on average in late summer 1987 than in late summer 1978. The surface was lower by 0.2 +/- 0.5 m on average in late summer 1988 than in late summer 1978. As a control case, the computations art also carried out using altimetry referenced to orbits not adjusted into a common ocean surface

138-Tbt/s mode- and wavelength-multiplexed transmission over six-Mode graded-index fiber

\u3cp\u3eWe report on the multiplexing of 12 spatial and polarization channels and 120 wavelength channels in the C -band, each carrying 16 quadratic-amplitude modulation symbols at 30 GBd over graded-index few-mode fiber. A combination of multiple fiber spools with positive and negative modal dispersion values is exploited to form a 59-km link with 0.35-ns differential mode group delay. The link is placed inside a sixfold synchronized recirculating loop transmission setup. Photonic lanterns with low insertion and mode-dependent loss are employed to excite the six spatial modes in the few-mode fiber. A net transmission rate of 138 Tb/s at a spectral efficiency of 34.91 b/s/Hz over 590 km is demonstrated.\u3c/p\u3