The Experts below are selected from a list of 138942 Experts worldwide ranked by ideXlab platform
A Petty - One of the best experts on this subject based on the ideXlab platform.
-
atmospheric form drag coefficients over arctic sea ice using remotely sensed ice topography data spring 2009 2015
Journal of Geophysical Research, 2017Co-Authors: A Petty, Michel Tsamados, N T KurtzAbstract:Sea ice topography significantly impacts turbulent energy/momentum exchange, e.g., atmospheric (wind) drag, over Arctic sea ice. Unfortunately, observational estimates of this contribution to atmospheric drag variability are spatially and temporally limited. Here we present new estimates of the neutral atmospheric form drag coefficient over Arctic sea ice in early spring, using high-resolution Airborne Topographic Mapper elevation data from NASA's Operation IceBridge mission. We utilize a new three-dimensional ice topography data set and combine this with an existing parameterization scheme linking Surface Feature height and spacing to form drag. To be consistent with previous studies investigating form drag, we compare these results with those produced using a new linear profiling topography data set. The form drag coefficient from Surface Feature variability shows lower values ( 0.5–1 ×10−3) in the more deformed ice regimes of the Central Arctic (north of Greenland and the Canadian Archipelago), which increase with coastline proximity. The results show moderate interannual variability, including a strong increase in the form drag coefficient from 2013 to 2014/2015 north of the Canadian Archipelago. The form drag coefficient estimates are extrapolated across the Arctic with Advanced Scatterometer satellite radar backscatter data, further highlighting the regional/interannual drag coefficient variability. Finally, we combine the results with existing parameterizations of form drag from floe edges (a function of ice concentration) and skin drag to produce, to our knowledge, the first pan-Arctic estimates of the total neutral atmospheric drag coefficient (in early spring) from 2009 to 2015.
N T Kurtz - One of the best experts on this subject based on the ideXlab platform.
-
atmospheric form drag coefficients over arctic sea ice using remotely sensed ice topography data spring 2009 2015
Journal of Geophysical Research, 2017Co-Authors: A Petty, Michel Tsamados, N T KurtzAbstract:Sea ice topography significantly impacts turbulent energy/momentum exchange, e.g., atmospheric (wind) drag, over Arctic sea ice. Unfortunately, observational estimates of this contribution to atmospheric drag variability are spatially and temporally limited. Here we present new estimates of the neutral atmospheric form drag coefficient over Arctic sea ice in early spring, using high-resolution Airborne Topographic Mapper elevation data from NASA's Operation IceBridge mission. We utilize a new three-dimensional ice topography data set and combine this with an existing parameterization scheme linking Surface Feature height and spacing to form drag. To be consistent with previous studies investigating form drag, we compare these results with those produced using a new linear profiling topography data set. The form drag coefficient from Surface Feature variability shows lower values ( 0.5–1 ×10−3) in the more deformed ice regimes of the Central Arctic (north of Greenland and the Canadian Archipelago), which increase with coastline proximity. The results show moderate interannual variability, including a strong increase in the form drag coefficient from 2013 to 2014/2015 north of the Canadian Archipelago. The form drag coefficient estimates are extrapolated across the Arctic with Advanced Scatterometer satellite radar backscatter data, further highlighting the regional/interannual drag coefficient variability. Finally, we combine the results with existing parameterizations of form drag from floe edges (a function of ice concentration) and skin drag to produce, to our knowledge, the first pan-Arctic estimates of the total neutral atmospheric drag coefficient (in early spring) from 2009 to 2015.
Isamu Akasaki - One of the best experts on this subject based on the ideXlab platform.
-
high quality aln film grown on a nanosized concave convex Surface sapphire substrate by metalorganic vapor phase epitaxy
Applied Physics Letters, 2017Co-Authors: Akira Yoshikawa, Takaharu Nagatomi, Tomohiro Morishita, Motoaki Iwaya, Tetsuya Takeuchi, Satoshi Kamiyama, Isamu AkasakiAbstract:We developed a method for fabricating high-crystal-quality AlN films by combining a randomly distributed nanosized concavo–convex sapphire substrate (NCC-SS) and a three-step growth method optimized for NCC-SS, i.e., a 3-nm-thick nucleation layer (870 °C), a 150-nm-thick high-temperature layer (1250 °C), and a 3.2-μm-thick medium-temperature layer (1110 °C). The NCC-SS is easily fabricated using a conventional metalorganic vapor phase epitaxy reactor equipped with a showerhead plate. The resultant AlN film has a crack-free and single-step Surface with a root-mean-square roughness of 0.5 nm. The full-widths at half-maxima of the X-ray rocking curve were 50/250 arcsec for the (0002)/(10–12) planes, revealing that the NCC Surface is critical for achieving such a high-quality film. Hexagonal-pyramid-shaped voids at the AlN/NCC-SS interface and confinement of dislocations within the 150-nm-thick high-temperature layer were confirmed. The NCC Surface Feature and resultant faceted voids play an important role in...
Michel Tsamados - One of the best experts on this subject based on the ideXlab platform.
-
atmospheric form drag coefficients over arctic sea ice using remotely sensed ice topography data spring 2009 2015
Journal of Geophysical Research, 2017Co-Authors: A Petty, Michel Tsamados, N T KurtzAbstract:Sea ice topography significantly impacts turbulent energy/momentum exchange, e.g., atmospheric (wind) drag, over Arctic sea ice. Unfortunately, observational estimates of this contribution to atmospheric drag variability are spatially and temporally limited. Here we present new estimates of the neutral atmospheric form drag coefficient over Arctic sea ice in early spring, using high-resolution Airborne Topographic Mapper elevation data from NASA's Operation IceBridge mission. We utilize a new three-dimensional ice topography data set and combine this with an existing parameterization scheme linking Surface Feature height and spacing to form drag. To be consistent with previous studies investigating form drag, we compare these results with those produced using a new linear profiling topography data set. The form drag coefficient from Surface Feature variability shows lower values ( 0.5–1 ×10−3) in the more deformed ice regimes of the Central Arctic (north of Greenland and the Canadian Archipelago), which increase with coastline proximity. The results show moderate interannual variability, including a strong increase in the form drag coefficient from 2013 to 2014/2015 north of the Canadian Archipelago. The form drag coefficient estimates are extrapolated across the Arctic with Advanced Scatterometer satellite radar backscatter data, further highlighting the regional/interannual drag coefficient variability. Finally, we combine the results with existing parameterizations of form drag from floe edges (a function of ice concentration) and skin drag to produce, to our knowledge, the first pan-Arctic estimates of the total neutral atmospheric drag coefficient (in early spring) from 2009 to 2015.
Akira Yoshikawa - One of the best experts on this subject based on the ideXlab platform.
-
high quality aln film grown on a nanosized concave convex Surface sapphire substrate by metalorganic vapor phase epitaxy
Applied Physics Letters, 2017Co-Authors: Akira Yoshikawa, Takaharu Nagatomi, Tomohiro Morishita, Motoaki Iwaya, Tetsuya Takeuchi, Satoshi Kamiyama, Isamu AkasakiAbstract:We developed a method for fabricating high-crystal-quality AlN films by combining a randomly distributed nanosized concavo–convex sapphire substrate (NCC-SS) and a three-step growth method optimized for NCC-SS, i.e., a 3-nm-thick nucleation layer (870 °C), a 150-nm-thick high-temperature layer (1250 °C), and a 3.2-μm-thick medium-temperature layer (1110 °C). The NCC-SS is easily fabricated using a conventional metalorganic vapor phase epitaxy reactor equipped with a showerhead plate. The resultant AlN film has a crack-free and single-step Surface with a root-mean-square roughness of 0.5 nm. The full-widths at half-maxima of the X-ray rocking curve were 50/250 arcsec for the (0002)/(10–12) planes, revealing that the NCC Surface is critical for achieving such a high-quality film. Hexagonal-pyramid-shaped voids at the AlN/NCC-SS interface and confinement of dislocations within the 150-nm-thick high-temperature layer were confirmed. The NCC Surface Feature and resultant faceted voids play an important role in...
