Author: Rhiannon DaviesPublisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
Modelling and Observations of the Atmospheric Boundary Layer of the Arctic Marginal Ice Zone
Author: Rhiannon DaviesA numerical model of the atmospheric boundary layer over a marginal ice zone
Author: L.H. KanthaNumerical Modeling and Observations of Atmospheric Boundary Layer Over Sea Ice
Author: Marta Aleksandra WentaIce at the Interface
Author: Publisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
The atmosphere-ocean boundary layer in which sea ice resides includes many complex processes that require a more realistic treatment in GCMs, particularly as models move toward full earth system descriptions. The primary purpose of the workshop was to define and discuss such coupled processes from observational and modeling points of view, including insight from both the Arctic and Antarctic systems. The workshop met each of its overarching goals, including fostering collaboration among experimentalists, theorists and modelers, proposing modeling strategies, and ascertaining data availability and needs. Several scientific themes emerged from the workshop, such as the importance of episodic or extreme events, precipitation, stratification above and below the ice, and the marginal ice zone, whose seasonal Arctic migrations now traverse more territory than in the past.
Air Mass Modification in the Marginal Ice Zone
Author: Theodore J Bennett (Jr)Publisher:
ISBN:
Category :
Languages : en
Pages : 38
Book Description
A case study of the Andreas et al. (1984) data on atmospheric boundary layer modification in the marginal ice zone is made. Our model is a two-dimensional, multi-level, linear model with turbulence, lateral and vertical advection, and radiation. Good agreement between observed and modeled temperature cross-sections is obtained. In contrast to the hypothesis of Andreas et al., we find the air flow is stable to secondary circulations. Cloud top longwave cooling, not an air-to-surface heat flux, dominates the cooling of the boundary layer. The accumulation with fetch over the ice of changes in the surface wind field are shown to have a large effect on estimates of the surface wind stress. We speculate that the Andreas et al. estimates of the drag coefficient over the compact sea ice are too high. Keywords: Atmospheric boundary layers; and Air-sea-ice interaction.
Air-Ice-Ocean Interaction
Author: Miles McPheePublisher: Springer
ISBN: 9780387783345
Category : Science
Languages : en
Pages : 0
Book Description
At a time when the polar regions are undergoing rapid and unprecedented change, understanding exchanges of momentum, heat and salt at the ice-ocean interface is critical for realistically predicting the future state of sea ice. By offering a measurement platform largely unaffected by surface waves, drifting sea ice provides a unique laboratory for studying aspects of geophysical boundary layer flows that are extremely difficult to measure elsewhere. This book draws on both extensive observations and theoretical principles to develop a concise description of the impact of stress, rotation, and buoyancy on the turbulence scales that control exchanges between the atmosphere and underlying ocean when sea ice is present. Several interesting and unique observational data sets are used to illustrate different aspects of ice-ocean interaction ranging from the impact of salt on melting in the Greenland Sea marginal ice zone, to how nonlinearities in the equation of state for seawater affect mixing in the Weddell Sea. The book’s content, developed from a series of lectures, may be appropriate additional material for upper-level undergraduates and first-year graduate students studying the geophysics of sea ice and planetary boundary layers.
Atmospheric boundary layer modification in the marginal ice zone
Author: T.J. BENNETTThe Variability of the Marine Atmospheric Boundary Layer in the Greenland Sea Marginal Ice Zone
Author: Karl L. DinklerPublisher:
ISBN:
Category : Boundary layer (Meteorology)
Languages : en
Pages : 0
Book Description
The vertical structure of the atmospheric boundary layer in the East Greenland Sea/Fram Strait marginal ice zone (MIZ) is examined for various wind flow regimes with respect to the ice edge. Rawinsonde profiles and surface observations collected from three ships during MIZEX-87 (20 March - 11 April 1987) served as the data set for the examination. Three specific flow regimes are discussed: On-ice flow, off-ice flow, and flow parallel to the ice. On-ice flow resulted in deep, moist mixed layers capped by high weak inversions at the MIZ. Off-ice flow resulted in multiple surface and elevated inversions, with specific humidity highest within an elevated lower-tropospheric layer and dry regions near the surface and aloft. Parallel flow led to the development of strikingly different boundary layer regimes separated by the ice edge: Over ice, deep surface and elevated inversions were associated with alternating moist and dry layers in the lower troposphere; over water, multiple elevated inversions were associated with an elevated lower-tropospheric moist layer and dry regions near the surface and alot. Possible physical processes important for the development of the observed features are discussed. Theses. (fr).
Marginal Ice Zone Bibliography
Author: Insights Into The Challenges Of Modeling The Atmospheric Boundary Layer
Author: Esa-Matti TastulaPublisher:
ISBN:
Category : Meteorology
Languages : en
Pages :
Book Description
This work approaches the topic of modeling the atmospheric boundary layer in four research projects, which are summarized below. i) The diurnal cycles of near-surface meteorological parameters over Antarctic sea ice in six widely used atmospheric reanalyses were validated against observations from Ice Station Weddell. The station drifted from February through May 1992 and provided the most extensive set of meteorological observations ever collected in the Antarctic sea ice zone. For the radiative and turbulent surface fluxes, both the amplitude and shape of the diurnal cycles varied considerably among different reanalyses. Near-surface temperature, specific humidity, and wind speed in the reanalyses all featured small diurnal ranges, which, in most cases, fell within the uncertainties of the observed cycle. A skill score approach revealed the superiority of the ERA-Interim reanalysis in reproducing the observed diurnal cycles. An explanation for the shortcomings in the reanalyses is their failure to capture the diurnal cycle in cloud cover fraction, which leads to errors in other quantities as well. Apart from the diurnal cycles, NCEP-CFSR gave the best error statistics. ii) The accuracy of prediction of stable atmospheric boundary layers depends on the parameterization of the surface layer which is usually derived from the Monin-Obukhov similarity theory. In this study, several surface-layer models in the format of velocity and potential temperature Deacon numbers were compared to observations from CASES-99, Cardington, and Halley datasets. The comparisons were hindered by a large amount of scatter within and among datasets. Tests utilizing R2 demonstrated that the Quasi-Normal Scale Elimination (QNSE) theory exhibits the best overall performance. Further proof of this was provided by 1D simulations with the Weather Research and Forecasting (WRF) model.