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An ensemble-based linearized forecast model has been developed for data assimilation applications for numerical weather prediction. Previous studies applied this local ensemble tangent linear model (LETLM) to various models, from simple one-dimensional models to a low-resolution (~2.5°) version of the Navy Global Environmental Model (NAVGEM) atmospheric forecast model. This paper applies the LETLM to NAVGEM at higher resolution (~1°), which required overcoming challenges including 1) balancing the computational stencil size with the ensemble size, and 2) propagating fast-moving gravity modes in the upper atmosphere. The first challenge is addressed by introducing a modified local influence volume, introducing computations on a thin grid, and using smaller time steps. The second challenge is addressed by applying nonlinear normal mode initialization, which damps spurious fast-moving modes and improves the LETLM errors above ~100 hPa. Compared to a semi-Lagrangian tangent linear model (TLM), the LETLM has superior skill in the lower troposphere (below 700 hPa), which is attributed to better representation of moist physics in the LETLM. The LETLM skill slightly lags in the upper troposphere and stratosphere (700–2 hPa), which is attributed to nonlocal aspects of the TLM including spectral operators converting from winds to vorticity and divergence. Several ways forward are suggested, including integrating the LETLM in a hybrid 4D variational solver for a realistic atmosphere, combining a physics LETLM with a conventional TLM for the dynamics, and separating the LETLM into a sequence of local and nonlocal operators.

We consider the role of the institution of tutors in system of distance learning in high school of physical culture and sports. Found that most teachers of high school and faculties of physical culture is not ready for the implementation of professional work in an information learning environment., Рассмотрена роль института тьюторов в системе дистанционного обучения в вузе физической культуры. Установлено, что большинство преподавателей вузов и факультетов физической культуры не готовы к осуществлению профессиональной деятельности в информационно насыщенной образовательной среде.

Many background error correlation (BEC) models in data assimilation are formulated in terms of a positive-definite smoothing operator B which simulates the action of correlation matrix on a vector in state space. To estimate the efficiency of such approach, numerical experiments with the Gaussian and spline models have been conducted. Here I is the identity operator and nu is the diffusion tensor, whose spatial variability is derived from the forecast field and m is the spline approximation order. Performance of these BEC representations are compared in the framework of numerical experiments with real 3dVar data assimilation into the Navy Coastal Ocean model (NCOM) in the Western Tropical Pacific. It is shown that both BEC models have similar forecast skills over a two-month time period, whereas the second-order spline model is several times more efficient computationally if the cost function is minimized in the state space., Published in Atmospheric Science and Ocean Sciences, Advances in Geosciences, v28, p1-14, 2012.

Toward the improved prediction and monitoring of deep-water currents and eddies in the Gulf of Mexico, the Gulf Eddy Monitoring System group (GEMS; researchers from University of Southern Mississippi, University of New Orleans, University of Louisiana at Lafayette, and the Naval Research Laboratory) proposes that a network of acoustic transmitter receiver pairs be deployed in the northeastern Gulf of Mexico. Acoustic travel times are inverted to recover temperature and velocity between transmitter-receiver pairs. This data can be fed into ocean dynamical models to improve simulation and prediction of the circulation in the deep ocean. While a proven technique, it has only recently been used successfully in deeper waters. The location is ideal for this type of tomographic application for its predictable oceanic parameters and convenient geomorphology. With a sound-channel axis at about 900 m, a lower power output transmission is required, thus providing negligible impact on marine mammals. Because no other technology can be used to monitor for similar events, we are introducing this method to the marine technology community., See also ADM202806. Presented at the MTS/IEEE Oceans 2009 Conference entitled Marine Technology for our Future: Global and Local Challenges, held in Biloxi, Mississippi on 26-29 Oct 2009. Prepared in cooperation with University of Southern Mississippi, MS; University of New Orleans, LA; and University of Louisiana at Lafayette, LA. Copyright belongs to the Marine Technology Society. The original document contains color images.