Finding appropriate boundary conditions for high frequency forcing of Regional Simulations – California Current System as a case study.

<p>Quite a handful of past studies have reported lack of energy near the tidal bands in high-resolution, regional model simulations’ frequency-wave number spectra when compared to observations. A plausible reason for this discrepancy could be the lack of remotely generated internal tides in regional simulations. In this study, we consider the impact of remote internal tides on the energetics in regional simulations of the California Current System (CCS). The CCS is an eddy-rich mid-latitude region, where energetic NIWs and internal tidal waves coexist. We run high-resolution realistic regional simulations using the Regional Ocean Modelling System (ROMS). The ROMS simulations are boundary-forced with high-frequency offline data from the Hybrid Coordinate Ocean Model (HYCOM). We consider a year-long HYCOM expt_06.1 simulation with 8-km horizontal grid resolution and 41 depth layers. The HYCOM simulation is realistically forced with tides and atmospheric forcing.</p><p>Time-mean and depth-integrated internal tidal flux computed for the parent HYCOM domain shows radiation of remotely generated internal tide beams into the ROMS domain. These beams comprise mainly of modes 1 & 2. To ensure that we provide satisfactory open boundary conditions (OBCs) for our regional simulation, we conduct sensitivity runs using two main types of OBCs (clamped and adaptive OBCs). For the runs with clamped OBCs, we varied the sponge layer viscosities at the open boundaries from 100 to 800 m<sup>2</sup>/s. Both nudging parameters and sponge layer viscosities are varied for simulations with the adaptive OBCs.  Although, we observe remotely generated internal tides in all our simulations, we find that the amount of internal tidal energy that is transmitted through the open boundaries and the internal tidal energetics in the interior of the domain depend on the nudging time scales, sponge layer width and/or viscosity values.</p><p>In the future, we plan to nest down to increasing high-resolution horizontal and vertical grids and perform simulations with different boundary forcings e.g. with total internal tides, stationary internal tides, and no internal tides. We will also force the ROMS model with unidirectional internal tides. We will evaluate the impacts of these scenarios on the internal tide energetics in the ROMS domain.</p>

Gravity wave driven seasonal variability of temperature differences between ECMWF IFS and lidar measurements at 54S in the lee of the Southern Andes

<p>In November 2017, the DLR Institute of Atmospheric Physics started running the ground-based Compact Rayleigh Autonomous Lidar (CORAL) at the southern tip of South America in Rio Grande that is located at the east coast of Argentina in the lee of the Andes. We used this independent (i.e., not assimilated in the ECMWF IFS) and high-resolution lidar data of the year 2018 and some individual months in 2019 and 2020 to investigate middle atmosphere temperature deviations in IFS analyses and short-term forecasts at higher mid-latitudes in the southern hemisphere (54 S).</p><p> </p><p>We found a generally good agreement between IFS and CORAL temperature data below 45 km altitude and the calculated monthly mean temperature deviations are smaller than +/-2 K.  The temperature deviations are more variable in time and the sign of the monthly mean deviations varies throughout the year above 45 km altitude. There, the largest positive differences (+2 K), i.e. IFS temperatures were too warm, are found for May 2018. The largest negative differences (-10 K), i.e. IFS temperatures were too cold, are found for August 2018.  The standard deviation of the temperature differences is significantly larger (up to 15 K) and increases with altitude in the winter half year (April to September 2018) compared to the summer half year. The better agreement of IFS temperature with ground-based lidar measurements in the summer months previously reported in literature for the northern hemisphere also manifests for the southern hemisphere and more recent cycles of the IFS. The largest temperature differences above 45 km altitude in the winter half year are due to gravity waves (GWs) and it was found that amplitude and phase deviations are equally important at the location of Rio Grande. In general, the IFS underestimates GW potential energy density in the middle atmosphere, especially within the sponge layer. Monthly mean GW potential energy density at 45-60 km altitude gets up to four times larger when the sponge is removed but is still less than 50 % of the amount of GW potential energy density found in the CORAL data.</p><p> </p>

Unravelling the Mysteries of the Mesentery

The mesentery and its folds tether the small bowel loops to the posterior abdominal wall. It transmits nerves, vessels, and lymph ensconced in a fatty sponge layer wrapped in a thin glistening peritoneum, from and to the small bowel. Not only does this flexible dynamic fatty apron house various localized primary benign and malignant lesions, it is often involved in and gives an indication of generalized or systemic diseases in the body. An understanding of the anatomy, components, and function of the mesentery helps to classify mesenteric abnormalities. This further allows for characterizing radiological patterns and appearances specific to certain disease entities. Recent reviews of mesenteric anatomy have kindled new interest in its function and clinical applications, heralding the possibility of revision of its role in diseases of the abdomen.

A Sponge-Like Double-Layer Wound Dressing with Chitosan and Decellularized Bovine Amniotic Membrane for Promoting Diabetic Wound Healing

The diabetic wounds do not heal easily in part because they are susceptible to infection due to environmental influences. Wound dressing is crucial to wound healing, as it can basically protect the wound from external damages and provide a suitable microenvironment for tissue regeneration. In this study, a double-layer membrane that consists of chitosan sponge and decellularized bovine amniotic membrane (dBAM) has been developed by freeze-casting method. The results showed that the porous structure of the sponge layer improved the performances of blood coagulation and swelling. The dense dBAM can optimize the mechanical property of wound dressing. In vitro studies revealed that the bilayer membrane had favorable biocompatible, especially for human foreskin fibroblast cells (HFF-1) cell adhesion and proliferation. Moreover, the full-thickness skin defects of diabetic model mice that treated with bilayer membrane showed over 80% closure in 8 days. Our findings imply that the double-layer dressing has great potentials to be used in diabetic patients.

Effective Removal of Nitrate, Nitrite, Ammonia and Iron from Contaminated Ground Water using Bio-Sand Method and Sponge Layer Filtration Method

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