Cloud Formation From a Localized Water Release in the Upper Mesosphere: Indication of Rapid Cooling.

Polar mesospheric clouds (PMCs) occur in the summer near 82 -85km altitude due to seasonal changes of temperature and humidity. However, water vapor and associated PMCs have also been observed associated with rocket exhaust. The effects of this rocket exhaust on the temperature of the upper mesosphere are not well understood. To investigate these effects, 220 kg of pure water was explosively released at 85 km as part of the Super Soaker sounding rocket experiment on the night of January 25-26, 2018 at Poker Flat Research Range (65°N, 147°W). A cloud formed within 18 s and was measured by a ground-based Rayleigh lidar. The peak altitude of the cloud appeared to descend from 92 to 78 km over 3 min. Temperatures leading up to the release were between 197 and 232 K, about 50 K above the summertime water frost point when PMCs typically occur. The apparent motion of the cloud is interpreted in terms of the expansion of the explosive release. Analysis using a water vapor radiative cooling code coupled to a microphysical model indicates that the cloud formed due to the combined effects of rapid radiative cooling (∼25 K) by meter-scale filaments of nearly pure water vapor (∼1 ppv) and an increase in the frost point temperature (from 150 to 200 K) due to the high concentration of water vapor. These results indicate that water exhaust not only acts as a reservoir for mesospheric cloud production but also actively cools the mesosphere to induce cloud formation.

Gravity Wave Dynamics in a Mesospheric Inversion Layer: 1. Reflection, Trapping, and Instability Dynamics.

An anelastic numerical model is employed to explore the dynamics of gravity waves (GWs) encountering a mesosphere inversion layer (MIL) having a moderate static stability enhancement and a layer of weaker static stability above. Instabilities occur within the MIL when the GW amplitude approaches that required for GW breaking due to compression of the vertical wavelength accompanying the increasing static stability. Thus, MILs can cause large-amplitude GWs to yield instabilities and turbulence below the altitude where they would otherwise arise. Smaller-amplitude GWs encountering a MIL do not lead to instability and turbulence but do exhibit partial reflection and transmission, and the transmission is a smaller fraction of the incident GW when instabilities and turbulence arise within the MIL. Additionally, greater GW transmission occurs for weaker MILs and for GWs having larger vertical wavelengths relative to the MIL depth and for lower GW intrinsic frequencies. These results imply similar dynamics for inversions due to other sources, including the tropopause inversion layer, the high stability capping the polar summer mesopause, and lower frequency GWs or tides having sufficient amplitudes to yield significant variations in stability at large and small vertical scales. MILs also imply much stronger reflections and less coherent GW propagation in environments having significant fine structure in the stability and velocity fields than in environments that are smoothly varying.

Observations of Reduced Turbulence and Wave Activity in the Arctic Middle Atmosphere Following the January 2015 Sudden Stratospheric Warming.

Measurements of turbulence and waves were made as part of the Mesosphere-Lower Thermosphere Turbulence Experiment (MTeX) on the night of 25-26 January 2015 at Poker Flat Research Range, Chatanika, Alaska (65°N, 147°W). Rocket-borne ionization gauge measurements revealed turbulence in the 70- to 88-km altitude region with energy dissipation rates between 0.1 and 24 mW/kg with an average value of 2.6 mW/kg. The eddy diffusion coefficient varied between 0.3 and 134 m2/s with an average value of 10 m2/s. Turbulence was detected around mesospheric inversion layers (MILs) in both the topside and bottomside of the MILs. These low levels of turbulence were measured after a minor sudden stratospheric warming when the circulation continued to be disturbed by planetary waves and winds remained weak in the stratosphere and mesosphere. Ground-based lidar measurements characterized the ensemble of inertia-gravity waves and monochromatic gravity waves. The ensemble of inertia-gravity waves had a specific potential energy of 0.8 J/kg over the 40- to 50-km altitude region, one of the lowest values recorded at Chatanika. The turbulence measurements coincided with the overturning of a 2.5-hr monochromatic gravity wave in a depth of 3 km at 85 km. The energy dissipation rates were estimated to be 3 mW/kg for the ensemble of waves and 18 mW/kg for the monochromatic wave. The MTeX observations reveal low levels of turbulence associated with low levels of gravity wave activity. In the light of other Arctic observations and model studies, these observations suggest that there may be reduced turbulence during disturbed winters.

In the trenches: primary care perspectives on implementation, prevention, and treatment.

A yearly influenza clinic with convenient hours and location is an efficient way to ensure that primary care patients receive their influenza vaccination. Physicians should also receive the influenza vaccine themselves, to lead by example and to help to dispel some of the myths that surround its administration.

Dialogues on depression management: the primary care and specialist perspectives.

Depression is a major public health problem in the United States and is responsible for an enormous economic burden and loss of productivity and quality of life. In many cases, PCPs are well situated to identify and treat unrecognized depression, but an optimal treatment program often comprises both medical and psychotherapeutic interventions. Many collaborative models that integrate the efforts of PCPs, psychiatrists, behavioral health organizations, and workplace assistance programs are being tested and may prove to be the best direction for improving care for patients with depression. Looking ahead, improvement in treatment of depression will depend on numerous factors, including educating health care practitioners to recognize silent depression, expanding current collaborative models to cover more of the population, involving MCOs and payers in the development of effective treatment systems, and improving workplace-support programs to encourage more patients to seek appropriate care.

Depression management: applying skills in the clinical setting.

Primary care and specialist providers face different challenges - and often make different choices when treating a severely depressed patient. To help attendees learn from the experiences of primary care physicians and mental health professionals, and to demonstrate how to incorporate the skills of each, Collins (the internist) and Escobar (the psychiatrist) reviewed two actual cases [the names of the patients have been changed] at the MOOD symposium in Philadelphia. They then advised on their chosen approaches to managing them. Questions from symposium attendees are referred to as audience.