A Note on Gravity Wave-driven Volume Emission Rate Weighted Temperature Perturbations Inferred from O₂ Atmospheric and O I 5577 Airglow Observations

A full-wave dynamical model and chemistry models that simulate ground-based observations of gravity wave-driven O₂ atmospheric and O I 5577 airglow fluctuations in the mesopause region are used to demonstrate that for many observable gravity waves modeling is required to infer temperature perturbation amplitudes from airglow observations. We demonstrate that the amplitude of the altitude-integrated volume emission rate weighted temperature perturbation differs by at least about 30% from the amplitude of the temperature perturbation of the major gas in the vicinity of the peak of the airglow volume emission rate for gravity waves with horizontal phase speeds less than about 150 m s¯¹ and vertical wavelengths less than about 50 km and that the amplitude of the altitude-integrated volume emission rate weighted temperature perturbation differs considerably from the amplitude of the temperature perturbation averaged over the vertical extent of the emission layer for waves with horizontal phase speeds less than about 65 m s¯¹ and vertical wavelengths less than about 20 km. For waves with phase speeds less than about 100 m s¯¹ and vertical wavelengths less than about 30 km the amplitude of the altitude-integrated volume emission rate weighted temperature perturbation differs by at least about 30% from the altitude-integrated mean volume emission rate weighted temperature perturbation, demonstrating that the nonthermal fluctuation contribution to the former (involving volume emission rate perturbations) needs to be included in such modeling. We conjecture that the observed brightness perturbation is a simpler and better quantity to simulate using detailed modeling than the observed airglow temperature perturbation for the determination of wave amplitude in cases where nonthermal effects or cancellation effects (for short vertical wavelengths) are strong

Venus Mountain Waves in the Upper Atmosphere Simulated by A Time-Invariant Linear Full-Wave Spectral Model

A 2-D spectral full-wave model is described that simulates the generation and propagation of mountain waves over idealized topography in Venus\u27 atmosphere. Modeled temperature perturbations are compared with the Akatsuki observations. Lower atmosphere eddy diffusivity and stability play a major role in the upward propagation of gravity waves from their mountain sources. Two local times (LT) are considered. For LT = 11 h the waves are blocked by a critical level near 100 km altitude, while for LT = 16 h the waves propagate into the thermosphere. As a result of the small scale height in the Venus thermosphere, for LT = 16 h wave amplitudes grow with increasing altitude up to ~200 km, despite the increasing kinematic viscosity. Although wave amplitudes can become very large in the thermosphere, the value of the total potential temperature gradient suggests that some of these fast waves having extremely large vertical wavelengths may remain convectively stable. Our simulations suggest that the momentum and thermal forcing of the mean state due to the dissipating waves may, at times, be extremely large in the thermosphere. At a given local time, the maximum forcing of the mean state always occurs at an altitude determined by the mean winds and the upper atmospheric viscosity. The surface conditions that determine the forcing (mountain parameters, surface mean wind, eddy diffusivity, and static stability) have little impact on this altitude, but they do significantly impact the magnitude of the forcing

Venus Mountain Waves in the Upper Atmosphere Simulated by a Time-Invariant Linear Full-Wave Spectral Model

A 2-D spectral full-wave model is described that simulates the generation and propagation of mountain waves over idealized topography in Venus’ atmosphere. Modeled temperature perturbations are compared with the Akatsuki observations. Lower atmosphere eddy diffusivity and stability play a major role in the upward propagation of gravity waves from their mountain sources. Two local times (LT) are considered. For LT = 11h the waves are blocked by a critical level near 100 km altitude, while for LT = 16 h the waves propagate into the thermosphere. As a result of the small scale height in the Venus thermosphere, for LT = 16 h wave amplitudes grow with increasing altitude up to ~ 200 km, despite the increasing kinematic viscosity. Although wave amplitudes can become very large in the thermosphere, the value of the total potential temperature gradient suggests that some of these fast waves having extremely large vertical wavelengths may remain convectively stable. Our simulations suggest that the momentum and thermal forcing of the mean state due to the dissipating waves may, at times, be extremely large in the thermosphere. At a given local time, the maximum forcing of the mean state always occurs at an altitude determined by the mean winds and the upper atmospheric viscosity. The surface conditions that determine the forcing (mountain parameters, surface mean wind, eddy diffusivity, and static stability) have little impact on this altitude, but they do significantly impact the magnitude of the forcing

The Low-Latitude Ionosphere/Thermosphere Enhancements in Density (LLITED) Mission

The Low-Latitude Ionosphere/Thermosphere Enhancements in Density (LLITED) CubeSat mission is a NASA funded HTIDs project. It is a 3-year grant with two 1.5U CubeSats with an estimated delivery in the spring of 2020 and a 1- year on-orbit mission life. Each CubeSat will host a miniature ionization gauge space instrument (MIGSI), planar ion probe (PIP), and GPS radio occultation sensor (CTECS-A). The mission is to provide both ionosphere and thermosphere measurements related to the Equatorial Ionization Anomaly (EIA) and the Equatorial Temperature and Wind Anomaly (ETWA). The EIA and ETWA are two of the dominant ionosphere/thermosphere interactions on the low-latitude duskside. While the EIA has been extensively studied both observationally and with modeling, the ETWA is less well known since observations are infrequent due to a lack of suitably instrumented spacecraft (s/c) at appropriate altitudes. LLITED will, for the first time, provide coincident high-resolution measurements of the duskside ionosphere/thermosphere at lower altitudes that will characterize and improve our understanding of the ETWA, provide insight into the coupling physics between the ETWA and EIA, and increase our knowledge of the duskside dynamics that may influence space weather. The following paper reviews the science mission and concepts and then provides the current status of the LLITED hardware

Twelve‐hour tides in the winter northern polar mesosphere and lower thermosphere

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/94767/1/jgra16221.pd

Numerical Simulations of Gravity Waves Imaged Over Arecibo During the 10-Day January 1993 Campaign

Recently, measurements were made of mesospheric gravity waves in the OI (5577 Å) nightglow observed from Arecibo, Puerto Rico, during January 1993 as part of a special 10-day campaign. Clear, monochromatic gravity waves were observed on several nights. By using a full-wave model that realistically includes the major physical processes in this region, we have simulated the propagation of two waves through the mesopause region and calculated the O(1 S) nightglow response to the waves. Mean winds derived from both UARS wind imaging interferometer (WINDII) and Arecibo incoherent scatter radar observations were employed in the computations as were the climatological zonal winds defined by COSPAR International Reference Atmosphere 1990 (CIRA). For both sets of measured winds the observed waves encounter critical levels within the O(1 S) emission layer, and wave amplitudes, derived from the requirement that the simulated and observed amplitudes of the O(1 S) fluctuations be equal, are too large for the waves to be gravitationally stable below the emission layer. Some of the model coefficients were adjusted in order to improve the agreement with the measurements, including the eddy diffusion coefficients and the height of the atomic oxygen layer. The effect of changing the chemical kinetic parameters was investigated but was found to be unimportant. Eddy diffusion coefficients that are 10 to 100 times larger than presently accepted values are required to explain most of the observations in the cases that include the measured background winds, whereas the observations can be modeled using the nominal eddy diffusion coefficients and the CIRA climatological winds. Lowering the height of the atomic oxygen layer improved the simulations slightly for one of the simulated waves but caused a less favorable simulation for the other wave. For one of the waves propagating through the WINDII winds the simulated amplitude was too large below 82 km for the wave to be gravitationally stable, in spite of the adjustments made to the model parameters. This study demonstrates that an accurate description of the mean winds is an essential requirement for a complete interpretation of observed wave-driven airglow fluctuations

Development of Level 1b Calibration and Validation Readiness, Implementation and Management Plans for GOES-R

A complement of Readiness, Implementation and Management Plans (RIMPs) to facilitate management of post-launch product test activities for the official Geostationary Operational Environmental Satellite (GOES-R) Level 1b (L1b) products have been developed and documented. Separate plans have been created for each of the GOES-R sensors including: the Advanced Baseline Imager (ABI), the Extreme ultraviolet and X-ray Irradiance Sensors (EXIS), Geostationary Lightning Mapper (GLM), GOES-R Magnetometer (MAG), the Space Environment In-Situ Suite (SEISS), and the Solar Ultraviolet Imager (SUVI). The GOES-R program has implemented these RIMPs in order to address the full scope of CalVal activities required for a successful demonstration of GOES-R L1b data product quality throughout the three validation stages: Beta, Provisional and Full Validation. For each product maturity level, the RIMPs include specific performance criteria and required artifacts that provide evidence a given validation stage has been reached, the timing when each stage will be complete, a description of every applicable Post-Launch Product Test (PLPT), roles and responsibilities of personnel, upstream dependencies, and analysis methods and tools to be employed during validation. Instrument level Post-Launch Tests (PLTs) are also referenced and apply primarily to functional check-out of the instruments

Rationales for the Lightning Flight-Commit Criteria

Since natural and artificially-initiated (or "triggered") lightning are demonstrated hazards to the launch of space vehicles, the American space program has responded by establishing a set of Lightning Flight Commit Criteria (LFCC), also known as Lightning Launch Commit Criteria (LLCC), and associated Definitions to mitigate the risk. The LLCC apply to all Federal Government ranges and similar LFCC have been adopted by the Federal Aviation Administration for application at state-operated and private spaceports. The LLCC and Definitions have been developed, reviewed, and approved over the years of the American space program, progressing from relatively simple rules in the mid-twentieth century (that were inadequate) to a complex suite for launch operations in the early 21st century. During this evolutionary process, a "Lightning Advisory Panel (LAP)" of top American scientists in the field of atmospheric electricity was established to guide it. Details of this process are provided in a companion document entitled "A History of the Lightning Launch Commit Criteria and the Lightning Advisory Panel for America s Space program" which is available as NASA Special Publication 2010-216283. As new knowledge and additional operational experience have been gained, the LFCC/LLCC have been updated to preserve or increase their safety and to increase launch availability. All launches of both manned and unmanned vehicles at all Federal Government ranges now use the same rules. This simplifies their application and minimizes the cost of the weather infrastructure to support them. Vehicle operators and Range safety personnel have requested that the LAP provide a detailed written rationale for each of the LFCC so that they may better understand and appreciate the scientific and operational justifications for them. This document provides the requested rationale

A History of the Lightning Launch Commit Criteria and the Lightning Advisory Panel for America's Space Program

The history of the Lightning Launch Commit Criteria (LLCC) used at all spaceports under the jurisdiction of the United States is provided. The formation and history of the Lightning Advisory Panel (LAP) that now advises NASA, the Air Force and the Federal Aviation Administration on LLCC development and improvement is emphasized. The period covered extends from the early days of space flight through 2010. Extensive appendices provide significant detail about important aspects that are only summarized in the main text

A Note on Gravity Wave-driven Volume Emission Rate Weighted Temperature Perturbations Inferred from O₂ Atmospheric and O I 5577 Airglow Observations

A full-wave dynamical model and chemistry models that simulate ground-based observations of gravity wave-driven O₂ atmospheric and O I 5577 airglow fluctuations in the mesopause region are used to demonstrate that for many observable gravity waves modeling is required to infer temperature perturbation amplitudes from airglow observations. We demonstrate that the amplitude of the altitude-integrated volume emission rate weighted temperature perturbation differs by at least about 30% from the amplitude of the temperature perturbation of the major gas in the vicinity of the peak of the airglow volume emission rate for gravity waves with horizontal phase speeds less than about 150 m s¯¹ and vertical wavelengths less than about 50 km and that the amplitude of the altitude-integrated volume emission rate weighted temperature perturbation differs considerably from the amplitude of the temperature perturbation averaged over the vertical extent of the emission layer for waves with horizontal phase speeds less than about 65 m s¯¹ and vertical wavelengths less than about 20 km. For waves with phase speeds less than about 100 m s¯¹ and vertical wavelengths less than about 30 km the amplitude of the altitude-integrated volume emission rate weighted temperature perturbation differs by at least about 30% from the altitude-integrated mean volume emission rate weighted temperature perturbation, demonstrating that the nonthermal fluctuation contribution to the former (involving volume emission rate perturbations) needs to be included in such modeling. We conjecture that the observed brightness perturbation is a simpler and better quantity to simulate using detailed modeling than the observed airglow temperature perturbation for the determination of wave amplitude in cases where nonthermal effects or cancellation effects (for short vertical wavelengths) are strong