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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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NASA NTRS2000

A Study of Meteorological Conditions Associated With Noctilucent Clouds

Temperature measurements were obtained in the upper stratosphere and mesosphere between 50 and 95 km with passive inflatable falling spheres launched on small meteorological rockets as part of the DROPPS (Distribution and Role of Particles in the Polar Summer Mesosphere) program. Temperatures of the neutral atmosphere have been combined with similar measurements obtained during 1991 and 1993. Temperatures were found to change monatonically with altitude except during the Nocticulent Clouds (NLC) occurrences during DROPPS. The temperature lapse rate changed between 5 July 1999, 2313 UTC and 6 July 1999, 0209 UTC; this included a lowering of the altitude of minimum temperature by about 5 km. Furthermore, winds backed from a northeasterly direction to a northwesterly direction. Whether the change in temperature observed is a result of advection related to the changes of the wind field due to advection. Comparisons will also concentrate on the meteorological conditions during the NLC event during DROPPS and earlier 1991 and 1993 NLC'S.

Schmidlin, F. J.↗
NASA NTRS1977

Solar polar coronal hole - A mathematical simulation

The northern polar region of the sun was studied during July 1973 by Munro and Jackson through use of the white-light coronagraph and the X-ray photographs produced by the Skylab mission. They described the northern polar hole as nearly axisymmetric and gave the geometry and density distribution under this approximation. The present work gives quasi-radial approximation to the full magnetohydrodynamic equations for axisymmetric, polytropic solar wind flow to simulate this polar hole, with the benefit that model temperature and magnetic field intensities and distributions in this particular polar hole can be deduced. It is concluded that from 2 out to 5 solar radii the temperature varies only slightly with radius, but is larger near the center of the polar hole than at the edge. It is also found that the magnetic field intensity at 2 solar radii could be about 1 gauss at the center of the hole, decreasing toward the edge of the hole. If this is extrapolated to the surface, a field as high as 20 gauss is suggested.

Suess, S. T.↗
NASA NTRS1977

Thermal microwave emission from a random inhomogeneous layer over a homogeneous medium using the method of invariant imbedding

The paper studies thermal microwave emission from an inhomogeneous slab of a random medium, with possible nonuniform absorption, scattering, and temperature profiles, bounded by different dielectrics on both sides. The invariant imbedding method is used to cast the boundary value problem of the radiative transfer equations into an initial value problem at zero slab thickness. As a numerical example, the angular and polarization variations of brightness temperatures for ice over water are considered.

Tsang, L.↗
NASA NTRS2007

Inter-annual and Long-term Temperature Variations in the Mesopause Region at High Latitudes Generated by the Stratospheric QBO

The Numerical Spectral Model (NSM) simulates the Quasi-biennial Oscillation (QBO) that dominates the zonal circulation of the lower stratosphere at low latitudes. In the model, the QBO is generated with parameterized small-scale gravity waves (GW), which are partially augmented in 3D with planetary waves owing to baroclinic instability. Due to GW filtering, the QBO extends into the upper mesosphere, evident in UARS zonal wind and TIMED temperature measurements. While the QBO zonal winds are confined to equatorial latitudes, even in simulations with latitude-independent wave source, the associated temperature variations extend to high latitudes. The meridional circulation redistributes some of the QBO energy to focus it partially onto the Polar Regions. The resulting QBO temperature variations away from the equator tend to increase at higher altitudes to produce inter-annual variations that can exceed 5 K in the polar mesopause region -- and our 3D model simulations show that the effect is variable from year to year and can produce large differences between the two hemispheres, presumably due to interactions involving the seasonal variations. Modeling studies with the NSM have shown that long-term variations can also be generated by the QBO interacting with the seasonal cycles through OW node-filtering. A 30-month QBO, optimally synchronized by the 6-month Semi-Annual Oscillation (SAO), thus produces a 5-year or semi-decadal (SD) oscillation -- and observational evidence for that has been provided by a recent analysis of stratospheric NCEP data. In a simulation with the 2D version of the NSM, this SD oscillation extends into the upper mesosphere, and we present results to show that the related temperature variations could contribute significantly to the long-term variations of the polar mesopause region. Quasi-decadal variations could furthermore arise from the modeled solar cycle modulations of the QBO and 12-month annual oscillation. Our numerical results are discussed in the context of the observed low summer temperatures reproduced by the model, to demonstrate that the above interannual and long-term variations could contribute significantly to the climatology of Polar Mesospheric Clouds (PMC) investigated by the Aeronomy of Ice in the Mesosphere (AIM) mission.

Mayr, Hans G.↗
NASA NTRS2001

A Methodology for Surface Soil Moisture and Vegetation Optical Depth Retrieval Using the Microwave Polarization Difference Index

A methodology for retrieving surface soil moisture and vegetation optical depth from satellite microwave radiometer data is presented. The procedure is tested with historical 6.6 GHz brightness temperature observations from the Scanning Multichannel Microwave Radiometer over several test sites in Illinois. Results using only nighttime data are presented at this time, due to the greater stability of nighttime surface temperature estimation. The methodology uses a radiative transfer model to solve for surface soil moisture and vegetation optical depth simultaneously using a non-linear iterative optimization procedure. It assumes known constant values for the scattering albedo and roughness. Surface temperature is derived by a procedure using high frequency vertically polarized brightness temperatures. The methodology does not require any field observations of soil moisture or canopy biophysical properties for calibration purposes and is totally independent of wavelength. Results compare well with field observations of soil moisture and satellite-derived vegetation index data from optical sensors.

Owe, Manfred↗
NASA NTRS1987

Temperature anisotropies in the terrestrial ionosphere and plasmasphere

Theoretical work in which the solution of closed sets of transport equations has predicted the existence of temperature anisotropies in the terrestrial ionosphere-plasmasphere system is discussed, considering only thermal (less than 1 eV) particle populations. Various models used to predict ion and electron temperature anisotropies, including kinetic, semikinetic, hydromagnetic, and generalized transport models, predict temperature anisotropies in the polar wind, along plasmapause field lines, during the refilling of the outer plasmasphere after depletion by a magnetic storm, and at F region altitudes in regions of rapid plasma convection. However, only some of the theoretical predictions agree with experimental evidence. Other models predict isotropic temperature distributions in regions where observations indicated the presence of temperature anisotropies.

Demars, H. G.↗
NASA NTRS1999

Structure-Property Study of Piezoelectricity in Polyimides

High performance piezoelectric polymers are of interest to NASA as they may be useful for a variety of sensor applications. Over the past few years research on piezoelectric polymers has led to the development of promising high temperature piezoelectric responses in some novel polyimides. In this study, a series of polyimides have been studied with systematic variations in the diamine monomers that comprise the polyimide while holding the dianhydride constant. The effect of structural changes, including variations in the nature and concentration of dipolar groups, on the remanent polarization and piezoelectric coefficient is examined. Fundamental structure-piezoelectric property insight will enable the molecular design of polymers possessing distinct improvements over state-of-the-art piezoelectric polymers including enhanced polarization, polarization stability at elevated temperatures, and improved processability.

Ounaies, Zoubeida↗
NASA NTRS1991

Satellite observations of polar lows by SSM/I, Geosat and TOVS

Satellite observations in high-latitude regions were used to detect polar lows and track their propagation and evolution. The Special Sensor Microwave/Imager (SSM/I) provided estimates of surface wind speed, integrated cloud liquid water, and water vapor contents over ocean; the Geosat radar altimeter measured surface wind speed and significant wave height; the TIROS-N Operational Vertical Sounder (TOVS) allowed the determination of temperature and humidity profiles in the atmosphere, as well as cloud information (cloud top pressure and temperature). The detection of polar lows at a very early stage, and their development, propagation, and decay is presented for a specific case occurring in the Norwegian Sea on 23-24 January 1988, using a combination of these three instruments, namely a passive and an active microwave sensor, and a vertical sounder (19 infrared, 1 visible, and 4 microwave channels). Advantage is taken of the time and coverage differences between these three satellite sensors for the observation of polar lows. A discussion of the results is given.

Claud, C.↗
NASA NTRS1974

Temperature and density structure of thermal proton flows

Thermal proton flows along magnetic field lines are an important feature of magnetosphere-ionosphere coupling. In this paper we report the results of a theoretical study of the thermal structure of such flows. The adopted steady state model is based upon O+, H+, and electrons with self-consistent solutions for the separate O+, H+, and electron temperatures, the O+ and H+ densities and the H+ drift velocity. Through investigation of a number of parameters affecting the model, it is shown that Joule heating arising from the flow of H+ through O+ preferentially heats H+, so that the H+ temperature is substantially greater than the O+ temperature. Low O+ densities characteristic of the trough region appear to give high H+/O+ temperature ratios. Typical O+ densities characteristic of polar wind flow regions give moderate H+/O3 temperature ratios. The Mach number of H+ outflow is substantially reduced in the present models in comparison with the older fixed temperature calculations.

Banks, P. M.↗
NASA NTRS1978

The response of the zonally averaged circulation to stratospheric ozone reductions

The effects of various ozone density reductions of the zonally averaged circulation are evaluated with a numerical quasi-geostrophic model. If the ozone perturbations are confined to the polar regions and are minuscule on a global basis as was characteristic of the August 1972 solar proton event, then the calculations indicate a negligible effect on the mean circulation. For global ozone perturbations by predicted halocarbon pollution, about 10% reduction in the zonal jet strength and less than a 5% change in global mean stratospheric temperature are calculated. Large, uniform ozone reductions (above 50%) produce significant effects on the mean circulation: a substantial collapse of the stratosphere due to cooler temperatures, and a weak polar night jet. The reflection and transmission of quasi-stationary planetary waves in the middle atmosphere are computed to be insensitive to solar activity as extreme as the August 1972 solar proton event. It thus seems improbable that planetary waves are a viable mechanism for solar-weather interactions that involve perturbations of the zonally averaged circulation by ozone density reductions.

Schoeberl, M. R.↗
NASA NTRS1979

Static stability and thermal wind in an atmosphere of variable composition Applications to Mars

Radiometric measurements of the temperature of the south polar cap of Mars in winter have yielded values significantly below the expected 148 K. One proposed explanation for this result is a substantial reduction in the CO2 content of the atmosphere and a lowering of the mean molecule weight near the surface. The meteorological consequences of this explanation are explored by deriving a criterion for vertical static stability and a thermal wind law for an atmosphere of variable composition. The atmosphere proves to be statically unstable unless the anomaly in the CO2 mixing ratio extends to heights of tens of kilometers. The effect of varying molecular weight exceeds the effect of temperature gradient, producing shears with height of reversed sign. The shears are baroclinically unstable, and this instability would eradicate the latitudinal gradient of molecular weight. This inconsistency can be resolved by invoking a reasonable elevation of the central polar cap and by imposing an adequate zonal wind. It is concluded that if the explanation requiring a change in atmospheric composition is correct, it must be accompanied by other special circumstances to make it meteorologically consistent.

Hess, S. L.↗
NASA NTRS2000

Evidence of Lunar Phase Influence on Global Surface Air Temperatures

Intraseasonal oscillations appearing in a newly available 20-year record of satellite-derived surface air temperature are composited with respect to the lunar phase. Polar regions exhibit strong lunar phase modulation with higher temperatures occurs near full moon and lower temperatures at new moon, in agreement with previous studies. The polar response to the apparent lunar forcing is shown to be most robust in the winter months when solar influence is minimum. In addition, the response appears to be influenced by ENSO events. The highest mean temperature range between full moon and new moon in the polar region between 60 deg and 90 deg latitude was recorded in 1983, 1986/87, and 1990/91. Although the largest lunar phase signal is in the polar regions, there is a tendency for meridional equatorward progression of anomalies in both hemispheres so that the warning in the tropics occurs at the time of the new moon.

Anyamba, Ebby↗
NASA NTRS2011

Inter-Hemispheric Coupling During Recent North Polar Summer Periods as Predicted by MaCWAVE/MIDAS Rocket Data and Traced by TIMED/SABER Measurements

In July, 2002, the MaCWAVE-MIDAS Rocket Program was launched from And0ya Rocket Range (ARR) in Norway. Data from these flights demonstrated that the polar summer mesosphere during this period was unusual, at least above ARR. Theoretical studies have since been published that imply that the abnormal characteristics of this polar summer were generated by dynamical processes occurring in the southern polar winter hemisphere. We have used data from the SABER instrument aboard the NASA TIMED Satellite to study these characteristics and compare them with the features observed in the ensuing eight years. For background, the TIMED Satellite was launched on December 7, 2001 to study the dynamics and energy of the mesosphere and lower thermosphere. The SABER instrument is a limb scanning infrared radiometer designed to measure temperature of the region as well as a large number of minor constituents. In this study, we review the MaCWAVE rocket results. Next, we investigate the temperature characteristics of the polar mesosphere as a function of spatial and temporal considerations. We have used the most recent SABER dataset (1.07). Weekly averages are used to make comparisons between the winter and summer hemispheres. Furthermore, the data analysis agrees with recent theoretical studies showing that this behavior is a result of anomalous dynamical events in the southern hemisphere. The findings discussed here clearly show the value of scientific rocket flights used in a discovery mode.

Goldberg, Richard A.↗
NASA NTRS2006

Polarization Effects Aboard the Space Interferometry Mission

For precision displacement measurements, laser metrology is currently one of the most accurate measurements. Often, the measurement is located some distance away from the laser source, and as a result, stringent requirements are placed on the laser delivery system with respect to the state of polarization. Such is the case with the fiber distribution assembly (FDA) that is slated to fly aboard the Space Interferometry Mission (SIM) next decade. This system utilizes a concatenated array of couplers, polarizers and lengthy runs of polarization-maintaining (PM) fiber to distribute linearly-polarized light from a single laser to fourteen different optical metrology measurement points throughout the spacecraft. Optical power fluctuations at the point of measurement can be traced back to the polarization extinction ration (PER) of the concatenated components, in conjunction with the rate of change in phase difference of the light along the slow and fast axes of the PM fiber.

fiber distribution↗
NASA NTRS2011

Inter-Hemispheric Coupling During Recent North Polar Summer Periods as Predicted by MaCWAVE/MIDAS Rocket Data and Traced by TIMED/SABER Measurements

In July, 2002, the MaCWAVE-MIDAS Rocket Program was launched from Andoya Rocket Range (ARR) in Norway. Data from these flights demonstrated that the polar summer mesosphere during this period was unusual, at least above ARR. Theoretical studies have since been published that imply that the abnormal characteristics of this polar summer were generated by dynamical processes occurring in the southern polar winter hemisphere. We have used data from the SABER instrument aboard the NASA Thermosphere Ionosphere Mesosphere Energetics and Dynamics (TIMED) Satellite to study these characteristics and compare them with the features observed in the ensuing eight years. For background, the TIMED Satellite was launched on December 7,2001 to study the dynamics and energy of the mesosphere and lower thermosphere. The SABER instrument is a limb scanning infrared radiometer designed to measure temperature of the region as well as a large number of minor constituents. In this study, we review the MaCWAVE rocket results. Next, we investigate the temperature characteristics of the polar mesosphere as a function of spatial and temporal considerations. We have used the most recent SABER dataset (1.07). Weekly averages are used to make comparisons between the winter and summer hemispheres. Furthermore, the data analysis agrees with recent theoretical studies showing that this behavior is a result of anomalous dynamical events in the southern hemisphere. The findings discussed here clearly show the value of scientific rocket flights used in a discovery mode.

Goldberg, Richard A.↗
NASA NTRS1987

Polar stratospheric optical depth observed between 1978 and 1985

Observations of the stratospheric optical depth at 1.0 micron obtained for high latitudes are presented for a 7-year period. Weekly averaged data determined from measurements made by the Stratospheric Aerosol Measurement experiment from October 1978-1985 show that the overall yearly values in both polar regions are controlled by volcanic perturbations, with most volcanic effects being experienced in Arctic latitudes. Conservatively, peak values found in the Antarctic region were approximately 0.02 and in the Arctic region about 0.55. Probable values for these regions are estimated to be 0.26 and 0.11, respectively. The weekly averaged data also show the seasonal fluctuations due to microphysical and dynamical processes. Comparison of the optical depth record with a weekly averaged 50-mbar temperature record indicates that polar stratospheric clouds are present in the southern high latitudes each year near this level from early June to early September. A depression observed in the optical depth record each austral spring season is believed to be the result of the downward displacement of particles caused by subsidence and sedimentation during the course of winter. Following the breakup of the vortex, optical depth values increase as aerosol is transported poleward. These features are noted to be present in the Arctic region as well, but on a smaller scale because of the satellite sampling methodology and the averaging scheme employed.

Mccormick, M. P.↗
NASA NTRS2012

Current Usage and Future Prospects of Multispectral (RGB) Satellite Imagery in Support of NWS Forecast Offices and National Centers

Current and future satellite sensors provide remotely sensed quantities from a variety of wavelengths ranging from the visible to the passive microwave, from both geostationary and low-Earth orbits. The NASA Short-term Prediction Research and Transition (SPoRT) Center has a long history of providing multispectral imagery from the Moderate Resolution Imaging Spectroradiometer (MODIS) aboard NASA s Terra and Aqua satellites in support of NWS forecast office activities. Products from MODIS have recently been extended to include a broader suite of multispectral imagery similar to those developed by EUMETSAT, based upon the spectral channel s available from the Spinning Enhanced Visible and InfraRed Imager (SEVIRI) aboard METEOSAT-9. This broader suite includes products that discriminate between air mass types associated with synoptic-scale features, assists in the identification of dust, and improves upon paired channel difference detection of fog and low cloud events. Similarly, researchers at NOAA/NESDIS and CIRA have developed air mass discrimination capabilities using channels available from the current GOES Sounders. Other applications of multispectral composites include combinations of high and low frequency, horizontal and vertically polarized passive microwave brightness temperatures to discriminate tropical cyclone structures and other synoptic-scale features. Many of these capabilities have been transitioned for evaluation and operational use at NWS Weather Forecast Offices and National Centers through collaborations with SPoRT and CIRA. Future instruments will continue the availability of these products and also expand upon current capabilities. The Advanced Baseline Imager (ABI) on GOES-R will improve the spectral, spatial, and temporal resolution of our current geostationary capabilities, and the recent launch of the Suomi National Polar-Orbiting Partnership (S-NPP) carries instruments such as the Visible Infrared Imager Radiometer Suite (VIIRS), the Cross-track Infrared Sounder (CrIS), and the Advanced Technology Microwave Sounder (ATMS), which have unrivaled spectral and spatial resolution, as precursors to the JPSS era (i.e., the next generation of polar orbiting satellites). At the same time, new image manipulation and display capabilities are available within AWIPS II, the next generation of the NWS forecaster decision support system. This presentation will present a review of SPoRT, CIRA, and NRL collaborations regarding multispectral satellite imagery and articulate an integrated and collaborative path forward with Raytheon AWIPS II development staff for integrating current and future capabilities that support new satellite instrumentation and the AWIPS II decision support system.

Molthan, Andrew L.↗