Vertical sounding balloons for stratospheric photochemistry

Vertical sounding balloons are unique tools for stratospheric photochemistry investigations. An example of the use of a vertically piloted gas balloon for nitrogen dioxide diurnal variation search is presented. Improvements of such a method with the use of montgolfieres (hot air balloons) are proposed.     

IR-spectroscopy of ionosphere from stratospheric balloons

The radiation spectra of the ionosphere in the 4–5 μm region have been determined from stratospheric balloons by means of the specially elaborated method of the registration of angular and spectral distribution of the radiation. The radiation bands of 4.4 μm and 4.8 μm which have 0.1–0.2 erg cm^?2 sr^?1s^?1. brightness obtained in two flights, are identified with the vibration-rotation transitions of the ion NO⁺ (0 - 1) and the molecules N¹⁴N¹⁵ (0 - 1) and CO (0 - 1) and (3 - 2) from altitudes between 120 and 500 km.     

Mass spectrometric measurements of stratospheric ions

Recent in situ measurements with balloon borne quadrupole mass spectrometers, between 20 and 45 km altitude, are reviewed and discussed.The major stratospheric positive ions observed are proton hydrates [H⁺(H₂O)_n] and non proton hydrates of the form H⁺X_m(H₂O)₂. The data analysis allows a derivation of the vertical mixing ratio profile of X (most probably CH₃CN), which is compared with recent model calculations. From negative ion composition data, showing the presence of NO₃^? and HSO₄^? cluster ions, the density of sulfuric acid in the stratosphere is deduced. The implications of these findings on our understanding of the sulfur chemistry is briefly treated.Finally some other aspects such as contamination, cluster break up and the use of stratospheric ion mass spectra for determination of thermochemical data and other minor constituents are discussed.     

Satellite stratospheric aerosol measurement validation

The validity of the stratospheric aerosol measurements made by the satellite sensors SAM II and SAGE has been tested by comparing their results with each other and with results obtained by other techniques (lidar, dustsonde, filter, impactor). The latter type of comparison has required the development of special techniques that (1) convert the quantity measured by the correlative sensor (e.g. particle backscatter, number, or mass) to that measured by the satellite sensor (extinction), and (2) quantitatively estimate the uncertainty in the conversion process. The results of both types of comparisons show agreement within the measurement and conversion uncertainties. Moreover, the satellite uncertainty is small compared to aerosol natural variability (caused by seasonal changes, volcanoes, sudden warmings, vortex structure, etc.). Hence, we conclude that the satellite measurements are valid.     

Some aspects of temperature sounding of the atmosphere

Based on measurements with the interferometer spectrometer SI-1 on board of Meteor satellites the following problems are investigated: the systematic effect of the spectral response function in deriving effective radiation temperatures; the selection of ‘optimal’ spectral channels within the 15 μm region, and effects of additional molecular absorbers on the determination of the temperature profile. It can be shown that using broad-band window channels (half width ?20cm^?1) the derived surface temperature is significantly different from the surface temperature derived from narrow spectral band channels (e.g. for the HIRS window channel 8 this difference is about 1° C). Simulations of some combinations of spectral channels including one proposed as an optimal approach show no significant difference in the derived temperature profile. Neglecting the ozone absorption of the 14.1 μm band leads to a change in radiance of about 1.5 mW/m²sr cm^?1 and to a systematic error of the derived temperature of about ?2° C in the troposphere.     

Possible influence of solar radiation variability on the stratospheric temperature

Using daily temperature data available from radio-sonde measurements over Barajas (Madrid), La Coruña and Palma de Mallorca stations, for the time span 1971–1982 and an altitude range 100-30 mb, a study is made comparing temperatures at differents levels with the 10.7 cm flux in order to check whether radiation variability must be included in lower stratospheric models. At the latitude studied, stratospheric temperatures are uninfluenced by sudden warming phenomena avoiding difficulties of masking found in previous studies.     

Verification of satellite observations of stratospheric minor constituents

The TIROS-N operational meteorological satellite observing system will have the capability of determining global ozone amounts from two instruments by 1985. The TIROS Operational Vertical Sounder (TOVS) yields total ozone amounts through measurements of atmospheric infrared radiances. The Solar Backscatter Ultraviolet (SBUV/2) spectrometer yields total ozone amounts and vertical ozone profiles through measurements of the solar ultraviolet radiation backscattered by the atmosphere. The current operations plan calls for single satellites containing both instruments system with local afternoon equator crossing times. They will be launched at approximately 18 month intervals.The satellite ozone products will require verification using commonly accepted references. For total ozone, Dobson spectrophotometer determinations are to be used. For vertical profiles, no clear choice now exists among balloon-launched chemical sondes, rocket-launched optical sondes or Dobson Umkehr measurements. The applicability and use of these measurement systems are discussed with emphasis on the need for the verification data consistent with the operational satellite lifetimes.Another major source of data for verification is other satellite systems. Comparisons of vertical ozone profiles from several concurrent satellites is discussed. This includes results from SAGE, LIMS and SBUV.     

A sounding rocket experiment on the marangoni convection

During a 6-minutes free flight of a sounding rocket an experiment on the thermal Marangoni convection in a right circular cylindric floating zone was carried out to verify the thermal Marangoni convection by flow visualisation for the first time at 10^?4 g. From the motion picture analysis the velocity distributions are obtained. The interdependence between the two velocity maxima and the S-shaped temperature distribution on the free surface is discussed. The influence of the heat transfer caused by the flow of the surrounding air induced by the thermal Marangoni convection itself is considered briefly.     

Oblique sounding of the ionosphere by powerful wave beams

The article is devoted to modeling the impact on the ionosphere powerful obliquely incident wave beam. The basis of this analysis will be orbital variational principle for the intense wave beams-generalization of Fermat’s principle to the case of a nonlinear medium (, ,  and ). Under the influence of a powerful wave beam appears manageable the additional stratification of the ionospheric layer F2. Explicit expressions show how the properties of the test beam, with a shifted frequency, released in the same direction as the beam depend on the intensity of a powerful beam and the frequency shift.     

Backstepping sliding-mode control of stratospheric airships using disturbance-observer

In the presence of unknown disturbances and model parameter uncertainties, this paper develop a nonlinear backstepping sliding-mode controller (BSMC) for trajectory tracking control of a stratospheric airship using a disturbance-observer (DO). Compared with the conventional sliding mode surface (SMS) constructed by a linear combination of the errors, the new SMS manifold is selected as the last back-step error to improve independence of the adjustment of the controller gains. Furthermore, a nonlinear disturbance-observer is designed to process unknown disturbance inputs and improve the BSMC performances. The closed-loop system of trajectory tracking control plant is proved to be globally asymptotically stable by using Lyapunov theory. By comparing with traditional backstepping control and SMC design, the results obtained demonstrate the capacity of the airship to execute a realistic trajectory tracking mission, even in the presence of unknown disturbances, and aerodynamic coefficient uncertainties.     

A constitutive equation for stratospheric balloon materials

The selection of a suitable material for use as a reliable stratospheric balloon gas barrier and structural component is based on a variety of properties. Due to a more desirable combination of properties, the low density polyethylene that has been used for the last half century has been replaced during the last decade by linear low density polyethylene (LLDPE). This paper describes the effort to characterize the time dependent properties of a 38 micron coextrusion of LLDPE. The nonlinear viscoelastic constitutive equation presented may be used to accurately describe the creep and/or relaxation of this film when subjected to a biaxial state of stress, such as might be required for an extended balloon flight. Recent laboratory data have been used to modify an existing model of LLDPE to account for differences caused by the coextrusion process. The new model will facilitate structural design optimization and reliability assessment, and may be further utilized as a predictive tool to benefit in-flight operations. Current structural analysis techniques based on linear elastic properties have predicted stresses in excess of those which would actually exist.     

Stratosphere-mesosphere coupling during stratospheric sudden warming events

In this review article we summarize recent results in the coupling of the stratosphere–mesosphere during stratospheric sudden warming (SSW) events. We focus on the role of planetary and gravity waves in driving the middle atmosphere circulation and illustrate the stratosphere–mesosphere coupling during undisturbed wintertime circulation, during an SSW event, and after an SSW event during the formation of an elevated stratopause using simulations of past Arctic and Antarctic winters from the Specified Dynamics version of the Whole Atmosphere Community Climate Model (SD-WACCM). We illustrate the transition of the polar stratopause from being a gravity wave driven phenomena to a planetary wave driven phenomena during SSW events and its subsequent reestablishment and control by gravity waves. We also examine the synoptic structure of the stratosphere, mesosphere, and lower thermosphere using SD-WACCM data fields that show the structure of the vortex during specific dynamical events in both hemispheres. We illustrate the longitudinal asymmetry in the thermal structure in the stratosphere and mesosphere driven by differences in circulation over the polar cap regions during an SSW event. We complement this analysis of the middle atmosphere circulation with a classification of both the Arctic and Antarctic winters since 1979 into major, minor, elevated stratopause or quiet winters based on the level of disturbance using the Modern Era-Retrospective Analysis for Research and Applications (MERRA) reanalysis data. From the MERRA data we find that the combined occurrences of both major and minor warmings in the Arctic have remained constant over the past three decades while we find a minor increase in their occurrences in the Antarctic.     

Developing a stratospheric climatology from NMC analyses

The National Meteorological Center of the National Oceanic and Atmospheric Administration (NOAA) has archived global, daily synoptic analyses and computer gridded fields of geopotential height and temperature for 8 stratospheric pressure levels (70, 50, 30, 10, 5, 2, 1 and 0.4 mb) since the Autumn of 1978. More restricted analyses are available since 1964. The fields are discussed, with special emphasis on improvement of the data bases and analysis procedures. Included in the discussions are screening procedures for the climatological data base. Examples are given with regard to monthly mean energy, wind and hemispheric temperature patterns calculated as the initial development of a stratospheric dynamic climatology.     

On the quasi-biennial oscillation in equatorial stratospheric temperatures and total ozone

The results of a cross-spectral analysis between monthly mean temperatures at 100 mb, 50 mb and 30 mb over the equator and the corresponding monthly mean BUV total ozone at different latitude zones are presented for the period 1970–1977. Significant squared coherences between total ozone and 50 mb equatorial temperatures at 26 months are only found between 5 degrees on each side of the equator, between 45 deg N and 55 deg N and at 45 deg S. At latitudes were the QBO in stratospheric temperature diminishes so does the QBO in total ozone (i.e. close to 35 deg N and 15 deg S). Over subtropical latitudes there is a tendency towards a more biennial oscillation in total ozone (not correlated with the equatorial QBO in stratospheric temperatures) and at 65 deg N and 65 deg S total ozone oscillates at periods greater than the equatorial QBO.     

The problem of indirect sounding of high clouds

Remote sounding of high cloud top temperatures by passive methods is a difficult venture due to the semitransparency of the clouds. Window channel measurements often overestimate the cloud top temperature. In this study it is experimentally shown and supported by theoretical considerations that water vapor channels, which are originally intended to sense the high tropospheric water vapor content, are more suitable than window channels. In addition, it is shown that measurements in the H₂O rotational band are superior to 6.3 μm channels due to higher intensity of the outgoing radiation and less contribution by scattering by cloud particles.     

Radio sounding of the solar wind acceleration region with spacecraft signals

Data from coronal radio-sounding experiments carried out on various interplanetary spacecraft are used to derive the empirical radial dependence of solar wind velocity and density at heliocentric distances from 3 to 60 solar radii for heliolatitudes below 60° and for low solar activity. The radial dependencies of solar wind power and acceleration are derived from these results. Summaries of the radial behavior of characteristic parameters of the solar wind turbulence (e.g., the spectral index and the inner and outer turbulence scales), as well as the fractional density fluctuation, are also presented. These radio-sounding results provide a benchmark for models of the solar wind in its acceleration region.     

Balloon observations of temporal and spatial fluctuations in stratospheric conductivity

The first campaign of the Polar Patrol Balloon (PPB) experiment (1st-PPB) was carried out at Syowa Station in Antarctica during 1990–1991 and 1992–1993. Based on the results of the 1st-PPB experiment, the next campaign (2nd-PPB) was carried out in the austral summer of 2002–2003. This paper will present stratospheric conductivity results from the 2nd-PPB experiment. In that experiment, three balloons were launched for the purpose of upper atmosphere physics observation (three balloons). Payloads of these three flights were identical with each other, and were launched as close together in time as allowed by weather conditions to constitute a cluster of balloons during their flights. Such a “Balloon Cluster” is suitable to observe temporal evolution and spatial distribution of phenomena in the ionospheric regions and boundaries that the balloons traversed during their circumpolar trajectory. More than 20 days of simultaneous fair weather 3-axis electric field and stratospheric conductivity data were obtained at geomagnetic latitudes ranging from sub-auroral to the polar cap. Balloon separation varied from ∼60 to >1000 km. This paper will present stratospheric conductivity observations with emphasis on the temporal and spatial variations that were observed.