Balloon-borne spectroscopy of stratospheric constituents
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Superpressure balloon-borne instruments that measure the vector stratospheric electric field at latitudes near 45 + or - 10 deg S reveal several features in fair weather that cannot be attributed to ionospheric, thunderstorm, or other known sources. Over 180 days of electric field, conductivity, and current density data have been taken at the constant altitude of 26 km, using long-duration balloon flights in the Southern Hemisphere. Throughout these data the fair-weather horizontal electric field has a magnitude (10-50 mV/m) that cannot be due to mid-latitude ionospheric dynamo action. Furthermore, the fields are highly variable in amplitude, almost turbulent in appearance, while the vector direction steadily rotates in a counterclockwise manner. The period of this rotation is close to the quasi-inertial wave period for the latitude of the balloon. For these flights, the electric field rotation period varies between 14 and 21 hours. Some possible causes that might explain the electric field and current measurements reported herein are discussed.
Brains of mice were exposed to cosmic rays in the stratosphere balloon flights carrying nuclear emulsions in order to determine whether injury was incurred
The leviathan silently slides through the upper atmosphere of the blue planet, its eye steadily staring into the cold, dark recesses of deep space. Periodically the eye looks at different points in the blackness while processing the information it sees.
The technique of nonlinear least squares spectral curve fitting has been used to derive the stratospheric vertical temperature profile from balloon-borne measurements of the 10.4 micron band of CO2. The spectral data were obtained at sunset with the approximately 0.02 per cm resolution University of Denver interferometer system from a float altitude of 33.5 km near Alamogordo, New Mexico, on 23 March 1981. The r.m.s. deviation between the retrieved temperature profile and correlative radiosonde measurements is 2.2 K.
Balloon-borne frost point measurements were performed over Antarctica during September-October 1987 as part of the NOZE II effort at McMurdo. The results show water mixing ratios on the order of 2 ppmv in the 20 km region, suggesting that models of the springtime Antarctic stratosphere should be based on approximately 2 ppmv water vapor. Evidence indicating that some PSCs form at temperatures higher than the frost point in the 15 to 20 km region is discussed. This supports the binary HNO3-H2O theory of PSC composition.
Data on species of interest in the photochemistry of the ozone layer obtained from balloon flights are presented. The flights made use of remote-sensing instruments that took measurements in the wavelength region from the ultraviolet to millimeter wavelengths. Most of the data were obtained with instruments whose readings were in the midinfrared wavelengths. Descriptions are given of the two techniques generally used in this type of research, namely solar absorption and atmospheric emission. The promise that these techniques hold for providing data on the photochemistry of the ozone layer is discussed.
A liquid-nitrogen cooled Fourier transform spectrometer (SIRIS) measures thermal limb-emission of the stratosphere from a balloon platform at a nominal altitude of 40 km, under night and day conditions, with a 3 km vertical resolution. N2O5 and HNO3 mixing ratios inferred from emission spectra are compared with previous measurements and with the predictions from a one-dimensional photochemical model.
Knowledge of the concentration of hydroxyl radical is crucial to understanding the chemistry of the stratosphere. Hydroxyl participates in several catalytic cycles which destroy ozone and strongly influences the cycles of chlorine and nitrogen oxides by its reactions which form or destroy reservoirs for chlorine and odd-nitrogen compounds. Measurements have been conducted of the concentration of hydroxyl radical between the altitudes of 32.5 and 38.5 km using the technique of laser-induced fluorescence. The results ranging from 4 to 9 x 10 to the 6th per cu cm (with an accuracy of + or - 50 percent) are about 2-3 times lower than predicted by current one-dimensional models, although the uncertainties in the determination and in the models are sufficiently large to explain the differences. A number of potential improvements to the instrument are discussed.
The use of current balloon, control and communication technologies to test multi-junction solar sell in the stratosphere to achieve near AMO conditions have been investigated. The design criteria for the technologies are that they be reliable, low cost and readily available. Progress is reported on a program to design, launch, fly and retrieve payloads dedicated to testing multi-junction solar cells.
Balloon-borne radiosonde sensors are a well characterized way of gathering data into the stratosphere; however, balloon launches have limitations such as the need to replace the balloon and sensors after each flight, as well the overall drift of the balloon over the course of the launch. Using sensors mounted on an uninhabited aerial system (UAS) allows for higher temporal-resolution vertical profiles in the lower troposphere and allows for full control of the flight profile of the sensors. This paper presents a drop-in solution for a balloon-borne radiosonde in which it is mounted on an uninhabited aerial system in lieu of a balloon with an additional connection to a 3D anemometer streaming atmospheric and wind data in near real-time to a ground station. This alternative platform for balloon-borne radiosondes has undergone extensive flight testing with the wind results being compared against a ground-based wind LiDAR for validation and the atmospheric results undergoing further data analysis against a wide variety of sensors for future validation. Indoor tests were also conducted and are discussed in order to determine the propeller’s influence on the anemometer. This alternative platform will allow for higher temporal and spatial resolution of atmospheric data collection in near-real time.
The Smithsonian Astrophysical Observatory's program of balloon-borne stratospheric spectroscopic measurements is described, including instrumentation, recent scientific results, and future plans. The design and operation of the FIRS-2 far-infrared spectrometer is discussed. The current status of our efforts to recover mixing-ratio profiles with about 1 percent precision is presented. Representative recent results are shown giving mixing-ratio profiles from 20 to 50 km, selected from the suite HOCl, HCl, HF, NO2, N2O, HNO3, OH, HO2, H2O2, H2O (and isotopes), O2 (and isotopes), O3 (and isotopes), and CO2 (and isotopes). The utility of O2 and CO2 spectral lines for information on view angle or temperature and pressure is discussed. Future plans are mentioned, including the use of FIRS-2 on a balloon platform for UARS correlative measurements, the use of FIRS-2 on the NASA DC-8 platform for polar measurements, and the potential benefits of a FIRS instrument on a Shuttle platform.
Low-frequency (f less than about 1 Hz) stratospheric electrical noise is occasionally observed by balloon-borne sensors. The phenomenon occurs 1-3 percent of the time, with maximum incidence during the morning hours. It appears to be related to fluctuations of the electrical conductivity of the medium around the balloons, produced by air turbulence due to the wind shear and/or gravity waves.
Balloons and U-2 aircraft were used to collect micrometer-sized stratospheric aerosols. It was discovered that for the past 6 years at least, aluminum oxide spheres have been the major stratospheric particulate in the size range from 3 to 8 micrometers. The most probable source of the spheres is the exhaust from solid-fuel rockets.
The Smithsonian far-infrared spectrometer (FIRS) is a remote sensing Fourier transform spectrometer that measures the mid- and far-infrared thermal emission spectrum of the stratosphere from balloon and aircraft platforms. The spectrometer has had nine successful balloon flights from 1987 to 1994, flying at float altitudes of 36 - 39 km and collecting 131 hours of midlatitude stratospheric limb spectra. The spectrometer also flew on a NASA CD-8 aircraft, as part of the second Airborne Arctic Stratospheric Expedition (AASE-2), collecting 140 hours of overhead spectra at latitudes ranging from the equator to the north pole. We present here a brief description of the instrument, a discussion of data reduction procedures, an estimation of both random and systematic errors, an outline of the procedure for retrieving mixing ratio profiles, and an explanation of the method of deriving temperature and pressure from the far- and mid-infrared spectra.
Balloon, control and communication technologies are under development in our laboratory for testing multi-junction solar cells in the stratosphere to achieve near AM0 conditions. One flight, Suntracker I, has been carried out reported earlier. We report on our efforts in preparation for a second flight, Suntracker II, that was aborted due to hardware problems. The package for Suntracker I system has been modified to include separate electronics and battery packs for the 70 centimeter and 2 meter systems. The collimator control system and motor gearboxes have been redesigned to address problems with the virtual stops and backlash. Surface mount technology on a printed circuit board was used in place of the through-hole prototype circuit in efforts to reduce weight and size, and improve reliability. A mobile base station has been constructed that includes a 35' tower with a two axis rotator and multi-element yagi antennas. Modifications in Suntracker I and the factors that lead to aborting Suntracker II are discussed.