Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “sonde”

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.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 145 records · Page 8
All sourcesNASA NTRSDOE OSTI
NASA NTRS1983

Equatorial ozone characteristics as measured at Natal (5.9 deg S, 35.2 deg W)

Ozone density profiles obtained through electrochemical concentration cell (ECC) sonde measurements at Natal were analyzed. Time variations, as expected, are small. Outstanding features of the data are tropospheric densities substantially higher than those measured at other stations, and also a total ozone content that is higher than the averages given by satellite measurements. Previously announced in STAR as A82-29798

Kirchhoff, V. W. J. H.↗
NASA NTRS1985

Dynamics of two-year cosmic ray variations inferred from the data of spacecraft and stratospheric measurements and from the neutron monitor data in 1959-1981

The two year cosmic ray variations are studied using the spacecraft measurements of 1967 to 1976, the sonde measurements at high latitudes in the stratosphere (Murmansk, Mirny), and the neutron monitor data of 1959 to 1981. The two year variations are most pronounced from 1967 to 1975. An anticorrelation is observed between the two year variations in cosmic rays and in geomagnetic activity.

Charakhchyan, T. N.↗
NASA NTRS1984

Radiosonde pressure sensor performance - Evaluation using tracking radars

The standard balloon-borne radiosonde employed for synoptic meteorology provides vertical profiles of temperature, pressure, and humidity as a function of elapsed time. These parameters are used in the hypsometric equation to calculate the geopotential altitude at each sampling point during the balloon's flight. It is important that the vertical location information be accurate. The present investigation was conducted with the objective to evaluate the altitude determination accuracy of the standard radiosonde throughout the entire balloon profile. The tests included two other commercially available pressure sensors to see if they could provide improved accuracy in the stratosphere. The pressure-measuring performance of standard baroswitches, premium baroswitches, and hypsometers in balloon-borne sondes was correlated with tracking radars. It was found that the standard and premium baroswitches perform well up to about 25 km altitude, while hypsometers provide more reliable data above 25 km.

Parsons, C. L.↗
NASA NTRS1985

Density and temperature structure over northern Europe

During the Energy Budget Campaign, a number of profiles of the density and temperature were obtained to study the structure and variability of the atmosphere. The measurements were made using rocketborne instrumentation launched from Esrange, Sweden, and Andoya Rocket Range, Norway, during November and December 1980. The techniques included meteorological temperature sondes, passive falling sphere, accelerometer instrumented falling spheres, density gauges, mass spectrometers and infrared emission experiments. The instruments provided data covering the altitude range from 20 to 150 km. The measurements were made during periods which have been grouped into three categories by level of geomagnetic activity. Analysis has been made to compare the results and to examine the wave features and variations in the vertical profiles for scales ranging between hundreds of meters and tens of kilometers. Most of the features observed fit qualitatively within the range expected for internal gravity waves. However, the features in the profiles during one of the measurement periods are unusual and may be due to aurorally generated shock waves. The geomagnetic storm conditions caused temperature increases in the lower thermosphere which maximized in the 120-140 km region.

Philbrick, C. R.↗
NASA NTRS1985

Balloon-borne observation of Aitken nuclei in the Antarctic stratosphere and troposphere

Aitken nuclei (0.002 or = r or = 0.1 microns in the atmosphere are produced through gas-to-particle conversion processes, and they grow in size by heterogeneous nucleation processes and others to produce larger aerosol particles. In the study of global background aerosol pollution, full knowledge of such aerosol processes in the clean atmosphere is essentially required. In this sense, it is important to examine the behavior of aerosols in a clean atmosphere which is not contaminated directly by aerosols and gases emitted from the Earth's surface. The Antarctic atmosphere is thought to be such a clean atmosphere. From an extensive surface observation of aerosols carried out at Syowa Station (69 deg 00'S, 39 deg 35'E) Antarctica, it has been revealed that various phenomena relating to long-range transport of trace constituents and/or photochemical processes resulting in production or growth of aerosol particles are clearly observed in Antarctica. This paper gives a preliminary report of observations made by balloon-borne Aitken nuclei sonde in 1983, at Syowa Station.

Ito, T.↗
NASA NTRS1985

Results from the Balloon Ozone Intercomparison Campaign (BOIC)

In the Balloon Ozone Intercomparison Campaign (BOIC), several in situ UV absorption photometers, two solar UV absorption photometers, electrochemical sondes, and a mass spectrometer were intercompared in three flight missions. Concurrent data from Umkehr and satellite observations are also intercompared. The National Bureau of Standards provided a 'standard' ozone source for intercomparing the in situ instruments and ground pressure. Preliminary findings indicate that the standard deviation of the sensitivities among 17 instruments against the NBS reference was about 11 percent. These differences appear in flight at the lower levels and change at higher altitudes, indicating height-dependent errors. The difference among five in-situ UV photometers flown together ranged by plus or minus 8 percent during ascent to about 41 km. During float at 42 km, the difference nearly doubled. During descent, the difference decreased to about 4 percent, which is much closer to the expected accuracy of these instruments. Results from UV solar radiometers have been systematically higher than those from UV photometers by 15 to 20 percent - a very important disagreement that needs to be resolved.

Hilsenrath, E.↗
NASA NTRS1986

Relationships between 6.7 micrometer imagery and radiosonde-derived parameters

The relationships between water vapor images and various thermodynamic and kinematic patterns derived from ground-based data obtained on March 6-7, 1982 are investigated. The synoptic-scale characteristics of the observed image streaks are studied. Water vapor budgets were calculated from sonde data. Variations in black body temperatures are analyzed using water vapor budgets. The data reveal that the observed warm image streaks are caused by subsidence and horizontal flux divergence of vapor.

Stewart, Michael R.↗
NASA NTRS1987

Ozone over McMurdo Station, Antarctica, austral spring 1986 - Altitude profiles for the middle and upper stratosphere

In the austral spring of 1986, a program of measurements of the ozone altitude profile (for the z values between 25 and 55 km), relevant to an understanding of the ozone hole, was conducted at McMurdo Station, Antarctica. The measurements were performed using ground-based millimeter-wave spectrometry. It was found that the ozone mixing ratio peaked at altitudes ranging from 28 to 34 km, with peak values between 5 and 9 ppm by volume. During the period between September 12 and October 29, the ozone mixing ratio decreased, with great variability, by about 15 percent at 25 km, with no significant decrease at higher altitudes. The observation of the depletion occurring only below 25 km is consistent with ozone-sonde observations during previous years.

Connor, Brian J.↗
NASA NTRS1988

The UW digital ozonesonde: Characteristics and flow rate calibration

During the austral springs of 1986 and 1987, a series of balloon soundings were conducted to characterize the temporal and vertical development of Antarctic ozone depletion using the electrochemical concentration cell method (ECC). An important part of this study was to perform correlative studies between ozone and aerosol particles. In order to facilitate these simultaneous measurements, a digital ozonesonde system was developed to interface with aerosol counters. The ozone measurements will be described herein. The ozonesonde modification was accomplished by converting the current output of the sonde to a frequency and adding this digital signal to the serial data stream of a Vaisala Corporation RS-80 radiosonde under microprocessor control. A number of advantages over the standard ozonesonde system currently in use are noted.

Harder, J. W.↗
NASA NTRS1988

Total ozone, ozone vertical distributions, and stratospheric temperatures at South Pole, Antarctica, in 1986 and 1987

Seventy-six electrochemical cell (ECC) ozonesondes were flown at South Pole, Antarctica, during 1987 in a continuing program to document year-round changes in Antarctica ozone that are dynamically and photochemically induced. Dobson spectrophotometer total ozone observations were also made. For the twilight months of March and September when Dobson instrument observations cannot be made at South Pole, total ozone amounts were deduced from the ECC ozonesonde soundings. ECC sonde total ozone data obtained during the polar night (April to August), supplemented the sparse total ozone data obtained from Dobson instrument moon observations. Similar ozone profile and total ozone observations were made at South Pole in 1986.

Komhyr, W. D.↗
NASA NTRS1988

Near UV atmospheric absorption measurements from the DC-8 aircraft during the 1987 airborne Antarctic ozone experiment

During the Airborne Antarctic Ozone Experiment from 28 August to 30 September 1987 near UV zenith scattered sky measurements were made over Antarctic from the NASA DC-8 aircraft using a one third m spectrograph equipped with a diode-array detector. Scattered sky light data in the wavelength range 348 nm to 388 nm was spectrally analyzed for O3, NO2, OClO, and BrO column abundances. Slant column abudances of O3, NO2, OClO and BrO were determined, using a computer algorithm of non-linear and linear least square correlation of Antarctic scattered sky spectra to laboratory absorption cross section data. Using measured vertical electrochemical sonde ozone profiles from Palmer, Halley Bay, and the South Pole Stations the slant columns of O3 were converted into vertical column abundances. The vertical column amounts of NO2, OClO, and BrO were derived using vertical profiles calculated by a chemical model appropriate for Antarctica. NO2 vertical column abundances show steep latitudinal decrease with increasing latitude for all 13 flights carried out during the mission. In the regions where NO2 abudances are low, OClO and BrO were observed. The spatial and temporal vertical column abundances of these species are discussed in the context of the chemistry and dynamics in the antarctic polar vortex during the austral spring.

Wahner, A.↗
NASA NTRS1988

Dehydration in the lower Antarctic stratosphere in late winter and spring

The history of minimum temperatures at 50 and 70 mb is examined from NMC, UK Met 0 and ECMWF analyses. MSU channel 24 data are similarly inspected. South Pole sonde data are used to calculate saturation humidity mixing ratio as a function of altitude and time throughout 1987. Saturation with respect to ice could be maintained for water mixing ratios of 3.5 ppmv for a period of about 80 days from mid-June to mid-September. Dehydration to mixing ratios of 1 ppmv or less was possible sporadically. Data from the ER-2 flights between 53 S and 72 S are used in conjunction with particle size measurements and air parcel trajectories to demonstrate the dehydration occurring over Antarctica. Water mixing ratios at the latitude of Punta Arenas (53 S), in conjunction with tracer measurements and trajectory analysis, show that at potential temperatures from about 325 to 400 K, the dryness (less than 3 ppmv) had its origin over Antarctica rather than in the tropics. Water mixing ratios within the Antarctic vortex varied from 1.5 to 3.8 ppmv, with a strong isentropic gradient being evident in the region of high potential vorticity gradients.

Kelly, K. K.↗
NASA NTRS1988

Brewer spectrophotometer measurements in the Canadian Arctic

In the winters of 1987 and 1988 measurements were conducted with the Brewer Spectrophotometer at Alert (82.5 N) and Resolute (74.5 N). The measurements were conducted as part of our Canadian Program to search for an Arctic Ozone Hole (CANOZE). Ozone measurements were conducted in the months of December, January and February using the moon as a light source. The total ozone measurements will be compared with ozonesonde profiles, from ECC sondes, flown once per week from Alert and Resolute. A modified Brewer Spectrophotometer was used in a special study to search for chlorine dioxide at Alert in March 1987. Ground based observations at Saskatoon in February and at Alert in March 1987 failed to detect any measureable chlorine dioxide. Interference from another absorbing gas, which we speculate may be nitrous acid, prevented the measurements at the low levels of chlorine dioxide detected in the Southern Hemisphere by Solomon et al.

Kerr, J. B.↗
NASA NTRS1989

Comparisons of satellite ozone data in the lower stratosphere for 1978/1979

Lower stratospheric zonal mean O3 distributions are compared in both hemispheres from the Nimbus 7 Solar Backscattered Ultraviolet (SBUV) and Limb Infrared Monitor of the Stratosphere (LIMS) data sets. Generally there is very good agreement with regard to individual profile shape and magnitude and with their longitudinal variability about the zonal mean. When the data are considered in terms of Umkehr layer amounts, there are subtle but significant differences in the respective meridional O3 gradients and their variations with time which are probably related to a changing O3 optical depth and constants to an assumed profile climatology in the retrieval. Stratospheric Aerosol and Gas Experiment (SAGE) satellite O3 results are presented which tend to split the differences between SBUV and LIMS. Additional comparisons with electrochemical concentration cell sonde and Mastsonde O3 profiles are presented in order to sort out the more noticeable differences.

Remsberg, Ellis E.↗
NASA NTRS1989

Evidence of the mid-latitude impact of Antarctic ozone depletion

Record low ozone values found over Australia and New Zealand during December 1987 following the record low Antarctic values of October 1987 are analyzed. The sudden decline of ozone amounts in midmonth rule out photochemical effects as a cause and permit the underlying processes to be investigated on a case study basis. Using data from ozone sondes, radiosondes, the Nimbus-7 total ozone mapping spectrometer, and meteorological analyses from the National Meteorological Center, it is argued that these low values resulted from transport of ozone-poor air from higher latitudes. Thus, it seems that the chemical destruction of ozone over Antarctica in early spring is having an impact on lower latitudes.

Atkinson, Roger J.↗
NASA NTRS1989

Stratospheric ozone measurements from the 1985 MAP/GLOBUS NO(x) campaign

Nine experiments obtained stratospheric ozone measurements during the fall 1985 Middle Atmosphere Program (MAP) Global Budget of Stratospheric Trace Constituents (GLOBUS) NO(x) campaign. Measurements are grouped into four sets from four air masses and compared. Agreement between individual experiments and weighted mean profiles is generally within 10 percent and within absolute accuracies. Dobson Umkehr values in layer 5 differ by more than absolute accuracies from weighted mean profiles. Brewer sonde values for one data set are outside absolute accuracies near the ozone peak. Solar UV occultation measurements are 30-35 percent less than the weighted mean profile and outside absolute accuracies. Measurements from the Exospheric Satellite backscattered ultraviolet experiment, not previously compared with other techniques, agree within 10-15 percent of weighted mean profiles. Results of the campaign are generally consistent with those of four previous intercomparison campaigns.

Robbins, D.↗
NASA NTRS1989

Dehydration in the lower Antarctic stratosphere during late winter and early spring, 1987

The history of minimum temperatures at 50 and 70 mb is examined from NMC, UK Met O and ECMWF analyses. MSU channel 24 data are similarly inspected. South Pole sonde data are used to calculate saturation humidity mixing ratio as a function of altitude and time throughout 1987. Saturation with respect to ice could be maintained for water mixing ratios of 3.5 ppmv for a period of about 80 days from mid-June to mid-September. Dehydration to mixing ratios of 1 ppmv or less was possible sporadically. Data from the ER-2 flights between 53 S and 72 S are used in conjunction with particle size measurements and air parcel trajectories to demonstrate the dehydration occurring over Antarctica. Water mixing ratios at the latitude of Punta Arens (53 S), in conjunction with tracer measurements and trajectory analysis, show that at potential temperatures from about 325 to 400 K, the dryness (less than 3 ppmv) had its origin over Antarctica rather than in the tropics. Water mixing ratios within the Antarctic vortex varied from 1.5 to 3.8 ppmv, with a strong isentropic gradient being evident in the region of high potential vorticity gradients.

Kelly, K. K.↗
NASA NTRS1989

Intercomparison of ozone measurements over Antarctica

Measurements of the abundances of ozone over Antarctica in August and September 1987 obtained during the Airborne Antarctic Ozone Experiment are intercompared. These measurements of ozone concentrations and total column abundance were obtained by three satellite instruments, two IR and one UV column-measuring instruments aboard the DC-8, one in situ DC-8, and two in situ ER-2 instruments, an upward looking lidar aboard the DC-8, and ozone sondes from four sites in Antarctica. This paper presents a summary of the ozone data, using the data and accuracies given by the individual investigators in the individual papers in this issue, without any attempt to critically review or evaluate the data. In general, very good agreement (within about 10-20 percent, limited by natural variability) among the various techniques was found, with no systematic biases detected. These observations confirm the low ozone amounts reported in the Antarctic stratosphere.

Margitan, J. J.↗