Reference Atmosphere Research Articles

Mars Global Reference Atmospheric Model for mission planning and analysis

An engineering model atmosphere for Mars has been developed with many of the same features and capabilities of the highly successful Global Reference Atmospheric Model (GRAM) program for Earth's atmosphere, including mean values for density, temperature, pressure, and wind components, and density perturbation magnitudes and random perturbation profiles for density variations along specified trajectories. This paper outlines the observational and modeling basis behind the development of the Mars-GRAM program, provides a general description of the operations of the Mars-GRAM program (available in FORTRAN-77 on IBM-PC compatible 360k diskettes), and presents some example applications for the Mars-GRAM model.

Comparisons between Satellite-derived Gradient Winds and Radar-derived Winds from the CIRA-86

The zonal and meridional wind contours in the 60-120 km region obtained from satellite radiance data were compared with radar-derived contours of winds obtained from the CIRA-1986 reference atmosphere. It was found that the agreement between the directly observed zonal winds and the zonal mean gradient winds from the reference atmosphere wind model was good, especially below 80 km. However, differences were found in both the Southern and the Northern Hemispheres.

Catalog of solar‐terrestrial models available

The National Space Science Data Center, Greenbelt, Md., recently published “Solar Terrestrial Models and Applications Software,” by Dieter Bilitza (NSSDC 90‐19, July 1990, 98 pp.), which identifies and describes more than 70 model software packages in several areas of the solar‐terrestrial environment. Some of these may be accessed and run on the NSSDC Online Data and Information Services (NODIS) account by external researchers.The principal areas and parameters covered include ionosphere (electron density and temperature, ion temperature, composition, and drift, electric field and current, precipitating particle flux, etc.), atmosphere (density, temperature, winds, etc.), magnetosphere (internal‐ and external‐source geomagnetic fields, energetic proton and electron fluxes, etc.), Sun and interplanetary space (IR and EUV reference spectra, solar protons, cosmic rays, etc.) and Venus atmosphere and ionosphere. Representative models include the International Reference Ionosphere (IRI), the Heppner‐Maynard‐Rich ionospheric electric field model, the Committee on Space Research (COSPAR) Interna tional Reference Atmosphere (CIRA), the International Geomagnetic Reference Field (IGRF), the Tsyganenko geomagnetic models (1982, 1987, and 1989), the AP8 and AE8 trapped particle models, the revised SERF2 solar EUV Flux model [Tobiskas, 1990], the Jet Propulsion Laboratory solar proton model, and the CREME cosmic ray program.

ハワイ島における気流と地形性降雨の3次元シミュレーション

A three-dimensional mesoscale numerical model is presented, designed with the capability of simulating the airflow and orographically-induced rain in the presence of steep irregular terrain. The model utilizes a fourth-order accurate version of Arakawa's potential enstrophy and total energy conserving scheme to improve the simulation of nonlinear aspects of the airflow over steep topography, along with an adiabatic reference atmosphere to reduce the effects of orographic truncation errors. The precipitation processes are represented by large-scale condensation. The model is applied to the island of Hawaii. The results of a 24-h simulation indicate the model is generally successful in reproducing leeward eddies depicted in the composite surface airflow patterns. A nondimensional analysis of vortex parameters suggests that the simulated vortex pattern is an atmospheric analog of the Karman vortex street and compares favorably with an observed case of Hawaii vortices. Spatial distribution of simulated rainfall is also generally in good agreement with observations. However, the lack of precipitation in the lowland along the windward as well as leeward coast is apparent. The excess rainfall over the southern peninsula suggests the need for an finer grid mesh to improve representation of the effects of subgrid-scale mountain forcing. An application of the model to regional climate modeling through the use of large-scale objective analyses is also discussed.

Mean state densities, temperatures and winds during the MAC/SINE and MAC/EPSILON campaigns

During 1987 two major field campaigns were conducted, mainly in northern Norway (in summer and late autumn), in which a total of 41 (26+15) in-situ temperature profiles were obtained by different techniques such as passive falling spheres, ionizalion gauges and mass spectrometers. Simultaneously, ground-based measurements of OH-temperatures and sodium lidar temperatures were performed for approximately 85 h and 104 h, respectively. In addition, a total of 67 (37 + 30) wind profiles were measured by in-situ techniques. Several radar systems measured winds almost continuously before, during and after the campaigns. The mean temperature profile for the summer campaign showed major deviations from a recently published reference atmosphere (CIRA 1986), whereas the differences between observations and model are smaller in autumn. In general, both the summer and autumn mean wind profiles agreed with CIRA 1986. Minor differences were attributed to tidal biases of the observations and ageostrophic components.

The Microdosimetry of Radon Decay Products in the Respiratory Tract

Abstract The purpose of this study was to develop methods for calculating the probability density in specific energy for cell nuclei of the respiratory tract epithelium irradiated by inhaled radon and daughter products. Microdosimetry also provides the probability that cell nuclei may be hit by alpha particles, the probability that cell nuclei are completely missed, and the mean (absorbed) dose to cell nuclei. Such information is useful for interpreting the significance of an inhalation exposure to radon and daughters. The secretory and basel cell nuclei were considered separately as potential targets of biological importance for exposure to radon daughters. A 30 day (0.023 WLM) and a 30 year (8.45 WLM) exposure to a reference atmosphere representing an average exposure to the US population to a radon concentration of 37 Bq.m-3 (1 pCi.l-1) in disequilibrium with its daughters were considered for sample calculations. About 0.3% and 10% of cell nuclear sites would be hit once for 30 day and 30 year exposures, respectively. Most cell nuclear sites (80-90%) would be missed by the 30 year exposure to alpha particles. The main, lobar, and segmental bronchi (generations 1-4) have the highest fraction of cell nuclei irradiated; these are also the epithelial tissues from which most bronchial tumours originate in humans exposed to radon atmospheres. The average 30 year reference atmosphere doses to secretory and basal cell nuclei in the segmental bronchi were 0.3 Gy and 0.2 Gy (30 rad and 20 rad), respectively. These values correspond to 0.035 Gy.WLM-1 and 0.024 Gy.WLM-1, respectively. For the whole bronchial tree, the average absorbed dose per unit exposure was 0.014-0.015 Gy.WLM-1 (1.4-1.5 rad.WLM-1).

Sensitivity of medium-range weather forecasts to the use of reference atmosphere

In this paper, the authors develop the earlier work of Chen Jiabin et al. (1986). In order to reduce spectral truncation errors, the reference atmosphere has been introduced in ECMWF model, and the spectrally-represented variables, temperature, geopotential height and orography, are replaced by their deviations from the reference atmosphere. Two modified semi-implicit schemes have been proposed to alleviate the computational instability due to the introduction of reference atmosphere. Concerning the deviation of surface geopotential height from reference atmosphere, an exact computational formulation has been used instead of the approximate one in the earlier work. To reduce aliasing errors in the computations of the deviation of the surface geopotential height, a spectral fit has been used slightly to modify the original Gaussian grid-point values of orography.

Development and test of hydrostatic extraction scheme in spectral model

The introduction of “hydrostatic extraction” scheme, or “standard stratification approximation”, into spectral model gained some advantages compared with commonly used schemes. However, computational instability may occur for high vertical resolution versions if the stratification parameterC0 taken as a constant. In this paper, the possible cause leading to the instability is discussed and an improved scheme presented whereC0 is generalized to be a function of both height and latitudes. Hence the reference atmosphere gets closer to the real atmosphere and the temperature deviation field to be expanded becomes smoother everywhere. Test by real case forecasts shows good computational stability of the new scheme and better prediction performance than usual schemes of spectral model.

ENEA Reference Atmosphere Facility for Testing Radon and Daughters Measuring Equipment.

This paper gives the technical characteristics of the Italian Committee for Research and Development of Nuclear Energy and Alternative Energy (ENEA) radon chamber and the operational procedures developed for testing radon and daughters measuring equipment. Runs were carried out under different experimental conditions defined in terms of radon and daughter concentrations, equilibrium ratio (F-factor), and aerosol concentration and size distribution. Stable radon reference atmospheres with known equilibrium factors were obtained using standard aerosols.

Mean temperature fields in the lower thermosphere

The PMR ch. 3000 radiance data are correlated with temperatures from a reference atmosphere at 85 and 90 km to obtain mean temperature fields at these heights. Another technique for this purpose is to extrapolate upwards temperature fields given by the Barnett-Corney model for the stratosphere and mesosphere. The results of the two techniques agree well. The temperature fields in the lower thermosphere are briefly analysed.

Contribution to the new reference atmosphere from ground-based lidar

Contribution to the new reference atmosphere from ground-based lidar

Comparison between reference atmosphere winds and radar winds from selected locations

Zonal and meridional 60-110-km wind profiles obtained by radar measurements at Saskatoon, Adelaide, Christchurch, Puerto Rico, and Mawson are presented graphically and compared with those from the COSPAR International Reference Atmosphere (CIRA) for 1986. Good general agreement is found below about 80 km, but above 80 km the CIRA 1986 models show discrepancies, including: (1) no spring tongue of weak westward flow at latitudes 20-70 deg; (2) too strong an eastward flow at 20-52 deg in summer; (3) too great reversal heights at 35-43 deg N in summer; and (4) too strong (by a factor of 2) summer and winter jets at 65-70 deg N.

Improved reference models for middle atmosphere ozone

Improvements are provided here for the ozone reference model which is to be incorporated in the COSPAR International Reference Atmosphere (CIRA). The ozone reference model will provide considerable information on the global ozone distribution, including ozone vertical structure as a function of month and latitude from approximately 25 to 90 km, combining data from five recent satellite experiments (Nimbus 7 LIMS, Nimbus 7 SBUV, AE-2 SAGE, Solar Mesosphere Explorer (SME) UVS, and SME IR). The improved models described here use reprocessed AE-2 SAGE data (sunset) and extend the use of SAGE data from 1981 to the period 1981–1983. It is found that these SAGE data agree at all latitudes and months with the ozone reference model within 15 percent and result in modifications in the reference model of less than 4 percent. In the mesosphere, a model of nighttime conditions (= 10 p.m.) has been added using Nimbus 7 LIMS data between pressures of 0.5 mb to 0.05 mb (= 54 to 70 km). Minimum nightside ozone mixing ratios occur at about 0.2 mb (= 61 km). The ratio of nightside LIMS data to dayside (= 3 p.m.) SME data gives diurnal variations as large as a factor of 6 at the highest levels. At 0.1 mb (= 66 km), the night-day diurnal variation can exceed 3 and maximizes during solstice periods near 45 degrees in the summer hemisphere and near the Equator during equinoctial periods. This may largely result from the dayside ozone being more strongly photodissociated by the more directly incident summer Sun at mid latitudes and the equinoctial Sun at the Equator. Comparisons are shown between the ozone reference model and various non-satellite measurements at different levels in the middle atmosphere.

Southern hemisphere reference middle atmosphere

Abstract The wind part of the rocket-based empirical model of the middle atmosphere of the Southern Hemisphere is revised on the basis of new rocket and radar data. Wind and temperature values from this empirical model are compared with corresponding values from the satellite-based reference atmosphere compiled by Barnett and Corney. General similarity of the two models is confirmed, though marked discrepancies are sometimes revealed.

COSPAR International reference atmosphere grand mean

The mean behavior of the earth atmosphere from 0 to 120 km altitude is briefly characterized on the basis of the COSPAR International Reference Atmosphere (CIRA) for 1986. The CIRA annual zonal mean for 30 deg N is used to derive single profiles for the pressure, height, temperature, and zonal wind, and the results are presented in a table.

Description and presentation of reference atmosphere radar winds (80–110 km)

Description and presentation of reference atmosphere radar winds (80–110 km)

Interannual variability

The new Reference Atmosphere presented here is based on global satellite data and forms a very useful basis for climatological studies. When using such climatologies it is important to be aware of the well known interannual variability which in the middle atmosphere is particularly large during the northern winters and southern springs.

Venus middle-atmosphere temperatures from Venera 15

The temperature structure of the Venusian middle atmosphere derived from the Venera-15 Fourier spectrometer confirms in general previous investigations summarized in the Venus International Reference Atmosphere 1985. A detailed Fourier analysis of the temperature field in the solar fixed coordinate system shows generally a different behaviour for low ( ϕ ≲ 50°) and high ( ϕ ≳ 55°) latitudes, a predominance of wavenumber-2 with a full cl (360°) from the cloud top up to about 95 km at low latitudes and an anti-clockwise rotation of 180° at high latitudes. The amplitudes are, however, for both Fourier components less than 2 – 3 K. Larger amplitudes (> 4 K) are found at high latitudes in spectral intervals representing the upper cloud top, where wavenumber-1 is dominant. The maximum wavenumber-1 amplitude for the cloud top occurs at the morning terminator at high latitudes and around 2 p.m. at low latitudes. Temporary changes in the outgoing longwave flux at the North Pole ( ϕ ≳ 85°) are closely related to the cloud top temperature, which indicates variation in the upper cloud top height by about 10 km. The accompanying temperature variations are different in different altitude ranges and reveal a complicated behaviour of the polar atmosphere.

Ozone reference models for the middle atmosphere

Data on monthly latitudinal variations in middle-atmosphere vertical ozone profiles are presented, based on extensive Nimbus-7, AE-2, and SME satellite measurements from the period 1978-1982. The coverage of the data sets, the characteristics of the sensors, and the analysis techniques applied are described, and the results are compiled in tables and graphs. These ozone data are intended to supplement the models of the 1986 COSPAR International Reference Atmosphere.

Zonal mean temperature, pressure, zonal wind and geopotential height as functions of latitude

The new zonal mean COSPAR International Reference Atmosphere (CIRA-86) of temperature, zonal wind, and geopotential/geometric height is presented. This data can be used as a function of altitude or pressure and has nearly pole-to-pole coverage (80°S-80°N) extending from the ground to approximately 120 km. Data sources and methods of computation are described; in general, hydrostatic and thermal wind balance are maintained at all levels and latitudes. As shown by a series of cross sectional plots, the new CIRA accurately reproduces most of the characteristic features of the atmosphere such as the equatorial wind and the general structure of the tropopause, stratopause, and mesopause.