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Cess, R. D.

Publications and source records attributed to Cess, R. D..

At least 37 records · Page 2
All sourcesNASA NTRSDOE OSTI
NASA NTRS1986

Vertical cloud structure models for the NTRZ EQZ, SEB and STRZ of Jupiter

Latitude-dependent models of the vertically inhomogeneous Jovian cloud structure are presented. The models assume an atmospheric composition with (CH4)/(H2) = 2.0 x .003, (He)/(H2) = 0.11 and (NH3)/(H2) = 2.0 x .0004 consistent with the Voyager IRIS measurements and employ refractive indices appropriate for ammonia ice particles and a photochemical stratospheric aerosol layer. The free parameters of the models are determined by fitting the results of multiple, scratching calculations to the near-infrared center and limb spectra of Clark and McCord and the center-to-limb 6190, 6350, 7250, 7500, 8900 and 9500 A photometric measurements of West. The resulting synthetic center-to-limb profiles are in excellent agreement with the observations. Of the regions studied the tropical zones are the most similar, with the observed differences explained by variations in the vertical extent of the cloudy layers. The Equatorial Zone is a unique region with denser NH3 clouds than either of the tropical zones. At visible and near-infrared wavelengths the belt-zone contrasts can be explained by opacity differences. The optical depth of the stratospheric aerosol layer is larger in a belt, while the tropospheric clouds are deeper and thinner.

Carlson, B. E.↗
NASA NTRS1986

Infrared radiation models for atmospheric methane

Mutually consistent line-by-line, narrow-band and broad-band infrared radiation models are presented for methane, a potentially important anthropogenic trace gas within the atmosphere. Comparisons of the modeled band absorptances with existing laboratory data produce the best agreement when, within the band models, spurious band intensities are used which are consistent with the respective laboratory data sets, but which are not consistent with current knowledge concerning the intensity of the infrared fundamental band of methane. This emphasizes the need for improved laboratory band absorptance measurements. Since, when applied to atmospheric radiation calculations, the line-by-line model does not require the use of scaling approximations, the mutual consistency of the band models provides a means of appraising the accuracy of scaling procedures. It is shown that Curtis-Godson narrow-band and Chan-Tien broad-band scaling provide accurate means of accounting for atmospheric temperature and pressure variations.

Cess, R. D.↗
NASA NTRS1986

First data from the earth radiation budget experiment (ERBE)

The first data obtained from the Earth Radiation Budget Experiment (ERBE) are presented. These data include emitted infrared radiation, albedo, and estimated scene types for Nov. 15, 1984, as well as measurements of the 'solar constant'. Images from the GOES on the same day are included for comparison with the ERBE scene identification. On an instantaneous basis, clouds appear colder and more reflective than seems to have been noted before. The experiment data will be applied to several key studies of cloud-radiation-climate interactions.

Barkstrom, B. R.↗
NASA NTRS1986

Solar calibration results from two earth radiation budget experiment nonscanner instruments

The Earth Radiation Budget Experiment (ERBE) makes use of three sets of two independent, but complementary, flight instruments. The two instruments in each set include a three-channel narrow field-of-view scanning instrument (scanner) and a five-channel wide field-of-view staring instrument (nonscanner). The ERBE nonscanner instruments are designed for the conduction of broad spectral and spatial measurements of the earth's reflected solar and emitted radiation and the determination of the incident solar flux. The nonscanner solar calibration process is considered along with the solar calibration results. A description of the data processing algorithms is also provided, taking into account the earth viewing channels and the solar monitor.

Luther, M. R.↗
NASA NTRS1985

Trace gas effects on climate

The two primary objectives are to describe the new scientific challenges posed by the trace gas-climate problem and to summarize current strategies, and to make an assessment of the trace gas effects on troposphere-stratosphere temperature trends. Numerous reports on CO2-climate problems are examined with respect to climate modeling issues. The role of the oceans in governing the transient climate response to time varying CO2 concentrations is discussed.

Ramanathan, V.↗
NASA NTRS1983

An analysis of periodicities in the 1470 to 1974 Beijing precipitation record

An analyis of a time series consisting of an annual index of dryness/wetness for the years 1470 to 1974 in Beijing, China is presented. Its power spectrum shows that dominant cycles occur with long periods of the order of 80 years. Cycles with periods of 11 and 22 years are weak or non-existent, but a significant signal at 18.7 years (which is also the period of a component of the lunar tide generating force) is detected. The long term variations in Beijing precipitation appear to lag long term (Gleissberg) variations in solar activity by nearly 75 years. A pattern which spans nearly 150 years in the Beijing record is found to be repeated with notable similarity.

Hameed, S.↗
NASA NTRS1982

Increased atmospheric carbon dioxide and climate feedback mechanisms

As a consequence of fossil fuel burning, the atmospheric concentration of carbon dioxide has increased from 314 ppm in 1958, when detailed measurements of this quantity began, to a present value of 335 ppm; and it is estimated that during the next century, the CO2 concentration will double relative to its assumed preindustrial value of 290 ppm. Since CO2 is an infrared-active gas, increases in its atmospheric concentration would lead to a larger infrared opacity for the atmospheric which, by normal logic, would result in a warmer Earth. A number of modeling endeavors suggest a 2 to 4 C increase in global mean surface temperature with doubling of the CO2 concentration. But such estimates of CO2-induced warming are highly uncertain because of a lack of knowledge of climate feedback mechanisms. Interactive influences upon the solar and infrared opacities of the Earth-atmosphere system can either amplify or damp a climate-forcing mechanism such as increasing CO2. Climate feedback mechanisms discussed include climate sensitivity, cloudiness-radiation feedback, climate change predictions, and interactive atmospheric chemistry.

Cess, R. D.↗
NASA NTRS1982

Laboratory band strengths of methane and their application to the atmospheres of Jupiter, Saturn, Uranus, Neptune, and Titan. II - The red region 6000-7600 A

Lutz et al. (1976) have reported the first quantitative analyses of the strengths of the blue-green bands of methane which dominate the visible spectra of the outer planets. The present investigation represents an extension of the first study to include a number of bands between 6000 and 7500 A. The objective of this extension is to establish the validity of the scaled numerical curve of growth of the first study further into the saturated region and to test the apparent pressure independence of the high-overtone bands over a large pressure range. In addition, it is desired to provide a set of homogeneously determined band strengths and curves of growth over a large spectral region and over a large range of band strengths. This will make it possible to investigate feasible apparent dependences of planetary methane abundances on wavelength and band strength as a probe of the scattering processes in the planetary atmospheres.

Lutz, B. L.↗
NASA NTRS1982

Low-latitude cloudiness and climate feedback - Comparative estimates from satellite data

Three studies of the relative albedo to the IR components of cloud amount feedback are reviewed, and an approach to the seasonal variability in low-level cloud numbers is presented. Comparisons are made and uncertainties calculated for the predictions of cloud amounts from satellite data sets for outgoing IR flux. IR data is used directly for a linear regression analysis and seasonal and latitudinal variations are considered in terms of monthly-annual means for particular latitude zones. Investigations of NOAA-NESS satellite data revealed that cirrus clouds are transparent in the 10.5-12.5 microns range and cloud albedos decrease at wavelengths greater than 0.7 micron, which suggests a possibility of cloud-sky and clear-sky albedo comparisons at 0.5-0.7 micron. The inclusion of Rayleigh scattering and atmospheric water vapor absorption of sunlight is recommended to test the effects on observed contracts.

Cess, R. D.↗
NASA NTRS1981

Latitudinal variations in Jovian stratospheric temperature

Ground-based observations of Jupiter show that the planet's stratospheric and tropospheric thermal emission are anticorrelated. The observations can possibly be explained by latitudinal variations in cloud altitude. These variations cause differential stratospheric heating by sunlight which is reflected off the clouds and then absorbed within the stratosphere by visible and near-infrared bands of methane.

Cess, R. D.↗
NASA NTRS1980

Response of the global climate to changes in atmospheric chemical composition due to fossil fuel burning

Recent modeling of atmospheric chemical processes (Logan et al, 1978; Hameed et al, 1979) suggests that tropospheric ozone and methane might significantly increase in the future as the result of increasing anthropogenic emissions of CO, NO(x), and CH4 due to fossil fuel burning. Since O3 and CH4 are both greenhouse gases, increases in their concentrations could augment global warming due to larger future amounts of atmospheric CO2. To test the possible climatic impact of changes in tropospheric chemical composition, a zonal energy-balance climate model has been combined with a vertically averaged tropospheric chemical model. The latter model includes all relevant chemical reactions which affect species derived from H2O, O2, CH4, and NO(x). The climate model correspondingly incorporates changes in the infrared heating of the surface-troposphere system resulting from chemically induced changes in tropospheric ozone and methane. This coupled climate-chemical model indicates that global climate is sensitive to changes in emissions of CO, NO(x) and CH4, and that future increases in these emissions could augment global warming due to increasing atmospheric CO2.

Hameed, S.↗
NASA NTRS1980

Impact of a global warming on biospheric sources of methane and its climatic consequences

Most of atmospheric methane originates by bacterial processes in anaerobic environments within the soil which are found to become more productive with increases in ambient temperature. A warming of climate, due to increasing levels of industrial gases resulting from fossil fuel burning, is thus likely to increase methane abundance within the atmosphere. This may lead to further heating of the atmosphere, since both methane and ozone (which is generated in the troposphere from reactions of methane) have greenhouse effects. This feedback mechanism has been explored with the use of a coupled climate-chemical model of the troposphere, by the calculation of the impact of the predicted global warming due to increased emissions of carbon dioxide and other industrial gases on the biospheric sources of methane.

Hameed, S.↗
NASA NTRS1980

Response of the global climate to changes in atmospheric chemical composition due to fossil fuel burning

Tropospheric ozone and methane might increase in the future as the result of increasing anthropogenic emissions of CO, NOx and CH4 due to fossil fuel burning. Since O3 and CH4 are both greenhouse gases, increases in their concentrations could augment global warming due to larger future amounts of atmospheric CO2. To test this possible climatic impact, a zonal energy-balance climate model has been combined with a vertically-averaged tropospheric chemical model. The latter model includes all relevant chemical reactions which affect species derived from H2O, O2, CH4 and NOx. The climate model correspondingly incorporates changes in the infrared heating of the surface-troposphere system resulting from chemically induced changes in tropospheric ozone and methane. This coupled climate-chemical model indicates that global climate is sensitive to changes in emissions of CO, NOx and CH4, and that future increases in these emissions could enhance global warming due to increasing atmospheric CO2.

Cess, R. D.↗
NASA NTRS1980

A model of Saturn's seasonal stratosphere at the time of the Voyager encounters

A polar-equatorial climate model by Cess and Cladwell (1979) is extended to all latitudes of Saturn. Modifications for solar absorption within the stratosphere are made in the extension to intermediate latitudes. The latitudinally and temporally variable effects of sunlight absorption by the rings of Saturn are included in the model. Temperature-latitude profiles for several levels within the Saturn stratosphere are presented for January 1981, which should be directly comparable with Saturn Voyager observations in November 1980 and August 1981. Temperature-pressure profiles for latitudes +30 degrees and -25 degrees are provided, which correspond to the planned points at which radio equipment aboard Voyager II will produce occultation observations.

Carlson, B. E.↗
NASA NTRS1980

The Martian paleoclimate and enhanced atmospheric carbon dioxide

Current evidence indicates that the Martian surface is abundant with water presently in the form of ice, while the atmosphere was at one time more massive with a past surface pressure of as much as 1 atm of CO2. In an attempt to understand the Martian paleoclimate, a past CO2-H2O greenhouse was modeled and global temperatures which are consistent with an earlier presence of liquid surface water are found in agreement with the extensive evidence for past fluvial erosion. An important aspect of the CO2-H2O greenhouse model is the detailed inclusion of CO2 hot bands. For a surface pressure of 1 atm of CO2, the present greenhouse model predicts a global mean surface temperature of 294 K, but if the hot bands are excluded, a surface temperature of only 250 K is achieved.

Cess, R. D.↗
NASA NTRS1979

Temporal characteristics of the Jovian atmosphere

Drift scans along the central meridian of Jupiter have been obtained at wavelengths of 7.9, 17.8, and 19.7 microns. These observations indicate a significant north-south temperature asymmetry within the Jovian stratosphere but not within its troposphere, results which agree with the recent Voyager 1 observations. Employing a time-dependent stratospheric model, it is found that the observed north-south asymmetry is consistent with seasonal stratospheric variability. In the model, the primary cause for this variability is the time-dependent absorption of sunlight by aerosols.

Caldwell, J.↗
NASA NTRS1979

A Saturnian stratospheric seasonal climate model

Motivated by recent observational evidence that seasonal processes occur within Saturn's stratosphere, a seasonal stratospheric climate model has been constructed. This model predicts stratospheric temperatures above the P = 0.1-atm level as a function of time throughout the Saturnian year. Specific results are presented for south-polar and equatorial temperatures. The model predicts that substantial seasonal phase lags exist; maximum stratospheric temperatures at the south pole occur at the southern hemisphere's autumnal equinox. Brightness temperature observations at 17.8 microns, taken during 1977/1978, indicate that stratospheric temperatures are greater at the south pole than at the equator. The model is consistent with these observations, predicting enhanced south polar temperatures, relative to the equator, from 1975 to 1983.

Cess, R. D.↗