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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.

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NASA NTRS1977

Estimating surface temperature in forced convection nucleate boiling - A simplified method

A simplified expression to estimate surface temperatures in forced convection boiling was developed using a liquid nitrogen data base. Using the principal of corresponding states and the Kutateladze relation for maximum pool boiling heat flux, the expression was normalized for use with other fluids. The expression was applied also to neon and water. For the neon data base, the agreement was acceptable with the exclusion of one set suspected to be in the transition boiling regime. For the water data base at reduced pressure greater than 0.05 the agreement is generally good. At lower reduced pressures, the water data scatter and the calculated temperature becomes a function of flow rate.

Hendricks, R. C.↗
NASA NTRS2016

Surface Temperatures on Titan During Northern Winter and Spring

Meridional brightness temperatures were measured on the surface of Titan during the 2004-2014 portion of the Cassini mission by the Composite Infrared Spectrometer. Temperatures mapped from pole to pole during five two year periods show a marked seasonal dependence. The surface temperature near the south pole over this time decreased by 2 K from 91.7 plus or minus 0.3 to 89.7 plus or minus 0.5 K while at the north pole the temperature increased by 1 K from 90.7 plus or minus 0.5 to 91.5 plus or minus 0.2 K. The latitude of maximum temperature moved from 19 S to 16 N, tracking the subsolar latitude. As the latitude changed, the maximum temperature remained constant at 93.65 plus or minus 0.15 K. In 2010 our temperatures repeated the north-south symmetry seen by Voyager one Titan year earlier in 1980. Early in the mission, temperatures at all latitudes had agreed with GCM predictions, but by 2014 temperatures in the north were lower than modeled by 1 K. The temperature rise in the north may be delayed by cooling of sea surfaces and moist ground brought on by seasonal methane precipitation and evaporation.

Cassini↗
NASA NTRS1976

Can internal heat contribute to the high surface temperature of Venus

It is shown that current observational data on conditions at the Venusian surface are adequate to exclude the possibility that thermal energy from a hot interior contributes to the high surface temperature of the planet. The maximum energy flux conducted from the interior is estimated by assigning a maximum thermal conductivity and a minimum thickness to the crust. It is found that the crust must be at least 10 km thick and that the maximum thermal flux for this thickness is about 6 millionths of a calorie per sq cm/sec. The relative importance of this internal energy source is assessed by comparing it with the amount of solar energy deposited at the surface. The result demonstrates that the absorbed solar energy is at least one and probably two orders of magnitude higher than the minimum flux conducted from the interior. It is concluded that a very efficient atmospheric trapping mechanism (the greenhouse effect) is operating on Venus.

Morrison, D.↗
NASA NTRS2021

Impacts of the Eruption of Mount Pinatubo on Surface Temperatures and Precipitation Forecasts With the NASA GEOS Subseasonal-to-Seasonal System

A contemporary seasonal forecasting system is used to study the impacts of a volcanic sulfate injection into the stratosphere on the seasonal forecasts for surface temperatures, the El Niño Southern Oscillation (ENSO), and precipitation. The focus is a case study of the June 1991 eruption of Mt. Pinatubo, Philippines and the period from July 1991 to February 1992. Version 2 of the Goddard Earth Observing System (GEOS) subseasonal-to-seasonal (S2S) forecasting system is used in this study. GEOS-S2S includes the GOddard Chemistry, Aerosols, Radiation and Transport (GOCART) aerosol module, which allows to prognostically simulate aerosol distributions. GOCART is coupled to the radiation and cloud modules to include the impact of the eruption on forecasted radiation and precipitation. The coupled GEOS-S2S system was initialized in May 1991 with fields based on observations to produce ten-member 9-month forecasts with and without the volcanic sulfur injection. The results of these ensemble experiments demonstrate that including Mt. Pinatubo in seasonal forecasts would improve the forecasts of the 1991–1992 global mean temperature and precipitation but worsen the forecast of ENSO by strengthening of El Niño beyond what showed in observations. Most significant changes in the forecasts of temperatures and precipitation are limited to the tropics. The only land area where the inclusion of Pinatubo significantly lowered the forecasted precipitation is tropical Africa.

Mt. Pinatubo↗
NASA NTRS1972

Pyrometer for measurement of surface temperature distribution on a rotating turbine blade.

A conceptual optical method and some test results are presented for measuring the surface temperature distribution on one of the rotating turbine blades with a surface resolution of 0.05 cm spot diameter at a tip speed of 400 m/sec. The blade is scanned line-by-line by a fixed optical system. During each line-scan, the detector analog output signal is converted to 200 consecutive digital values that are temporarily stored in a high-speed buffer memory and then transferred at a slower rate to a computer for processing. The signal-to-noise ratio of the silicon avalanche detector is large enough to obtain an accuracy of 1% at 1050 K blade temperature. By averaging 25 scans of the same line the same accuracy can be obtained at 900 K.

Buchele, D. R.↗
NASA NTRS1972

Pyrometer for measurement of surface temperature distribution on a rotating turbine blade

A conceptual optical method and some test results are presented for measuring the surface temperature distribution on one of the rotating turbine blades with a surface resolution of 0.05 cm spot diameter at a tip speed of 400 m/sec. The blade is scanned line-by-line by a fixed optical system. During each line-scan, the detector analog output signal is converted to two hundred consecutive digital values that are temporarily stored in a high speed buffer memory, and then transferred at a slower rate to a computer for processing. The signal-to-noise ratio of the silicon avalanche detector is large enough to obtain an accuracy of one percent at 1050 K blade temperature. By averaging 25 scans of the same line the same accuracy can be obtained at 900 K.

Buchele, D. R.↗
NASA NTRS1987

Surface temperature and albedo relationships in Senegal derived from NOAA-7 satellite data

The interaction between surface albedo and local climate in Senegal, Africa, is examined using NOAA AVHRR data collected from September 1981-October 1982. The temporal variations of albedo and surface temperature are calculated and examined. It is observed that the albedo and ground temperature are largest in the winter and spring (dry season) and smallest in the late summer and fall (wet season). From the wet to the dry seasons the albedo varied by about 3 percentage points and the ground temperature by about 13 K. A positive correlation between albedo and ground temperatures is detected; this indicates that the albedo does not control the ground temperature. Other factors that can influence ground temperatures are atmospheric turbulence, soil moisture, thermal inertia, and ground emissivity, which are all affected by the presence or absence of vegetation.

Vukovich, Fred M.↗
NASA NTRS1990

Sensitivity of the equilibrium surface temperature of a GCM to systematic changes in atmospheric carbon dioxide

The equilibrium response of surface temperature to atmospheric CO2 concentration, for six values between 100 and 1000 ppm, is calculated from a series of GCM experiments. This response is nonlinear, showing greater sensitivity for lower values of CO2 than for the higher values. It is suggested that changes in CO2 concentration of a given magnitude (e.g., 100 ppm) played a larger role in the Pleistocene ice-age-type temperature variations than in causing global temperature changes due to anthropogenic increases.

Oglesby, Robert J.↗
NASA NTRS1992

A global monthly sea surface temperature climatology

The paper presents a new global 2 deg x 2 deg monthly sea surface temperature (SST) climatology, referred here to as the Shea-Trenberth-Reynolds (STR) climatology, which was derived by modifying a 1950-1979-based SST climatology from the Climate Analysis Center (CAC), by using data from the Comprehensive Ocean-Atmosphere Data Set to improve the SST estimates in the regions of the Kuroshio and the Gulf Stream. A comparison of the STR climatology with the Alexander and Mobley SST climatology showed that the STR climatology is warmer in the Northern Hemisphere, and colder poleward of 45 deg S.

Shea, Dennis J.↗
NASA NTRS1992

Global relationships among the earth's radiation budget, cloudiness, volcanic aerosols, and surface temperature

Global relationships among the earth's radiation budget, cloudiness, solar constant, volcanic aerosols, and surface temperature are analyzed using data obtained by the Nimbus-7 spacecraft. It was found that these parameters were interrelated on interannual time scales, demonstrating that the interannual variability in the earth's climate (i.e., radiation budget) is detectable and observable by current spaceborne instruments. The degree of global interannual variation is on the order of tenths of percent.

Ardanuy, Philip E.↗
NASA NTRS2000

The Effect of Ocean Currents on Sea Surface Temperature Anomalies

We investigate regional and global-scale correlations between observed anomalies in sea surface temperature and height. A strong agreement between the two fields is found over a broad range of latitudes for different ocean basins. Both time-longitude plots and wavenumber-frequency spectra suggest an advective forcing of SST anomalies by a first-mode baroclinic wave field on spatial scales down to 400 km and time scales as short as 1 month. Even though the magnitude of the mean background temperature gradient is determining for the effectiveness of the forcing, there is no obvious seasonality that can be detected in the amplitudes of SST anomalies. Instead, individual wave signatures in the SST can in some cases be followed over periods of two years. The phase relationship between SST and SSH anomalies is dependent upon frequency and wavenumber and displays a clear decrease of the phase lag toward higher latitudes where the two fields come into phase at low frequencies. Estimates of the damping coefficient are larger than generally obtained for a purely atmospheric feedback. From a global frequency spectrum a damping time scale of 2-3 month was found. Regionally results are very variable and range from 1 month near strong currents to 10 month at low latitudes and in the sub-polar North Atlantic. Strong agreement is found between the first global EOF modes of 10 day averaged and spatially smoothed SST and SSH grids. The accompanying time series display low frequency oscillations in both fields.

Stammer, Detlef↗
NASA NTRS2008

The Impact of High-Resolution Sea Surface Temperatures on the Simulated Nocturnal Florida Marine Boundary Layer

High- and low-resolution sea surface temperature (SST) analysis products are used to initialize the Weather Research and Forecasting (WRF) Model for May 2004 for short-term forecasts over Florida and surrounding waters. Initial and boundary conditions for the simulations were provided by a combination of observations, large-scale model output, and analysis products. The impact of using a 1-km Moderate Resolution Imaging Spectroradiometer (MODIS) SST composite on subsequent evolution of the marine atmospheric boundary layer (MABL) is assessed through simulation comparisons and limited validation. Model results are presented for individual simulations, as well as for aggregates of easterly- and westerly-dominated low-level flows. The simulation comparisons show that the use of MODIS SST composites results in enhanced convergence zones. earlier and more intense horizontal convective rolls. and an increase in precipitation as well as a change in precipitation location. Validation of 10-m winds with buoys shows a slight improvement in wind speed. The most significant results of this study are that 1) vertical wind stress divergence and pressure gradient accelerations across the Florida Current region vary in importance as a function of flow direction and stability and 2) the warmer Florida Current in the MODIS product transports heat vertically and downwind of this heat source, modifying the thermal structure and the MABL wind field primarily through pressure gradient adjustments.

LaCasse, Katherine M.↗
NASA NTRS1980

A study of radiometric surface temperatures: Their fluctuations, distribution and meaning

A consecutive night and day flight and measurements on the ground, were made in the region of Voves, south of Chartres. The statistical analysis of the thermal scanner data permitted the establishment of criteria for the homogeneity of surfaces. These criteria were used in defining the surface temperature values which are most representative for use in an energy balance approach to evapotranspiration (day) and heat balance (night). For a number of maize fields that airborne thermal scanner data permitted a detailed energy analysis of different fields of a same crop to be carried out. Such a detailed analysis was not necessary for a calculation of crop evapotranspiration which could be evaluated from the mean temperature of the crop surface. A differential analysis day night is of interest for enhancing the contrast between types of surfaces, as well as for a better definition of the daily energy balance. It should be stressed that, for a homogeneous region, a study such as the present one, could be carried out on a relatively small part of the total surface, as the results for a surface of 2.5 x 2 sq km were not significantly different from those obtained from a surface three times larger.

Perrier, A.↗
NASA NTRS1984

GCM sensitivity to 1982 - 1983 equatorial Pacific sea surface temperature anomalies

The response of the GLAS climate model to the much larger 1982-83 sea surface temperatures (SST) anomalies is discussed. Two separate 75 day experiments (control and anomaly simulation pairs) were started from observed initial conditions on 16 Dec. 1982 and initial conditions on 16 Dec. 1979 taken from a 2 year model control run after one year of simulation, respectively. The January control and anomaly SST fields used in both experiments are given. Notable is the greatly extended region of very warm (approximately equal to 29 C) SST water in the anomaly simulation. The January SST anomaly field is representative of the other months of the experiments, all of which had a much larger region of very warm SST in the anomaly simulation than in the previously noted general circulation model studies. The model used is an improved version of the GLAS B-grid GCM used by Shukla and Wallace (1983). The most important physical change in the model is the inclusion of the surface flux parameterization of Deardorff (1972) as modified by Randall (1976). An important improvement in the model simulations is the removal of the climate drift towards unrealistically high temperatures in the tropics, which was moted by Shukla and Wallace (1983).

Fennessy, M. J.↗
NASA NTRS1981

Remote sensing of sea surface temperature in the 3.7 micron CO2 band

The main sources of error in remote sensing of sea surface temperature are discussed. The interfering effects of reflected solar radiation, reflected thermal flux, clouds and haze and atmospheric attenuation are examined. The components of measured sea surface radiances, such as clear column radiance, surface emission, atmospheric emission, reflected thermal downward flux, and reflection of solar flux, are analytically presented. The use of the 3.7 micron region window to obtain the radiance to four percent accuracy is discussed. The advantages to be obtained by the use of narrow bandpass channels are assessed.

Chahine, M. T.↗
NASA NTRS1998

Radar Backscatter Across the Gulf Stream Sea Surface Temperature Front

Ocean backscatter signatures were measured by the Jet Propulsion Laboratory airborne NUSCAT K(sub u)-band scatterometer across the Gulf Stream sea surface temperature front. The measurements were made during the Surface Wave Dynamics Experiment (SWADE) off the coast of Virginia and Maryland in the winter of 1991.

Ocean Backscatter Temperature front Gulf Stream↗