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NASA NTRS1996

Temporal Evolution of SL-9 Impact Sites on Jupiter and Global Maps of Jupiter from Multi-Observatory Visible and Infrared Images

The objective of this research was to investigate the temporal behavior of the impact features on Jupiter created by the fragments of the Shoemaker Levy-9 comet that collided with the planet in July 1994. The primary observations used in the study were ground based images of Jupiter acquired from the Swedish Solar Vacuum Tube on the island of La Palma in the Canary Islands. The measurement of position of the impact features in images acquired immediately after the impact over a period of a few days revealed that the apparent drift rates were too high and that a repetitive pattern could be seen in the longitude position on successive rotations. This could be explained only by the fact that the measured longitudes of the impact sites were being affected by parallax due to a significant elevation of the impact debris above the nominal cloud top altitude value used for image navigation. Once the apparent positions are analyzed as a function of the meridian angle, the parallax equation can be used to infer the height of the impact features above the cloud deck, once the true impact position (longitude) for the feature is known. Due to their inherent high spatial resolution, the HST measurements of the impact site locations have been accepted widely. However, these suffer from the parallax themselves since few of them were obtained at central meridian. Ground based imaging have the potential to improve this knowledge as they do observe most of the impact sites on either side of the central meridian, except for the degraded resolution. Measurements over a large number of images enables us to minimize the position error through regression and thus estimate both the actual impact site location devoid of parallax bias, and also of the altitude level of the impact debris above the cloud deck. With rapid imaging there is the potential to examine the time evolution of the altitude level. Several hundred ground based images were processed, navigated and subjected to the impact site location measurements. HST images were also acquired and used to calibrate the results and to improve the sample. The resources available enabled an in-depth study only of impact site A, however, many more images have since become available through the global network observations through Lowell Observatory.

Limaye, Sanjay S.↗
NASA NTRS2020

Ozone Production in the Soberanes Smoke Haze: Implications for Air Quality in the San Joaquin Valley During the California Baseline Ozone Transport Study

The Soberanes Fire burned 132,127 acres along the central California coast between July 22 and October 12, 2016, generating dense smoke and a variety of gaseous compounds that drifted eastward into the San Joaquin Valley Air Basin (SJVAB), an ‘extreme’ non‐attainment area for ozone (O3). These gases included nitrogen oxides (NOx) and volatile organic compounds (VOC), the photochemical precursors of O3. The fire started during the California Baseline Ozone Transport Study (CABOTS), a field campaign that brought aircraft, surface, and remote sensing measurements of O3 and related species to central California. In this paper, we use the CABOTS measurements to assess the impact of the Soberanes Fire on ozone and particulate air quality in the SJVAB. We focus our analysis on July 27 ‐ August 2 when the smoke haze was heaviest and the highest O3 concentrations in the SJVAB during 2016 were recorded. Our analyses suggest that while 40 to 60 ppbv of fire‐generated O3 was transported to the eastern SJVAB in the 1‐3 km altitude range, relatively little smoke or fire‐generated O3 reached the surface in the Visalia area.

Andrew O. Langford↗
NASA NTRS1946

Comparison of Measured and Calculated Stresses in Built-up Beams

Web stresses and flange stresses were measured in three built-up beams: one of constant depth with flanges of constant cross-section, one linearly tapered in depth with flanges of constant cross section, and one linearly tapered in depth with tapered flanges. The measured stresses were compared with the calculated stresses obtained by the methods outlined in order to determine the degree of accuracy that may be expected from the stress analysis formulas. These comparisons indicated that the average measured stresses for all points in the central section of the beams did not exceed the average calculated stresses by more than 5 percent. It also indicated that the difference between average measured flange stresses and average calculated flange stresses on the net area and a fully effective web did not exceed 6.1 percent.

Levin, L Ross↗
NASA NTRS2006

A Climatology of Midlatitude Continental Clouds from the ARM SGP Site: Cloud Fraction and Surface Radiative Forcing - Part II

Data collected at the Department of Energy Atmospheric Radiation Measurement (ARM) Southern Great Plains (SGP) Central Facility (SCF) are analyzed to determine the monthly and hourly variations of cloud fraction and radiative forcing between January 1997 and December 2002. Cloud fractions are estimated for total cloud cover and for single-layered low (0-3 km), middle (3-6 km), and high clouds (more than 6 km) using ARM SCG ground-based paired lidar-radar measurements. Shortwave (SW) and longwave (LW) fluxes are derived from up- and down-looking standard precision spectral pyranometers and precision infrared radiometer measurements with uncertainties of approximately 10 Wm(exp -2). The annual averages of total, and single-layered low, middle and high cloud fractions are 0.49, 0.11, 0.03, and 0.17, respectively. Both total and low cloud amounts peak during January and February and reach a minimum during July and August, high clouds occur more frequently than other types of clouds with a peak in summer. The average annual downwelling surface SW fluxes for total and low clouds (151 and 138 Wm(exp-2), respectively) are less than those under middle and high clouds (188 and 201 Wm(exp -2), respectively), but the downwelling LW fluxes (349 and 356 Wm(exp -2)) underneath total and low clouds are greater than those from middle and high clouds (337 and 333 Wm(exp -2)). Low clouds produce the largest LW warming (55 Wm(exp -2) and SW cooling (-91 Wm(exp -2)) effects with maximum and minimum absolute values in spring and summer, respectively. High clouds have the smallest LW warming (17 Wm(exp -2)) and SW cooling (-37 Wm(exp -2)) effects at the surface. All-sky SW CRF decreases and LW CRF increases with increasing cloud fraction with mean slopes of -0.984 and 0.616 Wm(exp -2)%(exp -1), respectively. Over the entire diurnal cycle, clouds deplete the amount of surface insolation more than they add to the downwelling LW flux. The calculated CRFs do not appear to be significantly affected by uncertainties in data sampling and clear-sky screening. Traditionally, cloud radiative forcing includes, not only the radiative impact of the hydrometeors, but also the changes in the environment. Taken together over the ARM SCF, changes in humidity and surface albedo between clear and cloudy conditions offset approximately 20% of the NET radiative forcing caused by the cloud hydrometeors alone. Variations in water vapor, on average, account for 10% and 83% of the SW and LW CRFs, respectively, in total cloud cover conditions. The error analysis further reveals that the cloud hydrometeors dominate the SW CRF, while water vapor changes are most important for LW flux changes in cloudy skies. Similar studies over other locales are encouraged where water and surface albedo changes from clear to cloudy conditions may be much different than observed over the ARM SCF.

Xi, B.↗
NASA NTRS1998

The Atmospheric Structure of Triton and Pluto

The goal of this research was to better determine the atmospheric structures of Triton and Pluto through further analysis of three occultation data sets obtained with the Kuiper Airborne Observatory (KAO.) As the research progressed, we concentrated our efforts on the Triton data, as this appeared to be the most fruitful. Three papers have been prepared as a result of this research. The first paper presents new results about Triton's atmospheric structure from the analysis of all ground-based stellar occultation data recorded to date, including one single-chord occultation recorded on 1993 July 10 and nine occultation lightcurves from the double-star event on 1995 August 14. These stellar occultation observations made both in the visible and in the infrared have good spatial coverage of Triton, including the first Triton central-flash observations, and are the first data to probe the altitude level 20-100 km on Triton. The small-planet lightcurve model of J. L. Elliot and L. A. Young was generalized to include stellar flux refracted by the far limb, and then fitted to the data. Values of the pressure, derived from separate immersion and emersion chords, show no significant trends with latitude, indicating that Triton's atmosphere is spherically symmetric at approximately 50 km altitude to within the error of the measurements; however, asymmetry observed in the central flash indicates the atmosphere is not homogenous at the lowest levels probed (approximately 20 km altitude). From the average of the 1995 occultation data, the equivalent isothermal temperature of the atmosphere is 47 plus or minus 1 K and the atmospheric pressure at 1400 km radius (approximately 50 km altitude) is 1.4 plus or minus 0.1 microbar. Both of these are not consistent with a model based on Voyager UVS and RSS observations in 1989. The atmospheric temperature from the occultation is 5 K colder than that predicted by the model and the observed pressure is a factor of 1.8 greater than the model. In our opinion, the disagreement in temperature and pressure is probably due to modeling problems at the microbar level, since measurements at this level have not previously been made. Alternatively, the difference could be due to seasonal change in Triton's atmospheric structure. The second paper reports observations of a recent stellar occultation by Triton which, when combined with earlier results, show that Triton has undergone a period of global warming since 1989. The most conservative estimates of the rate of temperature and surface-pressure increase during this period imply that the atmosphere is doubling in bulk every 10 years -- significantly faster than predicted by published frost model for Triton. Our results suggests that permanent polar caps on Triton play a dominant role in regulating seasonal atmospheric changes. Similar processes should also be active on Pluto. A third paper 'Global Warming on Triton' will appear in a the January 1999 issue of Sky and Telescope.

Elliot, James L.↗
NASA NTRS1991

Gravity survey of the Mt. Toondina impact structure, South Australia

The Mt. Toondina impact structure is located in northern South Australia, about 45 km south of the town of Oodnadatta. Only the central uplift is exposed. The outcrops at Mt. Toondina reveal a remarkable structural anomaly surrounded by a broad expanse of nearly flat-lying beds of the Bulldog Shale of Early Cretaceous age. A gravity survey was undertaken in 1989 to determine the diameter of the impact structure, define the form of the central uplift, and understand the local crustal structure. Data were collected along two orthogonal lines across the structure. In addition to the profiles, a significant number of measurements were made on and around the central uplift. The 1989 gravity data combined with 1963 gravity data and the seismic reflection data provide an excellent data base to interpret the subsurface structure of the Mt. Toondina feature.

Plescia, J. B.↗
NASA NTRS1973

Radionuclides at Descartes in the central highlands

Throium, uranium, potassium, aluminium-26, and sodium-22 were measured by nondestructive gamma ray spectrometry in six soil and two rock samples gathered by Apollo 16 in the lunar central highlands. The soil samples probably include both major geologic formations in the vicinity, the Cayley and Descartes Formations, although it is possible that the Descartes Formation is not represented. The rock samples have low concentrations of primordial radionuclides. The Al concentrations were lower than could be expected from the high abundance of alumina in the Apollo 16 soils reported earlier, but this could be due to lower concentrations of target elements in these soils, sampling depth variations, or regolithic mixing (exposure age variations).

Wrigley, R. C.↗
NASA NTRS1998

Galaxy Cluster Masses at Moderate Redshifts

The masses of galaxy clusters are dominated by dark matter, and a robust determination of their masses has the potential of indicating how much dark matter exists on large scales in the universe, and the cosmological parameter Omega. X-ray observations of galaxy clusters provide a direct measure of both the gas mass in the intra-cluster medium, and also the total gravitating mass of the cluster. We used new and archival ROSAT observations to measure these quantities for a sample of intermediate redshift clusters which have also been subject to intensive dynamical studies, in order to compare the mass estimates from different methods. We used data from 14 of the CNOC cluster sample at 0.18 less than z less than 0.55 for this study. A direct comparison of dynamical mass estimates from Carlberg, Yee & Ellingson (1997) yielded surprisingly good results. The X-ray/dynamical mass ratios have a mean of 0.96+/- 0.10, indicating that for this sample, both methods are probably yielding very robust mass estimates. Comparison with mass estimates from gravitational lensing studies from the literature showed a small systematic with weak lensing estimates, and large discrepancies with strong lensing estimates. This latter is not surprising, given that these measurement are made close to the central core, where optical and X-ray estimates are less certain, and where substructure and the effects of individual galaxies will be more pronounced. These results are presented in Lewis, Ellingson, Morris/Carlberg, 1998, submitted to the Astrophysical Journal. (Note that Lewis is Ellingson's Ph.D. thesis, who received direct support from this grant and is using this investigation as part of his thesis.) Three additional papers are in preparation. The first provides a comparison of the mass profiles as measured in X- rays and in galaxy dynamics. These profiles are difficult to determine for individual clusters, and are subject to asphericity and other individual quirks of each cluster. However, a composite profile for each method will allow us to test our assumptions of hydrostatic/dynamical equilibrium in the sample as a whole. A second paper provides a more detailed look at the cluster MS0906+11, which is a merging system. A third paper authord with J. Mohr at U. Chicago will invetigate the size-temoerature relationship for intermediate redshift clusters and its impications on cluster formation and cosmology. Future work on these data will include comparisons of the cluster galaxy populations and the extent of the intra-cluster medium, and a more homogeneous analysis of gravitational lensing.

Ellingson, E.↗
NASA NTRS1984

Comet Bowell (1980b) - Measurement of the optical thickness of the coma and particle albedo from a stellar occultation

Comet Bowell (1980b) was observed to pass within 0.25 + or 0.09 arc sec of a star (about 540 km at the comet), where the absorption of starlight by the dust coma was found to be 3 percent (+ or - 1 percent). The implied optical thickness of 0.03 differs greatly from other determinations and gives a mass of 3 x 10 to the 13th g for the coma within 10,000 km of the nucleus. Coupled with absolute continuum filter photometry, these results indicate a very low particle albedo consistent with fluffy carbonaceous material. This experiment indicates the need to observe nearly central occultations by several observers to measure the optical thickness profile of a comet. The advantages of using a charge-coupled device area photometer for such observations are discussed.

Larson, S. M.↗
NASA NTRS1987

Methane flux from the Central Amazonian Floodplain

A total of 186 methane measurements from the three primary Amazon floodplain environments of open water lakes, flood forests, and floating grass mats were made over the period 18 July through 2 September 1985. These data indicate that emissions were lowest over open water lakes. Flux from flooded forests and grass mats was significantly higher. At least three transport processes contribute to tropospheric emissions: ebullition from sediments, diffusion along the concentration gradient from sediment to overlaying water to air, and transport through the roots and stems of aquatic plants. Measurements indicate that the first two of these processes are most significant. It was estimated that on the average bubbling makes up 49% of the flux from open water, 54% of that from flooded forests, and 64% of that from floating mats. If the measurements were applied to the entire Amazonian floodplain, it is calculated that the region could supply up to 12% of the estimated global natural sources of methane.

Bartlett, Karen B.↗
NASA NTRS1988

Methane flux from the central Amazonian floodplain

A total of 186 methane measurements from the three primary Amazon floodplain environments of open water lakes, flood forests, and floating grass mats were made over the period 18 July through 2 September 1985. These data indicate that emissions were lowest over open water lakes. Flux from flooded forests and grass mats was significantly higher. At least three transport processes contribute to tropospheric emissions: ebullition from sediments, diffusion along the concentration gradient from sediment to overlaying water to air, and transport through the roots and stems of aquatic plants. Measurements indicate that the first two of these processes are most significant. It was estimated that on the average bubbling makes up 49 percent of the flux from open water, 54 percent of that from flooded forests, and 64 percent of that from floating mats. If the measurements were applied to the entire Amazonian floodplain, it is calculated that the region could supply up to 12 percent of the estimated global natural sources of methane.

Bartlett, Karen B.↗
NASA NTRS2005

Coupled Gravity and Elevation Measurements of Ice Sheet Mass Change

We measured surface gravity and position at ten locations about two glaciological measurement networks located on the South-central Greenland Ice during June 2004. Six of the individual sites of the first network were occupied the previous year. At the repeat sites we were able to measure annual accumulation rate and surface displacement by referencing measurements to aluminum poles left in the firn the previous year. We occupied 4 additional sites at a second measurement network for the first time since initial observations were last made at the network in 1981. At each individual site, we operated a GPS unit for 90 minutes - the unit was operated simultaneously with a base station unit in Sondrestrom Fjord so as to enable differential, post-processing of the data. We installed an aluminum, accumulation-rate-pole at each site. The base section of the pole also served as the mount for the GPS antenna. A new, Scintrex gravimeter was used at each site and relative gravity measurements were tied to the network of absolute gravity stations in Sondrestrom. We measured snow physical properties in two shallow pits. This report summarizes our observations and data analysis.

Jezek, K. C.↗
NASA NTRS1977

The effects of target characteristics on fresh crater morphology - Preliminary results for the moon and Mercury

The results are reported of an analysis of the characteristics of fresh crater samples occurring on the two major geologic units on the moon (maria and highlands) and on Mercury (smooth plains and cratered terrain). In particular, the onset diameters and abundances of central peaks and terraces are examined and compared for both geologic units on each planet in order to detect any variations that might be due to geologic unit characteristics. The analysis of lunar crater characteristics is based on information provided in the LPL Catalog of Lunar Craters of Wood and Andersson (1977). The Mercurian data set utilized is related to a program involving the cataloguing of Mercurian craters visible in Mariner 10 photography. It is concluded that the characteristics of the substrate have exerted a measurable influence on the occurrence of central peaks, terraces, and scallops in flash crater samples. Therefore, in order to compare the morphologic characteristics of fresh crater populations between planets, an analysis of possible substrate-related differences must first be undertaken for each planet under consideration. It is suggested that large variations in gravity do not produce major variations in crater wall failure.

Cintala, M. J.↗
NASA NTRS1998

Stellar Occultation Probe of Triton's Atmosphere

The goals of this research were (i) to better characterize Triton's atmospheric structure by probing a region not well investigated by Voyager and (ii) to begin acquiring baseline data for an investigation of the time evolution of the atmosphere which will set limits on the thermal conductivity of the surface and the total mass of N2 in the atmosphere. Our approach was to use observations (with the Kuiper Airborne Observatory) of a stellar occultation by Triton that was predicted to occur on 1993 July 10. As described in the attached reprint, we achieved these objectives through observation of this occultation and a subsequent one with the KAO in 1995. We found new results about Triton's atmospheric structure from the analysis of the two occultations observed with the KAO and ground-based data. These stellar occultation observations made both in the visible and infrared, have good spatial coverage of Triton including the first Triton central-flash observations, and are the first data to probe the 20-100 km altitude level on Triton. The small-planet light curve model of Elliot and Young (AJ 103, 991-1015) was generalized to include stellar flux refracted by the far limb, and then fitted to the data. Values of the pressure, derived from separate immersion and emersion chords, show no significant trends with latitude indicating that Triton's atmosphere is spherically symmetric at approximately 50 km altitude to within the error of the measurements. However, asymmetry observed in the central flash indicates the atmosphere is not homogeneous at the lowest levels probed (approximately 20 km altitude). From the average of the 1995 occultation data, the equivalent-isothermal temperature of the atmosphere is 47 +/- 1 K and the atmospheric pressure at 1400 km radius (approximately 50 km altitude) is 1.4 +/- 0.1 microbar. Both of these are not consistent with a model based on Voyager UVS and RSS observations in 1989 (Strobel et al, Icarus 120, 266-289). The atmospheric temperature from the occultation is 5 K colder than that predicted by the model and the observed pressure is a factor of 1.8 greater than the model.

Elliot, James L.↗
NASA NTRS1984

Venous pressure in man during weightlessness

To determine whether the body fluid shift from the lower limbs toward the head that occurs during spaceflight leads to lasting increases of venous pressure in the upper body, venous pressure and hematocrit measurements were made on four astronauts before flight and 1 and 12 hours after recovery and compared with measurements in space. During the mission the hematocrit was elevated and the venous pressure lowered by 1 to 8 centimeters of water as compared with the preflight data. One hour after landing the hematocrit decreased, indicating a hemodilution, venous pressures were unexpectedly high, and a body weight loss of 4 to 5 percent was observed. Twelve hours later the venous pressures were the lowest recorded during the study. The fluid shift apparently takes place during the first several hours of spaceflight. Thereafter, the pressure in the peripheral veins and the central circulation is lower than that measured before flight.

Kirsch, K. A.↗
NASA NTRS2011

Sensitivity of C-Band Polarimetric Radar-Based Drop Size Distribution Measurements to Maximum Diameter Assumptions

The estimation of rain drop size distribution (DSD) parameters from polarimetric radar observations is accomplished by first establishing a relationship between differential reflectivity (Z(sub dr)) and the central tendency of the rain DSD such as the median volume diameter (D0). Since Z(sub dr) does not provide a direct measurement of DSD central tendency, the relationship is typically derived empirically from rain drop and radar scattering models (e.g., D0 = F[Z (sub dr)] ). Past studies have explored the general sensitivity of these models to temperature, radar wavelength, the drop shape vs. size relation, and DSD variability. Much progress has been made in recent years in measuring the drop shape and DSD variability using surface-based disdrometers, such as the 2D Video disdrometer (2DVD), and documenting their impact on polarimetric radar techniques. In addition to measuring drop shape, another advantage of the 2DVD over earlier impact type disdrometers is its ability to resolve drop diameters in excess of 5 mm. Despite this improvement, the sampling limitations of a disdrometer, including the 2DVD, make it very difficult to adequately measure the maximum drop diameter (D(sub max)) present in a typical radar resolution volume. As a result, D(sub max) must still be assumed in the drop and radar models from which D0 = F[Z(sub dr)] is derived. Since scattering resonance at C-band wavelengths begins to occur in drop diameters larger than about 5 mm, modeled C-band radar parameters, particularly Z(sub dr), can be sensitive to D(sub max) assumptions. In past C-band radar studies, a variety of D(sub max) assumptions have been made, including the actual disdrometer estimate of D(sub max) during a typical sampling period (e.g., 1-3 minutes), D(sub max) = C (where C is constant at values from 5 to 8 mm), and D(sub max) = M*D0 (where the constant multiple, M, is fixed at values ranging from 2.5 to 3.5). The overall objective of this NASA Global Precipitation Measurement Mission (GPM/PMM Science Team)-funded study is to document the sensitivity of DSD measurements, including estimates of D0, from C-band Z(sub dr) and reflectivity to this range of D(sub max) assumptions. For this study, GPM Ground Validation 2DVD's were operated under the scanning domain of the UAHuntsville ARMOR C-band dual-polarimetric radar. Approximately 7500 minutes of DSD data were collected and processed to create gamma size distribution parameters using a truncated method of moments approach. After creating the gamma parameter datasets the DSD's were then used as input to a T-matrix model for computation of polarimetric radar moments at C-band. All necessary model parameterizations, such as temperature, drop shape, and drop fall mode, were fixed at typically accepted values while the D(sub max) assumption was allowed to vary in sensitivity tests. By hypothesizing a DSD model with D(sub max) (fit) from which the empirical fit to D0 = F[Z(sub dr)] was derived via non-linear least squares regression and a separate reference DSD model with D(sub max) (truth), bias and standard error in D0 retrievals were estimated in the presence of Z(sub dr) measurement error and hypothesized mismatch in D(sub max) assumptions. Although the normalized standard error for D0 = F[Z(sub dr)r] can increase slightly (as much as from 11% to 16% for all 7500 DSDs) when the D(sub max) (fit) does not match D(sub max) (truth), the primary impact of uncertainty in D(sub max) is a potential increase in normalized bias error in D0 (from 0% to as much as 10% over all 7500 DSDs, depending on the extent of the mismatch between D(sub max) (fit) and D(sub max) (truth)). For DSDs characterized by large Z(sub dr) (Z(sub dr) > 1.5 to 2.0 dB), the normalized bias error for D0 estimation at C-band is sometimes unacceptably large (> 10%), again depending on the extent of the hypothesized D(sub max) mismatch. Modeled errors in D0 retrievals from Z(sub dr) at C-band are demonstrated in detail and comparedo similar modeled retrieval errors at S-band and X-band where the sensitivity to D(sub max) is expected to be less. The impact of D(sub max) assumptions to the retrieval of other DSD parameters such as Nw, the liquid water content normalized intercept parameter, are also explored. Likely implications for DSD retrievals using C-band polarimetric radar for GPM are assessed by considering current community knowledge regarding D(sub max) and quantifying the statistical distribution of Z(sub dr) from ARMOR over a large variety of meteorological conditions. Based on these results and the prevalence of C-band polarimetric radars worldwide, a call for more emphasis on constraining our observational estimate of D(sub max) within a typical radar resolution volume is made

Carey, Lawrence D.↗
NASA NTRS1985

Mass distribution in the galactic centre

New infrared and submillimeter spectroscopic measurements of the gas dynamics in the central 10 pc of the Galaxy make a convincing case that the mass distribution at the center of the Galaxy is more concentrated than a spherical isothermal stellar cluster. The measurements fit a point mass of about 4 million solar masses, but are also consistent with a cluster where stellar density decreases with radius (R) at least as fast as R to the -2.7, or a combination of a point mass and a stellar cluster. The dynamical information combined with previous 2-micron observations favor a large point mass, which is presumably a massive black hole.

Crawford, M. K.↗
NASA NTRS1994

The integrated sounding system: Description and preliminary observations from TOGA COARE

An Integrated Sounding System (ISS) that combines state-of-the-art remote and in situ sensors into a single transportable facility has been developed jointly by the National Center for Atmospheric Research (NCAR) and the Aeronomy Laboratory of the National Oceanic and Atmospheric Administration (NOAA/AL). The instrumentation for each ISS includes a 915-MHz wind profiler, a Radio Acoustic Sounding System (RASS), an Omega-based NAVAID sounding system, and an enhanced surface meteorological station. The general philosophy behind the ISS is that the integration of various measurement systems overcomes each system's respective limitations while taking advantage of its positive attributes. The individual observing systems within the ISS provide high-level data products to a central workstation that manages and integrates these measurements. The ISS software package performs a wide range of functions: real-time data acquisition, database support, and graphical displays; data archival and communications; and operational and posttime analysis. The first deployment of the ISS consists of six sites in the western tropical Pacific--four land-based deployments and two ship-based deployments. The sites serve the Coupled Ocean-Atmosphere Response Experiment (COARE) of the Tropical Ocean and Global Atmosphere (TOGA) program and TOGA's enhanced atmospheric monitoring effort. Examples of ISS data taken during this deployment are shown in order to demonstrate the capabilities of this new sounding system and to demonstrate the performance of these in situ and remote sensing instruments in a moist tropical environment. In particular, a strong convective outflow with a pronounced impact of the atmospheric boundary layer and heat fluxes from the ocean surface was examined with a shipboard ISS. If these strong outflows commonly occur, they may prove to be an important component of the surface energy budget of the western tropical Pacific.

Parsons, David↗