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All sourcesNASA NTRSDOE OSTI
NASA NTRS1989

Space Station Freedom Workshop Opportunities for Commercial Users and Providers: Issues and Recommendations

The responses to issues and questions raised at the Space Station Freedom Workshops are compiled. The findings are presented under broad divisions of general, materials processing in space, commercial earth and ocean observations, life sciences, infrastructure services, and infrastructure policy. The responses represent the best answers available at this time and future modifications may be expected. Contact names, telephone numbers, and organizations are included.

Source record↗
NASA NTRS1991

Seasat-A - A retrospective

This paper traces the highlights of the Seasat-A project from its earliest conceptual phases through the orbital operations phase. The primary objective of the project was to demonstrate the feasibility of remotely sensing fundamental oceanographic phenomena on a global, accurate, reliable and timely basis from an earth-orbiting platform. The project successfully achieved its primary objective, in spite of a premature spacecraft failure, and thus provided a firm basis for the development of sensors for future ocean-observing space missions.

Giberson, W. E.↗
NASA NTRS1992

Proceedings of the Ocean Climate Data Workshop

The First Consultative Meeting on Responsible National Oceanographic Data Centres (RNODC's) and Climate DataServices met in February 1988 and made a number of recommendations related to improving services to meet the needs of climate programmes. Included in these discussions was a recommendation for a Workshop on Ocean Climate Data Management. This workshop will be talking about ways to establish a Global Ocean Observing System (GOOS).

Churgin, James↗
NASA NTRS1992

Indian Ocean analyses

The background and goals of Indian Ocean thermal sampling are discussed from the perspective of a national project which has research goals relevant to variation of climate in Australia. The critical areas of SST variation are identified. The first goal of thermal sampling at this stage is to develop a climatology of thermal structure in the areas and a description of the annual variation of major currents. The sampling strategy is reviewed. Dense XBT sampling is required to achieve accurate, monthly maps of isotherm-depth because of the high level of noise in the measurements caused by aliasing of small scale variation. In the Indian Ocean ship routes dictate where adequate sampling can be achieved. An efficient sampling rate on available routes is determined based on objective analysis. The statistical structure required for objective analysis is described and compared at 95 locations in the tropical Pacific and 107 in the tropical Indian Oceans. XBT data management and quality control methods at CSIRO are reviewed. Results on the mean and annual variation of temperature and baroclinic structure in the South Equatorial Current and Pacific/Indian Ocean Throughflow are presented for the region between northwest Australia and Java-Timor. The mean relative geostrophic transport (0/400 db) of Throughflow is approximately 5 x 106 m3/sec. A nearly equal volume transport is associated with the reference velocity at 400 db. The Throughflow feeds the South Equatorial Current, which has maximum westward flow in August/September, at the end of the southeasterly Monsoon season. A strong semiannual oscillation in the South Java Current is documented. The results are in good agreement with the Semtner and Chervin (1988) ocean general circulation model. The talk concludes with comments on data inadequacies (insufficient coverage, timeliness) particular to the Indian Ocean and suggestions on the future role that can be played by Data Centers, particularly with regard to quality control of data as research bodies are replaced by operational bodies in the Global Ocean Observing System.

Meyers, Gary↗
NASA NTRS1999

Acoustic Studies of the Large Scale Ocean Circulation

Detailed knowledge of ocean circulation and its transport properties is prerequisite to an understanding of the earth's climate and of important biological and chemical cycles. Results from two recent experiments, THETIS-2 in the Western Mediterranean and ATOC in the North Pacific, illustrate the use of ocean acoustic tomography for studies of the large scale circulation. The attraction of acoustic tomography is its ability to sample and average the large-scale oceanic thermal structure, synoptically, along several sections, and at regular intervals. In both studies, the acoustic data are compared to, and then combined with, general circulation models, meteorological analyses, satellite altimetry, and direct measurements from ships. Both studies provide complete regional descriptions of the time-evolving, three-dimensional, large scale circulation, albeit with large uncertainties. The studies raise serious issues about existing ocean observing capability and provide guidelines for future efforts.

Menemenlis, Dimitris↗
NASA NTRS1995

An Overview of the TOPEX/Poseidon Outreach Program

The TOPEX/Poseidon program will observe ocean circulation for 3 to 5 years and monitor the effects of currents on global climate change. To communicate the results of this study to the public, this project will use printed materials, CD-ROM tutorials, a computer network, and lecturers.

education climate change ocean currents outreach↗
NASA NTRS2003

Air-sea interaction with multiple sensors - Seasat legacy

By flying a number of ocean observing sensors together, Seasat demonstrated potential of not only sensor synergism, but also science synergism, which has illuminated the path of spacebased air-sea interaction studies in more than two decades since its demise.

air-sea-interaction hurricane El Nino Kelvin wave ↗
NASA NTRS2010

Ocean and Atmospheric Profiling Lidar Observations and Its Link to Ocean Carbon Cycle

This study introduces space-based ocean and atmospheric profiling lidar for improving modeling and understanding of ocean carbon cycle. Unique measurements from space-based profiling lidars include (1) the global ocean surface mean square slope measurements for improving air-sea turbulence exchange estimates; (2) the backscatter and beam attenuation measurements for improving the global estimate of partial pressure of CO2 of the ocean with the reduction of uncertainties in primary productivity estimates. Global statistics of CALIOP integrated ocean subsurface backscatter measurements of coastal waters will be presented. The study will also assess the impact of CALIOP on the uncertainty reduction of primary productivity and the improvement of CO2 partial pressure estimates. Ocean surface roughness statistics, its applications in air-sea interaction and its comparisons with other measurements will also be presented

Hu, Yongxiang↗
NASA NTRS2014

Aggregation Tool to Create Curated Data albums to Support Disaster Recovery and Response

Despite advances in science and technology of prediction and simulation of natural hazards, losses incurred due to natural disasters keep growing every year. Natural disasters cause more economic losses as compared to anthropogenic disasters. Economic losses due to natural hazards are estimated to be around $6-$10 billion dollars annually for the U.S. and this number keeps increasing every year. This increase has been attributed to population growth and migration to more hazard prone locations such as coasts. As this trend continues, in concert with shifts in weather patterns caused by climate change, it is anticipated that losses associated with natural disasters will keep growing substantially. One of challenges disaster response and recovery analysts face is to quickly find, access and utilize a vast variety of relevant geospatial data collected by different federal agencies such as DoD, NASA, NOAA, EPA, USGS etc. Some examples of these data sets include high spatio-temporal resolution multi/hyperspectral satellite imagery, model prediction outputs from weather models, latest radar scans, measurements from an array of sensor networks such as Integrated Ocean Observing System etc. More often analysts may be familiar with limited, but specific datasets and are often unaware of or unfamiliar with a large quantity of other useful resources. Finding airborne or satellite data useful to a natural disaster event often requires a time consuming search through web pages and data archives. Additional information related to damages, deaths, and injuries requires extensive online searches for news reports and official report summaries. An analyst must also sift through vast amounts of potentially useful digital information captured by the general public such as geo-tagged photos, videos and real time damage updates within twitter feeds. Collecting and aggregating these information fragments can provide useful information in assessing damage in real time and help direct recovery efforts. The search process for the analyst could be made much more efficient and productive if a tool could go beyond a typical search engine and provide not just links to web sites but actual links to specific data relevant to the natural disaster, parse unstructured reports for useful information nuggets, as well as gather other related reports, summaries, news stories, and images. This presentation will describe a semantic aggregation tool developed to address similar problem for Earth Science researchers. This tool provides automated curation, and creates "Data Albums" to support case studies. The generated "Data Albums" are compiled collections of information related to a specific science topic or event, containing links to relevant data files (granules) from different instruments; tools and services for visualization and analysis; information about the event contained in news reports, and images or videos to supplement research analysis. An ontology-based relevancy-ranking algorithm drives the curation of relevant data sets for a given event. This tool is now being used to generate a catalog of Hurricane Case Studies at Global Hydrology Resource Center (GHRC), one of NASA's Distribute Active Archive Centers. Another instance of the Data Albums tool is currently being created in collaboration with NASA/MSFC's SPoRT Center, which conducts research on unique NASA products and capabilities that can be transitioned to the operational community to solve forecast problems. This new instance focuses on severe weather to support SPoRT researchers in their model evaluation studies

Ramachandran, Rahul↗
NASA NTRS2011

Current-Sensitive Path Planning for an Underactuated Free-Floating Ocean Sensorweb

This work investigates multi-agent path planning in strong, dynamic currents using thousands of highly under-actuated vehicles. We address the specific task of path planning for a global network of ocean-observing floats. These submersibles are typified by the Argo global network consisting of over 3000 sensor platforms. They can control their buoyancy to float at depth for data collection or rise to the surface for satellite communications. Currently, floats drift at a constant depth regardless of the local currents. However, accurate current forecasts have become available which present the possibility of intentionally controlling floats' motion by dynamically commanding them to linger at different depths. This project explores the use of these current predictions to direct float networks to some desired final formation or position. It presents multiple algorithms for such path optimization and demonstrates their advantage over the standard approach of constant-depth drifting.

oceanography↗
NASA NTRS2021

Tropospheric Age-of-Air: Influence of SF6 Emissions on Recent Surface Trends and Model Biases

The mean age since air was last at the Northern Hemisphere (NH) midlatitude surface is a fundamental property of tropospheric transport. Here we approximate the mean age in terms of an "SF6 age" (ΓSF6), derived from surface and aircraft measurements of SF6 that are broader in spatial scope and cover a longer time period (1997-2018) than considered previously. At the surface, ΓSF6 increases from near-zero values north of 30°N to ~1.5 years over the Southern Hemisphere (SH) extratropics, with the largest meridional gradients occurring in the tropics. By comparison, vertical gradients in ΓSF6 are weak throughout, with only slight increases/decreases with height in the NH/SH. The broader spatial coverage of the measurements reveals strong variations in the seasonal cycle of ΓSF6 within the (sub)tropics that are weaker over the Atlantic and Paci c oceans, compared to over the Indian Ocean. Observations from 2000-2018 reveal that the SF6 age at sites in the SH has been decreasing by ~0.12 yr/dec. However, this decrease is not due to changes in transport but, rather, is likely related to changes in emissions, which have increased globally and reportedly shifted from northern midlatitudes into the subtropics. Simulations, which reproduce the SF6 age trends, show no decreases in an age-of-air tracer, reinforcing the fact that ΓSF6 represents only an approximation to the mean age. Finally, the modeled SF6 ages are older than observed, by ~0.3-0.4 years throughout the southern extratropics. We show that this bias is partly related to an overestimation in simulated SF6 near emissions regions,

Mean age↗
NASA NTRSDate not supplied

Microwave and mm-Wave Radiometry for Earth and Planetary Science

Microwave radiometry has been an indispensable tool for observing Earth and the solar system since the 1960s. On Earth, microwave radiometers are used to observe ocean, land, ice, and atmosphere. Calibrating a microwave radiometer and measuring an LNA noise figure use the same principals. There is opportunity to improve upon the state-of-the-art methods in both space and lab environments by leveraging lessons learned in one for the other.

microwave radiometry↗
NASA NTRS1990

Influence of penetrating solar radiation on the heat budget of the equatorial Pacific Ocean

Recent satellite observations of ocean transparency, coupled with climatological surface heat fluxes and ocean density profiles, are used here to show that solar radiation in visible frequencies, usually assumed to be absorbed at the sea surface, in fact penetrates to a significant degree to below the upper mixed layer of the ocean which interacts actively with the atmosphere. The net effect is a reduction of the heat input into the upper layer; for a 20 m-thick mixed layer this is equivalent to an annual reduction in temperature of about 5-10 K. The results provide a natural explanation for the discrepancy between the SSTs predicted by models and those observed.

Lewis, Marlon R.↗
NASA NTRS1991

A TOPEX/Poseidon study of oceanic effects on observations of the Earth's interior

The primary objective of our research program is the application of TOPEX/POSEIDON oceanic data to the study of various geophysical observations, thereby improving our knowledge of the Earth's interior. Observations of the Earth's solid tides, rotation, time-dependent gravity, and crustal deformation provide potentially useful constraints on properties of the solid Earth and its liquid core, but all these parameters are also sensitive to oceanic effects. Depending on the type of observation, those effects are usually either removed by modeling (often using particularly simple assumptions about the dynamics of the ocean) or ignored entirely. Useful oceanic data are rarely available. In many cases, the uncertainty in the oceanic correction is the main source of error in the geophysical interpretation of the results. We describe, below several of these geophysical observations, how their interpretation in terms of the Earth's interior is affected by the oceans, and how data from the TOPEX/POSEIDON mission can be used to improve this situation.

Wahr, John↗
NASA NTRS1995

Light response of phytoplankton in the South Atlantic Ocean: Interpretation of observations and application to remote sensing

A simplified, nonspectral derivation of a classical theory in plant physiology is presented and used to derive an absorption-based primary productivity algorithm. Field observations from a meridional transect (4 deg N to 42 deg S) in the Atlantic Ocean are then described and interpreted in this theoretical context. The observations include photosynthesis-irradiance curve parameters (alpha and P(sub max)), chlorophyll a and phaeopigment concentration, and estimated phytoplankton absorption coefficients at wavelength = 440 nm (a(sub ph)(440)). Observations near the top (50% I(sub 0)) and bottom (6% I(sub 0)) of the euphotic zone are contrasted. At both light levels, alpha, P(sub max), a(sub ph)(440), and pigment concentration varied similarly along the transect: values were highest at the equator and at the southern end of the transect and lowest in the central South Atlantic. It is concluded that this pattern was related to increased nutrient availability due to equatorial upwelling in the north, and increased wind mixing in the south. At the 50% light level, alpha increased relative to a(sub ph) at the southern end of the transect. This result appears to reflect a large-scale meridional (southward) increase in the average quantum efficiency of the photosynthetic units of the phytoplankton. A correlation analysis of the data reveals that at the 50% light level, variations in P(sub max) were more closely related to a(sub ph)(440) than chlorophyll concentration and that phytoplankton absorption explains 90% of the variability in P(sub max). In theory, this shows that the ratio of the average quantum efficiency of the photosynthetic units of the phytoplankton to the product of their average absorption cross section and turnover time is relatively constant. This result is used to simplify the absorption-based primary productivity algorithm derived previously. The feasibility of using this model to estimate production rate from satellite ocean color observations is discussed. It is concluded that an absorption-based algorithm should provide more accurate production rate estimates than one based upon chlorophyll (pigment) concentration.

Hood, Raleigh R.↗
NASA NTRS1992

Morning-evening differences in global and regional oceanic precipitation as observed by the SSM/I

For the present preliminary analysis of oceanic rainfall statistics, global oceanic SSM/I data were simply scanned for pixels which exhibited a 37 GHz polarization difference (vertically polarized brightness temperatures minus horizontally polarized brightness temperatures) of less than 15 K. Such a low polarization difference over the open ocean is a completely unambiguous indication of moderate to intense precipitation. Co-located brightness temperatures from all seven channels of the SSM/I were saved for each pixel so identified. Bad scans and geographically mislocated block of data were objectively identified and removed from the resulting data base. We collected global oceanic rainfall data for two time periods, each one month in length. The first period (20 July-19 August 1987) coincides with the peak of the Northern Hemisphere summer. The second period (13 January-12 February 1988) coincides with the Northern Hemisphere winter.

Petty, Grant W.↗