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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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At least 73 records · Page 4
All sourcesNASA NTRSDOE OSTI
NASA NTRS1976

Response of deep and shallow tropical maritime cumuli to large-scale processes

The bulk diagnostic method of Yanai et al. (1973) and a simplified version of the spectral diagnostic method of Nitta (1975) are used for a more quantitative evaluation of the response of various types of cumuliform clouds to large-scale processes, using the same data set in the Marshall Islands area for a 100-day period in 1956. The dependence of the cloud mass flux distribution on radiative cooling, large-scale vertical motion, and evaporation from the sea is examined. It is shown that typical radiative cooling rates in the tropics tend to produce a bimodal distribution of mass spectrum exhibiting deep and shallow clouds. The bimodal distribution is further enhanced when the large-scale vertical motion is upward, and a nearly unimodal distribution of shallow clouds prevails when the relative cooling is compensated by the heating due to the large-scale subsidence. Both deep and shallow clouds are modulated by large-scale disturbances. The primary role of surface evaporation is to maintain the moisture flux at the cloud base.

Yanai, M.↗
NASA NTRS1981

A low cost maritime control aircraft-ship-weapons system

It is pointed out that the long-range antiship standoff missile is emerging as the foremost threat on the seas. Delivered by high speed bombers, surface ships, and submarines, a missile attack can be mounted against selected targets from any point on the compass. An investigation is conducted regarding the configuration of a system which could most efficiently identify and destroy standoff threats before they launch their weapons. It is found that by using ships for carrying and launching missiles, and employing aircraft with a powerful radar only for search and missile directing operations, aircraft cost and weight can be greatly reduced. The employment of V/STOL aircraft in preference to other types of aircraft makes it possible to use ships of smaller size for carrying the aircraft. However, in order to obtain an all-weather operational capability for the system, ships are selected which are still big enough to display the required stability in heavy seas.

Fluk, H.↗
NASA NTRS1984

SAR maritime missions

The U.S. Coast Guard missions (search and rescue, enforcement of laws and treaties, marine environmental patrol, and light utility transport) are discussed.

Young, D. A.↗
NASA NTRS1985

Resolution enhancement of multichannel microwave imagery from the Nimbus-7 SMMR for maritime rainfall analysis

A restoration of the 37, 21, 18, 10.7, and 6.6 GHz satellite imagery from the scanning multichannel microwave radiometer (SMMR) aboard Nimbus-7 to 22.2 km resolution is attempted using a deconvolution method based upon nonlinear programming. The images are deconvolved with and without the aid of prescribed constraints, which force the processed image to abide by partial a priori knowledge of the high-resolution result. The restored microwave imagery may be utilized to examined the distribution of precipitating liquid water in marine rain systems.

Olson, W. S.↗
NASA NTRS1986

Resolution enhancement of multichannel microwave imagery from the Nimbus-7 SMMR for maritime rainfall analysis

A restoration of the 37, 21, 18, 10.7, and 6.6 GHz satellite imagery from the scanning multichannel microwave radiometer (SMMR) aboard Nimbus-7 to 22.2 km resolution is attempted using a deconvolution method based upon nonlinear programming. The images are deconvolved with and without the aid of prescribed constraints, which force the processed image to abide by partial a priori knowledge of the high-resolution result. The restored microwave imagery may be utilized to examine the distribution of precipitating liquid water in marine rain systems.

Olson, William S.↗
NASA NTRS1987

Correlations between ozone and carbon monoxide in the lower stratosphere, folded tropopause, and maritime troposphere

The variations of ozone and carbon monoxide with respect to the atmospheric flow structure are investigated for two aircraft flights: one in the upper troposphere/lower stratosphere over the continental United States on April 20, 1984, and the other in the marine troposphere over the eastern Pacific on April 26, 1984. The high frequency (1 Hz) and precision of the measurements allow detailed analysis of the species distribution down to length scales of the order of 1 km. Correlations between the two species are made on large, medium, and small scales of motion, and the results are interpreted. In general, the correlations are negative with some regions of positive correlation. The interpretation of these results is discussed.

Hipskind, R. Stephen↗
NASA NTRS1989

Surface dynamics of observed maritime fronts

The importance of various dynamical processes in the surface fronts over the ocean is investigated using the unique data set supplied by the Seasat-A satellite scatterometer, in conjunction with a planetary boundary layer model. The governing equations are presented, and a similarity model that includes the effects of shear and the effects of shear and deformation on an Ekman solution is derived. It is shown that surface friction is important in frontal processes through its role in determining the dissipation and the ageostrophic terms in the vorticity and divergence equations; the former normally acts to weaken a front while the latter acts to strengthen it. The magnitude and importance of these terms vary considerably at different stages and with stratification, thermal advection, and the deformation and shear forcing.

Levy, Gad↗
NASA NTRS1993

Phenytoin as a countermeasure for motion sickness in NASA maritime operations

Seasickness is the most prevalent form of motion sickness and is an operational problem during Space Shuttle Solid-fueled Rocket Booster (SRB) retrieval. Phenytoin has been shown to protect against motion sickness induced by Coriolis stress. We exposed SRB recovery personnel to off-vertical rotation and sea motion after phenytoin or placebo. Phenytoin blood levels of at least 9 micrograms/ml were protective against motion sickness at sea. No change in susceptibility to nitrogen narcosis was seen in divers in chamber tests at 460 KPa. Phenytoin was used during the performance of critical and hazardous tasks during training and actual SRB recovery operations. Phenytoin is an effective operational countermeasure for motion sickness for selected SRB crew members.

Woodard, Daniel↗
NASA NTRS1994

A preliminary design proposal for a maritime patrol strike aircraft: MPS-2000 Condor

The four member graduate design team assembled to submit a proposal for the 1993/1994 RFP at the University of Kansas has designed a four seat, variable swept wing, twin turbofan aircraft with STOL capabilities. The aircraft is named the MPS-2000 Condor and is capable of carrying air-to-surface or air-to-air weapon systems along with attack and surveillance radar and IRF systems. The aircraft has a cruise range of 800 nautical miles, a loiter of 4 hours, and a dash speed of 500 kts.

Source record↗
NASA NTRS2001

Background Maritime Aerosol: Their Optical Thickness and Scattering Properties

The effect of human induced change in the aerosol concentration and properties, or the aerosol response to climate change (e.g. droughts producing fires or dust) should be measured relative to a "background aerosol". How to define this background aerosol, so that it is both measurable and useful? Here we use 10 stations located in the Pacific, Atlantic and Indian Oceans to answer this question. Using a data set of the spectral optical thickness measured by the Aerosol Robotic network (AERONET), extending 1-3 years, we find the background conditions for these stations. The oceanic background aerosol is the result of ocean emission and spray, and some residual long lived continental aerosol. Its source is very broadly spread and is expected to vary little in time. Pollution or dust sources are from specific locations, emitted and transported to the measuring site in specific combination of meteorological conditions. Therefore they are expected to vary with time. It follows that the background aerosol can be identified as the median for conditions with small variations. To define the background we compute the median of N consequent measurements. We use N=50 that in average cloudy conditions corresponds to 2-3 days of measurements and N=100 (4-5 days). Most high polluted or dusty conditions correspond to data sequences with high standard deviation (greater than 0.02 in optical thickness) and are excluded. From the remaining N point running medians with low standard deviations we derive again the median. This excludes those rare cases of pollution or dust that is stable during the N measurements. The results show that the background aerosol over the Pacific Ocean is characterize by optical thickness of 0.055 at 500 nm and Angstrom exponent of 0.74. Over the Atlantic Ocean the values are 0.070 and 1.1 respectively, with little influence of the assumed value of N (50 or 100). The derivation of the background uses 20,000 and 5000 medians respectively that passed the criteria. The contribution of coarse and fine aerosol to the background aerosol is also calculated.

Kaufman, Yoram J.↗
NASA NTRS2001

Baseline Maritime Aerosol: Methodology to Derive the Optical Thickness and Scattering Properties

Satellite Measurements of the global distribution of aerosol and their effect on climate should be viewed in respect to a baseline aerosol. In this concept, concentration of fine mode aerosol particles is elevated above the baseline by man-made activities (smoke or urban pollution), while coarse mode by natural processes (e.g. dust or sea-spray). Using 1-3 years of measurements in 10 stations of the Aerosol Robotic network (ACRONET we develop a methodology and derive the optical thickness and properties of this baseline aerosol for the Pacific and Atlantic Oceans. Defined as the median for periods of stable optical thickness (standard deviation < 0.02) during 2-6 days, the median baseline aerosol optical thickness over the Pacific Ocean is 0.052 at 500 am with Angstrom exponent of 0.77, and 0.071 and 1.1 respectively, over the Atlantic Ocean.

Kaufman, Yoram J.↗
NASA NTRS2008

Aerosol and Cloud Microphysical Characteristics of Rifts and Gradients in Maritime Stratocumulus Clouds

A cloud rift is characterized as a large-scale, persistent area of broken, low reflectivity stratocumulus clouds usually surrounded by a solid deck of stratocumulus. A rift observed off the coast of Monterey Bay, California on 16 July 1999 was studied to compare the aerosol and cloud microphysical properties in the rift with those of the surrounding solid stratus deck. Variables measured from an instrumented aircraft included temperature, water vapor, and cloud liquid water. These measurements characterized the thermodynamic properties of the solid deck and rift areas. Microphysical measurements made included aerosol, cloud drop and drizzle drop concentrations and cloud condensation nuclei (CCN) concentrations. The microphysical characteristics in a solid stratus deck differ substantially from those of a broken, cellular rift where cloud droplet concentrations are a factor of 2 lower than those in the solid cloud. Further, CCN concentrations were found to be about 3 times greater in the solid cloud area compared with those in the rift and aerosol concentrations showed a similar difference as well. Although drizzle was observed near cloud top in parts of the solid stratus cloud, the largest drizzle rates were associated with the broken clouds within the rift area. In addition to marked differences in particle concentrations, evidence of a mesoscale circulation near the solid cloud rift boundary is presented. This mesoscale circulation provides a mechanism for maintaining a rift, but further study is required to understand the initiation of a rift and the conditions that may cause it to fill.

Sharon, Tarah M.↗
NASA NTRS2008

Maritime Aerosol Network (MAN) as a Component of AERONET

The World Ocean produces a large amount of natural aerosols that have all impact on the Earth's albedo and climate. Sea-salt is the major contributor to aerosol optical depth over the oceans. [Mahowald et al. 2006; Chin et al. 2002; Satheesh et al. 1999; Winter and Chylek, 1997] and therefore affects the radiative balance over the ocean through the direct [Haywood et al. 1999] and indirect aerosol effect [O'Dowd et al. 1999]. Aerosols over the oceans (produced marine and advected from land sources) are important for various atmospheric processes [Lewis and Schwartz, 2004] and remote sensing studies [Gordon, 1997].

Smirnov, A.↗
NASA NTRS2014

Safe Maritime Autonomous Path Planning in a High Sea State

This paper presents a path planning method for sea surface vehicles that prevents capsizing and bow-diving in a high sea-state. A key idea is to use response amplitude operators (RAOs) or, in control terminology, the transfer functions from a sea state to a vessel's motion, in order to find a set of speeds and headings that results in excessive pitch and roll oscillations. This information is translated to arithmetic constraints on the ship's velocity, which are passed to a model predictive control (MPC)-based path planner to find a safe and optimal path that achieves specified goals. An obstacle avoidance capability is also added to the path planner. The proposed method is demonstrated by simulations.

Ono, Masahiro↗
NASA NTRS2017

Weathering the Storm: Unmanned Aircraft Systems in the Maritime, Atmospheric and Polar Environments

Remotely piloted aircraft (RPA) have the potential to revolutionize local to regional data collection for geophysicists as platform and payload size decrease while aircraft capabilities increase. In particular, data from RPAs combine high-resolution imagery available from low flight elevations with comprehensive areal coverage, unattainable from ground investigations and difficult to acquire from manned aircraft due to budgetary and logistical costs. Low flight elevations are particularly important for detecting signals that decay exponentially with distance, such as electromagnetic fields. Onboard data processing coupled with high-bandwidth telemetry open up opportunities for real-time and near real-time data processing, producing more efficient flight plans through the use of payload-directed flight, machine learning and autonomous systems. Such applications not only strive to enhance data collection, but also enable novel sensing modalities and temporal resolution. NASAs Airborne Science Program has been refining the capabilities and applications of RPA in support of satellite calibration and data product validation for several decades. In this paper, we describe current platforms, payloads, and onboard data systems available to the research community. Case studies include Fluid Lensing for littoral zone 3D mapping, structure from motion for terrestrial 3D multispectral imaging, and airborne magnetometry on medium and small RPAs.

data collection↗
NASA NTRS2016

Weathering the Storm: Unmanned Aircraft Systems in the Maritime, Atmospheric and Polar Environments

Unmanned systems have the potential to efficiently, effectively, economically, and safely bridge critical observation requirements in an environmentally friendly manner. As the United States Atmospheric, Marine and Arctic areas of interest expand and include hard-to-reach regions of the Earth (such as the Arctic and remote oceanic areas) optimizing unmanned capabilities will be needed to advance the United States science, technology and security efforts. Through increased multi-mission and multi-agency operations using improved inter-operable and autonomous unmanned systems, the research and operations communities will better collect environmental intelligence and better protect our country against hazardous weather, environmental, marine and polar hazards. This presentation will examine UAS (Unmanned Aircraft Systems) operations which includes developing a coordinated effort to maximize the efficiency and capabilities of unmanned systems across the federal government and research partners. Numerous intra- and inter-agency operational demonstrations and assessments have been made to verify and validated these UAS observations. The NASA-specific elements will consist of an overview of NASA UAVs (Unmanned Aerial Vehicles) available to science and recent missions.

Atmospheric↗