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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 109 records · Page 6
All sourcesNASA NTRSDOE OSTI
NASA NTRS1981

A possible dependence of tectonic strength on the age of the crust in Asia

In Asia, the intensity and style of active tectonics appears to depend on the age of the last orogenic activity. The shields have remained essentially undeformed during the India-Eurasian collision, but Paleozoic and Mesozoic orogenic belts apparently have been reactivated by this collision, with a suggestion of greater reactivation and more diffuse deformation of the younger belts. If the greater observed heat flow in regions of more recent orogenic activity reflects, at least in part, a greater heat flow from the mantle beneath the younger belts, then the temperatures in the mantle beneath the younger belts should be higher than beneath older belts and shields. Because of the strong dependence on temperature of the creep strength of minerals, particularly of olivine, the crust and mantle beneath the hotter, younger belts should be much weaker than those beneath older belts. This difference in temperature, and consequent difference in strength, may be the cause of the greater reactivation of younger belts.

Molnar, P.↗
NASA NTRS1982

Magsat scalar anomalies and major tectonic boundaries in Asia

The distribution of Magsat scalar anomalies is compared with locations of major tectonic boundaries in Asia. Foldbelts separate large-scale positive and negative anomalies inside and outside the Siberian Platform, and sediment-filled aulacogens within the Platform separate the anomalies into two parts which overlie the Anabar and Aldan Shields. Tectonic boundaries appear to exercise some control over the extent and distribution of the satellite-observed crustal anomalies.

Frey, H.↗
NASA NTRS1984

The monsoon of East Asia and its global associations - A survey

Observations concerning the summer and winter monsoons of East Asia and their global associations are reviewed. The seasonal mean structure, transient variation, (intraseasonal to interannual), and synoptic-to-planetary scale fluctuations are discussed separately for the two monsoon components. Similarities and differences between the East Asian monsoon and that of India are also surveyed. Also presented is a description of the current status of monsoon-related observational and theoretical research. The importance of understanding the long-term anomalies of the monsoon is stressed, and an attempt is made to put the East Asian monsoon in a global perspective with a view towards its identification with the problems of long-range weather forecasting or short-term climate prediction in general. Finally, some future directions of research are suggested.

Lau, K.-M.↗
NASA NTRS1985

Structural Mapping of Folded Sedimentary Environments from Satellite Images: an Example from Central Asia

In the Tadjik Depression, in Soviet Central Asia, in the absence of existing geologic or topographic maps, an enhanced LANDSAT multispectral scanner image was used in combination with field data to produce a 1:250000 geologic map of the Vakhsh fold-and-thrust belt and adjacent autochthon. Several structural conclusions are reached as a result of this mapping. Deformation of the Cretaceous and Tertiary strata of the fold-and-thrust belt is, in the central Tadjik Depression, conspicuously absent north of a buried basement fault that marks the hinge-zone of the Late Mesozoic passive margin. But, in the eastern half of the depression, thrusting has moved coherent sheets northward, over the block fault, these sheets now lie flat atop the autochthon to the north. The crustal structure inherited from the Mesozoic extensional phase has strongly influenced the Late Cenozoic pattern of deformation, producing the fold-and-thrust belt that is markedly asymmetric. The development of the thrust system has included the progressive overlapping of thrust: the later thrusts apparently formed internal to the older thrusts, and subsequently overrode them.

Leith, W.↗
NASA NTRS1986

Finite strain calculations of continental deformation. I - Method and general results for convergent zones. II - Comparison with the India-Asia collision zone

The present investigation has the objective to perform numerical experiments on a rheologically simple continuum model for the continental lithosphere. It is attempted to obtain a better understanding of the dynamics of continental deformation. Calculations are presented of crustal thickness distributions, stress, strain, strain rate fields, latitudinal displacements, and finite rotations, taking into account as basis a model for continental collision which treats the litoshphere as a thin viscous layer subject to indenting boundary conditions. The results of this paper support the conclusions of England and McKenzie (1982) regarding the role of gravity in governing the deformation of a thin viscous layer subject to indenting boundary conditions. The results of the experiments are compared with observations of topography, stress and strain rate fields, and palaeomagnetic latitudinal displacements in Asia.

Houseman, G.↗
NASA NTRS1989

Jet stream winds - Enhanced aircraft data acquisition and analysis over Southwest Asia

A project is described for providing the accurate initial and verification analyses for the jet stream in regions where general circulation models are known to have large systematic errors, either due to the extreme sparsity of data or to incorrect physical parameterizations. For this purpose, finely spaced aircraft-based meteorological data for the Southwest Asian regions collected for three 10-day periods in the winter of 1988-1989 will be used, together with corresponding data for the North American regions used as a control, to rerun the assimilation cycles and forecast models of the NMC and the NASA Goddard Laboratory for Atmospheres. Data for Southeast Asia will be collected by three carriers with extensive wide-body routes crossing the total region, while data for the North American region will be obtained from the archives of ACARS and GTS.

Tenenbaum, J.↗
NASA NTRS1992

A test of present-day plate geometries for northeast Asia and Japan

Alternative geometries for the present-day configuration of plate boundaries in northeast Asia and Japan are tested using NUVEL-1 and 256 horizontal earthquake slip vectors from the Japan and northern Kuril trenches. Statistical analysis of the slip vectors is used to determine whether the North American, Eurasian, or Okhotsk plate overlies the trench. Along the northern Kuril trench, slip vectors are well-fit by the NUVEL-1 Pacific-North America Euler pole, but are poorly fit by the Pacific-Eurasia Euler pole. Results for the Japan trench are less conclusive, but suggest that much of Honshu and Hokkaido are also part of the North American plate. The simplest geometry consistent with the trench slip vectors is a geometry in which the North American plate extends south to 41 deg N, and possibly includes northern Honshu and southern Hokkaido. Although these results imply that the diffuse seismicity that connects the Lena River delta to Sakhalin Island and the eastern Sea of Japan records motion between Eurasia and North America, onshore geologic and seismic data define an additional belt of seismicity in Siberia that cannot be explained with this geometry. Assuming that these two seismic belts constitute evidence for an Okhotsk block, two published kinematic models for motion of the Okhotsk block are tested. The first model, which predicts motion of up to 15 mm/yr relative to North America, is rejected because Kuril and Japan trench slip vectors are fit more poorly than for the simpler geometry described above. The second model gives a good fit to the trench slip vectors, but only if Okhotsk-North America motion is slower than 5 mm/yr.

Demets, Charles↗
NASA NTRS2002

Overview of ACE-Asia Spring 2001 Investigations On Aerosol-Radiation Interactions

ACE-Asia's extensive measurements from land, ocean, air and space quantified aerosol-radiation interactions. Results from each platform type, plus satellite-suborbital combinations, include: 1. Time series of multiwavelength aerosol optical depth (ADD), Angstrom exponent (alpha), single-scattering albedo (SSA), and size distribution from AERONET radiometry at 13 stations. In China and Korea AOD and alpha were strongly anticorrelated (reflecting transient dust events); dust volume-size modes peaked near 8 microns diameter; and SSA(dust) greater than SSA(pollution). 2. Calculations and measurements of photosynthetically active radiation and aerosols in China yield 24-h average downward surface radiative forcing per AOD(500 nm) of -27 W/sq m (400-700 nm). 3. The Hawaii-Japan cruise sampled a gradient with AOD(500 nm) extremes of 0.1 and 1.1. Shipboard measurements showed that adding dust to pollution increased SSA(550 nm, 55% RH), typically from -0.91 to approx. 0.97. Downwelling 8-12 micron radiances showed aerosol effects, especially in the major April dust event, with longwave forcing estimated at -5 to 15 W/sq m. 4. Extinction profiles from airborne sunphotometry and total-direct-diffuse radiometry show wavelength dependence often varying strongly with height, reflecting layering of dust-dominated over pollution-dominated aerosols. Comparing sunphotometric extinction profiles to those from in situ measurements (number and composition vs size, or scattering and absorption) shows layer heights agree, but extinction sometimes differs. 5. Airborne solar spectral flux radiometry yields absorption spectra for layers. Combining with AOD spectra yields best-fit aerosol single scattering albedo spectra. 6. Visible, NIR and total solar fluxes combined with AOD give radiative forcing efficiencies at surface and aloft.

Russell, P. B.↗
NASA NTRS2002

Simulation of the Climate of South-West Asia with a Regional Model

The ability of the regional model RegCM2 to simulate the climate of South-West Asia is examined. The climate of the region displays high spatial, seasonal and interannual variability, providing a strong test of climate model capabilities. RegCM2 captures the spatial variability of temperature and precipitation despite cold biases being present in the model. RegCM2 does not capture the annual cycle of precipitation on the Black and Caspian Sea coasts where very steep topography exists, nor on the eastern Mediterranean coast where the coastal mountains are not resolvable. RegCM2 does capture the seasonal cycle in the Fertile Crescent and Zagros mountains, where it is strongly influenced by a plateau circulation above the Iranian plateau. It is shown that accurate simulation of precipitation in these regions, including the inter-annual variability, requires the correct simulation of both storm tracks and topographic interactions. Through the use of regional climate models the concentration and transport pathways of water vapor through the Middle East can be explored. The results demonstrate that short lived 'events' have little impact on monthly mean atmospheric fields yet provide a significant amount of the precipitated water which flows in the Tigris river.

Evans, J. P.↗
NASA NTRS2004

Characteristics and Global Impact of Aerosols from Southern Africa and Eastern Asia

Supported mainly by the NASA GACP and ACMAP, we have made significant progress in the global modeling of tropospheric aerosols and their precursors in the past few years, especially in the development of the GOCART model, simulation of anthropogenic and natural aerosols, data analysis of field observations and satellite retrievals, assessment of global and regional budgets, estimate of aerosol direct radiative forcing, and aerosol forecasting and data analysis for the ACE-Asia field experiment. Our results and findings are summarized in Chin et al. Model calculated multiple-year optical thickness for individual and total aerosols are at internet. These results have been frequently used by other groups, for example, to impose initial conditions for regional models, provide dust source functions for other global models, supply aerosol fields for chemistry and climate models, help data group interpret their measurements, select monitoring sites for ground observation network, and assist satellite retrievals.

Chin, Mian↗
NASA NTRS2004

The Misnomer of East Asia Summer Monsoon

The terminology East Asian summer monsoon is used to refer to the heavy rainfall in southeast China including the Yangtze River Valley starting in May and ending in August (e.g., Chen and Chang 1980, Tao and Chen 1987, Ding 1992, Chang et al. 2000a.) This rainfall region is associated with the Mei-Yu front, which extends to Japan and its neighborhood and is called Baiu there. The Mei-Yu front becomes prominent in May and has a slow northward movement. From May to July the elongated rain belt moves from the southeast coast of China to the Yangtze River Valley. The rain belt extends north-east-ward to south of Japan in May and later covers Korea also. The purpose of this note is to point out that the terminology of East Asian summer monsoon is a misnomer to refer to the portion of this rainbelt residing over East Asia, in the sense that it is not a monsoon.

Chao, Winston C.↗
NASA NTRS2003

Results of 17 Independent Geopositional Accuracy Assessments of Earth Satellite Corporation's GeoCover Landsat Thematic Mapper Imagery. Geopositional Accuracy Validation of Orthorectified Landsat TM Imagery: Northeast Asia

This report provides results of an independent assessment of the geopositional accuracy of the Earth Satellite (EarthSat) Corporation's GeoCover, Orthorectified Landsat Thematic Mapper (TM) imagery over Northeast Asia. This imagery was purchased through NASA's Earth Science Enterprise (ESE) Scientific Data Purchase (SDP) program.

Smith, Charles M.↗
NASA NTRS2005

Growing Typhoon Influence on East Asia

Numerical model studies have suggested that the ongoing global warming will likely affect tropical cyclone activity. But so far little observed evidence has been detected to support the projected future changes. Using satellite-supported best-track data from 1965 to 2003, we show for the first time that over the past four decades the two prevailing typhoon tracks in the western North Pacific (WNP) have shifted westward significantly; the typhoon activity over the South China Sea has considerably decreased; and East Asia has experienced increasing typhoon influence. Our trajectory model simulation indicates that the long-term shifts in the typhoon tracks result primarily from the changes in the mean translation velocity of typhoons or the large-scale steering flow, which is associated with the westward expansion and strengthening of the WNP subtropical high.

Wu, Liguang↗
NASA NTRS2005

Aerosol properties computed from aircraft-based observations during the ACE- Asia campaign: A case study of lidar ratio closure and aerosol radiative effects - 2

For a vertical profile with three distinct layers (marine boundary, pollution and dust), observed during the ACE-Asia campaign, we carried out a comparison between the modeled lidar ratio vertical profile and that obtained from collocated airborne NASA AATS-14 sunphotometer and shipborne Micro-Pulse Lidar (MPL) measurements. Vertically resolved lidar ratio was calculated from two size distribution vertical profiles - one obtained by inversion of sunphotometer-derived extinction spectra, and one measured in-situ - combined with the same refractive index model based on aerosol chemical composition. The aerosol model implies single scattering albedos of 0.78 - 0.81 and 0.93 - 0.96 at 0.523 microns (the wavelength of the lidar measurements), in the pollution and dust layers, respectively. The lidar ratios calculated from the two size distribution profiles have close values in the dust layer; they are however, significantly lower than the lidar ratios derived from combined lidar and sunphotometer measurements, most probably due to the use of a simple nonspherical model with a single particle shape in our calculations. In the pollution layer, the two size distribution profiles yield generally different lidar ratios. The retrieved size distributions yield a lidar ratio which is in better agreement with that derived from lidar/sunphotometer measurements in this layer, with still large differences at certain altitudes (the largest relative difference was 46%). We explain these differences by non-uniqueness of the result of the size distribution retrieval and lack of information on vertical variability of particle refractive index. Radiative transfer calculations for this profile showed significant atmospheric radiative forcing, which occurred mainly in the pollution layer. We demonstrate that if the extinction profile is known then information on the vertical structure of absorption and asymmetry parameter is not significant for estimating forcing at TOA and the surface, while it is of importance for estimating vertical profiles of radiative forcing and heating rates.

Kuzmanoski, Maja↗
NASA NTRS2006

Comparisons of Remote Sensing Retrievals and in situ Measurements of Aerosol Fine Mode Fraction during ACE-Asia

We present sunphotometer-retrieved and in situ fine mode fractions (FMF) measured onboard the same aircraft during the ACE-Asia experiment. Comparisons indicate that the latter can be used to identify whether the aerosol under observation is dominated by a mixture of modes or a single mode. Differences between retrieved and in situ FMF range from 5-20%. When profiles contained multiple layers of aerosols, the retrieved and measured FMF were segregated by layers. The comparison of layered and total FMF from the same profile indicates that columnar values are intermediate to those derived from layers. As a result, a remotely sensed FMF cannot be used to distinguish whether the aerosol under observation is composed of layers each with distinctive modal features or all layers with the same modal features. Thus, the use of FMF in multiple layer environments does not provide unique information on the aerosol under observation.

Gasso, Santiago↗
NASA NTRS2010

Towards Global Simulation of Irrigation in a Land Surface Model: Multiple Cropping and Rice Paddy in Southeast Asia

Agricultural land use significantly influences the surface water and energy balances. Effects of irrigation on land surface states and fluxes include repartitioning of latent and sensible heat fluxes, an increase in net radiation, and an increase in soil moisture and runoff. We are working on representing irrigation practices in continental- to global-scale land surface simulation in NASA's Global Land Data Assimilation System (GLDAS). Because agricultural practices across the nations are diverse, and complex, we are attempting to capture the first-order reality of the regional practices before achieving a global implementation. This study focuses on two issues in Southeast Asia: multiple cropping and rice paddy irrigation systems. We first characterize agricultural practices in the region (i.e., crop types, growing seasons, and irrigation) using the Global data set of monthly irrigated and rainfed crop areas around the year 2000 (MIRCA2000) dataset. Rice paddy extent is identified using remote sensing products. Whether irrigated or rainfed, flooded fields need to be represented and treated explicitly. By incorporating these properties and processes into a physically based land surface model, we are able to quantify the impacts on the simulated states and fluxes.

Beaudoing, Hiroko Kato↗
NASA NTRS2010

Aerosol Absorption by Black Carbon and Dust: Implications of Climate Change and Air Quality in Asia

Atmospheric aerosol distributions from 2000 to 2007 are simulated with the global model GOCART to attribute light absorption by aerosol to its composition and sources. We show the seasonal and interannual variations of absorbing aerosols in the atmosphere over Asia, mainly black carbon and dust. and their linkage to the changes of anthropogenic and dust emissions in the region. We compare our results with observations from satellite and ground-based networks, and estimate the importance of black carbon and dust on regional climate forcing and air quality.

Chin, Mian↗
NASA NTRS2010

Utilizing Higher Resolution Land Surface Remote Sensing Data for Assessing Recent Trends over Asia Monsoon Region

The slide presentation discusses the integration of 1-kilometer spatial resolution land temperature data from the Moderate Resolution Imaging Spectroradiometer (MODIS), with 8-day temporal resolution, into the NASA Monsoon-Asia Integrated Regional Study (MAIRS) Data Center. The data will be available for analysis and visualization in the Giovanni data system. It discusses the NASA MAIRS Data Center, presents an introduction to the data access tools, and an introduction of Products available from the service, discusses the higher resolution Land Surface Temperature (LST) and presents preliminary results of LST Trends over China.

Shen, Suhung↗