Search NASA⌕ Search

SEARCH · Search NASA

Results for “Pacific Ocean”

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.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 127 records · Page 7
All sourcesNASA NTRSDOE OSTI
NASA NTRS1997

Chemical Characteristics of Continental Outflow from Asia to the Troposphere Over the Western Pacific Ocean during February - March 1994: Results from PEM-West B

We present here the chemical composition of outflow from the Asian continent to the atmosphere over the western Pacific basin during the Pacific Exploratory Mission-West (PEM-West B) in February-March 1994. Comprehensive measurements of important tropospheric trace gases and aerosol particulate matter were performed from the NASA DC-8 airborne laboratory. Backward 5 day isentropic trajectories were used to partition the outflow from two major source regions- continental north (greater than 20 deg N) and continental south (less than 20 deg N). Air parcels that had not passed over continental areas for the previous 5 days were classified as originating from an aged marine source. The trajectories and the chemistry together indicated that there was extensive rapid outflow of air parcels at altitudes below 5 km, while aged marine air was rarely encountered and only at less than 20 deg N latitude. The outflow at low altitudes had enhancements in common industrial solvent vapors such as C2Cl4, CH3CCl3, and C6H6, intermixed with the combustion emission products C2H2, C2H6, CO, and NO. The mixing ratios of all species were up to tenfold greater in outflow from the continental north compared to the continental south source region, with Pb-210 concentrations reaching 38 fCi (10(exp -15) curies) per standard cubic meter. In the upper troposphere we again observed significant enhancements in combustion-derived species in the 8-10 km altitude range, but water-soluble trace gases and aerosol species were depleted. These observations suggest that ground level emissions were lofted to the upper troposphere by wet convective systems which stripped water-soluble components from these air parcels. There were good correlations between C2H2 and CO and C2H6 (r(sup 2) = 0.70 - 0.97) in these air parcels and much weaker ones between C2H2 and H2O2 or CH3OOH (r(sup 2) = 0.50). These correlations were the strongest in the continental north outflow where combustion inputs appeared to be recent (1 - 2 days old). Ozone and PAN showed general correlation in these same air parcels but not with the combustion products. It thus appears that several source inputs were intermixed in these upper tropospheric air masses, with possible contributions from European or Middle Eastern source regions. In aged marine air mixing ratios of 03 (approximately equals 20 parts per billion by volume) and PAN (less than or equal to 10 parts per trillion by volume) were nearly identical at less than 2 km and 10 - 12 km altitudes due to extensive convective uplifting of marine boundary layer air over the equatorial Pacific even in wintertime. Comparison of the Pacific Exploratory Mission-West A and PEM-West B data sets shows significantly larger mixing ratios of SO2 and H2O2 during PEM-West A. Emissions from eruption of Mount Pinatubo are a likely cause for the former, while suppressed photochemical activity in winter was probably responsible for the latter. This comparison also highlighted the twofold enhancement in C2H2, C2H6, and C3H8 in the continental north outflow during /PEM-West B. Although this could be due to reduced OH oxidation rates of these species in wintertime, we argue that increased source emissions are primarily responsible.

Talbot, R. W.↗
NASA NTRS1999

Reconstruction of the 1997/1998 El Nino from TOPEX/POSEIDON and TOGA/TAO Data Using a Massively Parallel Pacific-Ocean Model and Ensemble Kalman Filter

Two massively parallel data assimilation systems in which the model forecast-error covariances are estimated from the distribution of an ensemble of model integrations are applied to the assimilation of 97-98 TOPEX/POSEIDON altimetry and TOGA/TAO temperature data into a Pacific basin version the NASA Seasonal to Interannual Prediction Project (NSIPP)ls quasi-isopycnal ocean general circulation model. in the first system, ensemble of model runs forced by an ensemble of atmospheric model simulations is used to calculate asymptotic error statistics. The data assimilation then occurs in the reduced phase space spanned by the corresponding leading empirical orthogonal functions. The second system is an ensemble Kalman filter in which new error statistics are computed during each assimilation cycle from the time-dependent ensemble distribution. The data assimilation experiments are conducted on NSIPP's 512-processor CRAY T3E. The two data assimilation systems are validated by withholding part of the data and quantifying the extent to which the withheld information can be inferred from the assimilation of the remaining data. The pros and cons of each system are discussed.

Keppenne, C. L.↗
NASA NTRS1987

Moisture bursts over the tropical Pacific Ocean

The frequency and location of moisture bursts are examined. A moisture burst is described and defined, and this definition is applied to IR imagery for four six-month cool seasons (November-April) in the eastern North Pacific. It is observed that about ten moisture bursts/month occur during the cool seasons; the bursts last about 2-4 days and no more than 10 days; and they are distributed uniformly across the Pacific to the west of 110 deg W. The relation between the moisture bursts and the El Nino event of 1982-1983, and moisture bursts in the general circulation are analyzed. The analyses reveal that few bursts occur in the region associated with the El Nino event, and the moisture bursts resemble transient intensification of the mean meridional circulation in regions with a weak Hadley cell. Two modes for the behavior of the Hadley cell in the Pacific are proposed.

Mcguirk, James P.↗
DOE OSTI2025

Genetic Identification of Lamprey Genera and Anadromous Ecotypes in Watersheds of the Northeastern Pacific Ocean

ABSTRACT Nonparasitic, nonmigratory Western Brook Lamprey (WBL; Lampetra ayresii ), and parasitic, anadromous Western River Lamprey (WRL; L. ayresii ) are sympatric lampreys that likely represent different life history variations of a single species. Novel genetic tools are critical for differentiating WBL and WRL, whose larvae preclude morphological identification (ID) and will enable comprehensive assessment of imperiled native lampreys of the Northeastern Pacific (including WBL, WRL, and Pacific Lamprey, Entosphenus tridentatus ). We developed 47 candidate single nucleotide polymorphism (SNP) markers using whole genome resequencing of WBL ( N = 24) and WRL ( N = 15) from Ksi Ts'oohl Ts'ap Creek (Nass River, British Columbia, Canada) which are likely ecotypes distinguished by few divergent SNPs across multiple chromosomes. We used five novel candidate SNPs to perform genetic ID of WBL and WRL ecotypes in collections of mixed native lampreys from lower Columbia River tributaries ( N = 1474), Ksi Ts'oohl Ts'ap Creek ( N = 352), and ocean phase WRL from the Georgia Basin (Salish Sea, British Columbia, Canada; N = 91). Two previously published SNPs were used to ID genera, Entosphenus versus Lampetra . Morphological ID utilized photographs collected from a subset of genotyped lampreys, and high concordance was demonstrated between ID methods for genera (99%) and Lampetra ecotypes (> 98%). We characterized spatial and temporal composition of lamprey genera and ecotypes surveyed across NE Pacific tributaries under the expectation these compositions would be similar across nearby sites and across years at the same site. Proportions of lamprey genera were highly variable within regions and across years; however, Lampetra ecotypic proportions were spatially and temporally stable. WRL were rare in lower Columbia tributaries (~1% average rate among Lampetra ) and common further north (> 40% of Lampetra ). Genetic ID methods are powerful monitoring tools that create the novel ability to ascertain genera and ecotypes regardless of life stage, while increasing the efficiency of surveys by eliminating time‐intensive morphological data collection.

Silver, G. S. [Columbia River Inter‐Tribal Fish Co↗
NASA NTRS1996

Gyre-scale Circulation and Coupling in the North Atlantic and North Pacific Oceans

I proposed to examine the annual cycle of intensity, latitudinal position and amount of meandering in the Gulf Stream, and compare the altimetric cycle with seasonal transport estimates from hydrographic data. We also proposed to examine large-scale fluctuations which alter the strength and location of the currents at gyre boundaries in the North Pacific.

Kelly, Kathryn A.↗
DOE OSTI2020

Influences of North Pacific Ocean Domain Extent on the Western U.S. Winter Hydroclimatology in Variable-Resolution CESM

Variable-resolution global climate models (VRGCMs) are a dynamical downscaling method that can reach spatiotemporal scales needed for regional climate assessments. Over the years, several users of VRGCMs have assumed where the location and extent of the refinement domain should be based on knowledge of the prevailing storm tracks and resolution dependence of important regional climate processes (e.g., atmospheric rivers [ARs] and orographic uplift), but the effect of high-resolution domain size and extent on the simulation of downstream hydroclimatic phenomena has not been systematically evaluated. Here, we use variable resolution in the Community Earth System Model (VR-CESM) to perform such a test. To do this, three VR-CESM grids were generated that span the entire, two thirds, and one third of the North Pacific and evaluated for a 30-year climatology using Atmospheric Model Intercomparison Project protocols. Simulations are compared with reanalysis products offshore (fifth-generation of the European Centre for Medium-Range Weather Forecasts atmospheric reanalysis [ERA5]) and onshore (Livneh, 2015, https://doi.org/10.1038/sdata.2015.42, and Parameter-elevation Regressions on Independent Slopes Model [PRISM]) of the western United States. The westward expansion of refinement domain influenced integrated vapor transport (IVT), which was generally high biased but minimally impacted AR characteristics. Due to slight differences in landfalling AR counts in the western United States, California winter precipitation generally improved with westward expansion of the refinement domain. Western U.S. mountain snowpack and surface temperatures were insensitive to refinement domain size and were more influenced by changes in topographic resolution and/or land surface model version. Here, given minimal dependence of simulated western U.S. hydroclimate on refinement domain size over the North Pacific, we advise future VR-CESM studies to focus grid resolution on better resolving land surface heterogeneity.

54 ENVIRONMENTAL SCIENCES↗
NASA NTRS1992

Tropical Pacific Ocean response to observed winds in a layered general circulation model

The effect of forcing by monthly wind-stress variability is assessed with respect to the behavior of an isopycnic coordinate general circulation model. The isopycnic model incorporates an embedded mixed layer, and the equations are given for the interior layers, the surface mixed layer, and the atmospheric forcing. The anomalous variability of several variables is examined in a simulation using data from 1970-1985 with specific attention given to the anomalous response related to the 1982-1983 ENSO. The model fields describing sea-surface temperature (SST), sea level, and currents are found to be comparable to those reported from observational campaigns. Anomalous values of SST compare best with observed data when averaged over large spatial regions, and the amplitudes of the mean horizontal currents and anomalous zonal currents are comparable except with respect to amplitude data. The present study permits the simulation of basin-scale tropical Pacific mixed-layer depth and the mean vertical velocity field.

Miller, Arthur J.↗
NASA NTRS1996

The Determination of the Large-Scale Circulation of the Pacific Ocean from Satellite Altimetry using Model Green's Functions

A Green's function method for obtaining an estimate of the ocean circulation using both a general circulation model and altimetric data is demonstrated. The fundamental assumption is that the model is so accurate that the differences between the observations and the model-estimated fields obey a linear dynamics. In the present case, the calculations are demonstrated for model/data differences occurring on very a large scale, where the linearization hypothesis appears to be a good one. A semi-automatic linearization of the Bryan/Cox general circulation model is effected by calculating the model response to a series of isolated (in both space and time) geostrophically balanced vortices. These resulting impulse responses or 'Green's functions' then provide the kernels for a linear inverse problem. The method is first demonstrated with a set of 'twin experiments' and then with real data spanning the entire model domain and a year of TOPEX/POSEIDON observations. Our present focus is on the estimate of the time-mean and annual cycle of the model. Residuals of the inversion/assimilation are largest in the western tropical Pacific, and are believed to reflect primarily geoid error. Vertical resolution diminishes with depth with 1 year of data. The model mean is modified such that the subtropical gyre is weakened by about 1 cm/s and the center of the gyre shifted southward by about 10 deg. Corrections to the flow field at the annual cycle suggest that the dynamical response is weak except in the tropics, where the estimated seasonal cycle of the low-latitude current system is of the order of 2 cm/s. The underestimation of observed fluctuations can be related to the inversion on the coarse spatial grid, which does not permit full resolution of the tropical physics. The methodology is easily extended to higher resolution, to use of spatially correlated errors, and to other data types.

Stammer, Detlef↗
NASA NTRS1973

Principal sources and dispersal patterns of suspended particulate matter in nearshore surface waters of the northeast Pacific Ocean and the Hawaiian Islands

The author has identified the following significant results. Numerous geologic features can be discerned on ERTS-1 imagery of the northwestern Olympic Peninsula, Washington, and southern Vancouver Island, British Columbia. A thick homoclinal sequence of north-dipping Tertiary marine strata along the northwestern Olympic Peninsula is readily discernible because of the banded nature of its outcrop. The submarine basalt on which the sequence rests shows as a high, rugged ridge. Within the sedimentary sequence, alternating sandstone and siltstone members 100 m or more thick show in the southeast corner of the image. Broad folds in this banded sequence and faults that cut it can be detected. One large fault, the Pysht River fault, and a large syncline in sandstone and siltstone east of it show prominently on the image. Numerous lineations on the image of southern Vancouver Island correlate with faults shown on Muller's map. Particularly prominent are the Leech River and San Juan faults along the southernmost part of the island.

Carlson, P. R.↗