134 research outputs found
Archived time-series of Atlantic Ocean meteorological variables and surface fluxes
Includes ErrataTime-series of monthly averages of latent, sensible and radiational
heat fluxes and momentum fluxes at the surfaces of the North
and South Atlantic Oceans were calculated from ship weather observations.
These fluxes, together with values of meteorological variables
have been averaged over entire Marsden squares (10X10° squares) for
all months from January 1948 through December 1972. The method of
computing fluxes from ship weather observations, listing of variables
averaged, addition of sea-ice coverage of sub-polar regions, correction
of albedos for the presence of sea ice, correction of infrared
radiational exchange for humidity conditions of the upper atmosphere,
and format of the data on magnetic tapes are described. Statistics
of the fluxes and variables have been computed. Standard data tapes
containing these time series and statistics are available.Prepared for Climate Dynamics Research Program~
Division of Atmospheric Sciences, National Science
Foundation under Grant ATM 77-01475 A01
Woods Hole Oceanographic Institution collection of Climatology and Air/Sea Interaction (CASI) data
Scientists at Woods Hole routinely collect and analyze a considerable
amount of data relating to the oceans of the world. Of the many different
kinds of data, one particular subset concerns those events occurring at the
sea surface. A large number of sea surface environmental observations have
been collected at Woods Hole. These data, and the subsequent analyses
generated from the Air/Sea Heat Flux and the Climatology study projects,
have been collected and archived. This document describes the W.H.O.I./
Climatology and Air/Sea Interaction (WHOI/CASI) data collection and provides
an initial index to its various components.Prepared for the Office of Naval Research under Contract
N00014-74-C-0262; NR 083-004 and for the National Science
Foundation (Climate Dynamics Program, Atmospheric Sciences
Division) under Grant ATM 77-014?5
Numerical simulations of Columbus’ Atlantic crossings
The transatlantic route of Columbus was simulated incorporating historical winds, currents and hypothetical magnetic
variation in order to estimate where the first landfall occured. Earlier simulations using an 1899 map by Van Bemmelen
and assuming zero magnetic variation in the Bahamas to produce a landfall near San Salvador (Watlings Island). New
theories postulating a Geometric league of 2.67 nautical miles and a westerly magnetic variation of approximately one
point (11.25°) for the western terminus result in a landfall near the Turks and Caicos Islands. A westerly variation of this
magnitude in the Bahamas has been inferred from early charts - the islands are shown several degrees too far north, which
would have occurred if early navigators had been set imperceptibly southward by westerly variation - by studies of
directions within the islands, and by studies of early navigation books. The simulation of subsequent voyages by Columbus
lend further weight to a westerly variation of about one point in the region of Bahamas. Our work shows that a Grand Turk
landfall cannot be ruled out based on the transatlantic portion of the voyage as has been suggested in the past. A more
accurate simulation of the voyage and first landfall still requires a more accurate representation of the field of magnetic
variation.Funding was provided by a grant from the Nova Albion Foundation and the
Government of the Turks and Caicos Islands
Reconstructing Columbus’s first transatlantic track and landfall using climatological winds and currents
An article in the November 1986 National Geographic magazine examined the
question of Columbus's first landfall in the Americas. The author, Luis Marden, was
the first to quantitatively include the effects of the winds and currents in reconstructing
the transoceanic portion of the voyage. There seemed, however, to be two major
weaknesses in his analysis. First, the leeway effect on the ship by the wind was
ignored for that portion of the voyage west of 40W, the whole second half of the
voyage. Second, currents from pilot charts were used with the corresponding speed
determined by the prevailing current. We sought to reanalyze the track using the
leeway effect for the whole transatlantic track and using more appropriate average
vector velocities of the current. Using climatological winds and currents we found
the island of San Salvador (Watling Island) to be the most likely site of the first
landfall of Columbus. This paper discusses the effects of wind, current, leeway, and
magnetic variation on the determination of the landfall.Funding was provided in part by the National Science Foundation under
grant Number DCE 85-14885
Heave and roll response of free floating bodies of cylindrical shape
The following report describes a computer solution to help predict
the heave and roll response of free floating bodies of cylindrical shape
when excited by random seas with known spectra.
The basic concepts of harmonic analysis and statistics used in the
method are first briefly reviewed. The report then presents a detailed
derivation of the linear heave and roll response amplitude operators,
that is the expressions of the vertical and angular displacements produced
by a simple harmonic wave of one foot amplitude.
The second part of the report reviews the computation procedure
and the program's logic. It gives a detailed set of instructions for the
program users, reviews the program's capabilities and limitations, and
presents three case studies.
The heave and roll response programs are written for use with
XEROX SIGMA 7 computers. Program listings are given in the appendix.Prepared for the Office of Naval Research under
Contract N00014-75-C-l064; NR 294-004 and from the NOAA Data Buoy Office
Upwelling on the continental slope of the Alaskan Beaufort Sea : storms, ice, and oceanographic response
Author Posting. © American Geophysical Union, 2009. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research 114 (2009): C00A13, doi:10.1029/2008JC005009.The characteristics of Pacific-born storms that cause upwelling along the Beaufort Sea continental slope, the oceanographic response, and the modulation of the response due to sea ice are investigated. In fall 2002 a mooring array located near 152°W measured 11 significant upwelling events that brought warm and salty Atlantic water to shallow depths. When comparing the storms that caused these events to other Aleutian lows that did not induce upwelling, interesting trends emerged. Upwelling occurred most frequently when storms were located in a region near the eastern end of the Aleutian Island Arc and Alaskan Peninsula. Not only were these storms deep but they generally had northward-tending trajectories. While the steering flow aloft aided this northward progression, the occurrence of lee cyclogenesis due to the orography of Alaska seems to play a role as well in expanding the meridional influence of the storms. In late fall and early winter both the intensity and frequency of the upwelling diminished significantly at the array site. It is argued that the reduction in amplitude was due to the onset of heavy pack ice, while the decreased frequency was due to two different upper-level atmospheric blocking patterns inhibiting the far field influence of the storms.The following grants provided
support for this study: National Science Foundation grants OPP-0731928
(R.S.P.) and OPP-0713250 (R.S.P. and P.S.F.), Office of Naval Research
grant N00014-07-1-1040 (D.J.T. and R.A.G.), Natural Sciences and Engineering
Research Council of Canada (G.W.K.M.), Woods Hole Oceanographic
Institution Arctic Initiative (J.Y.)
The 2017 Terahertz Science and Technology Roadmap
Science and technologies based on terahertz frequency electromagnetic radiation (100GHz-30THz) have developed rapidly over the last 30 years. For most of the 20th century, terahertz radiation, then referred to as sub-millimeter wave or far-infrared radiation, was mainly utilized by astronomers and some spectroscopists. Following the development of laser based terahertz time-domain spectroscopy in the 1980s and 1990s the field of THz science and technology expanded rapidly, to the extent that it now touches many areas from fundamental science to “real world” applications. For example THz radiation is being used to optimize materials for new solar cells, and may also be a key technology for the next generation of airport security scanners. While the field was emerging it was possible to keep track of all new developments, however now the field has grown so much that it is increasingly difficult to follow the diverse range of new discoveries and applications that are appearing. At this point in time, when the field of THz science and technology is moving from an emerging to a more established and interdisciplinary field, it is apt to present a roadmap to help identify the breadth and future directions of the field. The aim of this roadmap is to present a snapshot of the present state of THz science and technology in 2016, and provide an opinion on the challenges and opportunities that the future holds. To be able to achieve this aim, we have invited a group of international experts to write 17 sections that cover most of the key areas of THz Science and Technology. We hope that The 2016 Roadmap on THz Science and Technology will prove to be a useful resource by providing a wide ranging introduction to the capabilities of THz radiation for those outside or just entering the field as well as providing perspective and breadth for those who are well established. We also feel that this review should serve as a useful guide for government and funding agencies
Connective tissue growth factor(CCN2), a pathogenic factor in diabetic nephropathy. What does it do? How does it do it?
Connective tissue growth factor (CTGF/CCN2) is a member of the CCN family of matricellular proteins. Its expression is induced by a number of factors including TGF-β. It has been associated with fibrosis in various tissues including the kidney. Diabetic nephropathy (DN) develops in about 30% of patients with diabetes and is characterized by thickening of renal basement membranes, fibrosis in the glomerulus (glomerulosclerosis), tubular atrophy and interstitial fibrosis, all of which compromise kidney function. This review examines changes in CTGF expression in the kidney in DN, the effects they have on glomerular mesangial and podocyte cells and the tubulointerstitium, and how these contribute to driving fibrotic changes in the disease. CTGF can bind to several other growth factors modifying their function. CTGF is also able to interact with receptors on cells, including integrins, tyrosine receptor kinase A (TrkA), low density lipoprotein receptor-related protein (LRP) and heparan sulphate proteoglycans. These interactions, the intracellular signalling pathways they activate, and the cellular responses evoked are reviewed. CTGF also induces the expression of chemokines which themselves have pharmacological actions on cells. CTGF may prompt some responses by acting through several different mechanisms, possibly simultaneously. For example, CTGF is often described as an effector of TGF-β. It can promote TGF-β signalling by binding directly to the growth factor, promoting its interaction with the TGF-β receptor; by triggering intracellular signalling on binding the TrkA receptor, which leads to the transcriptional repression of Smad7, an inhibitor of the TGF-β signalling pathway; and by binding to BMP-7 whose own signalling pathway opposing TGF-β is inhibited, leading to enhanced TGF-β signalling
Metarhodopsin control by arrestin, light-filtering screening pigments, and visual pigment turnover in invertebrate microvillar photoreceptors
The visual pigments of most invertebrate photoreceptors have two thermostable photo-interconvertible states, the ground state rhodopsin and photo-activated metarhodopsin, which triggers the phototransduction cascade until it binds arrestin. The ratio of the two states in photoequilibrium is determined by their absorbance spectra and the effective spectral distribution of illumination. Calculations indicate that metarhodopsin levels in fly photoreceptors are maintained below ~35% in normal diurnal environments, due to the combination of a blue-green rhodopsin, an orange-absorbing metarhodopsin and red transparent screening pigments. Slow metarhodopsin degradation and rhodopsin regeneration processes further subserve visual pigment maintenance. In most insect eyes, where the majority of photoreceptors have green-absorbing rhodopsins and blue-absorbing metarhodopsins, natural illuminants are predicted to create metarhodopsin levels greater than 60% at high intensities. However, fast metarhodopsin decay and rhodopsin regeneration also play an important role in controlling metarhodopsin in green receptors, resulting in a high rhodopsin content at low light intensities and a reduced overall visual pigment content in bright light. A simple model for the visual pigment–arrestin cycle is used to illustrate the dependence of the visual pigment population states on light intensity, arrestin levels and pigment turnover
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