National Ocean Service

About: National Ocean Service is a government organization based out in Silver Spring, Maryland, United States. It is known for research contribution in the topics: Algal bloom & Population. The organization has 500 authors who have published 643 publications receiving 46096 citations.

Applying kinematic GPS techniques at our nation's airports

Abstract: The National Geodetic Survey (NGS) began surveying US airports using a mixture of static, kinematic, antenna swap, and pseudokinematic techniques. The methodologies and the associated theoretical rationale are described. The NGS performed an online operational test of GPS (Global Positioning System) kinematic surveying at several Florida airports, and it was found to be a complete success. All successful processing variations in the Apalachicola example agreed at the 1-cm level. >

Chapter 12: Sea Level Rise

Abstract: Global mean sea level (GMSL) has risen by about 7-8 inches (about 16-21 cm) since 1900, with about 3 of those inches (about 7 cm) occurring since 1993. Human-caused climate change has made a substantial contribution to GMSL rise since 1900, contributing to a rate of rise that is greater than during any preceding century in at least 2,800 years. Relative to the year 2000, GMSL is very likely to rise by 0.3-0.6 feet (9-18 cm) by 2030, 0.5-1.2 feet (15-38 cm) by 2050, and 1.0-4.3 feet (30-130 cm) by 2100. Future pathways have little effect on projected GMSL rise in the first half of the century, but significantly affect projections for the second half of the century. Emerging science regarding Antarctic ice sheet stability suggests that, for high emission scenarios, a GMSL rise exceeding 8 feet (2.4 m) by 2100 is physically possible, although the probability of such an extreme outcome cannot currently be assessed. Regardless of pathway, it is extremely likely that GMSL rise will continue beyond 2100. Relative sea level (RSL) rise in this century will vary along U.S. coastlines due, in part, to changes in Earth's gravitational field and rotation from melting of land ice, changes in ocean circulation, and vertical land motion (very high confidence). For almost all future GMSL rise scenarios, RSL rise is likely to be greater than the global average in the U.S. Northeast and the western Gulf of Mexico. In intermediate and low GMSL rise scenarios, RSL rise is likely to be less than the global average in much of the Pacific Northwest and Alaska. For high GMSL rise scenarios, RSL rise is likely to be higher than the global average along all U.S. coastlines outside Alaska. Almost all U.S. coastlines experience more than global mean sea level rise in response to Antarctic ice loss, and thus would be particularly affected under extreme GMSL rise scenarios involving substantial Antarctic mass loss. As sea levels have risen, the number of tidal floods each year that cause minor impacts (also called "nuisance floods") have increased 5- to 10-fold since the 1960s in several U.S. coastal cities. Rates of increase are accelerating in over 25 Atlantic and Gulf Coast cities. Tidal flooding will continue increasing in depth, frequency, and extent this century. Assuming storm characteristics do not change, sea level rise will increase the frequency and extent of extreme flooding associated with coastal storms, such as hurricanes and nor'easters. A projected increase in the intensity of hurricanes in the North Atlantic could increase the probability of extreme flooding along most of the U.S. Atlantic and Gulf Coast states beyond what would be projected based solely on RSL rise. However, there is low confidence in the projected increase in frequency of intense Atlantic hurricanes, and the associated flood risk amplification and flood effects could be offset or amplified by such factors as changes in overall storm frequency or tracks.

Semisynthesis of radiolabeled amino acid and lipid brevetoxin metabolites and their blood elimination kinetics in C57BL/6 mice.

Abstract: Brevetoxin B (BTX-B), produced by dinoflagellates of the species Karenia, is a highly reactive molecule, due in part to an α,β-unsaturated aldehyde group at the terminal side chain, leading to the production of metabolites in shellfish by reduction, oxidation, and conjugation. We have investigated in mice the blood elimination of three common bioactive brevetoxin metabolites found in shellfish, which have been semisynthesized from BTX-B in radioactive forms. BTX-B was reduced at C42 to yield [3H] dihydro-BTX-B. [3H] S-desoxy-BTX-B2 (cysteine brevetoxin B) was semisynthesized from BTX-B by the conjugation of cysteine at the C50 olefinic group then [3H] radiolabeled by C42 aldehyde reduction. [14C] N-Palmitoyl-S-desoxy-BTX-B2 was prepared using S-desoxy-BTX-B2 as the starting material with addition of the [14C] radiolabeled fatty acid via cysteine–amide linkage. The elimination of intravenously administered [3H] S-desoxy-BTX-B2, [14C] N-palmitoyl-S-desoxy-BTX-B2, or [3H] dihydro-BTX-B was measured in blood ...

CODAR intercomparison: Delaware Bay 1984

Abstract: During the fall of 1984 surface current measurements were made by means of a Coastal Ocean Dynamics Application Radar (CODAR) in the Delaware Bay during the National Ocean Service's (NOS) Delaware River and Bay Project. This project included a survey of the circulation of the estuary, operation of a real-time numerical circulation model, and real-time instrumentation. The purpose of the CODAR operation in Delaware Bay was to quantify how CODAR could contribute to NOAA's circulation survey operation. The cost, planning, and operation of the project was jointly shared by NOS and the U.S. Army Corps of Engineers (COE). In this study CODAR measurements were compared with Remote Acoustic Doppler system (RADS) measurements and with a Vector Measuring Current Meter (VMCM) that was situated near the RADS site. Ten days of concurrent data starting on October 16, 1984, were used in this study. The intercomparison of the results is qualified by the inherent nature of comparing entirely different measurement systems. The horizontal spatial averages for CODAR were on the order of 1,000 times that of RADS. The temporal sampling was different between the RADS and CODAR because the two CODAR sites did not operate simultaneously. The CODAR sites were operated sequentially for 45 minutes yielding an "averaging time" of 1.5 hours, thereby biasing the total measurement. By going to a two-frequency system and sampling simultaneously from both sites, differences in temporal sampling can be eliminated. The differences caused by horizontal averaging are not as easily overcome. The major observations of the performance of CODAR are given below: 1. CODAR functioned without major interruption from October 15, 1984, through November 6, 1984. 2. CODAR surface current maps revealed mesoseale features such as eddies and fronts. 3. The threshold velocity for CODAR was 10cm/s. 4. Radial components of velocity would be useful for system diagnosis and oceanographic applications. 5. CODAR is suitable for mapping the flow patterns in estuaries the size of Delaware Bay and larger. 6. CODAR, RADS, and VMCM showed general agreement in the along-channel direction especially during spring tide. 7. The resolution of CODAR was finer than the along-channel length scale. 8. The semidiurnal tidal component of all three devices were within 5cm/s and 30 degrees of phase. 9. The average bias between RADS and CODAR was 12cm/s in the along-channel component of flow. 10. The uncertainty in phase in the along-channel direction might be due to the non-simultaneity of the CODAR averaging period. 11. Cross-channel flow comparisons were inconclusive due to the low signal to noise ratio in the flow and due to the large resolution scale of CODAR when compared to the short cross-channel flow scales.