Atlantic Station Research Articles

The Leaving of Halifax: The abrupt recall of Admiral Sir William Parker in 1801

This article aims to clarify the origins of the animosity that developed between Admiral Sir William Parker (1742–1802), one of the Royal Navy’s senior commanders at the battle of Cape St Vincent in 1797, and Admiral Sir John Jervis, who became Earl St Vincent following the victory. It traces the deterioration of their relationship, which culminated in Parker’s recall from his final post in Halifax, where he was serving as commander in chief of the North Atlantic Station, a few months after St Vincent was appointed First Lord of the Admiralty in 1801. On his return to England, Parker requested a court martial to clear his name and was acquitted of any wrongdoing.

Wintertime Observations of Tropical Northwest Atlantic Aerosol Properties During ATOMIC: Varying Mixtures of Dust and Biomass Burning

AbstractThe Atlantic Tradewind Ocean‐Atmosphere Mesoscale Campaign (ATOMIC) took place from 7 January to 11 July 2020 in the tropical North Atlantic between the east coast of Barbados and the Northwest Tropical Atlantic Station (NTAS) mooring. Measurements of aerosol chemical, microphysical, optical, and cloud‐nucleating properties were made during boreal winter onboard the NOAA RV Ronald H. Brown from 7 January to 13 February 2020. Observed aerosol properties indicate there were distinct periods when the aerosol was typical of clean marine conditions (particle number concentrations <400 cm−3, light absorption levels <1 Mm−1, and 222Rn concentrations <500 mBq m−3) and when there were intrusions of dust mixed to varying degrees with biomass burning aerosol. In comparison to the long‐term dust record at the Barbados Atmospheric Chemistry Observatory, the fraction of samples collected during ATOMIC with dust concentrations greater than 20 μg m−3 exceeded all years of the Barbados January to February record with the exception of 1983. The degree of mixing of the dust with biomass burning aerosol was modulated by the location of the North Atlantic subtropical high. A high located to the west of Africa led to a more northerly transport route and more dust‐like (MDL) aerosol arriving at the ship. A location of the high further to the east over northern Africa led to a more southerly transport route and more biomass burning aerosol mixed with the dust. Properties for the marine, MDL, and mixed dust and biomass burning aerosol are presented.

Measurements from the RV <i>Ronald H. Brown</i> and related platforms as part of the Atlantic Tradewind Ocean-Atmosphere Mesoscale Interaction Campaign (ATOMIC)

Abstract. The Atlantic Tradewind Ocean-Atmosphere Mesoscale Interaction Campaign (ATOMIC) took place from 7 January to 11 July 2020 in the tropical North Atlantic between the eastern edge of Barbados and 51∘ W, the longitude of the Northwest Tropical Atlantic Station (NTAS) mooring. Measurements were made to gather information on shallow atmospheric convection, the effects of aerosols and clouds on the ocean surface energy budget, and mesoscale oceanic processes. Multiple platforms were deployed during ATOMIC including the NOAA RV Ronald H. Brown (RHB) (7 January to 13 February) and WP-3D Orion (P-3) aircraft (17 January to 10 February), the University of Colorado's Robust Autonomous Aerial Vehicle-Endurant Nimble (RAAVEN) uncrewed aerial system (UAS) (24 January to 15 February), NOAA- and NASA-sponsored Saildrones (12 January to 11 July), and Surface Velocity Program Salinity (SVPS) surface ocean drifters (23 January to 29 April). The RV Ronald H. Brown conducted in situ and remote sensing measurements of oceanic and atmospheric properties with an emphasis on mesoscale oceanic–atmospheric coupling and aerosol–cloud interactions. In addition, the ship served as a launching pad for Wave Gliders, Surface Wave Instrument Floats with Tracking (SWIFTs), and radiosondes. Details of measurements made from the RV Ronald H. Brown, ship-deployed assets, and other platforms closely coordinated with the ship during ATOMIC are provided here. These platforms include Saildrone 1064 and the RAAVEN UAS as well as the Barbados Cloud Observatory (BCO) and Barbados Atmospheric Chemistry Observatory (BACO). Inter-platform comparisons are presented to assess consistency in the data sets. Data sets from the RV Ronald H. Brown and deployed assets have been quality controlled and are publicly available at NOAA's National Centers for Environmental Information (NCEI) data archive (https://www.ncei.noaa.gov/archive/accession/ATOMIC-2020, last access: 2 April 2021). Point-of-contact information and links to individual data sets with digital object identifiers (DOIs) are provided herein.

The influence of infill development on travel behavior

While the evidence that the built environment can influence travel behavior to date is fairly robust, the influence of specific, identifiable policy actions is limited. One policy action that can potentially change travel behavior is increasing infill development, particularly if that development is located near the center of a major metropolitan region. This study examines the influence of a large-scale, infill development, Atlantic Station, which opened in 2005 just west of Midtown Atlanta. The study uses propensity scores and differences-in-differences research designs to identify how travel patterns changed for new residents and for existing residents of the area around Atlantic Station, respectively. Atlantic Station reduced vehicle miles traveled and increased alternative mode share for its new residents, but it did not reduce the vehicle miles traveled or increase alternative mode share for the existing residents of the area around Atlantic Station.

Temporal dynamics of P rochlorococcus cells with the potential for nitrate assimilation in the subtropical Atlantic and Pacific oceans

Utilization of nitrate as a nitrogen source is broadly conserved among marine phytoplankton, yet many strains of Prochlorococcus lack this trait. Among cultured strains, nitrate assimilation has only been observed within two clades of Prochlorococcus: the high-light adapted HLII clade and the low-light adapted LLI clade. To better understand the frequency and dynamics of nitrate assimilation potential among wild Prochlorococcus, we measured seasonal changes in the abundance of cells containing the nitrate reductase gene (narB) in the subtropical North Atlantic and North Pacific oceans. At the Atlantic station, the proportion of HLII cells containing narB varied with season, with the highest frequency observed in stratified waters during the late summer, when inorganic nitrogen concentrations were lowest. The Pacific station, with more persistent stratification and lower N : P ratios, supported a perennially stable subpopulation of HLII cells containing narB. Approximately 20–50% of HLII cells possessed narB under stratified conditions at both sites. Since HLII cells dominate the total Prochlorococcus population in both ecosystems, nitrate potentially supports a significant fraction of the Prochlorococcus biomass in these waters. The abundance of LLI cells containing narB was positively correlated with nitrite concentrations at the Atlantic station. These data suggest that Prochlorococcus may contribute to the formation of primary nitrite maxima through incomplete nitrate reduction and highlight the potential for interactions between Prochlorococcus and sympatric nitrifying microorganisms. Further examination of these relationships will help clarify the selection pressures shaping nitrate utilization potential in low-light and high-light adapted Prochlorococcus.

James C. Rentfrow. Home Squadron: The U.S. Navy on the North Atlantic Station.

James C. Rentfrow. Home Squadron: The U.S. Navy on the North Atlantic Station.

Interannual Caribbean salinity in satellite data and model simulations

AbstractAquarius sea surface salinity (SSS) reveals the presence of interannual variations in the Caribbean with about 0.5 psu change between salty and fresh events, which propagate westward across that basin at an average speed of 11 cm/s and are preceded by corresponding SSS anomalies east of the Lesser Antilles. These upstream SSS anomalies are produced by interannual changes in the Amazon plume. Their presence is verified using in situ measurements from the northwest tropical Atlantic station. In contrast to SSS, which displays westward propagation, SST changes almost immediately across the Caribbean, suggesting large‐scale atmospheric processes have a primary role in regulating interannual SST in contrast to SSS. A global 1/10° mesoscale ocean model is used to quantify possible origination mechanisms of the Caribbean salinity anomalies and their fate. Simulations confirm that they are produced by anomalous horizontal salt advection, which conveys these salinity anomalies from an area east of the Lesser Antilles across the Caribbean. Anomalous horizontal advection is dominated by mean currents acting on anomalous salinity. The model suggests that interannual Caribbean salinity anomalies eventually enter the Florida Current and reach the Gulf Stream 6–12 months after crossing the central Caribbean. Previous studies link the origin of salinity anomalies in the Amazon plume to variations in the annual freshwater discharge from the continent. In this model interannual discharge variations are absent while simulated SSS variability is in line with observations. This suggests that interannually forced ocean dynamics plays a key role in river plume variability and its spatial dispersion.

Home Squadron: The U.S. Navy on the North Atlantic Station

This study examines the transformation of the United States Navy as a fighting organization that took place on the North Atlantic Station between 1874 and 1897. At the beginning of this period, the warships assigned to this station were collectively administered by a rear-admiral, but were operationally deployed as individual units, each of whose actions were directed by their captains. By 1897 the North Atlantic, or Home Squadron as it was known, was a group of warships constituting a protean battle fleet that is, an organized body moving and fighting in close-order, which meant that the actions of the captains were directed by a commanding admiral. The process of the development of an American battle fleet resulted in the construction of a new organizational identity for the North Atlantic Squadron. This process was as critical as the eventual outcome. It was not linear, but one in which progress in critical areas was modulated by conflicting demands that caused distraction. From 1874-1888, exercises in fleet tactics under steam were carried out sporadically utilizing existing wooden cruising vessels. From 1889-1894, the last wooden cruisers were decommissioned and the Squadron consisted entirely of new steel warships. Ad-hoc concentrations of vessels for purposes besides exercise and training retarded the continued development of doctrine and tactics necessary for a multi-ship fighting capability during this time. However, much work was done to develop a concept of multi-ship operations. From 1895-1897, the identity of the North Atlantic Squadron as a combat unit solidified. Tactical exercises were held that had specific offensive and defensive wartime applications. These exercises were necessary to develop a combat capability. The results of this study demonstrate that the United States government had an interest in developing an offensive naval combat capability as early as the 1870 s. Based on the record of the North Atlantic Squadron, it is argued that imperial aspirations, in the sense of possessing a capability to restrict the actions of other great powers in the Caribbean region, existed prior to the War of 1898. However, the process of change often resulted in the appearance of capability without the rigorous exercise necessary to possess it.

Enzymatic Activities and Prokaryotic Abundance in Relation to Organic Matter along a West–East Mediterranean Transect (TRANSMED Cruise)

The distribution of extracellular enzymatic activities (EEA) [leucine aminopeptidase (LAP), ß-glucosidase (GLU), alkaline phosphatase (AP)], as well as that of prokaryotic abundance (PA) and biomass (PB), dissolved organic carbon (DOC), particulate organic carbon and particulate total nitrogen (POC, PTN), was determined in the epi-, meso-, and bathypelagic waters of the Mediterranean Sea along a West-East transect and at one Atlantic station located outside the Strait of Gibraltar. This study represents a synoptical evaluation of the microbial metabolism during early summer. Decreasing trends with depth were observed for most of the parameters (PA, PB, AP, DOC, POC, PTN). Significant differences between the western and eastern basins of the Mediterranean Sea were found, displaying higher rates of LAP and GLU and lower C/N ratios more in the eastern than in the western areas. Conversely, in the epipelagic layer, PA and PB were found to be higher in the western than in the eastern basins. PB was significantly related to DOC concentration (all data, n = 145, r = 0.53, P < 0.01), while significant correlations of EEA with POC and PTN were found in the epipelagic layer, indicating an active response of microbial metabolism to organic substrates. Specific enzyme activities normalized to cell abundance pointed out high values of LAP and GLU in the bathypelagic layer, especially in the eastern basin, while cell-specific AP was high in the epi- and bathypelagic zone of the eastern basin indicating a rapid regeneration of inorganic P for both prokaryotes and phytoplankton needs. Low activity and abundance characterized the Atlantic station, while opposite trends of these parameters were observed along the Mediterranean transect, showing the uncoupling between abundance and activity data. In the east Mediterranean Sea, decomposition processes increased probably in response to mesoscale structures which lead to organic matter downwelling.

Changes in Physical Activity and Travel Behaviors in Residents of a Mixed-Use Development

Mixed-use developments may be especially promising settings for encouraging walking and other types of physical activity. This study examined the physical activity and travel behaviors of individuals before and after they relocated to Atlantic Station, a mixed-use redevelopment community in metropolitan Atlanta. A survey study was conducted to compare the behaviors, experiences, and attitudes of Atlantic Station residents before and after moving to a mixed-use neighborhood. Data were collected in 2008 and 2009 and analyzed in 2010. Key dependent variables were self-reported physical activity and travel behaviors including walking for recreation and transport, automobile use, and use of public transportation. Study participants included 101 adult residents of Atlantic Station, most of whom were female, young, and well educated. There were significant increases in walking for recreation or fitness (46%-54%; p<0.05) and walking for transportation (44%-84%; p<0.001) after moving into the mixed-use development. Respondents also reported reduced automobile travel and increased time spent using public transportation after moving to Atlantic Station. Because this study used individuals as their own controls, there is more control over confounding lifestyle variables compared to cross-sectional studies of individuals living in different neighborhoods. Adults who move to a denser, mixed-use neighborhood increase their levels of walking for both recreation and transportation, decrease their automobile travel, and increase their use of public transportation.

Wind Speed Influences on Marine Aerosol Optical Depth

The Mulcahy (Mulcahy et al., 2008) power‐law parameterization, derived at the coastal Atlantic station Mace Head, between clean marine aerosol optical depth (AOD) and wind speed is compared to open ocean MODIS‐derived AOD versus wind speed. The reported AOD versus wind speed (U) was a function of ~U2. The open ocean MODIS‐derived AOD at 550 nm and 860 nm wavelengths, while in good agreement with the general magnitude of the Mulcahy parameterization, follows a power‐law with the exponent ranging from 0.72 to 2.47 for a wind speed range of 2–18 m s−1. For the four cases examined, some MODIS cases underestimated AOD while other cases overestimated AOD relative to the Mulcahy scheme. Overall, the results from MODIS support the general power‐law relationship of Mulcahy, although some linear cases were also encountered in the MODIS dataset. Deviations also arise between MODIS and Mulcahy at higher wind speeds (&gt;15 m s−1), where MODIS‐derived AOD returns lower values as compared to Mulcahy. The results also support the suggestion than wind generated sea spray, under moderately high winds, can rival anthropogenic pollution plumes advecting out into marine environments with wind driven AOD contributing to AOD values approaching 0.3.

The Disappearance of the State from “Livable” Urban Spaces

Abstract: This paper examines the absence of the state from the discourses and practices of “livable” urban spaces. Drawing from an ethnography of Atlantic Station, the USA's largest new urbanist infill development, we argue that “livable” urban spaces are increasingly arenas for luxury, theater, and consumption, and that the state, while an important actor in the creation of urban spaces such as Atlantic Station, has largely been made invisible. We see this in the absence of public institutions, such as schools, parks, and libraries, and in the absence of a collective political identity among Atlantic Station patrons. The disappearance of the state in the material spaces of the city suggests that the neoliberal project of individualism and consumerism is transforming the very notion of livability and the democratic possibilities of what makes urban space “livable”.

Research Article: Measuring the Benefits of Compact Development on Vehicle Miles and Climate Change

For climate stabilization, the United States (US) will need to cut its transportation carbon dioxide (CO2) emissions by 60%–80% by 2050. As we cannot accomplish this reduction through vehicle and fuel technology alone, the environmental and transportation communities are focusing on strategies to reduce growth in vehicle miles traveled (VMT), reversing recent trends. The majority of recent VMT growth is due, not to population growth, but to the effects of urban environment, such as increased auto ownership, longer trips, and driving alone. The US Department of Energy forecasts that driving will continue to increase at almost threefold the growth in population. Even under the most stringent vehicle and fuel standards, transportation-related CO2 emissions will be 40% above the target level. In response, climate-change legislation has been passed in California and is pending in other states and in the US Congress that places strict new requirements on mandated environmental impact documentation. One limitation on compliance has been the lack of a unified set of scientific information on the underlying relationships between development form and VMT generation. This article distills and reconciles various forms of prior research on the subject, producing a unified quantitative understanding of the mechanisms that relate urban development forms with VMT and CO2. The findings will help improve the insightfulness and accuracy of the next generation of environmental documents. The article provides results of research and planning studies from throughout the US that indicate the degree to which developments with higher densities, mix of uses, accessible destinations, and interconnected streets reduce vehicle trips and VMT. Sources include regional blueprint studies, as well as project-specific studies such as Atlanta's Atlantic Station development, whose predicted trip reduction was found to be so compelling that the development was deemed a transportation control measure and air quality benefit by the Environmental Protection Agency and Federal Highway Administration. The article identifies the emerging practices in transportation impact analysis for assessing the degree to which the characteristics of development can reduce VMT and carbon impacts. It presents the empirical evidence of how vehicle travel is affected by density, diversity, walkability, regional accessibility, and distance from transit. It also reviews tools that transportation planners and analysts have available to capture these effects, including simple elasticities and new trip generation rates under consideration by the Institute of Transportation Engineers.Environmental Practice 11:196–208 (2009)

Suitable methods for cryopreservation of semen from Atlantic halibut, Hippoglossus hippoglossus L.

Decrease in the quality and quantity of Atlantic halibut, Hippoglossus hippoglossus L., semen towards the end of the reproductive season hampers production of good-quality embryos. Therefore, cryopreservation of spermatozoa is a method showing potential to facilitate controlled reproduction in Atlantic halibut. The present study aimed at establishing the appropriate cryopreservation procedure. We tested 20 extenders composed of four various diluents and five cryoprotectants (DMSO, DMA, methanol, propylene glycol, and glycerol) to determine the best extender. Then, we examined cryopreservation quality using various methods of loading and various volumes of cryopreserved samples. In most of the tested variants, sperm diluted with an extender showed high motility after 24-h incubation despite the high osmotic pressure of the extender. Modified turbot extender (MTE) was the best of the tested diluents, securing the highest post-thaw motility (P 0.05). MTE-based extender was chosen as the most suitable. Semen cryopreserved in straws, Eppendorfs or Ziploc bags in volumes ranging from 0.25 to 20 ml showed similar high fertilization ability. Survival of larvae produced with the cryopreserved sperm did not differ from controls produced with freshly collected sperm. Motility 3 h after thawing was high but depended on the type of cryoprotectant and the volume of cryopreserved sperm (P < 0.05). The developed cryopreservation procedure has been applied at our Atlantic halibut breeding station for seed production.

Tax increment financing: A property-based tool for local regeneration?

Tax increment financing (TIF) is a technique for harnessing future property tax revenues to pay for current expenditures that local governments in the US have used extensively to finance regeneration activities. The paper provides an overview of the mechanism and presents a case study — the mixed-use Atlantic Station in Atlanta, Georgia — to illustrate the mechanics of TIF use and to discuss when it is appropriate for public officials to rely on TIF. It ends with some thoughts on the potential for exporting this regeneration tool to countries with different fiscal structures.

The 17th Street Bridge in Atlanta, Georgia: Context-Sensitive Design Process

The new 17th Street Bridge provides a vital link between midtown Atlanta, Georgia, and the proposed Atlantic Station development. The project was presented to the community as an opportunity to create a signature structure for Atlanta—a gateway into the city. The community was extensively involved in the development of the bridge. Through a series of community workshops, focus groups, and architectural task groups, the bridge was defined and detailed, and pedestrian mobility and safety were the focus of the final product. The resulting bridge, though significantly different from the original vision, has met with approval from the community.

The 17th Street Bridge in Atlanta, Georgia

The new 17th Street Bridge provides a vital link between midtown Atlanta, Georgia, and the proposed Atlantic Station development. The project was presented to the community as an opportunity to create a signature structure for Atlanta–-a gateway into the city. The community was extensively involved in the development of the bridge. Through a series of community workshops, focus groups, and architectural task groups, the bridge was defined and detailed, and pedestrian mobility and safety were the focus of the final product. The resulting bridge, though significantly different from the original vision, has met with approval from the community.

Tropospheric ozone over a tropical Atlantic station in the Northern Hemisphere: Paramaribo, Surinam (6oN, 55oW)

Tropospheric ozone over a tropical Atlantic station in the Northern Hemisphere: Paramaribo, Surinam (6oN, 55oW)

Tropospheric ozone over a tropical Atlantic station in the Northern Hemisphere: Paramaribo, Surinam (6¼N, 55¼W)

We present an analysis of 2.5 yr of weekly ozone soundings conducted at a new monitoring station in Paramaribo, Surinam (6¼N, 55¼W). This is currently one of only three ozone sounding stations in the Northern Hemisphere (NH) tropics, and the only one in the equatorial Atlantic region. Paramaribo is part of the Southern Hemisphere Additional Ozone Sounding program (SHADOZ). Owing to its position close to the equator, the inter-tropical convergence zone (ITCZ) passes over Paramaribo twice per year, which results in a semi-annual seasonality of many parameters including relative humidity and ozone. The dataset from Paramaribo is used to: (1) evaluate the ozone variability relative to precipitation, atmospheric circulation patterns and biomass burning; (2) contrast ozone at the NH equatorial Atlantic with that at nearby Southern Hemisphere (SH) stations Natal (6¼S, 35¼W) and Ascension (8¼S, 14¼W); (3) compare the seasonality of tropospheric ozone with a satellite-derived ozone product: tropical tropospheric ozone columns from the modified residual method (MR-TTOC). We find that Paramaribo is a distinctly Atlantic station. Despite its position north of the equator, it resembles nearby SH stations during most of the year. Transport patterns in the lower and middle troposphere during February and March differ from SH stations, which leads to a seasonality of ozone with two maxima. MR-TTOC over Paramaribo does not match the observed seasonality of ozone due to the use of a SH ozone sonde climatology in the MR method. The Paramaribo ozone record is used to suggest an improvement for Northern Hemisphere MR-TTOC retrievals. We conclude that station Paramaribo shows unique features in the region, and clearly adds new information to the existing SHADOZ record.

Interannual variability of carbon fluxes at the North Atlantic Station ESTOC

Abstract The impact of sea surface temperature and wind stress on primary production, export production, and CO2 air–sea exchange at the ESTOC station (29°N, 15.5°W) north of the Canary Islands is the focus of our investigations. A one-dimensional carbon and nitrogen cycling model was applied for the 10-year period 1987–1996. The simulation results compare well with upper layer observations for 1994–1996. Our simulated deep-water particle fluxes mostly overestimate the originally observed values for 1992–1996. On the other hand, the simulated fluxes underestimate the 230Th corrected particle fluxes (Scholten et al., Deep Sea Res. 48 (2001) 1413). Identifying the original observations as lower and the corrected values as upper estimate for the particle flux the simulation results falls in the range between these estimates. The large simulated interannual variability of carbon fluxes is in apparent contrast to the low interannual variability of the meteorological forcing typical for this subtropical regime. The key to this phenomenon lies in the sensitivity of this ecosystem to nutrient supply: depending on the meteorological situation, in different years the mixed-layer depth can or cannot reach the nitracline.