Seasonal and diurnal variations of Hg° over New England

Abstract. Factors influencing diurnal to interannual variability in Hg° over New England were investigated using multi-year measurements conducted by AIRMAP at the Thompson Farm (TF) coastal site, an inland elevated site at Pac Monadnock (PM), and two month measurements on Appledore Island (AI) in the Gulf of Maine. Mixing ratios of Hg° at TF showed distinct seasonality with maxima in March and minima in October. Hg° at AI tracked the trend at TF but with higher minima, while at PM the diurnal and annual cycles were dampened. In winter, Hg° was correlated most strongly with CO and NOy, indicative of anthropogenic emissions as their primary source. Our analysis indicates that Hg° had a regional background level of ~160 fmol/mol in winter, a dry deposition velocity of ~0.20 cm s−1 with a ~16 day lifetime in the coastal boundary layer in summer. The influence of oceanic emissions on ambient Hg° levels was identified using the Hg°-CHBr3 correlation at both TF and AI. Moreover, the lower Hg° levels and steeper decreasing warm season trend at TF (0.5–0.6 fmol/mol d−1) compared to PM (0.2–0.3 fmol/mol d−1) likely reflected the impact of marine halogen chemistry. Large interannual variability in warm season Hg° levels in 2004 versus 2005/2006 may be due to the role of precipitation patterns in influencing surface evasion of Hg°. In contrast, changes in wintertime maximum levels of Hg° were small compared to drastic reductions in CO, CO2, NOy, and SO2 from 2004/2005 to 2006/2007. These trends could be explained by a homogeneous distribution of Hg° over North American in winter due to its long lifetime and/or rapid removal of reactive mercury from anthropogenic sources. We caution that during warmer winters, the Hg°-CO slope possibly reflects Hg° loss relative to changes in CO more than their emission ratio.

Download Full-text

Seasonal and diurnal variations of Hg° over New England

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-7-17213-2007 ◽

2007 ◽

Vol 7 (6) ◽

pp. 17213-17260 ◽

Cited By ~ 1

Author(s):

H. Mao ◽

R. W. Talbot ◽

J. M. Sigler ◽

B. C. Sive ◽

J. D. Hegarty

Keyword(s):

New England ◽

Interannual Variability ◽

Gulf Of Maine ◽

Deposition Velocity ◽

Warm Season ◽

Anthropogenic Sources ◽

Surface Distribution ◽

Homogeneous Surface ◽

Seasonal And Diurnal Variations ◽

The Impact

Abstract. Factors influencing diurnal to interannual variability in Hg° over New England were investigated using multi-year measurements conducted by the AIRMAP program at the Thompson Farm (TF) coastal site, an inland elevated site at Pac Monadnock (PM), and one summer of measurements on Appledore Island (AI) in the Gulf of Maine. Mixing ratios of Hg° at TF showed distinct seasonality with maxima in March and minima in October. In comparison, Hg° at AI tracked the trend at TF but with higher minima, while at PM the diurnal and annual cycles were dampened. In winter, Hg° was correlated most strongly with CO and NOy, indicative of anthropogenic emissions as their primary source. Our analysis indicates that Hg° had a regional background level of ~160 fmol/mol, a summertime dry deposition velocity of ~0.20 cm s−1, and a ~16 day lifetime in the coastal boundary layer. The influence of oceanic emissions on ambient Hg° levels was identified using the Hg°-CHBr3 correlation at both TF and AI. Moreover, the lower Hg° levels and steeper decreasing warm season trend at TF (0.5–0.6 fmol/mol d−1) compared to PM (0.2–0.3 fmol/mol d−1) likely reflected the impact of marine halogen chemistry. Large interannual variability in warm season Hg° levels in 2004 versus 2005/2006 may be due to the role of precipitation patterns in influencing surface evasion of Hg°. In contrast, changes in wintertime maximum levels of Hg° were small compared to drastic reductions in CO, CO2, NOy, and SO2 from 2004/2005 to 2006/2007. These trends could be explained by a homogeneous surface distribution of Hg° over the North American continent in winter and/or rapid removal of mercury released from anthropogenic sources. We caution that during warmer winters, the Hg°-CO slope possibly reflects the ratio of Hg° loss relative to changes in CO more than their emission ratio.

Download Full-text

Implications of ocean bottom temperatures on the catch ability of American lobster

E3S Web of Conferences ◽

10.1051/e3sconf/20197903007 ◽

2019 ◽

Vol 79 ◽

pp. 03007

Author(s):

Xiaoxu Zhao ◽

Pengwen Ding ◽

Jilei Pang

Keyword(s):

New England ◽

Gulf Of Maine ◽

Recent Decade ◽

Temporal Variations ◽

Effect Of Temperature ◽

American Lobster ◽

Ocean Bottom ◽

Bottom Temperature ◽

Using Data ◽

The Impact

Since the beginning of the satellite era, the general trend of global and regional sea-surface temperature (SST) have continued to rise and, in the recent decade, the rate of warming has increased dramatically in the Gulf of Maine. However, due to variations in thermal stratification in the water column, SST is not the best measure to determine the impact on benthic organisms. So understanding the spatial and temporal variations of the ocean bottom temperature is critical to fisheries management. Since 2001, the Environmental Monitors on Lobster Traps (eMOLT) project has been implemented. The lobster fishermen have volunteered to collect bottom temperature and American lobster catch data from dozens of locations off the New England coast. Now we can use these data to analyze the relationship between ocean bottom temperature and lobster catch. Using data collected over the past decade, we examine the effect of temperature, temperature change, soak time and other factors on the catchability of lobsters. Our results suggest that there is a increase in catchability at the same time there is a) a temperature rise over many years and b) day-to-day temperature changes.

Download Full-text

The POWER Experiment: Impact of Assimilation of a Network of Coastal Wind Profiling Radars on Simulating Offshore Winds in and above the Wind Turbine Layer

Weather and Forecasting ◽

10.1175/waf-d-15-0104.1 ◽

2016 ◽

Vol 31 (4) ◽

pp. 1071-1091 ◽

Cited By ~ 9

Author(s):

Irina V. Djalalova ◽

Joseph Olson ◽

Jacob R. Carley ◽

Laura Bianco ◽

James M. Wilczak ◽

...

Keyword(s):

New England ◽

Gulf Of Maine ◽

Negative Impact ◽

Positive Impact ◽

Weather Prediction ◽

Department Of Energy ◽

Offshore Wind ◽

Model Skill ◽

Nwp Model ◽

The Impact

Abstract During the summer of 2004 a network of 11 wind profiling radars (WPRs) was deployed in New England as part of the New England Air Quality Study (NEAQS). Observations from this dataset are used to determine their impact on numerical weather prediction (NWP) model skill at simulating coastal and offshore winds through data-denial experiments. This study is a part of the Position of Offshore Wind Energy Resources (POWER) experiment, a Department of Energy (DOE) sponsored project that uses National Oceanic and Atmospheric Administration (NOAA) models for two 1-week periods to measure the impact of the assimilation of observations from 11 inland WPRs. Model simulations with and without assimilation of the WPR data are compared at the locations of the inland WPRs, as well as against observations from an additional WPR and a high-resolution Doppler lidar (HRDL) located on board the Research Vessel Ronald H. Brown (RHB), which cruised the Gulf of Maine during the NEAQS experiment. Model evaluation in the lowest 2 km above the ground shows a positive impact of the WPR data assimilation from the initialization time through the next five to six forecast hours at the WPR locations for 12 of 15 days analyzed, when offshore winds prevailed. A smaller positive impact at the RHB ship track was also confirmed. For the remaining three days, during which time there was a cyclone event with strong onshore wind flow, the assimilation of additional observations had a negative impact on model skill. Explanations for the negative impact are offered.

Download Full-text

A Predictive Model of the Impact of the Skidding System on Forest Soil in Severe Climatic Conditions

Lesnoy Zhurnal (Forestry Journal) ◽

10.37482/0536-1036-2020-5-131-144 ◽

2020 ◽

pp. 131-144

Author(s):

S.E. Rudov ◽

◽

V.Ya. Shapiro ◽

O.I. Grigoreva ◽

I.V. Grigorev ◽

...

Keyword(s):

Forest Soil ◽

Warm Season ◽

Climatic Conditions ◽

Soil Freezing ◽

Class Iii ◽

Freezing And Thawing ◽

Metal Structures ◽

Rapid Adjustment ◽

Soil Freezing And Thawing ◽

The Impact

In the Russian Federation logging operations are traditionally carried out in winter. This is due to the predominance of areas with swamped and water-logged (class III and IV) soils in the forest fund, where work of forestry equipment is difficult, and sometimes impossible in the warm season. The work of logging companies in the forests of the cryolithozone, characterized by a sharply continental climate, with severe frosts in winter, is hampered by the fact that forest machines are not recommended to operate at temperatures below –40 °C due to the high probability of breaking of metal structures and hydraulic system. At the same time, in the warm season, most of the cutting areas on cryosolic soils become difficult to pass for heavy forest machines. It turns out that the convenient period for logging in the forests of the cryolithozone is quite small. This results in the need of work in the so-called off-season period, when the air temperature becomes positive, and the thawing processes of the soil top layer begin. The same applies to the logging companies not operating in the conditions of cryosolic soils, for instance, in the Leningrad, Novgorod, Pskov, Vologda regions, etc. The observed climate warming has led to a significant reduction in the sustained period of winter logging. Frequent temperature transitions around 0 °C in winter, autumn and spring necessitate to work during the off-season too, while cutting areas thaw. In bad seasonal and climatic conditions, which primarily include off-season periods in general and permafrost in particular, it is very difficult to take into account in mathematical models features of soil freezing and thawing and their effect on the destruction nature. The article shows that the development of long-term predictive models of indicators of cyclic interaction between the skidding system and forest soil in adverse climatic conditions of off-season logging operations in order to improve their reliability requires rapid adjustment of the calculated parameters based on the actual experimental data at a given step of the cycles.

Download Full-text

OFFSHORE RING STRUCTURES AND IGNEOUS BODIES BENEATH THE CONTINENTAL MARGIN OF THE NORTHEASTERN UNITED STATES AND THE GULF OF MAINE: EVIDENCE SUPPORTING THE NEW ENGLAND HOTSPOT TRACK BETWEEN THE WHITE MOUNTAIN MAGMA SERIES AND THE NEW ENGLAND SEAMOUNTS

10.1130/abs/2016am-287889 ◽

2016 ◽

Author(s):

Ronald Marple ◽

◽

Robert J. Altamura

Keyword(s):

United States ◽

New England ◽

Continental Margin ◽

Gulf Of Maine ◽

Northeastern United States ◽

Ring Structures ◽

Magma Series

Download Full-text

Towards Including Dynamic Vegetation Parameters in the EUMETSAT H SAF ASCAT Soil Moisture Products

Remote Sensing ◽

10.3390/rs13081463 ◽

2021 ◽

Vol 13 (8) ◽

pp. 1463

Author(s):

Susan C. Steele-Dunne ◽

Sebastian Hahn ◽

Wolfgang Wagner ◽

Mariette Vreugdenhil

Keyword(s):

Soil Moisture ◽

Interannual Variability ◽

Incidence Angle ◽

Pearson Correlation ◽

The United States ◽

Research Network ◽

Window Width ◽

High Frequency Variability ◽

Vegetation Parameters ◽

The Impact

The TU Wien Soil Moisture Retrieval (TUW SMR) approach is used to produce several operational soil moisture products from the Advanced Scatterometer (ASCAT) on the Metop series of satellites as part of the EUMETSAT Satellite Application Facility on Support to Operational Hydrology and Water Management (H SAF). The incidence angle dependence of backscatter is described by a second-order Taylor polynomial, the coefficients of which are used to normalize ASCAT observations to the reference incidence angle of 40∘ and for correcting vegetation effects. Recently, a kernel smoother was developed to estimate the coefficients dynamically, in order to account for interannual variability. In this study, we used the kernel smoother for estimating these coefficients, where we distinguished for the first time between their two uses, meaning that we used a short and fixed window width for the backscatter normalisation while we tested different window widths for optimizing the vegetation correction. In particular, we investigated the impact of using the dynamic vegetation parameters on soil moisture retrieval. We compared soil moisture retrievals based on the dynamic vegetation parameters to those estimated using the current operational approach by examining their agreement, in terms of the Pearson correlation coefficient, unbiased RMSE and bias with respect to in situ soil moisture. Data from the United States Climate Research Network were used to study the influence of climate class and land cover type on performance. The sensitivity to the kernel smoother half-width was also investigated. Results show that estimating the vegetation parameters with the kernel smoother can yield an improvement when there is interannual variability in vegetation due to a trend or a change in the amplitude or timing of the seasonal cycle. However, using the kernel smoother introduces high-frequency variability in the dynamic vegetation parameters, particularly for shorter kernel half-widths.

Download Full-text

The Management of Myelomeningocele Study: Short-Term Neonatal Outcomes

Fetal Diagnosis and Therapy ◽

10.1159/000509245 ◽

2020 ◽

Vol 47 (12) ◽

pp. 865-872 ◽

Cited By ~ 1

Author(s):

Natalie E. Rintoul ◽

Roberta L. Keller ◽

William F. Walsh ◽

Pamela K. Burrows ◽

Elizabeth A. Thom ◽

...

Keyword(s):

New England ◽

Gestational Age ◽

Periventricular Leukomalacia ◽

Ductus Arteriosus ◽

Outcome Data ◽

Neonatal Outcomes ◽

Increased Risk ◽

Significant Difference ◽

The Impact ◽

Prenatal Surgery

Introduction: The Management of Myelomeningocele Study was a multicenter randomized trial to compare prenatal and standard postnatal repair of myelomeningocele (MMC). Neonatal outcome data for 158 of the 183 randomized women were published in The New England Journal of Medicine in 2011. Objective: Neonatal outcomes for the complete trial cohort (N = 183) are presented outlining the similarities with the original report and describing the impact of gestational age as a mediator. Methods: Gestational age, neonatal characteristics at delivery, and outcomes including common complications of prematurity were assessed. Results: Analysis of the complete cohort confirmed the initial findings that prenatal surgery was associated with an increased risk for earlier gestational age at birth. Delivery occurred before 30 weeks of gestation in 11% of neonates that had fetal MMC repair. Adverse pulmonary sequelae were rare in the prenatal surgery group despite an increased rate of oligohydramnios. There was no significant difference in other complications of prematurity including patent ductus arteriosus, sepsis, necrotizing enterocolitis, periventricular leukomalacia, and intraventricular hemorrhage. Conclusion: The benefits of prenatal surgery outweigh the complications of prematurity.

Download Full-text

Characterization of the inter-annual, seasonal, and diurnal variations of condensation particle concentrations at Neumayer, Antarctica

Atmospheric Chemistry and Physics ◽

10.5194/acp-11-13243-2011 ◽

2011 ◽

Vol 11 (24) ◽

pp. 13243-13257 ◽

Cited By ~ 30

Author(s):

R. Weller ◽

A. Minikin ◽

D. Wagenbach ◽

V. Dreiling

Keyword(s):

Ultrafine Particles ◽

Particle Diameter ◽

Austral Summer ◽

Southern Annular Mode ◽

Contamination Control ◽

Atmospheric Circulation Indices ◽

Seasonal And Diurnal Variations ◽

Time Series Analyses ◽

June July ◽

The Impact

Abstract. Continuous condensation particle (CP) observations were conducted from 1984 through 2009 at Neumayer Station under stringent contamination control. During this period, the CP concentration (median 258 cm−3) showed no significant long term trend but exhibited a pronounced seasonality characterized by a stepwise increase starting in September and reaching its annual maximum of around 103 cm−3 in March. Minimum values below 102 cm–3 were observed during June/July. Dedicated time series analyses in the time and frequency domain revealed no significant correlations between inter-annual CP concentration variations and atmospheric circulation indices like Southern Annular Mode (SAM) or Southern Ocean Index (SOI). The impact of the Pinatubo volcanic eruption and strong El Niño events did not affect CP concentrations. From thermodenuder experiments we deduced that the portion of volatile (at 125 °C) and semi-volatile (at 250 °C) particles which could be both associated with biogenic sulfur aerosol, was maximum during austral summer, while during winter non-volatile sea salt particles dominated. During September through April we could frequently observe enhanced concentrations of ultrafine particles within the nucleation mode (between 3 nm and 7 nm particle diameter), preferentially in the afternoon.

Download Full-text

To what extent does the environmental magnetism technique acts as a way of assessing the uptake of atmospheric particles by plants?

10.5194/egusphere-egu21-8263 ◽

2021 ◽

Author(s):

Sarah Letaïef ◽

Pierre Camps ◽

Thierry Poidras ◽

Patrick Nicol ◽

Delphine Bosch ◽

...

Keyword(s):

Air Quality ◽

Endemic Species ◽

Fine Particles ◽

Magnetic Measurements ◽

Deposition Velocity ◽

Environmental Magnetism ◽

Air Pollutant ◽

Atmospheric Pollutants ◽

Area Index ◽

The Impact

Numerous studies have already shown the possibility of tracing the sources, the compositions, and the concentration of atmospheric pollutants deposited on plant leaves. In environmental geochemistry, inter-element and isotope ratios from chemical element assays have been used for these purposes. Alternatively, environmental magnetism represents a quick and inexpensive asset that is increasingly used as a relative indicator for concentrations of air pollutant on bio accumulator surfaces such as plants. However, a fundamental issue is still pending: Do plants in urban areas represent a sink for fine particles that is sufficiently effective to improve air quality? This is a very topical issue because some studies have shown that the foliage can trap fine particles by different dry deposition processes, while other studies based on CFD models indicate that plant hedges in cities can hinder the atmospheric dispersion of pollutants and therefore increase pollution at the level of emission sources such as traffic. To date, no consensus was made because several factors not necessary well known must be taken into account, such as, PM concentration and size, prevailing wind, surface structures, epicuticular wax, to mention just a few examples. A first step toward the understanding of the impact of urban greens on air quality is the precise determination of the deposition velocity (Vd) parameter. This latter is specific for each species and it is most of the time underestimated in modeling-based studies by taking standard values. In that perspective, we built a wind tunnel (6 m long, 86 cm wide and 86 cm high) to perform analogical experiments on different endemic species. All parameters are controlled, i.e, the wind speed, the nature and the injection time of pollutants (Gasoline or Diesel exhausts, brakes or tires dust, etc&#8230;). We can provide the PM concentrations upwind and downwind of natural reconstituted hedges by two dustmeters (LOACs - M&#233;t&#233;oModem). Beforehand, parameters such as the hedge resistance (%) or the leaf area index (LAI) have been estimated for each studied specie to allow comparability between plants removal potential. The interest would ultimately combine PM concentration measured by size bins from the LOACs with magnetic measurements (ARM, IRM100mT, IRM300mT and SIRM) of plant leaves. The idea is to check whether it would be possible to precisely determine in situ the dust removal rate by urban greens with environmental magnetism measurements. Up to now, we have carried out on different endemic species such as Elaeagnus x ebbingei leaves and Mediterranean pine needles, the results of which will be presented.

Download Full-text