摘要:

This paper is an overview of an intensive period of data collection performed as part of the Western Atlantic Ocean Experiment (WATOX) during early 1986. The objective of WATOX‐86 was to determine the flux and fate of a variety of atmospheric materials that are advected eastward from North America to the atmosphere of the western North Atlantic Ocean (WNAO). WATOX‐86 used two National Oceanic and Atmospheric Administration aircraft, a twin engine King Air and a four engine WP‐3D, to collect gases and aerosols off the east coast of North America from Florida to Newfoundland. The WP‐3D was based at McGuire Air Force Base, New Jersey, during the first 10 days of January 1986. The King Air was based at Hanscom Field, Massachusetts, during periods in January and February 1986 and on Bermuda during May 1986. Measurements were made of a variety of gases including SO2, NOx, NOy, peroxyacetyl nitrate, CO, O3, C2−C6hydrocarbons, N2O and dimethyl sulfide. In addition, aerosols were collected and analyzed for black carbon, SO4=, NO3−, NH4+and trace metals. The individual papers of this special issue provide details on the results and analysis of the individual measurement programs. This paper provides a brief summary of each program. During WATOX‐86, there were large regions of the WNAO atmosphere that had elevated concentrations of the measured gas and aerosol species. The elevated concentrations were the result of transport of the products of anthropogenic activities from North America to the WNAO atmosphere. The high degree of correlation among the concentrations of the different species indicated that these materials were transported in “clouds” of polluted air that covered thousands of square kilometers. The WATOX‐86 data on sulfur and nitrogen oxides are analyzed in the context of atmospheric budgets for WNAO. Approximately 25 to 35% of the sulfur and 15 to 25% of the nitrogen oxides emitted to the eastern North American atmosphere are advected eastward to the WNAO atmosphere. Of this material, about half of the sulfur and most of the nitrogen oxides are deposited to the WNAO. For both sulfur and nitrogen oxides, wet and dry deposition are of approximate

ISSN:0886-6236    

DOI:10.1029/GB001i004p00261

年代:1987

数据来源: WILEY

摘要:

During the January 1986 Western Atlantic Ocean Experiment (WATOX), two research aircraft (the WP‐3D and King Air) flew a series of flights off the east coast of North America, with the purpose of determining chemical and air fluxes off North America. An overview of the meteorological conditions during the WP‐3D flights is presented. Surface and 850‐mbar synoptic charts, isobaric air parcel back trajectories, and vertical cross sections of potential temperature and water vapor mixing ratio are also presented. The surface synoptic conditions were typically characterized by low pressure near Newfoundland and high pressure over the southeastern United States, causing generally northwesterly winds north of about 38°N latitude and more variable winds farther south. In general, the flights were characterized by a well‐defined marine boundary layer capped by a layer of stratus clouds. Wind climatologies suggest that the meteorology during the four flights was typical of much of January and possibly much of th

ISSN:0886-6236    

DOI:10.1029/GB001i004p00283

年代:1987

数据来源: WILEY

摘要:

A National Oceanic and Atmospheric Administration WP‐3D meteorological research aircraft was instrumented with a wide range of gas and aerosol sampling equipment to conduct a component of the Western Atlantic Ocean Experiment (WATOX‐86) intensive study. The added instrumentation provided for measurements of condensation nuclei, aerosol scattering extinction, ozone, soot carbon, NOx, SO2, H2O2, NO2, peroxyacetyl nitrate, CO, HNO3, and aerosol particle size/number. Discrete air samples were collected in both glass and metal flasks for analyses of a wide range of gaseous species. Aerosol collections included bulk samples on high‐volume filters, single‐particle collections with impactors, continuous size segregated aerosol impactors (with up to nine size cuts), and a range of specialty filters designed to collect gases and gases adsorbed on aerosols. Operational aspects of the four WP‐3D WATOX flights are described along with pertinent observer notes and

ISSN:0886-6236    

DOI:10.1029/GB001i004p00297

年代:1987

数据来源: WILEY

摘要:

During the Western Atlantic Ocean Experiment 1986, the National Oceanic and Atmospheric Administration WP‐3D aircraft collected meteorological data and samples of atmospheric gases and aerosols during approximately 40 hours of flying time on January 4, 6, 8, and 9, 1986. This research effort attempted to quantify the fluxes of materials off the Atlantic coast following periods of frontal passage. The meteorological data are averaged into 15‐min periods and grouped into boundary layer and free tropospheric sections. Areas of clouds and precipitation were not included in the analysis. Air mass fluxes are calculated and air mass flux cross sections are presented using ambient temperature and pressure values. The range of boundary layer flux values was calculated to be from approximately ‐4 kg/(m2/s) indicating onshore flow, to about 25 kg/(m2/s); free tropospheric flux values ranged from approximately 5 kg/(m2/s) to 30 kg/(m2/s). The uncertainty of the air flux data was estimated to be less tha

ISSN:0886-6236    

DOI:10.1029/GB001i004p00309

年代:1987

数据来源: WILEY

摘要:

We have made in‐flight determinations of SO2in clouds, the cloud‐free boundary layer, and the free troposphere in a wintertime marine environment . The salient feature of the SO2vertical distribution was the consistently low SO2levels (0.14 parts per billion by volume (ppbv) mean; 0.065 ppbv median) in the free troposphere compared to the boundary/mixed layers (1.83 ppbv mean; 1.02 ppbv median). In some instances SO2in the clouds that capped the boundary layer was as high as in the air below the clouds. The estimated SO2fluxes were 2.1 Tg S−1for the boundary layer, 0.21 Tg S yr−1for the free troposphere between 850 and 700 hPa, 0.36 Tg S yr−1for the free troposphere between 700 an

ISSN:0886-6236    

DOI:10.1029/GB001i004p00317

年代:1987

数据来源: WILEY

摘要:

This paper describes the measurement of reactive nitrogen compounds as part of the 1986 Western Atlantic Ocean Experiment (WATOX). Species measured include NO and NOY(NOY= NO + NO2+ NO3+ HNO3+ 2N2O5+ HONO + PAN + R‐ONOx + fine NO3, where PAN is peroxyacetyl nitrate). A ferrous sulfate converter, which was subsequently determined to respond to PAN, was used to measure NOx' (NOx' = NO + NO2+ ˜0.7 PAN). Although concentrations of NOYreached several parts per billion in offshore urban plumes, average levels of NOYin the planetary boundary layer (PBL) resemble those measured at rural sites along the east coast. Free tropospheric concentrations of NOYwere near continental background levels observed in previous studies. Concentrations of NO were typically below the detection limit of 20 parts per trillion in the free troposphere, with higher concentrations detected in the PBL. By combining the odd nitrogen data set with calculations of ambient air mass fluxes observed on each flight, we calculate an instantaneous gross N flux through the area from 31.5 to 44.1°N and 0 to 3000 m to be 18.5 kg N/s. The dependence of the magnitude of this flux upon specific meteorological conditions is discussed. For comparative purposes, we also combine our odd nitrogen data set with climatological wind data for the eastern seaboard to estimate an annual gross N flux of 0.5 Tg N/yr, significantly less than previous estima

ISSN:0886-6236    

DOI:10.1029/GB001i004p00329

年代:1987

数据来源: WILEY

摘要:

Measurements of NO and NOx' (as measured by a chemiluminescent analyzer equipped with a FeSO4converter) were made from an aircraft off the east coast of North America in January and February 1986. These measurements show the mixing ratios of the nitrogen oxides to be higher than encountered in remote continental or marine environments. Both the free troposphere and boundary layer mixing ratio distributions are skewed to ward high mixing ratios and are best described by a gamma probability distribution. The mean mixing ratios observed were 2.9 parts per billion by volume (ppbv) in the boundary layer and 0.55 ppbv in the free troposphere for NOx', and 0.56 ppbv in the boundary layer and 0.18 in the free troposphere for NO.

ISSN:0886-6236    

DOI:10.1029/GB001i004p00345

年代:1987

数据来源: WILEY

摘要:

Filter pack and aethalometer systems were successfully used aboard the National Oceanic and Atmospheric Administration WP‐3D and King Air aircraft during the January 1986 intensive field investigation of the Western Atlantic Ocean Experiment (WATOX) to measure concentrations of sulfur and nitrogen species and black carbon aerosol. The mean boundary layer concentrations of SO4=−e, NO3−, NH4+and black carbon measured on the WP‐3D were 16, 6.6, 23 and 16 nmol m−3(STP), respectively, and those of SO2and HNO3were 0.9 and 0.1 parts per billion by volume (ppbv), respectively. Mean boundary layer concentrations of SO4=−e, NH4+and HNO3measured on the King Air were 20 nmol m−3(STP), 41.4 nmol m−3(STP) and 0.13 ppbv, respectively. Concentrations in the free troposphere were consistently lower by factors of 1.5 to 4.5 than those in the boundary layer. In the boundary layer SO4=−e accounted for approximately 30% of the total non‐sea‐salt sulfur, and particulate NO3‐ accounted for 40% of the total nitrate. NH4+and SO4=−e were significantly correlated and present in a molar ratio of approximately 2:1, suggesting that the species existed in the aeros

ISSN:0886-6236    

DOI:10.1029/GB001i004p00357

年代:1987

数据来源: WILEY

摘要:

Measurements of PAN (peroxyacetyl nitrate) over the western Atlantic Ocean, collected during four aircraft missions in January 1986, are reported. The observed concentrations at circa 150‐200 km off the coast while the general airflow was directly from the coast to the sampling location were surprisingly low, ranging from 20‐510 ppt in the planetary boundary layer (PBL) and 25‐230 ppt in the free troposphere (FT). Most PAN was found in pollution plumes in the PBL. With the exception of one small plume, the level in the FT appeared to be indicative of a continental background air mass. It is speculated that the low average PAN level in the PBL was due to efficient dilution of the air, transported over the open ocean, thereby preventing extensive oxidation of NOxinto PAN and inorganic nitrates, or alternatively to the preferential production of other not identified organic nitrates. Averaged over the total data set the PAN mixing ratio was determined at 184 ± 115 ppt and 94 ± 48 ppt for the PBL and FT, respectively. Comparison with NOxdata suggests that for flux calculations most of the N flux in the PBL can be assumed to be in the form of NOx(≡ NO + NO2), but a similar assumption for FT flow would lead to an underestimation of tot

ISSN:0886-6236    

DOI:10.1029/GB001i004p00369

年代:1987

数据来源: WILEY