摘要:

The concentrations of Cd, Cu, Fe, Mn, Ni, Pb, and Zn have been measured in Bermuda rainwater. Factor analysis indicates that Fe, Mn, and Pb have similar origins to acidic components derived from North America. The other metals all behave similarly but differently to the acids. Sea salt, even after allowances for fractionation, apparently contributes minor amounts of Cu, Pb, and Zn and uncertain amounts of Fe, Mn, and Cd to Atlantic Ocean precipitation. Wash‐out ratios, calculated from this data along with earlier measurements of atmospheric trace metal concentrations on Bermuda, are of the same order as those reported from other remote ocean areas. The wet depositional fluxes of Cu, Ni, Pb, and Zn to the western Atlantic Ocean are significant compared to measured oceanic flux rates. However, the wet depositional fluxes of Fe and Mn to this area are relatively small, suggesting additional inputs, while an excess wet depositional flux of Cd suggests large‐scale atmospheric recycling of this elem

ISSN:0148-0227    

DOI:10.1029/JD089iD01p01423

年代:1984

数据来源: WILEY

摘要:

An atmospheric tracer study using SF6was conducted on July 22, 1977, to examine the origin of the high particulate sulfate concentrations observed in coastal Los Angeles County. It was found that the sea breeze/land breeze circulation system in the Los Angeles Basin both increases the retention time for sulfate formation in the marine environment and causes individual air parcels to make multiple passes over large coastal emissions sources. Day‐old sulfur oxides emissions advected out to sea by the land breeze at night were estimated to be the largest single contributor to 24‐hour average sulfate air quality over land the next day. In contrast, 24‐hour average SO2concentrations were dominated by fresh emissions from nearby sources. The overall rate of SO2transformation to form particulate sulfur oxides along some trajectories that spent a considerable time over the ocean at night probably exceeds the rate that can be explained by known photochemical processes acting during the daylight portion of these trajectories. This suggests that appreciable aerosol formation may occur in a polluted marine environment at

ISSN:0148-0227    

DOI:10.1029/JD089iD01p01429

年代:1984

数据来源: WILEY

摘要:

A model is presented for the flux of a nonreactive gas through the air‐sea interface characterized by patches of breaking waves. A jet of entrained air bubbles resulting from sufficiently large convergence of the surface drift current is visualized as the physical mechanism associated with the gas transfer. The development is based on the work of Yaglom and Kader for rough wall transfer of heat and momentum and is applied here to a compliant rather than a solid surface. An extension of the Charnock relationship for surface roughness is provided to account for contributions to surface root mean square elevation from a band of wave numbers, centered about the minimum phase velocity of short gravity‐capillary waves, which are hypothesized to support most of the wind stress. The transfer is considered to occur only in regions of active breaking, not necessarily visible, which, although occupying a small percentage of the total surface area, are quite sensitive to wind effects. Comparison with data confirms the general validity of the model, but the scatter and limited representativeness of various data sets precludes a more definitive testing of the mo

ISSN:0148-0227    

DOI:10.1029/JD089iD01p01439

年代:1984

数据来源: WILEY

摘要:

Composition of cloud liquid water and interstitial air is reported for aircraft measurements near Charleston, South Carolina, in February 1982. Cloud water was collected by means of a slotted‐rod impactor. Cloud‐free interstitial air was obtained by a centrifugal separator. Principal ionic species in cloud water were H+, SO4=, NO3−, and NH4+. The relative acidity of cloud water, as measured by the ratio of H+to NH4+, was much greater than that of the interstitial aerosol or of clear‐air aerosol samples. Gaseous O3, NOx(i.e., NO+NO2), and SO2were present in interstitial air within clouds, whereas HNO3and NH3were below limit of detection (0.4 ppb for both species). Comparison of relative aciditiy of cloud water samples with that of clear‐air samples suggests that clear‐air aerosol and HNO3are incapable of providing the levels of acidity observed in cloud water. Such acidity would be consistent with in‐cloud conversion of prevailing concentrations of SO2or SO2+NOxto aqueous strong acid, although other hypotheses cannot be excluded. Comparison of absolute concentrations of cloudwater constituents to concentrations in clear‐air measurements gives no indication of accumulation of sulfur and nitrogen sp

ISSN:0148-0227    

DOI:10.1029/JD089iD01p01447

年代:1984

数据来源: WILEY

摘要:

The associations of meteorological parameters with aerosol elemental concentrations in the boundary layer have been studied with measurements obtained at the Boulder Atmospheric Observatory from November 29 to December 6, 1979. Air motions were documented by measurements at the tower up to 300 meters and by regional weather data. Aerosols were sampled at 4, 9, 23, and 49 meters by particle size selective cascade impactors and by time sequence filter samplers and were analyzed by proton induced X ray emission (PIXE). Principal sources of fine particle (<1 μ m aerodynamic diameter) components were automotive emissions for Pb and Br and tall stack emissions and atmospheric conversion of pollution gases to sulfate for S. In coarse particles the major earth crustal elements Al, Si, K, Ca, and Fe were soil derived. Pb and Br concentrations and the ratio Br/Pb generally decreased with height. Also, these concentrations varied with ventilation and vertical mixing and were greatest during southerly air flow from Denver. S concentrations did not generally vary with height, ventilation, vertical mixing, or wind direction, suggesting long‐range transport, although 10‐fold temporal variations were observed. Crustal element concentrations generally decreased with height but depended in part on sampler position on the tower structure, indicating microscale shielding effects of coarse particles which were not observed for fine particle elements. Temporal variations of all elements were associated with major meteorological changes, including a cold front passage and a chinook

ISSN:0148-0227    

DOI:10.1029/JD089iD01p01459

年代:1984

数据来源: WILEY

摘要:

Measurements with an electric field mill beneath a thundercloud show that space charge produced by corona from a surrounding, horizontal, fine‐wire antenna that is connected to the earth greatly reduces the electric field intensit

ISSN:0148-0227    

DOI:10.1029/JD089iD01p01468

年代:1984

数据来源: WILEY

摘要:

It is shown that the occurrence of different monsoon cloud amounts is closely associated with the integrated field intensity of atmospherics simultaneously recorded over Calcutta at 10, 20, and 30kHz. Some of the interesting results achieved from an analysis of the observations during the monsoons of 1977 to 1979 are reported here, and the results are critically discussed in light of the present knowledge of monsoon characteristics.

ISSN:0148-0227    

DOI:10.1029/JD089iD01p01471

年代:1984

数据来源: WILEY

ISSN:0148-0227    

DOI:10.1029/JD089iD01p01474

年代:1984

数据来源: WILEY

ISSN:0148-0227    

DOI:10.1029/JD089iD01p01475

年代:1984

数据来源: WILEY