摘要:

Fields of sea surface temperature anomalies from the Global Ocean Surface Temperature Atlas (GOSTA) and microwave sounding measurements (MSU) of temperature in the troposphere are examined separately and together for the 1979–1988 period. Global correlation patterns of both sets of fields are investigated at a range of leads and lags up to 6 months and exhibit a wide range of correlation structure. There are regions, such as the tropical eastern Pacific, where sea surface temperature anomalies persist for several months and are associated with local air temperature anomalies; in this particular example, about 0.7°C air temperature change is associated with a 1.0°C sea temperature change. By contrast, some ocean regions and many atmospheric regions, mostly in middle and high latitude, show only local spatial correlations that disappear completely in a month or two. The most persistent and extensive spatial correlation patterns are quite different for the sea and the air. In the sea the “butterfly” pattern of the Pacific is the most important and reverses sign between the eastern equatorial Pacific and the western Pacific and subtropics. In the warm phase the temperature anomalies associated with this pattern are similar to the correlation pattern. For the atmosphere the main correlation pattern is an equatorial belt with no sign changes in the tropics; this pattern is linked to the oceanic El Niño mode. In the warm phase the temperature anomalies show peak values on both sides of the equator in the eastern and central Pacific. Based mainly on the results from the spatial patterns, certain regions are selected for intercomparison of time series. In the tropical eastern Pacific the sea leads the air by about a month while in the Gulf Stream and Kuroshio regions the sequence is

ISSN:0148-0227    

DOI:10.1029/91JD03079

年代:1992

数据来源: WILEY

摘要:

We have analyzed responses of the surface energy budgets and hydrologic cycles of 19 atmospheric general circulation models to an imposed, globally uniform sea surface temperature perturbation of 4 K. The responses of the simulated surface energy budgets are extremely diverse and are closely linked to the responses of the simulated hydrologic cycles. The response of the net surface energy flux is not controlled by cloud effects; instead, it is determined primarily by the response of the latent heat flux. The prescribed warming of the oceans leads to major increases in the atmospheric water vapor content and the rates of evaporation and precipitation. The increased water vapor amount drastically increases the downwelling infrared radiation at the Earth's surface, but the amount of the change varies dramatically from one model to another.

ISSN:0148-0227    

DOI:10.1029/91JD03120

年代:1992

数据来源: WILEY

摘要:

A simple quasi‐two‐dimensional model is used to study the zonal distribution of NOx. The model includes vertical transport in the form of eddy diffusion and deep convection, zonal transport by a vertically uniform wind, and a simplified chemistry of NO, NO2, and HNO3. The NOxsources considered are surface emissions (mostly from the combustion of fossil fuel), lightning, aircraft emissions, and downward transport from the stratosphere. The model is applied to the latitude band of 40° to 50°N during the month of June; the contributions to the zonal NOxdistribution from the individual sources and transport processes are investigated. The model predicted NOxconcentration in the upper troposphere is dominated by air lofted from the polluted planetary boundary layer over the large industrial areas of eastern North America and Europe. Aircraft emissions are also important and contribute on average 30%. Stratospheric input is minor about 10%, less even than that by lightning. The model provides a clear indication of intercontinental transport Of NOxand HNO3in the upper troposphere. Comparison of the modeled NO profiles over the western Atlantic with those measured during STRATOZ III in 1984 shows good agreement at all alti

ISSN:0148-0227    

DOI:10.1029/91JD03081

年代:1992

数据来源: WILEY

摘要:

Boreal wetlands are thought to be a large source of atmospheric methane, but this idea is based on very few measurements. Thus a regional survey in the low boreal forest region of central Ontario, Canada, consisting of 24 sites over 12 wetlands and 3 beaver ponds was conducted to determine the temporal and spatial trends in emissions and the net annual methane (CH4) flux. Conifer swamps represented nearly 50% of the wetland coverage, but emit a small amount of CH4(seasonal means<8 mg m−2d−1). The significant emitters of CH4, in order from highest to lowest seasonal means, were beaver ponds (30–90 mg m−2d−1), thicket swamps (0.1–88 mg m−2d−1), and bogs (6–21 mg m−2d−1). Mixed swamps, marshes, and fens emitted very little CH4(<3 mg m−2d−1). Moisture saturation was the key determinant of high emissions, and when satisfied, differences in emissions could be explained by peat and sediment temperatures. On the basis of the areal extent of wetlands from peatland inventories we calculate that the low boreal region of Canada contributes approximately 0.15Tg CH4yr−1to the atmosphere. This is an order of magnitude lower than the flux would be using the estimate of Aselmann and Crutzen (1989)

ISSN:0148-0227    

DOI:10.1029/91JD03109

年代:1992

数据来源: WILEY

摘要:

Methane is an important greenhouse constituent of the atmosphere. Its global source inventory is briefly reviewed, and the aggregated source in the range 270–760 Tg CH4/yr is compatible with independent measurement. The constraints imposed by isotopic information are also discussed. We then exploit this global data base to provide a first detailed estimate of New Zealand sources of methane and their uncertainties, placing these in global perspective. The aggregate New Zealand methane source is estimated to lie in the range 1.3 –2.2 Tg/yr. Nearly all of this emission is caused by human modification of the environment and is dominated ( ∼75%) by “enterically fermented” methane from farmed livestock, predominantly by sheep and lambs (58%) and by cattle (40%). At about 0.3% of global emissions, New Zealand is a disproportionately large methane source on either a per capita or land area basis, or when compared with the New Zealand share (0.13%) of global carbon dioxide emissions from industry and from fossil fuel co

ISSN:0148-0227    

DOI:10.1029/91JD02294

年代:1992

数据来源: WILEY

摘要:

Aerosol particle samples collected in Beijing, China, and Mallipo, South Korea, were analyzed by instrumental neutron activation to (1) determine the atmospheric concentrations of trace elements over the Yellow Sea and (2) to estimate the atmospheric deposition of selected trace elements to this region. The atmospheric concentrations of trace elements decreased from April to May at these two sampling sites, but the percentages of the concentration decreases varied among elements. A decrease in the concentrations of mineral aerosol with distance was modeled using an exponential decay pattern. The estimated atmospheric deposition of mineral aerosol to the Yellow Sea, based on the representative crustal elements, was 9 to 76gm−2yr−1. This flux is comparable to that for any coastal region studied to date, and it can account for 20–70% of the total input of mineral material to the Yellow Sea. The atmospheric deposition of pollutant metals to the Yellow Sea apparently is comparable to the atmospheric fluxes to several European seas and to coastal sites in North Am

ISSN:0148-0227    

DOI:10.1029/91JD02686

年代:1992

数据来源: WILEY

摘要:

Results from extensive lidar measurements on atmospheric atomic mercury in Italian geothermal fields are reported. A mobile differential absorption lidar system operating on the 254‐nm mercury resonance line with a measuring range of about 1 km was used in mineralized as well as nonmineralized areas. Measurements were performed at geothermal power stations and in an unexploited field with natural surface geothermic manifestations. Atomic mercury concentrations ranging from 2 to 1000 ng/m3were mapped. The high Italian geothermal mercury concentrations are in strong contrast to the recent lidar finding of the absence of atomic mercury in Icelandic geothermal field

ISSN:0148-0227    

DOI:10.1029/91JD03108

年代:1992

数据来源: WILEY

摘要:

The geographical distributions on the global scale of trace gas surface emission and deposition are established on the basis of a variety of technical, geographic, and climatic data. The 5° × 5° resolution maps of the sources and deposition velocities are constructed, which can be used as surface boundary conditions in a three‐dimensional chemical/transport model of the troposphere. Special attention is devoted to emissions of CO, NOx, and several nonmethane hydrocarbons (NMHC) and to the fossil fuel emissions of methane. Anthropogenic sources, i.e., the emissions produced or controlled by human activities, represent about 75% or more of the total surface emissions of CO, CH4, SOxand NOxand about two thirds of the total production of atmospheric CO (from surface sources and atmospheric oxidation of hydrocarbons). The possibility arises that methane releases from natural gas exploitation in the USSR are substantially larger than accounted for in previous studies, implying possible important consequences for the methane bu

ISSN:0148-0227    

DOI:10.1029/91JD02757

年代:1992

数据来源: WILEY

摘要:

Satellite data have been used increasingly during the past few years to examine burning around the globe. One such satellite instrument, the advanced very high resolution radiometer (AVHRR), has been found useful for the location and monitoring of both smoke and fires because of the daily observations, the large geographical coverage of the imagery, the spectral characteristics of the instrument, and the spatial resolution of the instrument. Earlier studies using AVHRR imagery have focused on locating and monitoring fires and studying the characteristics of smoke. This paper will discuss the application of AVHRR data to assess the geographical extent of burning. Methods have been developed to estimate the surface area of burning by analyzing the surface area effected by fire with AVHRR imagery. Characteristics of the AVHRR instrument, its orbit, field of view, and archived data sets are discussed relative to the unique surface area of each pixel. The errors associated with this surface area estimation technique are determined using AVHRR‐derived area estimates of target regions with known sizes. This technique is used to evaluate the area burned during the Yellowstone fires of 198

ISSN:0148-0227    

DOI:10.1029/91JD03080

年代:1992

数据来源: WILEY

摘要:

Accurate measurement of atmospheric aerosol from aircraft platforms is of importance to a variety of research interests. Representative measurement of aerosol from aircraft‐aspirated systems requires special efforts in order to (1) maintain near isokinetic sampling conditions, (2) estimate aerosol losses in the sample system, and (3) obtain a measurement of sufficient duration to be statistically significant for all sizes of interest. This last point is especially critical for aircraft measurements which typically require fast response times while sampling in clean remote regions. Here we present size‐resolved tests, intercomparisons, and analysis of aerosol inlet performance as determined by a custom laser optical particle counter. Measurements discussed here took place during the Global Backscatter Experiment (1988–1989) and the Central Pacific Atmospheric Chemistry Experiment (1988). System configurations are discussed including (1) nozzle design and performance, (2) system transmission efficiency, (3) nonadiabatic effects in the sample line and its effect on sample line relative humidity, and (4) the use and calibration of a virtual imp

ISSN:0148-0227    

DOI:10.1029/91JD02886

年代:1992

数据来源: WILEY