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The midocean trough in the North Pacific may form a favorable environment for the genesis of some synoptic disturbances. In contrast, the North Pacific anticyclone may hinder the downward penetration of these disturbances into the...
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The midocean trough in the North Pacific may form a favorable environment for the genesis of some synoptic disturbances. In contrast, the North Pacific anticyclone may hinder the downward penetration of these disturbances into the lower troposphereand prevent the moisture supply to these disturbances from the lower troposphere. Because no thick clouds, rainfall, and destructive surface winds are associated with these disturbances to attract attention, they have not been analyzed or documented. Actually, the upper-level wind speed within these disturbances is sometimes as strong as tropical cyclones and has the possibility of causing air traffic hazards in the western subtropic Pacific. With infrared images of the Japanese Geostationary Meteorological Satellite and the NCEP-NCAR reanalysis data, 25 North Pacific disturbances were identified over six summers (1993-98). Two aspects of these disturbances were explored: spatial structure and basic dynamics. For their structure, the disturbances possess a well-organized vortex in the middle to upper troposphere with a descending dry/cold core encircled by the moist ascending air around the vortex periphery; the secondary circulation of the vortex is opposite to other types of synoptic disturbances. Since vorticity reaches maximum values along the midocean trough line, barotrophic instability is suggested as a likely genesis mechanism of the vortex. After the vortex is formed, the horizontal advection of total vorticity results in its westward propagation, while the secondary circulation hinders this movement. Along its westward moving course, close to East Asia, there is a reduction in vortex size and a tangential speed increase inversely proportional to the vortex size. Diminishing its horizontalconvergence/descending motion by the upper-tropospheric East Asian high and the lower-tropospheric monsoon low, the vortex eventually dissipates along the East Asian coast.
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Through the use of a graphical interface, regional modeling systems can now be employed for a variety of applications by those who are not experts in modeling. Operational numerical weather forecasts are traditionally performed wi...
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Through the use of a graphical interface, regional modeling systems can now be employed for a variety of applications by those who are not experts in modeling. Operational numerical weather forecasts are traditionally performed with fixed model configurations. That is, an expert in the use of a particular model, with formal training in numerical weather prediction, sets up the model grids and makes many other decisions about model options in configuring the system for a particular geographic area, This approach has been satisfactory for most U.S. National Weather Service (NWS) and Department of Defense (DOD) operations because the larger coarser-resolution model grids cover the entire geographic area of responsibility and do not need to be moved. However, with very-high-resolution models, where the computational resources need to be focused over relatively small areas, the small model grids need to be relocated as the area of interest changes, One alternative to a single, large immobile grid is tohave preestablished model "windows" over different geographic areas, This alternative, employed by the U.S. Air Force Weather Agency and the NWS's National Centers for Environmental Prediction (NCEP), is most practical if it is possible to always anticipate future needs, but this is obviously not the case.
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Many atmospheric chemicals occur in the gas phase as well as in liquid cloud droplets and aerosol particles. Therefore, it is necessary to understand the distribution between the phases. According to Henry's law, the equilibrium r...
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Many atmospheric chemicals occur in the gas phase as well as in liquid cloud droplets and aerosol particles. Therefore, it is necessary to understand the distribution between the phases. According to Henry's law, the equilibrium ratio between the abundances in the gas phase and in the aqueous phase is constant for a dilute solution. Henry's law constants of trace gases of potential importance in environmental chemistry have been collected and converted into a uniform format. The compilation contains 17 350 values of Henry's law constants for 4632 species, collected from 689 references. It is also available at http://www.henrys-law.org.
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摘要 :
Many atmospheric chemicals occur in the gas phase as well as in liquid cloud droplets and aerosol particles. Therefore, it is necessary to understand the distribution between the phases. According to Henry's law, the equilibrium r...
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Many atmospheric chemicals occur in the gas phase as well as in liquid cloud droplets and aerosol particles. Therefore, it is necessary to understand the distribution between the phases. According to Henry's law, the equilibrium ratio between the abundances in the gas phase and in the aqueous phase is constant for a dilute solution. Henry's law constants of trace gases of potential importance in environmental chemistry have been collected and converted into a uniform format. The compilation contains 17 350 values of Henry's law constants for 4632 species, collected from 689 references. It is also available at http://www.henrys-law.org. chemicals from rivers and during waste water treatment (e.g., Shen, 1982; Hawthorne et al., 1985; David et al., 2000). Section 2 provides the theoretical background of Henry's law and commonly used quantities and units. In Sect. 3, the compilation of Henry's law constants is described in detail. Additional information can be found in the Supplement, which is described in Sect. 4.
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摘要 :
Many atmospheric chemicals occur in the gasphase as well as in liquid cloud droplets and aerosol particles.Therefore, it is necessary to understand the distributionbetween the phases. According to Henry's law, the equilibriumratio...
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Many atmospheric chemicals occur in the gasphase as well as in liquid cloud droplets and aerosol particles.Therefore, it is necessary to understand the distributionbetween the phases. According to Henry's law, the equilibriumratio between the abundances in the gas phase and inthe aqueous phase is constant for a dilute solution. Henry'slaw constants of trace gases of potential importance in environmentalchemistry have been collected and converted intoa uniform format. The compilation contains 17 350 values ofHenry's law constants for 4632 species, collected from 689references. It is also available at http://www.henrys-law.org.
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This article, the second in the series, presents kinetic and photochemicaldata evaluated by the IUPAC Subcommittee on Gas Kinetic Data Evaluation forAtmospheric Chemistry. It covers the gas phase and photochemical reactions ofOrga...
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This article, the second in the series, presents kinetic and photochemicaldata evaluated by the IUPAC Subcommittee on Gas Kinetic Data Evaluation forAtmospheric Chemistry. It covers the gas phase and photochemical reactions ofOrganic species, which were last published in 1999, and were updated on theIUPAC website in late 2002, and subsequently during the preparation of this article. The article consists of a summary tableof the recommended rate coefficients, containing the recommendedkinetic parameters for the evaluated reactions, and eight appendicescontaining the data sheets, which provide informationupon which the recommendations are made.
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This article, the fourth in the series, presents kinetic andphotochemical data sheets evaluated by the IUPAC Subcommittee on GasKinetic Data Evaluation for Atmospheric Chemistry. It covers the gasphase and photochemical reactions ...
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This article, the fourth in the series, presents kinetic andphotochemical data sheets evaluated by the IUPAC Subcommittee on GasKinetic Data Evaluation for Atmospheric Chemistry. It covers the gasphase and photochemical reactions of organic halogen species, whichwere last published in 1997, and were updated on the IUPAC website in2006/07. The article consists of a summary sheet, containing therecommended kinetic parameters for the evaluated reactions, and fourappendices containing the data sheets, which provide information uponwhich the recommendations are made.
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Evolution of monodisperse and polydisperse droplet size distributions (DSD) during homogeneous mixing is analyzed. Time-dependent universal analytical expressions for supersaturation and liquid water content are derived. For an in...
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Evolution of monodisperse and polydisperse droplet size distributions (DSD) during homogeneous mixing is analyzed. Time-dependent universal analytical expressions for supersaturation and liquid water content are derived. For an initial monodisperse DSD, these quantities are shown to depend on a sole non-dimensional parameter. The evolution of moments and moment-related functions in the course of homogeneous evaporation of polydisperse DSD is analyzed using a parcel model. It is shown that the classic conceptual scheme, according to which homogeneous mixing leads to a decrease in droplet mass at constant droplet concentration, is valid only in cases of monodisperse or initially very narrow polydisperse DSD. In cases of wide polydisperse DSD, mixing and successive evaporation lead to a decrease of both mass and concentration, so the characteristic droplet sizes remain nearly constant. As this feature is typically associated with inhomogeneous mixing, we conclude that in cases of an initially wide DSD at cloud top, homogeneous mixing is nearly indistinguishable from inhomogeneous mixing.
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In 2017, the dominant greenhouse gases released into Earth's atmosphere—carbon dioxide, methane, and nitrous oxide— reached new record highs. The annual global average carbon dioxide concentration at Earth's surface for 2017 was...
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In 2017, the dominant greenhouse gases released into Earth's atmosphere—carbon dioxide, methane, and nitrous oxide— reached new record highs. The annual global average carbon dioxide concentration at Earth's surface for 2017 was 405.0 ± 0.1 ppm, 2.2 ppm greater than for 2016 and the highest in the modern atmospheric measurement record and in ice core records dating back as far as 800 000 years. The global growth rate of C02 has nearly quadrupled since the early 1960s.With ENSO-neutral conditions present in the central and eastern equatorial Pacific Ocean during most of the year and weak La Nina conditions notable at the start and end, the global temperature across land and ocean surfaces ranked as the second or thirdhighest, depending on the dataset, since records began in the mid-to-late 1800s. Notably, it was the warmest non-El Nino year in the instrumental record. Above Earth's surface, the annual lower tropospheric temperature was also either second or third highest according to all datasets analyzed. The lower stratospheric temperature was about 0.2°C higher than the record cold temperature of 2016 according to most of the in situ and satellite datasets.Several countries, including Argentina, Uruguay, Spain, and Bulgaria, reported record high annual temperatures. Mexico broke its annual record for the fourth consecutive year. On 27 January, the temperature reached 43.4°C at Puerto Madryn, Argentina—the highest temperature recorded so far south (43°S) anywhere in the world. On 28 May in Turbat, western Pakistan, the high of 53.5°C tied Pakistan's all-time highest temperature and became the world-record highest temperature for May.In the Arctic, the 2017 land surface temperature was l.6°C above the 1981-2010 average, the second highest since the record began in 1900, behind only 2016. The five highest annual Arctic temperatures have all occurred since 2007. Exceptionally high temperatures were observed in the permafrost across the Arctic, with record values reported in much of Alaska and northwestern Canada. In August, high sea surface temperature (SST) records were broken for the Chukchi Sea, with some regions as warm as + 11°C, or 30 to 4°C warmer than the long-term mean (1982-present). According to paleoclimate studies, today's abnormally warm Arctic air and SSTs have not been observed in the last 2000 years. The increasing temperatures have led to decreasing Arctic sea ice extent and thickness. On 7 March, sea ice extent at the end of the growth season saw its lowest maximum in the 37-year satellite record, covering 8% less area than the 1981-2010 average. The Arctic sea ice minimum on 13 September was the eighth loweston record and covered 25% less area than the long-term mean.Preliminary data indicate that glaciers across the world lost mass for the 38th consecutive year on record; the declines are remarkably consistent from region to region. Cumulatively since 1980, this loss is equivalent to slicing 22 meters off the top of the average glacier.
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