摘要:

AbstractThe fraction,r, of the net in‐cloud radiative flux difference existing within the mean capping inversion of a stratocumulus‐topped mixed layer is calculated, assuming an exponential diminution of radiative flux belowlocalcloud‐top height. Its dependence upon hoλ and Δh/hois presented, wherehois the depth of the well‐mixed portion of the boundary layer, λ is the radiative extinction length, and Δhis the thickness of the mean capping inversion, or entrainment zone, within the context of ensemble averaging or horizontal averaging. the calculation makes use of laboratory observations on the distribution of mixed‐layer matter within the entrainment zone of a convectively mixed layer. the fractionris shown to vary widely between its limits of 0 and 1 and under different configurations of stratocumulus mixed layers.For a given net radiative flux at the top of the cloud, it is shown that changes in λ andrhave a modest effect upon the buoyancy flux profile and a strong effect upon the entrainment rate. Buoyant production of turbulence within the well‐mixed layer is found to be maximized whenrlies in the

ISSN:0035-9009    

DOI:10.1002/qj.49710745112

出版商:John Wiley&Sons, Ltd    

年代:1981

数据来源: WILEY

摘要:

AbstractAcoustic sounder derived profiles of the atmospheric velocity and temperature structure parameters,Cv2andCT2, are presented. the former is obtained using a novel bistatic acoustic sounder comprising a fan beam transmitter and a vertically directed receiver. Simultaneous profiles of the temperature structure parameter are obtained using a conventional monostatic sounder.Time histories of these quantities at two heights in the boundary layer are given and are compared with in‐situ measurements. the results indicate significant anisotropy in the temperature field at scales greater than a few metres and emphasize the care required when comparing directly measured and acoustically estimated turbulence quantities. the significance of anisotropy in the assessment of excess attenuation is also discusse

ISSN:0035-9009    

DOI:10.1002/qj.49710745113

出版商:John Wiley&Sons, Ltd    

年代:1981

数据来源: WILEY

摘要:

AbstractThe tropospheric measurements, atmospheric release rates, and OH reaction rates for methyl chloroform are consistent with present estimates of the tropospheric OH distribution and a methyl chloroform lifetime of about 5 years. Reaction with OH radicals is found to be the major atmospheric removal process for this species. Although excellent agreement is obtained in the northern hemisphere, recent southern hemisphere observations have indicated a much more rapid growth than can be accounted for by model calculations. A comparison of the two‐dimensional model with simpler formulations such as global, hemispheric or one‐dimensional models, shows that the simpler models may not adequately represent tropospheric transport and removal by OH radic

ISSN:0035-9009    

DOI:10.1002/qj.49710745114

出版商:John Wiley&Sons, Ltd    

年代:1981

数据来源: WILEY

摘要:

AbstractRegression equations have been derived for albedo in the United States, summer and winter, as a function of conventional meteorological variables of the type that might be available from a numerical model. For monthly mean patterns, the variance reduction was from 60% in summer to 84% in winter on test samples. On a day to day basis, the reduction of variance was from 45% in summer to 55% in winter. Still, errors of estimate are smaller in summer than in winter.The principal predictors were the mean relative humidity below 500 mb, and the pole‐ward meridional wind component aloft. In addition, a snow‐cover variable was needed in winter. Dynamic predictors, such as vorticity advection or vertical velocity, had relatively little skill and did not enter the equations consistently. Also, stability parameters played an unimportant p

ISSN:0035-9009    

DOI:10.1002/qj.49710745115

出版商:John Wiley&Sons, Ltd    

年代:1981

数据来源: WILEY

摘要:

AbstractReturn values of an environmental parameter, such as wind speed or wave height, are frequently estimated from an extreme value analysis of observed annual maxima assuming that the parameter is identically distributed throughout the year. Environmental data generally have considerable within‐year variation. an indication of the error in return values resulting from this assumption is obtained by analysing monthly maxima of wave height and wind speed data. It appears that the assumption leads to an underestimation of return value

ISSN:0035-9009    

DOI:10.1002/qj.49710745116

出版商:John Wiley&Sons, Ltd    

年代:1981

数据来源: WILEY

ISSN:0035-9009    

DOI:10.1002/qj.49710745117

出版商:John Wiley&Sons, Ltd    

年代:1981

数据来源: WILEY

ISSN:0035-9009    

DOI:10.1002/qj.49710745118

出版商:John Wiley&Sons, Ltd    

年代:1981

数据来源: WILEY

ISSN:0035-9009    

DOI:10.1002/qj.49710745119

出版商:John Wiley&Sons, Ltd    

年代:1981

数据来源: WILEY

ISSN:0035-9009    

DOI:10.1002/qj.49710745120

出版商:John Wiley&Sons, Ltd    

年代:1981

数据来源: WILEY

ISSN:0035-9009    

DOI:10.1002/qj.49710745121

出版商:John Wiley&Sons, Ltd    

年代:1981

数据来源: WILEY