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Zachary J. Lebo and Hugh Morrison

line was sensitive to the raindrop breakup parameterization implemented in a bulk microphysics model. Given that the ambient aerosol number concentration leads to substantial changes in droplet number and thus collection processes, it is postulated that increased anthropogenic aerosol loading could have similar effects on squall-line dynamics by impacting cold pool evolution. Since aerosols can affect cold pool characteristics because of their impact on cloud microphysics, RKW theory provides a

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Chia-Ying Lee, Michael K. Tippett, Suzana J. Camargo, and Adam H. Sobel

distribution to account for uncertainty. While such models are relevant to operational intensity forecasts, our interest is more directed at the capability of such a model to downscale TC intensity from the large-scale environment. The ability of the MLR to relate variations in the large-scale environment to TC intensity has applications beyond short-term forecasting and can be a tool toward understanding the distribution of TC intensities in a climate undergoing natural or anthropogenic changes. The MLR

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Hung-Neng S. Chin, Martin J. Leach, Gayle A. Sugiyama, John M. Leone Jr., Hoyt Walker, J. S. Nasstrom, and Michael J. Brown

study, additional modifications to BW’s scheme are made to accommodate the model physics in COAMPS and to represent the urban canopy effects in a more consistent way. These modifications include the additions of building drag term in the vertical momentum equation and rooftop surface energy equation, changes in the effects of anthropogenic heat and rooftop in the heat equation, and drag terms in the momentum equations. The main differences of the urban canopy to the forest canopy are marked in two

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Douglas V. Hoyt, Charles P. Turner, and Robert D. Evans

smallnear their presumed sources, then the global increase in aerosols must be very small indeed. Consequently, the effects of anthropogenic aerosols onclimate is probably negligible. There now appear to be two schools of thoughtconcerning anthropogenic aerosols. One schoolargues that their increase has caused much of theobserved cooling of the Northern Hemisphere since1940. Some proponents of this viewpoint are Brysonand Dittberner (1976) and Budyko (1969). The otherschool of thought contends that

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Robert D. Bornstein and Alan D. Robock

step Run 3. The final difference betweenthe results of the two runs is about 5 cm s-t, or about10% of the maximum value of AU from Run 3.7. Rough, warm, wet city simulations The simulations in this section attempt to reproducethe effects of an anthropogenic source of moisture onthe structure of the urban boundary layer. Thus, theconditions expressed by (19) are no longer used; insteadthe background level of moisture q,~ was arbitrarily setequal to 10 g kg-L In addition, it was assumed thatthe

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Jinfang Yin, Da-Lin Zhang, Yali Luo, and Ruoyun Ma

et al. 2011 ). All the three nested domains of the WRF Model are integrated for 18 h, starting from 2000 BST 6 May, with outputs at 6-min intervals. The initial and outermost boundary conditions are interpolated from the NCEP-FNL 0.25° analysis data at 6-h intervals. To introduce realistically Guangzhou’s UHI effects due to the release of daytime-absorbed sensible heat by urban structures and anthropogenic heat during the evening hours, the four-dimensional data assimilation (FDDA) functions are

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Teddy Holt and Julie Pullen

impact on mesoscale dynamics. For example, synoptic and sea-breeze frontal passages can be retarded due to frictional effects by 50% as they approach NYC ( Loose and Bornstein 1977 ; Bornstein and Thompson 1981 ). Urban heating also appears to play a role in distorting near-surface temperatures as sea-breeze fronts pass ( Novak and Colle 2006 ). Also, summer thunderstorm lines have been observed to bifurcate and go around the metropolitan region in response to localized urban-induced convection

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Michael Matson, E. Paul Mcclain, David F. McGinnis Jr., and John A. Pritchard

with the 1970U.S. Census maps of urbanized areas for the three cities indicates the extent of possible urbanizationchanges in the last seven years.1. Introduction In recent years there has been increased concernabout anthropogenic effects on the environment.Excellent summaries of the possible results of theseeffects are found in Landsberg (1970), Chandler(1970) and Kellogg (1977). Increased urbanizationand industrialization in many cities since 1940 hasincreased the intensity and extent of the

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Angela Benedetti and Frédéric Vitart

– 554 , https://doi.org/10.5194/bg-9-527-2012 . 10.5194/bg-9-527-2012 Koch , D. , and A. D. Del Genio , 2010 : Black carbon semi-direct effects on cloud cover: Review and synthesis . Atmos. Chem. Phys. , 10 , 7685 – 7696 , https://doi.org/10.5194/acp-10-7685-2010 . 10.5194/acp-10-7685-2010 Lamarque , J.-F. , and Coauthors , 2010 : Historical (1850–2000) gridded anthropogenic and biomass burning emissions of reactive gases and aerosols: Methodology and application . Atmos. Chem. Phys

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L. P. Stearns

studies were used to demonstratethese problems.1. Introduction The need for accurate determination of the radiative heating and cooling of the atmosphere and surface on a regional and global basis is a growing problem. The increases in anthropogenic and natural(volcanic) aerosols and CO: have led to many controversies concerning the potential climatic effects ofthese changes. The interest in the effects of cloud andmoist layer distributions in the atmosphere on mesoscale/regional weather prediction

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