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Marie Drouard and Christophe Cassou

projecting the wintertime daily outputs of each 30-yr member onto the reference weather regimes centroids obtained from piControl. The changes of ENSO teleconnectivity in a warmer climate are assessed below by contrasting the modification of the occurrence of the NAE regimes with respect to the restored Niño-3.4 SST anomalies, which are common in the two ensembles by construction ( Fig. 1c ). 2) Extended Eliassen–Palm vectors The E vectors are computed using the formula of Trenberth (1986) : (3) E = 1

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J. Craig Collier and Guang J. Zhang

, b ). Therefore, it is useful to evaluate such modifications in other climate regimes such as the North American monsoon region. This paper documents the differences that arise from using the two different parameterizations. In addition, it identifies the North American summertime convective regime for which each scheme is more successful. Special emphasis is placed on the model’s simulation of the diurnal cycle of precipitation in the monsoon domain. At a given location, the diurnal variation of

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Pavlos Kollias and Bruce Albrecht

1. Introduction Trade wind cumuli and fair-weather cumuli in general play an important role in the climate system. These clouds are observed over extensive areas of the earth and outrank in number any other type of cloud ( Norris 1998 ). Although their fractional cloud coverage is small, fair-weather cumuli play key roles in maintaining the energy and moisture budgets of the tropics ( Neggers et al. 2009 ) and the lower-tropospheric thermodynamic structure over extensive areas of the earth

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Thomas M. Seidel, Andrea N. Grant, Alexander A. P. Pszenny, and Daniel J. Allman

the station (changes in dry air types), 2) constant frequency of air masses with modification at their source regions, 3) constant frequencies of air masses with modification during transport, or 4) a combination of all three. In addition, any synoptic change is likely to produce mesoscale and orographic effects, potentially modifying water vapor concentrations further. Airmass frequency can be determined by defining synoptic classes based on either interpretation of source regions on weather maps

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Eduardo Zorita, James P. Hughes, Dennis P. Lettemaier, and Hans von Storch

altered climate regimes. Two regions, one in the Pacific-American sector (westernregion) and one in the American-Mid-Atlantic sector (eastern region), are explored. The first method is based on Classification and Regression Trees (CART) analysis. The CART methodclassifies observed daily sea level pressure (SLP) fields into weather types that are most strongly associated withthe presence/absence of rainfall at selected index stations. After applying this method to historical SLP observations

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Conor I. Anderson and William A. Gough

anomalies from the 1981–2010 GHCN baseline across the northeastern United States and much of eastern Canada (see Fig. 1 , bottom), with an overall temperature anomaly of −0.29°C. In Toronto, the cold February weather in 2015 took its toll on city infrastructure, with 48 water main breaks by mid-February and over 1000 reports of frozen pipes in households across Toronto ( Environment Canada 2015 ). According to Environment Canada (2015) , February also saw agricultural impacts, including delayed maple

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Jinyoung Rhee and Gregory J. Carbone

were slight (in agreement over 90%). This method was adopted by the National Oceanic and Atmospheric Administration (NOAA)/National Weather Service (NWS)/Climate Prediction Center (CPC). However, in contrast to Palmer’s findings with weekly analysis, the operationally produced weekly PDI from the CPC sometimes shows contrary results from the monthly PDI from the NOAA/National Environmental Satellite, Data, and Information Service (NESDIS)/National Climatic Data Center (NCDC; Heim 2005 ). Thus

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Heather Purdie, Nancy Bertler, Andrew Mackintosh, Joel Baker, and Rachael Rhodes

different concentrations and patterns, even if the snow is derived from the same precipitation event. To evaluate this effect in New Zealand ice, we compare data from fresh snow, concurrently collected at two sites during snow precipitation events. Postdepositional modification of stable water isotopes and trace elements may affect the climate integrity of ice core records, especially on temperate maritime glaciers at relatively low altitude ( Raben and Theakstone 1994 ; Yoshimura et al. 2000

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Xiaoqing Wu and Liping Deng

a combination of low-level moist static energy buildup, which is controlled by a corresponding increase in the low-level moisture. Due to the uncertainties in representing the convection and clouds in GCMs and numerical weather prediction (NWP) models, the simulation and prediction of MJO have long been a challenging problem. Impacts of convection schemes on the MJO simulations have been investigated by increasing numbers of studies (e.g., Tokioka et al. 1988 ; Wang and Schlesinger 1999

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Val Bennington, Michael Notaro, and Kathleen D. Holman

Theoretical Physics (ICTP) Regional Climate Model, version 4 (RegCM4), a widely utilized regional climate model ( Giorgi et al. 2012 ), couples the one-dimensional, energy-balance lake model of Hostetler and Bartlein (1990) to the ice model of Patterson and Hamblin (1988) to the hydrostatic fifth-generation Penn State/National Center for Atmospheric Research (NCAR) Mesoscale Model (MM5) in order to simulate both short periods of weather and the long-term climate of a region. The Hostetler model is

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