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Amy H. Butler, David W. J. Thompson, and Ross Heikes

1. Introduction There is increasing evidence that anthropogenic forcing has driven and will drive several robust changes in the extratropical circulation. Among the most robust changes are poleward shifts in the extratropical storm tracks consistent with positive trends in the northern and southern annular modes of variability. Observations reveal robust positive trends in the southern annular mode (SAM) during austral spring/summer that are consistent with forcing by the Antarctic ozone hole

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Chiel C. van Heerwaarden, Jordi Vilà-Guerau de Arellano, Amanda Gounou, Françoise Guichard, and Fleur Couvreux

, only the studies of Brubaker and Entekhabi (1996) and Margulis and Entekhabi (2001) have provided methods to quantify the influence of individual forcings and feedbacks in the coupled land–atmosphere system on evapotranspiration. Our study focuses on evapotranspiration on the diurnal time scale and is therefore complementary to the work of Brubaker and Entekhabi . Their study aims at understanding the longer time scales involved in the heat and moisture budget, which can for instance be seen

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O. E. García, A. M. Díaz, F. J. Expósito, J. P. Díaz, A. Redondas, and T. Sasaki

1999 ; Arimoto et al. 2006 ; Shen et al. 2006 ) and hence different radiative traces. In particular, Sokolik and Toon (1999) found that aerosol optical properties are very sensitive to the individual minerals and their mixtures in dust composition, even modifying the net effect (i.e., the sign) of mineral dust radiative forcing. Thus, the present study examines the impact of the natural mineral dust on the UV energy transfer by analyzing the influence of the source region. 2. Instrumentation

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S. J. Ghan, X. Liu, R. C. Easter, R. Zaveri, P. J. Rasch, J.-H. Yoon, and B. Eaton

1. Introduction Anthropogenic aerosol is thought to play an important role in driving climate change, but its role is so complex that uncertainty in estimates of radiative forcing of climate change is dominated by uncertainty associated with forcing by anthropogenic aerosol ( Forster et al. 2007 ). This complexity arises because anthropogenic aerosol alters the planetary energy balance through a variety of mechanisms operating across a wide range of spatial scales: direct effects ( Haywood and

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Hiroki Ichikawa, Hirohiko Masunaga, Yoko Tsushima, and Hiroshi Kanzawa

1. Introduction The radiative effect of clouds, often called cloud radiative forcing (CRF), associated with convective activity largely controls the radiative balance–imbalance at the top of the atmosphere (TOA) over the tropics through the horizontal extension of high clouds that accompany deep convection ( Ramanathan and Collins 1991 ; Lindzen et al. 2001 ; Hartmann et al. 2001 ). The response of CRF associated with convective activity to an imposed climate perturbation is thus fundamental

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Michael P. Meredith, Alberto C. Naveira Garabato, Andrew McC. Hogg, and Riccardo Farneti

help to evaluate changes in the overturning. In this paper, we investigate an ocean at (or close to) the eddy-saturated limit, and evaluate how the overturning circulation will behave at this limit. The overall response of the overturning circulation in the Southern Ocean to changes in wind stress forcing will depend on the differing responses of the Eulerian mean and eddy-induced components ( Fig. 1 ). The magnitude of the Eulerian mean overturning is reasonably expected to be linear with wind

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Vasubandhu Misra

Amazon, French Guiana, Suriname, Guyana, and Venezuela. This region is hereafter referred as the EA and is outlined in Fig. 1a . Given the EA’s close proximity to the equator, the motivation for this paper is to understand if local processes, such as the diurnal variation, amplify the remote ENSO forcing. 2. Model description and data a. Model description The Center for Ocean–Land–Atmosphere Studies (COLA) coupled climate model ( Misra et al. 2007 ; Misra and Marx 2007 ) is used in this study. Its

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Simone Lolli, James R. Campbell, Jasper R. Lewis, Yu Gu, Jared W. Marquis, Boon Ning Chew, Soo-Chin Liew, Santo V. Salinas, and Ellsworth J. Welton

1. Motivation Campbell et al. (2016) isolate top-of-atmosphere (TOA) net cirrus cloud radiative forcing (CRF) properties for a continuous 1-yr, single-layer cloud dataset developed from NASA ground-based Micro-Pulse Lidar Network (MPLNET; http://mplnet.gsfc.nasa.gov/ ) ( Welton et al. 2001 ; Campbell et al. 2002 ; Lolli et al. 2013 ) observations collected at Greenbelt, Maryland [38.99°N, 76.84°W; 50 m above mean sea level (MSL)]. They estimate that cirrus clouds exert an absolute net

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Gang Chen and Pablo Zurita-Gotor

2004 ; Haigh et al. 2005 ). However, the mechanism through which increased lower-stratospheric winds shift the tropospheric jet remains obscure. Previous studies have mainly focused on the effects of the eddy-induced zonal forcings and the vertical wind shears in the lower stratosphere. These zonal forcings can induce a meridional residual circulation that extends downward and closes in the planetary boundary layer. This provides a zonally symmetric pathway to redistribute momentum in the vertical

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Amanda C. Maycock, Christopher J. Smith, Alexandru Rap, and Owain Rutherford

1. Introduction Radiative forcing (RF) quantifies the change in Earth’s energy balance from an imposed perturbation of natural or anthropogenic origin (e.g., IPCC 1990 ). Given knowledge of climate feedback processes, RF is a useful measure to predict the eventual global mean surface temperature change resulting from a climate perturbation (e.g., Hansen et al. 1985 ); as a consequence, it is a common measure of interest for climate science ( Shine and Forster 1999 ). Various incarnations of

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