Search Results

You are looking at 21 - 30 of 9,617 items for :

  • Journal of Climate x
  • Refine by Access: All Content x
Clear All
Xuebin Zhang, Bruce Cornuelle, and Dean Roemmich

wind forcing in the western and central equatorial Pacific (e.g., Zhang and McPhaden 2006 , hereafter ZM06 ). Because the remote wind forcing plays a dominant role in ENSO-related SST variations in the eastern equatorial Pacific (e.g., Rasmusson and Carpenter 1982 ; Harrison and Larkin 1998 ; Wang and Picaut 2004 ), local wind forcing in the eastern equatorial Pacific and associated physical processes were often neglected in previous studies. However, local wind forcing may also vary on ENSO

Full access
Marius Bickel, Michael Ponater, Lisa Bock, Ulrike Burkhardt, and Svenja Reineke

et al. 2016 ). CO 2 emissions from fuel burning and several non-CO 2 effects contribute to the total radiative forcing of aviation with comparable magnitude. Indirect climate effects of aircraft aerosol emissions are potentially large (e.g., Gettelman and Chen 2013 ; Zhou and Penner 2014 ; Righi et al. 2016 ; Penner et al. 2018 ) but have remained highly uncertain due to open issues in our knowledge of aerosol–cloud interactions ( Kärcher 2017 ; Kärcher 2018 ). In contrast, the level of

Open access
Sang-Ik Shin, Prashant D. Sardeshmukh, and Robert S. Webb

oceans. A map of such sensitivities may also be interpreted as the “optimal” tropical SST forcing pattern of North American drought. The GCMs used were the National Center for Atmospheric Research (NCAR) atmospheric GCM community climate model version 3 (CCM3; Kiehl et al. 1998 ) and the Max Planck Institute for Meteorology (MPIM) atmospheric GCM ECHAM5 ( Roeckner et al. 2003 ). As a measure of drought, we employed the widely used Palmer drought severity index (PDSI; Palmer 1965 ), which is based

Full access
M. J. Woodage and S. Woodward

requirements; however, the atmospheric component of the U.K. High-Resolution Global Environmental Model (HiGEM) with horizontal resolution of 1.25° longitude × 0.83° latitude has been used for such experiments and has been shown to produce realistic simulations of the mineral dust aerosol distribution and its associated radiative forcing ( Woodage et al. 2010 ). The question of the sign and magnitude of radiative forcing due to dust has been addressed by many authors. In one of the earliest papers

Full access
Sarah M. Kang, Isaac M. Held, Dargan M. W. Frierson, and Ming Zhao

1. Introduction It is often assumed that the position of the ITCZ in the tropics is controlled by tropical mechanisms ( Xie 2004 ). However, there is paleoclimatic and modeling evidence that one can alter the position of the ITCZ by perturbing the thermal forcing in the extratropics, with the ITCZ moving away from a cooled hemisphere or toward a warmed hemisphere. For example, Koutavas and Lynch-Stieglitz (2004) find that the marine ITCZ in the eastern Pacific is displaced southward when the

Full access
Clark Weaver, Jay Herman, Gordon Labow, David Larko, and L.-K. Huang

1. Introduction Cloud radiative feedback quantifies an aspect of how clouds respond to a warming climate, specifically, the change in the top-of-atmosphere (TOA) reflected radiative flux from changes in cloud amount or morphology ( R cloud ) per degree temperature change at the earth’s surface. Here R cloud is called the cloud radiative forcing (watts per meter squared). Currently, the longest observational data record for shortwave (SW) R cloud is from the International Satellite Cloud

Full access
Alan Condron, Peter Winsor, Chris Hill, and Dimitris Menemenlis

, toward a more neutral state after the mid-1990s. The direct response of the Arctic freshwater budget to the positive and negative phases of the NAO pattern were recently examined by Zhang et al. (2003) , and then by Houssais et al. (2007) , using regional coupled ocean–ice models of the Arctic, forced with NCEP data. To create atmospheric forcing fields for the NAO, the NCEP data were regressed onto the positive and negative phases of the NAO index over the last 50 years. Interestingly, even though

Full access
Christopher B. Skinner, Moetasim Ashfaq, and Noah S. Diffenbaugh

predominant view among researchers largely attributes the variability of West African rainfall to changes in global sea surface temperatures, with localized land surface fluxes modulating the sea surface temperature forcing ( Zeng et al. 1999 ; Nicholson 2001 ; Giannini et al. 2003 ). Several studies have successfully reproduced the historical record of rainfall in the Sahel using climate models forced only with observed global SSTs (e.g., Giannini et al. 2003 ; Lu and Delworth 2005 ), and a number of

Full access
Bjorn Stevens

1. Introduction A perturbation to the composition of Earth’s atmosphere can be quantified through the degree to which it disturbs the radiative balance at the top of the atmosphere, its radiative forcing. This radiative forcing is a motive force for climate change as (at least for small perturbations) Earth’s globally averaged surface temperature is expected to change proportionally with the forcing (e.g., Myhre et al. 2013a ; Sherwood et al. 2015 ). More than 20 years ago Charlson et al

Full access
Takeaki Sampe and Shang-Ping Xie

circulation response in turn (e.g., Yamazaki and Chen 1993 ), so examining the observed convection or low-level circulation is not enough to elucidate the cause of the whole meiyu-baiu system. It is important to isolate the external forcing that anchors the climatological rainband. Fundamental questions remain unanswered: what determines the position and timing of the meiyu-baiu rainband? Why is convection active in the meiyu-baiu rainband while SST and surface equivalent potential temperature (cf. Figs

Full access