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Bohua Huang and J. Shukla

gradient and the warming in the western Indian Ocean precondition the subsequent warming over the basin. Overall, ENSO seems to be an effective and persistent remote factor to stimulate the air–sea feedback in the Indian Ocean, both dynamically and thermodynamically. However, it is not yet clear how important the regional air–sea feedback and oceanic dynamics are in shaping the spatial and temporal evolution in response to this external forcing. On the other hand, even though there is a historical

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Michael P. Erb, Anthony J. Broccoli, Neal T. Graham, Amy C. Clement, Andrew T. Wittenberg, and Gabriel A. Vecchi

-day eastern equatorial Pacific sea surface temperature (SST) cycle is characterized by maximum warmth in boreal spring and minimum warmth in boreal summer and autumn. Farther west, near the date line, the seasonal cycle is weaker, with the warm peak occurring a month or two later in the year. West of 160°E there is a semiannual cycle, with warm peaks in April–May and in November. Because tropical insolation forcing is semiannual, with maxima near the two equinoxes, the eastern equatorial Pacific SST cycle

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Yunfeng Cao, Shunlin Liang, Xiaona Chen, and Tao He

. Two recent typical studies based on satellite retrievals show large differences from one another. Flanner et al. (2011) used a synthesis of calculated sea ice albedo, with sea ice type derived from sea ice concentration and in situ measurements of sea ice albedo, and radiative kernels to estimate the sea ice radiative forcing (SIRF) in the Northern Hemisphere (NH). They found the change in SIRF from 1979 to 2008 was 0.22 (0.15–0.32) W m −2 , and the corresponding SIAF was 0.28 (0.19–0.41) W m −2

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Courtenay Strong and Gudrun Magnusdottir

1. Introduction The response of atmospheric general circulation models to boundary forcing is quite varied across models and experiments ( Kushnir et al. 2002 ) and has been challenging to interpret because of nonlinearities with respect to the sign of the forcing anomaly ( Kushnir and Lau 1992 ; Peng et al. 2002 , 2003 ; Ferreira and Frankignoul 2005 ) and the location of the forcing anomaly relative to the storm track ( Peng et al. 1997 ). Despite these complexities, studies of transient

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Thomas B. Richardson, Piers M. Forster, Timothy Andrews, and Doug J. Parker

1. Introduction Regional precipitation change is one of the most uncertain aspects of climate change prediction ( Stephens et al. 2010 ; Liepert and Previdi 2012 ; Stevens and Bony 2013 ) and can have major societal implications ( Wake 2013 ). On a global scale, the precipitation response to a forcing can be understood through atmospheric energy budget arguments ( Mitchell et al. 1987 ; Allen and Ingram 2002 ; O’Gorman et al. 2012 ). Tropospheric radiative cooling tightly constrains global

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Amato T. Evan, Gregory R. Foltz, and Dongxiao Zhang

. 2009 ) or the top of the atmosphere ( Evan and Mukhopadhyay 2010 ). Therefore, by bulk formulas, the presence of an elevated aerosol layer over water would tend to cool the ocean. Schollaert and Merrill (1998) showed a negative correlation between individual dust outbreaks and underlying SST and used a mixed-layer heat budget analysis to suggest that the magnitude of the aerosol direct effect was sufficiently large to force the observed cool anomalies. Evan et al. (2008) demonstrated that on

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James R. Campbell, Erica K. Dolinar, Simone Lolli, Gilberto J. Fochesatto, Yu Gu, Jasper R. Lewis, Jared W. Marquis, Theodore M. McHardy, David R. Ryglicki, and Ellsworth J. Welton

1. Introduction Campbell et al. (2016 , hereinafter C16 ) and Lolli et al. (2017 , hereinafter L17 ) describe multiyear ground-based NASA Micro-Pulse Lidar Network (MPLNET, 532 nm; Welton et al. 2001 ; Campbell et al. 2002 ) measurements of cirrus clouds and corresponding estimates of their net daytime top-of-the-atmosphere (TOA) cloud radiative forcing (CRF; i.e., the difference in TOA solar and infrared radiation budgets estimated in the presence of cloud versus that of the corresponding

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Amber M. Holdsworth and Paul G. Myers

strengthening of the cyclonic gyre that results in a convex doming of isopycnals, the presence of LSW from previously convected winters, or an increase in high-frequency forcing ( Marshall et al. 1998 ; Condron and Renfrew 2013 ). Changes in surface forcing due to cold air outbreaks, polar lows, or storms may induce deep convection ( Marshall and Schott 1999 ) or act to precondition the sea for convection depending on when they form. The extent of mixed layer deepening in the Labrador Sea has consequences

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Tyler J. Thorsen, David M. Winker, and Richard A. Ferrare

1. Introduction Aerosols continue to be responsible for the largest uncertainty in determining the anthropogenic radiative forcing of the climate. Aerosols influence anthropogenic forcing indirectly via modifications to cloud properties as well as directly through the scattering and absorption of solar radiation—the aerosol direct radiative forcing (DRF). Placing constraints on the DRF solely using observations is difficult since current satellite observations can only crudely identify

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S. Ramachandran

Satheesh and Srinivasan (2006 , henceforth SS06 ) discussed a method to determine aerosol radiative forcing from spectral optical depths. A more refined methodology applicable to a wide variety of environments, which employs stringent criteria and is statistically rigorous, for the first time has been published earlier by Ramachandran and Jayaraman (2003) , the details of which are given below. In addition the shortcomings in the method given in SS06 are pointed out in this work. The

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