Search Results

You are looking at 1 - 10 of 35 items for :

  • Cloud forcing x
  • Climate Implications of Frontal Scale Air–Sea Interaction x
  • Refine by Access: Content accessible to me x
Clear All
Hyodae Seo, Hajoon Song, Larry W. O’Neill, Matthew R. Mazloff, and Bruce D. Cornuelle

and meandering SST fronts extend beyond the air–sea fluxes and MABL winds, leaving discernible imprints in cloud liquid water, cloud-top temperatures, and temperature profiles ( O’Neill et al. 2003 , 2005 ; Liu et al. 2007 ; Perlin et al. 2014 , 2020 ). Several studies demonstrate that warm SSTs of the AC serve as a significant source of heat and water vapor to coastal storms, adding to their rain-bearing capacity ( Walker 1990 ; Jury et al. 1993 ; Mason 1995 ; Reason and Mulenga 1999

Full access
Morio Nakayama, Hisashi Nakamura, and Fumiaki Ogawa

landmass and sea ice exist, the forcing of planetary waves as in the Northern Hemisphere is suppressed, allowing us to investigate the fundamental dynamics of the BAM. The rest of this paper is structured as follows. Details of the aquaplanet experiments and analysis procedures are described in section 2 . After an overview of the climatological-mean fields simulated in our experiments is presented in section 3 , characteristics of the BAM and the effect of the oceanic frontal zone are described in

Open access
Yi-Hui Wang and W. Timothy Liu

; Minobe et al. 2008 ; Tokinaga et al. 2009 ). The local imprints of ocean currents, including surface wind, precipitation, and cloud formation, are well represented in satellite data from over a short period of just a few years. Two mechanisms, the vertical mixing mechanism and the pressure adjustment mechanism, have been proposed to explain the processes behind the ocean forcing on the overlying boundary layer at frontal scales. The vertical mixing mechanism attributes the correspondence of the SST

Full access
Ayumu Miyamoto, Hisashi Nakamura, and Takafumi Miyasaka

regression model cannot perfectly extract the impacts of individual large-scale forcing, since 1) it takes some time for clouds to respond to the forcing, and 2) the clouds and boundary layer properties are advected spatially by the large-scale horizontal airflow. Nevertheless, the derived local dependence is useful for quantifying their local control on LCF. The regression slope thus derived for each variable is shown in Table B1 . We have calculated confidence intervals following the supporting

Open access
Xiaohui Ma, Ping Chang, R. Saravanan, Raffaele Montuoro, Hisashi Nakamura, Dexing Wu, Xiaopei Lin, and Lixin Wu

frontal regions, on the other hand, can lead to an equatorward shift of the entire low-level atmospheric circulation system, including the surface westerlies, jet streams, and subtropical high pressure belt ( Sampe et al. 2010 ). By comparing atmosphere-only model simulations forced by prescribed SSTs, Taguchi et al. (2009) showed a reduced storm-track activity in response to a weakened SST gradient forcing due to the decreased meridional gradient of turbulent heat fluxes and moisture fluxes across

Full access
Satoru Okajima, Hisashi Nakamura, Kazuaki Nishii, Takafumi Miyasaka, and Akira Kuwano-Yoshida

( Lau 1997 ; Alexander et al. 2002 ) and internal atmospheric variability ( Frankignoul 1985 ; Kushnir et al. 2002 ). In fact, Robinson (2000) reported difficulties in atmospheric general circulation model (AGCM) experiments to yield systematic atmospheric responses to prescribed midlatitude SST anomalies. It has been suggested recently (e.g., Taguchi et al. 2012 ), however, that persistent SST anomalies in the North Pacific subarctic frontal zone (SAFZ) can force basin-scale atmospheric

Full access
Niklas Schneider and Bo Qiu

1. Introduction Satellite-borne observations of the atmospheric response to fronts of sea surface temperature (SST) have revolutionized the understanding of midlatitude air–sea interaction ( Xie 2004 ; Small et al. 2008 ). While the traditional, large-scale view holds that the ocean primarily responds to forcing by the atmosphere, the ocean mesoscale shows a ubiquitous imprint of SST fronts on the atmospheric boundary layer ( Chelton and Xie 2010 ; Xie 2004 ). For scales shorter than about

Full access
Satoru Okajima, Hisashi Nakamura, Kazuaki Nishii, Takafumi Miyasaka, Akira Kuwano-Yoshida, Bunmei Taguchi, Masato Mori, and Yu Kosaka

1. Introduction Owing to greater persistence of SST anomalies than atmospheric anomalies, a robust atmospheric response to oceanic forcing, if any, could contribute to improvement in seasonal forecast skill. Influence of extratropical SST anomalies on the large-scale atmospheric circulation has long been believed to be insignificant, in the presence of a prevailing remote influence from the tropics ( Lau 1997 ; Alexander et al. 2002 ) and large intrinsic atmospheric variability ( Frankignoul

Full access
Kotaro Katsube and Masaru Inatsu

midtroposphere at 0000 UTC 1 September 2004, when the typhoon center is located at 20.4°N, 146.4°E, between Guam and the Ogasawara Islands ( Fig. 2a ). A spiral feature around the typhoon can be identified, even in a 15-km-resolution simulation. We take the spatial average for diabatic heating rate as in Fig. 2a and provide it at only the typhoon central grid cell and eight surrounding grid cells of the LBM as the forcing. In this example, the diabatic heating rate rises to 900 K day −1 in the wall-cloud

Full access
Ryusuke Masunaga, Hisashi Nakamura, Takafumi Miyasaka, Kazuaki Nishii, and Youichi Tanimoto

). The formation of the SLP trough also acts to force frictional wind convergence near the surface and associated updraft at the MABL top. At the same time, static stability is also reduced within the overlying MABL, where the “vertical mixing effect” ( Wallace et al. 1989 ; Hayes et al. 1989 ), thus enhanced, translates a larger amount of westerly momentum down from the free troposphere to modify the ageostrophic wind field. Experiments by Koseki and Watanabe (2010) with an atmospheric general

Full access