Effects of meridional sea surface temperature changes on stratospheric temperature and circulation

Abstract

Article:Hu, D, Tian, W, Xie, F et al. (2 more authors) (2014) Effects of meridional sea surface temperature changes on stratospheric temperature and circulation. Advances in Atmospheric Sciences, 31 (4). 888 -900. ISSN 0256-1530 https://doi.org/10.1007/s00376-013-3152-6 eprints@whiterose.ac.uk https://eprints.whiterose.ac.uk/ Reuse Unless indicated otherwise, fulltext items are protected by copyright with all rights reserved. The copyright exception in section 29 of the Copyright, Designs and Patents Act 1988 allows the making of a single copy solely for the purpose of non-commercial research or private study within the limits of fair dealing. The publisher or other rights-holder may allow further reproduction and re-use of this version -refer to the White Rose Research Online record for this item. Where records identify the publisher as the copyright holder, users can verify any specific terms of use on the publisher's website. TakedownIf you consider content in White Rose Research Online to be in breach of UK law, please notify us by emailing eprints@whiterose.ac.uk including the URL of the record and the reason for the withdrawal request. ABSTRACT Using a state-of-the-art chemistry-climate model, we analyzed the atmospheric responses to increases in sea surface temperature (SST). The results showed that increases in SST and the SST meridional gradient could intensify the subtropical westerly jets and significantly weaken the northern polar vortex. In the model runs, global uniform SST increases produced a more significant impact on the southern stratosphere than the northern stratosphere, while SST gradient increases produced a more significant impact on the northern stratosphere. The asymmetric responses of the northern and southern polar stratosphere to SST meridional gradient changes were found to be mainly due to different wave properties and transmissions in the northern and southern atmosphere. Although SST increases may give rise to stronger waves, the results showed that the effect of SST increases on the vertical propagation of tropospheric waves into the stratosphere will vary with height and latitude and be sensitive to SST meridional gradient changes. Both uniform and non-uniform SST increases accelerated the large-scale Brewer-Dobson circulation (BDC), but the gradient increases of SST between 60 • S and 60 • N resulted in younger mean age-of-air in the stratosphere and a larger increase in tropical upwelling, with a much higher tropopause than from a global uniform 1.0 K SST increase.

The relationship between lower-stratospheric ozone at southern high latitudes and sea surface temperature in the East Asian marginal seas in austral spring

“…It is noteworthy that warm (cold) SST anomalies are generally thought to increase (suppress) planetary wave activity via strengthening (weakening) convection (Xie et al, 2008;Shu et al, 2011;Hu et al, 2014). However, this study shows that warm (cold) SST anomalies over the marginal seas of East Asia suppress (increase) planetary wave activity in the southern high-latitude stratosphere.…”

Brewer–Dobson Circulation: Recent-Past and Near-Future Trends Simulated by Chemistry-Climate Models

“…Previous studies have shown that an increase in GHGs leads to a warmer troposphere and a cooler stratosphere via its direct radiational effects and indirect SST effects, which in turn affects the wave propagation from the troposphere into the stratosphere and further strengthens the BDC [5]. Stratospheric ozone has important impacts on the BDC Advances in Meteorology through the radiational and chemical processes [2,45,46].…”

“…During 2001-2050, the warmed Antarctic stratosphere may lead to a weakened latitudinal temperature gradient ( Figure 6(c)), which, following the thermal wind relationship, would be accompanied by a weakened westerly wind in the Antarctic stratosphere and an equatorward displacement of the southern subtropical jet (Figure 6(d)). The above-mentioned zonal wind changes imply a change in refractive index [10], which in turn can influence the propagation of planetary waves from the troposphere to the stratosphere [5,43]. As the eddy heat flux (V ) can well represent the vertical flux of wave activity well [44], we examine the trends of eddy heat flux in DJF during the two periods (Figure 7).…”

“…Changes in the BDC can modulate the global radiation balance by affecting the meridional distribution of the natural and anthropogenic tracer gases in the stratosphere, further influencing climate and environmental changes at the global scale [2][3][4][5][6][7]. For example, ozone-depleting substances that follow the BDC are transported into the polar stratosphere where they influence the concentration of ozone [8][9][10][11][12].…”

“…Since the BDC has important impacts on the climate of the troposphere and stratosphere [2][3][4][5][6], it is also important to be able to predict its trend under the expected climatic conditions of the future. As mentioned above, an increase in the concentration of CO 2 results in an accelerated BDC [2,3,[18][19][20], and stratospheric ozone depletion can also lead to a strengthening of downwelling in the high-latitude stratosphere [2,25].…”