Temporal variations of Titan's middle-atmospheric temperatures from 2004 to 2009 observed by Cassini/CIRS
Temporal variations of Titan's middle-atmospheric temperatures from 2004 to 2009 observed by Cassini/CIRS
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DOI：
10.1016/j.icarus.2010.08.009
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发表时间：
2011-01-01
期刊：
影响因子：
3.2
通讯作者：
Nixon, Conor A.
中科院分区：
文献类型：
--
作者：
Achterberg, Richard K.;Gierasch, Peter J.;Nixon, Conor A.
我们使用五年半的临边和最低点观察温度映射观测的复合红外辐射计-光谱仪（CIRS）的卡西尼土星轨道器，2004年7月和2009年12月之间（L-S从293度到4度;北方仲冬到刚刚过北方春分），监测温度变化在上部同温层和下部中间层的土卫六。变化最大的是在北方（冬季）极地平流层顶，在2005年至2009年期间温度下降了20 K以上。在平流层中上部和中间层下部的其余部分，温度变化小于5 K。在南半球，从2004年到2007年初，平流层中层近1毫巴的温度上升了1-2 K，然后在2008年和2009年下降了2-4 K，在极地纬度变化更大。从2005年到2009年，中北纬平流层中层温度小幅上升1-2 K。在极涡内的北极纬度，2007年平流层中部的温度显示出类似于4 K的上升，随后在2008年和2009年初出现了类似的温度下降。北极地区观测到的温度变化与中层大气纬向环流下降分支内下沉的减弱是一致的。(C)2010年爱思唯尔公司All rights reserved.
We use five and one-half years of limb- and nadir-viewing temperature mapping observations by the Composite Infrared Radiometer-Spectrometer (CIRS) on the Cassini Saturn orbiter, taken between July 2004 and December 2009 (L-S from 293 degrees to 4 degrees; northern mid-winter to just after northern spring equinox), to monitor temperature changes in the upper stratosphere and lower mesosphere of Titan. The largest changes are in the northern (winter) polar stratopause, which has declined in temperature by over 20 K between 2005 and 2009. Throughout the rest of the mid to upper stratosphere and lower mesosphere, temperature changes are less than 5 K. In the southern hemisphere, temperatures in the middle stratosphere near 1 mbar increased by 1-2 K from 2004 through early 2007, then declined by 2-4 K throughout 2008 and 2009, with the changes being larger at more polar latitudes. Middle stratospheric temperatures at mid-northern latitudes show a small 1-2 K increase from 2005 through 2009. At north polar latitudes within the polar vortex, temperatures in the middle stratosphere show a similar to 4 K increase during 2007, followed by a comparable decrease in temperatures in 2008 and into early 2009. The observed temperature changes in the north polar region are consistent with a weakening of the subsidence within the descending branch of the middle atmosphere meridional circulation. (C) 2010 Elsevier Inc. All rights reserved.