MARCI-observed clouds in the Hellas Basin during northern hemisphere summer on Mars: Interpretation with the NASA/Ames Legacy Mars Global Climate Model
MARCI-observed clouds in the Hellas Basin during northern hemisphere summer on Mars: Interpretation with the NASA/Ames Legacy Mars Global Climate Model
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MARCI 在火星北半球夏季观测到的希腊盆地云：用 NASA/Ames Legacy 火星全球气候模型进行解释
DOI：
10.1016/j.icarus.2019.113512
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发表时间：
2020
期刊：
影响因子：
3.2
通讯作者：
M. Wolff
中科院分区：
文献类型：
--
作者：
M. Kahre;R. Haberle;J. Hollingsworth;M. Wolff
我们提出了一项研究，这项研究的动机是希腊盆地的水冰云数量，这是由火星勘测轨道器(MRO)上的火星彩色成像仪(MARCI)观测到的，将持续整个北半球(NH)夏季的大部分时间。尽管水冰云在整个NH春季都以极低的不透明度出现在希腊，但在Ls60°之后，水冰云明显增厚，并继续这样做，直到它们在LS~120°达到最大光学厚度。它们从Ls120°到150°迅速消散，到Ls150°时，Hellas中唯一的云在盆地的南侧，与极地风帽云难以区分。我们使用NASA/Ames Legacy火星全球气候模式(GCM)来研究控制希腊水冰云形成和演化的动力学和微物理机制。我们发现，水从北极残盖(NPRC)向南穿过赤道进入希腊地区。水汽被远日点云带中的云形成限制在较低的位置，从而限制了纬向平均翻转环流(即哈德利环流)输送的有效性。因此，与普遍认为的哈德利环流在这个季节控制着跨越赤道的水输送的概念相反，我们表明向南的水输送主要是在水汽相通过几乎所有纬度的静止涡流完成的，包括跨越赤道。当湿空气与希腊西侧的冷极地空气混合后，云在盆地的地面附近形成，随后通过低层气旋环流绕盆地北侧顺时针方向输送。模拟的Hellas云的粒子尺寸很小(~3-5 μm)，非常低，并且只要NPRC暴露就会存在。
We present a study that is motivated by a population of water ice clouds in the Hellas Basin that has been observed by the MARs Color Imager (MARCI) instrument on the Mars Reconnaissance Orbiter (MRO) to persist throughout the majority of Northern Hemisphere (NH) summer. Although water ice clouds are present in Hellas at very low opacities throughout NH spring, they noticeably thicken after Ls60° and continue to do so until their peak optical thickness is attained at Ls~120°. They dissipate rapidly from Ls120° to 150°, and by Ls150°, the only clouds in Hellas are on the southern side of the basin and are indistinguishable from the polar hood clouds. We use the NASA/Ames Legacy Mars Global Climate Model (GCM), which is supported by the Agency's Mars Climate Modeling Center, to investigate the dynamical and microphysical mechanisms that control the formation and evolution of Hellas water ice clouds. We show that water is transported from the North Polar Residual Cap (NPRC) southward across the equator and into the Hellas region. Water vapor is confined down low by cloud formation in the aphelion cloud belt, thus limiting the effectiveness of transport by the zonal mean overturning circulation (i.e., the Hadley cell). Thus, contrary to the commonly held conceptual understanding that the Hadley cell controls cross-equatorial water transport during this season, we show that the southward transport of water is done primarily in the vapor phase by stationary eddies at nearly all latitudes, including across the equator. Clouds form near the surface in the basin as moist air mixes with cold polar air on the western side of Hellas and are subsequently transported clockwise around the north side of the basin by the low-level cyclonic circulation. The simulated Hellas clouds have small particle sizes (~3–5 μm), are very low, and exist as long as the NPRC is exposed.
火星气候探测仪肢体轮廓检索大气温度、压力、灰尘和水冰不透明度
DOI：
10.1029/2009je003358
发表时间：
2009
期刊：
Planets
影响因子：
--
作者：
Kleinböhl A
通讯作者：
Kleinböhl A