Traveling waves in the martian atmosphere from MGS TES Nadir data
Traveling waves in the martian atmosphere from MGS TES Nadir data
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来自 MGS TES Nadir 数据的火星大气中的行波
DOI：
10.1016/j.icarus.2004.03.015
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发表时间：
2004
期刊：
影响因子：
3.2
通讯作者：
M. Smith
中科院分区：
文献类型：
--
作者：
D. Banfield;B. Conrath;P. Gierasch;R. Wilson;M. Smith
我们已经描述了火星大气行波在MGS TES数据集中的年度行为，这些数据集来自火星头两年的测绘。这两年之间有高度的可重复性。它们以靠近极地急流的强低纬向高振幅波数波为主，在北部秋末和北部初冬最强。m=1波的振幅高达约20k，垂直延伸，偶尔甚至延伸到热带地区。m=1的周期从2.5到30个太阳。在南部发现的波要弱得多，振幅小于3.5 K左右。也可以看到m=2和m=3的行波，但它们的振幅通常被限制在4 K以下，并且通常更局限于地表附近。在北方，它们在秋季和春季比冬至更明显，冬至明显以m=1波为主。数据中已经确定了一些风暴路径的证据，在东经200°至320°附近，在地表纬度±65°附近，南半球和北半球与天气有关的温度扰动都加剧了。还发现了一些证据，表明纵向梯度的锐化可能是锋面系统。EP通量散度显示波从纬向平均风中获取能量。当m=1波最强时，测得30 m/(ssol)数量级的纬向喷流减速。在1尺度高度以上，波主要通过正压过程从急流中获取能量，但总体上表现为正斜压混合。惯性不稳定性可能存在于极流赤道侧的高度，而边缘稳定性则延伸至热带。这可能解释了热带波的行为与以极地喷流为中心的波的协调，这与Wilson等人（2002年，《地球物理学》）所表达的观点一致。Res. Lett. 29, #1684)，类似于Barnes et al. （1993， J. Geophys.）。Res. 98, 3125-3148)。全年均存在较大的PV经向梯度小于零的区域，但在冬至附近最强。在冬季急流的极地方向，不稳定区域到达地表，而在赤道方向则没有。这些区域满足了不稳定的必要标准，可能解释了波浪的起源，也许也解释了它们在表面（较快的波浪）和高度（m=1的慢波）之间的双峰特征。
We have characterized the annual behavior of martian atmospheric traveling waves in the MGS TES data set from the first two martian years of mapping. There is a high degree of repeatability between the two years. They are dominated by strong low zonal wavenumber waves with high amplitudes near the polar jets, strongest in late northern fall and early northern winter. The m=1 waves have amplitudes up to about 20 K, are vertically extended, and occasionally extend even into the tropics. Periods for m=1 range from 2.5 to 30 sols. Much weaker waves were identified in the south, with amplitudes less than about 3.5 K. Traveling waves with m=2 and m=3 are also seen, but their amplitudes are typically limited to less than 4 K, and are generally more confined near the surface. In the north, they are more evident in fall and spring rather than winter solstice, which is clearly dominated by m=1 waves. Some evidence of storm tracks has been identified in the data, with accentuated weather-related temperature perturbations near longitudes 200° to 320° E for both the southern and northern hemispheres near latitude ±65° at the surface. Some evidence was also found for a sharpening of longitudinal gradients into what may be frontal systems. EP flux divergences show the waves extracting energy from the zonal mean winds. When the m=1 waves were strongest, decelerations of the zonal jet of order 30 m/(ssol) were measured. Above 1 scale height, the waves extract energy from the jet predominately through barotropic processes, but their character is overall mixed barotropic/baroclinic. Inertial instabilities may exist at altitude on the equatorward flanks of the polar jets, and marginal stability extends through to the tropics. This may explain the coordination of the tropical behavior of the waves with that centered along the polar jet, consistent with the ideas expressed in Wilson et al. (2002, Geophys. Res. Lett. 29, #1684) and similar to those in Barnes et al. (1993, J. Geophys. Res. 98, 3125–3148). Throughout the year, there exist large regions with the meridional gradient of PV less than zero, but they are strongest near winter solstice. Poleward of the winter jet, the regions of instability reach the surface, equatorward they do not. These regions, satisfying a necessary criterion for instability, likely explain the genesis of the waves, and perhaps also their bimodal character between surface (faster waves) and altitude (slow m=1 waves).