论文标题
海冰漂移对雪球气候开始的影响在快速旋转的水上行星上
Effect of Sea-ice Drift on the Onset of Snowball Climate on Rapidly Rotating Aqua-planets
论文作者
论文摘要
先前的研究表明，Sea-Ice漂移有效地促进了对古地地球的全球冰上雪球气候的发作，以及在低质量恒星周围潮汐锁定的行星。在这里，我们调查了Sea-Ice漂移是否会影响恒星气候在围绕阳光般的恒星迅速旋转的水上行驶星际行径上发作的恒星通量阈值。使用完全耦合的大气 - 陆 - - 冰冰模型，开启或关闭海冰漂移，没有偏心率（E = 0）的圆形轨道（E = 0）和一个偏心轨道（E = 0.2）。当关闭Sea-Ice漂移时，雪球发作的恒星通量阈值分别为1250--1275和1173---1199 W m^-2，分别为E = 0和0.2。差异主要是由于行星接近怪异轨道的围栏时海冰和雪边缘的极端撤退。当打开海冰漂移时，各自的恒星通量阈值为1335---1350和1250--1276 W m^-2。这些意味着Se-Ice漂移使E = 0和0.2的Sea-Ice Drift将雪球的发作阈值增加了约80 W m^-2，从而促进了雪球气候状态的形成。我们进一步表明，海洋动力学对雪球发作阈值的效果小于26 W m^-2。这是因为随着海冰边缘接近赤道，海洋热传输变得越来越弱。这些结果表明，海冰动力学对于靠近可居住区外边缘的行星气候很重要，但是海洋热传输不太重要。
Previous studies have shown that sea-ice drift effectively promote the onset of a globally ice-covered snowball climate for paleo Earth and for tidally locked planets around low-mass stars. Here, we investigate whether sea-ice drift can influence the stellar flux threshold for a snowball climate onset on rapidly rotating aqua-planets around a Sun-like star. Using a fully coupled atmosphere--land--ocean--sea-ice model with turning on or off sea-ice drift, a circular orbit with no eccentricity (e=0) and an eccentric orbit (e=0.2) are examined. When sea-ice drift is turned off, the stellar flux threshold for the snowball onset is 1250--1275 and 1173--1199 W m^-2 for e=0 and 0.2, respectively. The difference is mainly due to the poleward retreat of sea ice and snow edges when the planet is close to the perihelion in the eccentric orbit. When sea-ice drift is turned on, the respective stellar flux threshold is 1335--1350 and 1250--1276 W m^-2. These mean that sea-ice drift increases the snowball onset threshold by ~80 W m^-2 for both e=0 and 0.2, promoting the formation of a snowball climate state. We further show that oceanic dynamics have a small effect, <26 W m^-2, on the snowball onset threshold. This is because oceanic heat transport becomes weaker and weaker as the sea ice edge is approaching the equator. These results imply that sea-ice dynamics are important for the climate of planets close to the outer edge of the habitable zone, but oceanic heat transport is less important.
