Lucarini Valerio, Bódai Tamás
Centre for the Mathematics of Planet Earth, University of Reading, Reading, RG66AX United Kingdom.
Department of Mathematics and Statistics, University of Reading, Reading, RG66AX United Kingdom.
Phys Rev Lett. 2019 Apr 19;122(15):158701. doi: 10.1103/PhysRevLett.122.158701.
The Earth is well known to be, in the current astronomical configuration, in a regime where two asymptotic states can be realized. The warm state we live in is in competition with the ice-covered snowball state. The bistability exists as a result of the positive ice-albedo feedback. In a previous investigation performed on a intermediate complexity climate model we identified the unstable climate states (melancholia states) separating the coexisting climates, and studied their dynamical and geometrical properties. The melancholia states are ice covered up to the midlatitudes and attract trajectories initialized on the basin boundary. In this Letter, we study how stochastically perturbing the parameter controlling the intensity of the incoming solar radiation impacts the stability of the climate. We detect transitions between the warm and the snowball state and analyze in detail the properties of the noise-induced escapes from the corresponding basins of attraction. We determine the most probable paths for the transitions and find evidence that the melancholia states act as gateways, similarly to saddle points in an energy landscape.
众所周知，在当前的天文配置下，地球处于一种可以实现两种渐近状态的状态。我们生活的温暖状态与冰雪覆盖的雪球状态相互竞争。双稳态是由正冰反照率反馈导致的。在之前对一个中等复杂度气候模型进行的研究中，我们确定了分隔共存气候的不稳定气候状态（忧郁状态），并研究了它们的动力学和几何特性。忧郁状态是中纬度地区都被冰覆盖，并且吸引在盆地边界初始化的轨迹。在这封信中，我们研究随机扰动控制入射太阳辐射强度的参数如何影响气候的稳定性。我们检测温暖状态和雪球状态之间的转变，并详细分析噪声诱导的从相应吸引盆地逃逸的特性。我们确定了转变的最可能路径，并发现证据表明忧郁状态起到了通道的作用，类似于能量景观中的鞍点。
