罗斯冰流的正质量平衡,西南极洲
1Jet Propulsion Laboratory, California Institute of Technology, Mailstop 300-235, 4800 Oak Grove Drive, Pasadena, CA 91109, USA. ian@radar-sci.jpl.nasa.gov
概括
对西南极洲罗斯冰流的新研究揭示了冰盖的显著增长,而不是赤字. 这种对冰盖质量平衡的重新评估表明,这些关键的南极冰流的全新纪撤退可能已经结束.
科学领域:
- 冰川学的冰川学
- 气候科学 气候科学
- 遥感 遥感 遥感 遥感
背景情况:
- 南极冰盖的质量平衡对于了解全球海平面上升至关重要.
- 以前的估计表明罗斯冰流的质量平衡为负,这表明冰的损失.
研究的目的:
- 用先进的冰流速度测量方法重新评估罗斯冰流的质量平衡.
- 为了调查这些主要的西南极冰流的稳定性的当前状态和最近的变化.
主要方法:
- 利用合成孔径雷达 (SAR) 来获得精确的冰流速度测量.
- 分析速度数据以计算冰体积的变化并确定质量平衡.
主要成果:
- 强有力的证据表明,冰盖的总体增长率为每年26.8千亿,这与之前的赤字估计相矛盾.
- 观察到的平均积累率约为25%的加厚,主要是在冰流C上.
- 威兰斯冰流接近平衡,与预期的显著质量损失相反,由于其减速.
结论:
- 罗斯冰流目前正在增加质量,这表明质量平衡是正的.
- 这种增长可能意味着从全新纪时期观察到的长期撤退的过渡.
- 这些发现凸显了南极冰流的动态性质,以及最新的观测数据的重要性.
相关概念视频
Phase Transitions: Melting and Freezing
Heating a crystalline solid increases the average energy of its atoms, molecules, or ions, and the solid gets hotter. At some point, the added energy becomes large enough to partially overcome the forces holding the molecules or ions of the solid in their fixed positions, and the solid begins the process of transitioning to the liquid state or melting. At this point, the temperature of the solid stops rising, despite the continual input of heat, and it remains constant until all of the solid is...
Freezing Point Depression and Boiling Point Elevation
Boiling Point Elevation
The boiling point of a liquid is the temperature at which its vapor pressure is equal to ambient atmospheric pressure. Since the vapor pressure of a solution is lowered due to the presence of nonvolatile solutes, it stands to reason that the solution’s boiling point will subsequently be increased. Vapor pressure increases with temperature, and so a solution will require a higher temperature than will pure solvent to achieve any given vapor pressure, including one...
The boiling point of a liquid is the temperature at which its vapor pressure is equal to ambient atmospheric pressure. Since the vapor pressure of a solution is lowered due to the presence of nonvolatile solutes, it stands to reason that the solution’s boiling point will subsequently be increased. Vapor pressure increases with temperature, and so a solution will require a higher temperature than will pure solvent to achieve any given vapor pressure, including one...
Coriolis Force
An accelerating particle experiences a force equal to the mass multiplied by the acceleration in an inertial frame of reference. Consider a particle in a non-inertial frame of reference, such as a sliding ball on a rotating table. The acceleration of the ball in this rotating reference frame is different than in the intertial frame, which modifies its equation of motion. The fictitious forces acting additionally on a rotating frame of reference alter Newton's Second Law expression. Centripetal...
Freezing Point Depression and Boiling Point Elevation
When a non-volatile solute is added to a pure solvent, it results in the lowering of the freezing point of the solvent. This phenomenon is called freezing point depression. The extent to which the freezing point is lowered depends on the molality of the solute -the number of moles of solute per kilogram of solvent and the cryoscopic constant of the solvent.From the plot of chemical potential, μ, against temperature, it is evident that the μ of both solid and liquid solvents decrease with...
Irrotational Flow
Irrotational flow is characterized by fluid motion where particles do not rotate around their axes, resulting in zero vorticity. For a flow to be irrotational, the curl of the velocity field must be zero. This imposes specific conditions on velocity gradients. For instance, to maintain zero rotation about the z-axis, the gradient condition:
Steady, Laminar Flow Between Parallel Plates
Understanding steady, laminar flow between parallel plates is essential for analyzing and designing flow in narrow rectangular channels, commonly found in various water conveyance and drainage systems. The Navier-Stokes equations govern fluid motion and are generally challenging to solve due to their nonlinearity. However, simplifications are possible in certain cases, like the steady laminar flow between parallel plates. For this scenario, we assume steady, incompressible, laminar flow.


