Johnson Gregory C, Landerer Felix W, Loeb Norman G, Lyman John M, Mayer Michael, Swann Abigail L S, Zhang Jinlun
NOAA/Pacific Marine Environmental Laboratory, Seattle, WA 98115 USA.
Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA.
Surv Geophys. 2024;45(6):1785-1797. doi: 10.1007/s10712-023-09797-6. Epub 2023 Jul 18.
The global seasonal cycle of energy in Earth's climate system is quantified using observations and reanalyses. After removing long-term trends, net energy entering and exiting the climate system at the top of the atmosphere (TOA) should agree with the sum of energy entering and exiting the ocean, atmosphere, land, and ice over the course of an average year. Achieving such a balanced budget with observations has been challenging. Disagreements have been attributed previously to sparse observations in the high-latitude oceans. However, limiting the local vertical integration of new global ocean heat content estimates to the depth to which seasonal heat energy is stored, rather than integrating to 2000 m everywhere as done previously, allows closure of the global seasonal energy budget within statistical uncertainties. The seasonal cycle of energy storage is largest in the ocean, peaking in April because ocean area is largest in the Southern Hemisphere and the ocean's thermal inertia causes a lag with respect to the austral summer solstice. Seasonal cycles in energy storage in the atmosphere and land are smaller, but peak in July and September, respectively, because there is more land in the Northern Hemisphere, and the land has more thermal inertia than the atmosphere. Global seasonal energy storage by ice is small, so the atmosphere and land partially offset ocean energy storage in the global integral, with their sum matching time-integrated net global TOA energy fluxes over the seasonal cycle within uncertainties, and both peaking in April.
利用观测数据和再分析数据对地球气候系统中能量的全球季节循环进行了量化。去除长期趋势后，在大气层顶（TOA）进入和离开气候系统的净能量应与平均一年中进入和离开海洋、大气、陆地和冰的能量总和一致。通过观测实现这样一个平衡的收支一直具有挑战性。此前，差异被归因于高纬度海洋观测数据稀少。然而，将新的全球海洋热含量估计值的局部垂直积分限制在季节性热能储存的深度，而不是像以前那样在各处都积分到2000米，使得全球季节能量收支在统计不确定性范围内得以闭合。能量储存的季节循环在海洋中最大，在4月达到峰值，这是因为南半球海洋面积最大，且海洋的热惯性导致相对于南半球夏至存在滞后。大气和陆地中能量储存的季节循环较小，但分别在7月和9月达到峰值，这是因为北半球陆地较多，且陆地的热惯性比大气更大。冰的全球季节能量储存量较小，因此在全球积分中，大气和陆地部分抵消了海洋的能量储存，它们的总和在不确定性范围内与季节循环中全球TOA能量通量的时间积分相匹配，且两者均在4月达到峰值。
