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.

地球气候系统中的全球季节性能量循环是通过观测和再分析来量化的。消除长期趋势后，进入和退出大气层顶部气候系统的净能量（TOA）应与平均年份进出海洋、大气、陆地和冰的能量总和一致。通过观察实现如此平衡的预算具有挑战性。此前，人们将分歧归咎于高纬度海洋的观测稀疏。然而，将新的全球海洋热含量估计值的局部垂直整合限制为季节性热能存储的深度，而不是像以前那样整合到各处的 2000 米，可以在统计不确定性范围内关闭全球季节性能源预算。海洋中能量储存的季节性周期最大，在四月达到峰值，因为海洋面积是南半球最大的，并且海洋的热惯性导致相对于南半球夏至的滞后。大气和陆地储能的季节周期较小，但分别在7月和9月达到峰值，因为北半球陆地较多，且陆地比大气具有更大的热惯性。全球冰的季节性能量储存量很小，因此大气和陆地在全球积分中部分抵消了海洋能量储存，其总和与季节周期内的时间积分净全球 TOA 能量通量相匹配，在不确定性范围内，并且均在 4 月份达到峰值。