Spatiotemporal Variations in the Radiant Energy Budgets of Mars and Earth
A planetary body’s radiant energy budget is a critical geophysical parameter in the context of its climate. For a terrestrial planet, the delicate balancing between the absorbed solar power and emitted thermal power is directly responsible for the circulatory behavior its atmosphere (and oceans, in Earth’s case). Practically, energy budgets are challenging to measure, and investigations thereof beyond Earth are constricted by limited datasets. This dissertation investigates the energy budgets of Mars and Earth. First, the first meridional profiles of Mars’ energy budget are generated at seasonal and annual timescales from long-term, multi-instrument measurements returned by Mars Global Surveyor in Martian orbit. Mars, being a dry, dusty planet with a thin atmosphere, no oceans, and a fairly eccentric orbit, experiences temperamental interseasonal variations with significant hemispheric asymmetry. Near perihelion, global dust storms further perturb these transient, yet periodic energy imbalances. These results are immediately applied to analyze the CO2 budget of Mars’ ice caps. Secondly, Mars’ energy budget is compared to that of Earth, which is derived from modern, high fidelity radiance measurements provided by CERES-EBAF. Owing to the unique environments and characteristics of each planet, their energy budgets are dissimilar. Earth, with a much thicker atmosphere, a global ocean, and nearly circular orbit, exhibits smaller, consistent seasonal varia- tions. Annually, Mars’ energy budget features large polar excesses with minor equatorial deficits – the opposite is true for Earth. Finally, a deeper reanalysis of Earth’s energy budget demonstrates the scientific potential of large datasets. We examine ENSO (El Niño–Southern Oscillation) and its role within Earth’s energy budget during the years 2001–2022. They are strongly correlated – consistent with historical record. Variations in each energy budget component over the tropical Pacific Ocean were able to exceed 10% of their background values – 20% for net power. Principal component analysis further reaffirms ENSO’s state as the dominant source of tropical radiance anomalies and troubleshoots the performance of models. In the future, when more complete datasets are compiled for other planets, these procedures can serve as a foundation for exploring otherworldly climates.
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