This paper by Syukuro Manabe from the Geophysical Fluid Dynamics Laboratory (GFDL) of the Environmental Science Services Administration (ESSA) explores the interaction between the atmosphere and the Earth's surface hydrology. The study uses a numerical model of the general circulation of the atmosphere, incorporating the hydrologic cycle to simulate the Earth's climate. The model is based on the primitive equations of motion and is designed to resolve the surface boundary layer and the stratosphere. It considers the depletion of solar radiation and the transfer of terrestrial radiation, taking into account cloud cover and atmospheric absorbers like water vapor, carbon dioxide, and ozone. The model predicts water vapor in the atmosphere and soil moisture and snow cover on the continents. The continents are assumed to be covered by boxes that can store limited amounts of water, while the ocean surface is idealized as a completely wet surface without heat capacity. The temperature of the Earth's surface is determined to satisfy the heat balance condition. The study focuses on the atmospheric model without ocean circulation, neglecting the heat transfer by ocean currents. The results successfully simulate the qualitative features of hydrologic and thermodynamic regimes at the Earth's surface, particularly the horizontal distribution of rainfall. However, due to the lack of seasonal variation in solar insolation and the absence of poleward heat transport by ocean currents, excessive snow cover develops at higher latitudes, leading to lower temperatures than observed in the actual atmosphere. The paper also discusses the model's equations of motion, thermodynamics, and radiative transfer, as well as the prognostic equations for water vapor and the hydrology of the land surface. The distribution of the ocean and continent is chosen for simplicity, and the results are compared with observations to assess the model's accuracy. Overall, the study provides a preliminary understanding of how the ocean and atmosphere interact, with the next part focusing on the joint ocean-atmosphere model, which will include the transport of heat by ocean currents.This paper by Syukuro Manabe from the Geophysical Fluid Dynamics Laboratory (GFDL) of the Environmental Science Services Administration (ESSA) explores the interaction between the atmosphere and the Earth's surface hydrology. The study uses a numerical model of the general circulation of the atmosphere, incorporating the hydrologic cycle to simulate the Earth's climate. The model is based on the primitive equations of motion and is designed to resolve the surface boundary layer and the stratosphere. It considers the depletion of solar radiation and the transfer of terrestrial radiation, taking into account cloud cover and atmospheric absorbers like water vapor, carbon dioxide, and ozone. The model predicts water vapor in the atmosphere and soil moisture and snow cover on the continents. The continents are assumed to be covered by boxes that can store limited amounts of water, while the ocean surface is idealized as a completely wet surface without heat capacity. The temperature of the Earth's surface is determined to satisfy the heat balance condition. The study focuses on the atmospheric model without ocean circulation, neglecting the heat transfer by ocean currents. The results successfully simulate the qualitative features of hydrologic and thermodynamic regimes at the Earth's surface, particularly the horizontal distribution of rainfall. However, due to the lack of seasonal variation in solar insolation and the absence of poleward heat transport by ocean currents, excessive snow cover develops at higher latitudes, leading to lower temperatures than observed in the actual atmosphere. The paper also discusses the model's equations of motion, thermodynamics, and radiative transfer, as well as the prognostic equations for water vapor and the hydrology of the land surface. The distribution of the ocean and continent is chosen for simplicity, and the results are compared with observations to assess the model's accuracy. Overall, the study provides a preliminary understanding of how the ocean and atmosphere interact, with the next part focusing on the joint ocean-atmosphere model, which will include the transport of heat by ocean currents.