Important evidence of constant low CO2 windows and impacts on the non-closure of the greenhouse effect

Abstract

The CO2 distribution in the atmosphere remains unclear for the complexity of the long-range vertical transport process and other influencing factors. In this work, regression analysis was used to verify the accuracy of CO2 concentrations datasets. Geostatistical analyses were used to investigate the spatiotemporal distributions of CO2 at 7 levels from near the surface to the mid-troposphere (0~5 km). Spatial correlation and time series analyses were used to further determine the diffusion characteristics of the CO2 concentration based on the horizontal wind (NCEP R2), which is one of the main driving factors. The results showed that the horizontal, not vertical, diffusion of CO2 becomes increasingly more prominent with the decrease in atmospheric pressure to the mid-troposphere, whereas many regions, such as the Rocky Mountains and Qinghai-Tibet Plateau, have constant low values throughout the year due to the influence of high topography (up to 10.756 ppmv lower than that near the surface). These areas form low CO2 concentration ‘windows’ keeping letting thermal infrared energy out into space. This study is the first to question the existing view of the closure of the ‘greenhouse effect’. Future research studies should more precisely determine the closure threshold and the uncertainties about the surface fluxes.