Abstract

Based on the analysis of the radiative transfer equation in the integral form, we investigate the physical causes of changes in the Earth’s outgoing thermal radiation (OTR) during an increase in the atmospheric CO₂ content. Increased CO₂ content can lead to both an increase and decrease in various components of the OTR depending on the optical density in a spectral interval. We calculated and analyzed the spectra of OTR fluxes in the range 3–30 µm for five climatic atmospheric models and different CO₂ content in the atmosphere, from pre-industrial times (280 ppm) to the present day (407 ppm) and for forecasted values of 800 and 1200 ppm. Seasonal and spatial variations in the CO₂ radiative forcing (RF) are currently about 20% and 40%, respectively. The comparison of OTR measurements with different instruments in different years (for example, SI-1 in 1977 and 1979 and IKFS-2 in 2015–2017) demonstrates a decrease in the OTR values in the CO₂ absorption bands, caused by the upward displacement of radiating layers in the troposphere. We estimate the RF to be in the range (0.94–1.62) W/m² due to the increase in CO₂ content from preindustrial to present values.

中文翻译：

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上个世纪及未来CO 2辐射强迫变化的估计

摘要

基于对积分形式的辐射传递方程的分析，我们研究了大气CO ₂含量增加期间地球外出热辐射（OTR）变化的物理原因。取决于光谱间隔中的光密度，增加的CO ₂含量可导致OTR的各种成分增加和减少。我们计算并分析了从工业化前时间（280 ppm）到今天（407 ppm）的五个气候大气模型和大气中不同CO ₂含量的3–30 µm范围内OTR通量的光谱值分别为800和1200 ppm。CO _2的季节性和空间变化目前，辐射强迫（RF）分别约为20％和40％。使用不同仪器在不同年份进行的OTR测量值的比较（例如，1977年和1979年的SI-1和2015-2017年的IKFS-2）表明，由于向上位移，CO ₂吸收带中的OTR值降低了对流层的辐射层数。由于工业前到现值的CO ₂含量增加，我们估计RF处于（0.94-1.62）W / m ²范围内。