Outgoing longwave and incoming shortwave radiation levels have measurably changed over the past decades
the verdict
INSUFFICIENT LEANING
refutedsupported
the weight of evidence
3 sources for · 0 against
Three peer-reviewed studies discuss aspects of outgoing longwave radiation trends. However, this counted evidence is insufficient to fully support the claim regarding changes in both outgoing longwave and incoming shortwave radiation levels.
AbstractThe variability and change occurring in the outgoing longwave radiation (OLR) spectrum are investigated by using simulations performed with a Geophysical Fluid Dynamics Laboratory coupled atmosphere–ocean–land general circulation model. First, the variability in unforced climate (natural variability) is simulated. Then, the change of OLR spectrum due to forced changes in climate is analyzed for a continuous 25-yr time series and for the difference between two time periods (1860s and 2000s). Spectrally resolved radiances have more pronounced and complex changes than broadband fluxes. In some spectral regions, the radiance change is dominated by just one controlling factor (e.g., the window region and CO2 band center radiances are controlled by surface and stratospheric temperatures, respectively) and well exceeds the natural variability. In some other spectral bands, the radiance change is influenced by multiple and often competing factors (e.g., the water vapor band radiance is influenced by both water vapor concentration and temperature) and, although still detectable against natural variability at certain frequencies, demands stringent requirements (drift less than 0.1 K decade−1 at spectral resolution no less than 1 cm−1) of observational platforms. The difference between clear-sky and all-sky radiances in the forced climate problem offers a measure of the change in the cloud radiative effect, but with a substantive dependence on the temperature lapse rate change. These results demonstrate that accurate and continuous observations of the OLR spectrum provide an advantageous means for monitoring the changes in the climate system and a stringent means for validating climate models.
The Fengyun-3D (FY-3D) satellite is a Chinese Earth observation satellite with high spectral resolution that can provide multi-spectral observations under all weather conditions. Outgoing longwave radiation (OLR) is an important parameter in the earth radiation energy balance and can reflect changes in atmospheric circulation and convective activity in response to incoming solar radiation. To apply the OLR data of the FY-3D satellite (F_OLR) to weather and climate analyses, the traditional single-channel OLR inversion algorithm for the NOAA (National Oceanic and Atmospheric Administration) satellite was used to calculate F_OLR, and the difference between F_OLR and the OLR data of the NOAA 18 satellite (N_OLR) was analyzed. A correction algorithm was proposed to correct F_OLR to match N_OLR; the spatiotemporal consistency of the corrected F_OLR and N_OLR was evaluated, and the two types of OLR data were used to analyze the onset of the South China Sea Summer Monsoon (SCSSM) and typhoon precipitation in China. The results showed that the corrected F_OLR and N_OLR were consistent in both temporal variation and spatial distribution and that the monitoring of the SCSSM and typhoon precipitation by the two types of OLR data was also in agreement, showing their equivalent quality. Finally, the N_OLR (2006–2019) and the corrected F_OLR (2020-present) were combined to form a long time series OLR dataset that was used in the Beijing Climate Center climate monitoring system in China to monitor abnormal changes in the global convective activity. This study can provide a reference method for future weather and climate applications of Chinese satellites.
Abstract
Earth’s energy budget is modulated by climate forcings and feedbacks. Outgoing longwave radiation (OLR) is a critical component of the Earth’s energy budget, and the balance between absorbed solar radiation and OLR determines the net gain of energy of the entire climate system. Radiation computations using 43 years of ERA5 reanalysis profiles show an increase in clear-sky OLR in the polar regions and a decrease in the tropics. To understand this contrast, we analyze zonal- and annual-mean clear-sky OLR changes in the Northern Hemisphere from 1979 to 2021. We identify a transition in temporal clear-sky OLR changes from low to high latitudes, with a “crossover” point where the sign changes around 30°N. We improve upon previous studies by employing infrared spectrally-detailed line-by-line radiative transfer calculations, to decompose zonal-mean trends caused by forcing and feedback mechanisms. Our diagnostic investigation shows that the increase in water vapor exerts a dominant negative contribution to the OLR temporal change in the tropics due to a larger OLR sensitivity to water vapor increase there, while the increase in surface temperature (T
s) dominates the positive temporal change in the Arctic, both due to Arctic amplification and a larger OLR sensitivity to T
s increase. Greater greenhouse gases’ forcings and smaller OLR sensitivity to T
s change in the tropics, as well as an imperfect cancellation between atmospheric temperature and water vapor contribution, delineates the crossover point at around 30°N.
Everything we examined (3)
This check searched the claim as stated. It did not run a separate search for evidence against it.