A new benchmark for surface radiation products over the East Asia-Pacific region retrieved from the Himawari-8/AHI next-generation geostationary satellite

Surface downward radiation (SDR), including shortwave downward radiation (SWDR) and longwave downward radiation (LWDR), is of great importance to energy and climate studies. Considering the lack of reliable SDR data with a high spatiotemporal resolution in the East Asia-Pacific (EAP) region, we derived SWDR and LWDR at 10-min and 0.05° resolutions for this region from 2016-2020 based on the next-generation geostationary satellite Himawari-8 (H-8). The SDR product is unique in terms of its all-sky features, high accuracy and high resolution levels. The cloud effect is fully considered in the SDR product, and the influence of high aerosol loadings and topography on the SWDR are considered. Compared to benchmark products of the radiation, such as Clouds and the Earth’s Radiant Energy System (CERES) and the European Centre for Medium-Range Weather Forecasts (ECMWF) next-generation reanalysis (ERA5), and the Global Land Surface Satellite (GLASS), not only is the resolution of the new SDR product notably much higher but the product accuracy is also higher than that of those products. In particular, hourly and daily root mean square errors of the new SWDR are 104.9 and 31.5 Wm−2, respectively, which are much smaller than those of CERES (at 121.6 and 38.6 Wm−2, respectively), ERA5 (at 176.6 and 39.5 Wm−2, respectively) and GLASS (daily of 36.5 Wm−2). Meanwhile, RMSEs of hourly and daily values of the new LWDR are 19.6 and 14.4 Wm−2, respectively, which are comparable to that of CERES and ERA5, and even better over high altitude regions.

An analysis of interdecadal variations in the perturbational feedback parameter based on a MIROC6 piControl simulation

The climate feedback parameter is a useful indicator for estimating climate sensitivity relating to anthropogenic forcing. This study defines a new feedback parameter, the Perturbational Feedback Parameter (PFP), and the impacts of internally-generated climate variations are clarified using the MIROC piControl simulation. PFP values are found to vary significantly on interdecadal timescales. The equatorial sea surface temperature (SST) has a positive anomaly in the eastern Pacific and a negative anomaly in the western Pacific, and the thermocline tilts more gently than usual when the PFP is large. The statistical properties of the interannual fluctuations also simultaneously vary, and they correspond to the background state. For example, there is an increase in the El Niño Southern Oscillation (ENSO) amplitude relative to the global mean surface temperature rise, and the equatorial high SST more effectively contributes to the southward shift of the Intertropical Convergence Zone (ITCZ). In addition, a decadal fluctuation that dominates over the extratropical northern Pacific also plays an important role in PFP variations. These fluctuations on broad timescales cooperatively induce increases in lower clouds within the subtropics by strengthening the descending flow and static stability, and the consequential net downward radiation flux change through increases in reflection enhances the PFP. In summary, internal changes in both tropical and extratropical variability corresponding to the background state control the strength of the climate feedback on interdecadal timescales.

The Greenhouse Effect Definition

The greenhouse effect concept explains the Earth’s elevated temperature. The IPCC endorses the anthropogenic global warming theory, and it assumes that the greenhouse (GH) effect is due to the longwave (LW) absorption by GH gases and clouds. The IPCC’s GH definition lets to understand that the LW absorption is responsible for the downward radiation to the surface. According to the energy laws, it is not possible that the LW absorption of 155.6 Wm-2 by the GH gases could re-emit downward LW radiation of 345.6 Wm-2 on the Earth’s surface. When the shortwave (SW) absorption is decreased from this total LW radiation, the rest of the radiation is 270.6 Wm-2. This LW radiation downward is the imminent cause for the GH effect increasing the surface temperature by the 33°C. It includes LW absorption by the GH gases and clouds in the atmosphere and the latent and sensible heating effects. Without the latent and sensible heating impacts in the atmosphere, the downward LW radiation could not close the energy balance of the surface. The contribution of CO2 in the GH effect is 7.4% corresponding to 2.5°C in temperature. This result does not only mutilate the image of CO2 as a strong GH gas, but it has further consequences in climate models. It turned out that the IPCC’s climate model showing a climate sensitivity (CS) of 1.2°C (caused by CO2 effects only) could not be fitted into the total GH effect of CO2. A climate model showing a CS of 0.6°C matches the CO2 contribution in the GH effect.

Challenging the Greenhouse Effect Specification and the Climate Sensitivity of the IPCC

The greenhouse effect concept has been developed to explain the Earth’s elevated temperature. The prevailing theory of climate change is the anthropogenic global warming theory, which assumes that the greenhouse (GH) effect is due to the longwave (LW) absorption of 155.6 Wm-2 by GH gases and clouds. The actual warming increase to 33°C of the Earth’s surface temperature according to the present GH effect definition is the infrared downward LW radiation of 345.6 Wm-2 emitted by the atmosphere. The atmosphere’s temperature is the key element behind this radiation. According to the energy laws, it is not possible that the LW absorption of 155.6 Wm-2 by the GH gases could re-emit downward LW radiation of 345.6 Wm-2 on the Earth’s surface. In this study, the GH effect is 294.5 Wm-2, including shortwave radiation absorption by the atmosphere and the latent and sensible heating effect. This greater GH effect is a prerequisite for the present atmospheric temperature, which provides downward radiation on the surface. Clouds’ net effect is 1% based on the empirical observations. The contribution of CO2 in the GH effect is 7.3% corresponding to 2.4°C in temperature. The reproduction of CO2 radiative forcing (RF) showed the climate sensitivity RF value to be 2.16 Wm-2, which is 41.6% smaller than the 3.7 Wm-2 used by the IPCC. A climate model showing a climate sensitivity (CS) of 0.6°C matches the CO2 contribution in the GH effect, but the IPCC’s climate model showing a CS of 1.8°C or 1.2°C does not.