Interannual variation of global net radiation flux as measured from space

Abstract

International audienceThe global net radiation flux (NRF) in and out of the climate system at the top of the atmosphere (TOA) varies at interannual time scales, reflecting the complexity of the processes responsible for attaining global energy equilibrium. These processes are investigated in this study using the previously unexplored data acquired by a bolometric type sensor installed in the PICARD microsatellite. The obtained anomalies in the NRF (PICARD-NRF) are compared to the global NRF changes at the TOA measured by the Clouds and Earth's Radiant Energy System mission (CERES-NRF). The interanual PICARD-NRF is strongly correlated with the matching period CERES-NRF; the bootstrapped correlation at the 95%( +0.85 and +0.97) confidence intervals(CIs) is +0.93. Consistency in the interannual variability in the NRF derived by two completely independent measurement systems enhances confidence in the estimated magnitude of these variations. To reveal the possible drivers of the NRF interannual variability, the NRF values were compared with the multivariate El Niño Southern Oscillation index (ENSO)

Eddy covariance measurement-based differences in annual evapotranspiration between forests and grasslands in China

“…Forests employed in this study primarily distributed in eastern China, while grasslands were mainly located in the western China (Figure 1) (Guo et al, 2022), which made forests have a higher MAP than grasslands (Figure 2B). A higher MAP meant more water were available for an ecosystem to evaporate as the energy arriving at the land surface were much larger than that an ecosystem required for evaporation (Jin et al, 2011;Chapin et al, 2012;Williams et al, 2012;Zhu et al, 2016a;IPCC, 2021). Under similar MAP, both forests and grasslands had similar amounts of available water for evaporating, which made AET values of forests and grasslands comparable.…”

“…MAP directly provided the available water for evaporation (Chapin et al, 2012;Wang and Dickinson, 2012). Considering the available energy used for evapotranspiration represented by net radiation was much higher than that evapotranspiration required (Jin et al, 2011;Chapin et al, 2012;Williams et al, 2012;Zhu et al, 2016a;IPCC, 2021), MAP played a dominating role in AET spatial variations. However, the post processes after water arriving at the land surface like runoff or infiltration and vegetation metabolism limited the representativeness of MAP as water supply, which made AET not respond to MAP in a direct linear way (Figures 4C, D) (Williams et al, 2012).…”

Water and Carbon Dynamics, Ecosystem Stability of Forest and Grassland in Response to Climate Change

“…Forests employed in this study primarily distributed in eastern China, while grasslands were mainly located in the western China (Figure 1) (Guo et al, 2022), which made forests have a higher MAP than grasslands (Figure 2B). A higher MAP meant more water were available for an ecosystem to evaporate as the energy arriving at the land surface were much larger than that an ecosystem required for evaporation Chapin et al, 2012;Williams et al, 2012;Zhu et al, 2016a;. Under similar MAP, both forests and grasslands had similar amounts of available water for evaporating, which made AET values of forests and grasslands comparable.…”

Preface to Monitoring the Earth Radiation Budget and Its Implication to Climate Simulations: Recent Advances and Discussions

“…However, the goal could at the time not be achieved due to major technical problems (Wong et al, 2018). Later, Zhu et al (2016) determined the net radiative flux based on the bolometric sensor (BOS) onboard the Picard mission. Recently, a follow-up concept to accurately determine the difference of the EEI components has been proposed by Smeesters et al (2023).…”