2:45 PM - 3:00 PM
[ACG46-10] Long-term variation in top-of-atmosphere upward shortwave radiation over the Arctic and Antarctic regions
Keywords:shortwave radiation, sea ice, snow cover, cloud
Sea ice and snow cover in the Arctic have been decreasing. Sea ice cover in the Antarctic has also been decreasing recently. Sea ice and snow cover have high albedos, and these changes have a significant impact on shortwave radiation. Several studies have investigated the long-term variation in upward shortwave radiative flux at the top of the atmosphere (TOA SW) over the Arctic and Antarctic regions (Previdi et al. 2013; Hartmann et al. 2014; Pistone et al. 2014; Loeb et al. 2019; Wu et al. 2020). However, these studies have yet to examine the long-term variation in TOA SW well, focusing on seasonal changes in incoming solar radiation, snow, and ice, and differences between oceanic and land areas. Therefore, we investigate the long-term variation in TOA SW and its factors in the Arctic and Antarctic regions, focusing on seasonal changes and land-ocean differences. We also discuss the differences in the long-term variation in TOA SW over the Arctic and Antarctic regions. Here we use satellite observations (CERES EBAF Ed 4.1).
Over the Arctic, TOA SW decreases from 2001 to 2012 (-2.5 Wm-2 decade-1) and changes to having a large interannual variability. The decreasing trend from 2001 to 2012 is explained by the decrease in sea ice cover in June and July and snow cover in May and June. The large interannual variability after 2012 is explained by the sea ice cover in June and July, snow cover in May and June, and cloud over land in June and July. On the other hand, TOA SW in the Antarctic shows no significant trend from 2001 to 2015 but decreases after 2015. TOA SW variability in the Antarctic is mainly explained by the variability of sea ice cover from November to January.
Hartmann, D. L., and P. Ceppi, 2014, J. Climate, 27, 2444–2456, https://doi.org/10.1175/JCLI-D-13-00411.1.
Loeb, N. et al., 2019, J. Climate, 32, 5003–5019, https://doi.org/10.1175/JCLI-D-18-0826.1.
Pistone, K. et al., 2014, Proc. Natl. Acad. Sci. USA, 111, 3322–3326, https://doi.org/10.1073/pnas.1318201111.
Previdi, M. et al., 2013, J. Climate, 26, 6406–6418, https://doi.org/10.1175/JCLI-D-12-00640.1.
Wu, D. L., et al., 2020, Remote Sens., 12, 1460, https://doi.org/10.3390/rs12091460.
Over the Arctic, TOA SW decreases from 2001 to 2012 (-2.5 Wm-2 decade-1) and changes to having a large interannual variability. The decreasing trend from 2001 to 2012 is explained by the decrease in sea ice cover in June and July and snow cover in May and June. The large interannual variability after 2012 is explained by the sea ice cover in June and July, snow cover in May and June, and cloud over land in June and July. On the other hand, TOA SW in the Antarctic shows no significant trend from 2001 to 2015 but decreases after 2015. TOA SW variability in the Antarctic is mainly explained by the variability of sea ice cover from November to January.
Hartmann, D. L., and P. Ceppi, 2014, J. Climate, 27, 2444–2456, https://doi.org/10.1175/JCLI-D-13-00411.1.
Loeb, N. et al., 2019, J. Climate, 32, 5003–5019, https://doi.org/10.1175/JCLI-D-18-0826.1.
Pistone, K. et al., 2014, Proc. Natl. Acad. Sci. USA, 111, 3322–3326, https://doi.org/10.1073/pnas.1318201111.
Previdi, M. et al., 2013, J. Climate, 26, 6406–6418, https://doi.org/10.1175/JCLI-D-12-00640.1.
Wu, D. L., et al., 2020, Remote Sens., 12, 1460, https://doi.org/10.3390/rs12091460.