In this paper the characteristics of surface radiative fluxes and cloud radiative forcing are reviewed with a focus on the Arctic. Three aspects are addressed, including (i) changes in radiation flux over the global s...In this paper the characteristics of surface radiative fluxes and cloud radiative forcing are reviewed with a focus on the Arctic. Three aspects are addressed, including (i) changes in radiation flux over the global surface; (ii) characteristics of surface fluxes in the Arctic; and (iii) characteristics of cloud radiative forcing in the Arctic. The clouds not only significantly reduce the peak summer radiative heating of the surface but also reduce the wintertime radiative cooling at the surface inhigher latitudes. The downward longwave fluxes dominates the incident radiative fluxes in the Arctic during most of the year. Incoming shortwave fluxes are negligible during late fall, winter and early spring, and even during the midsummer the incoming shortwave fluxes are only slightly greater than the downward longwave fluxes. The total net surface radiative flux is negative for most of the year and only positive during midsummer in the Arctic. The global net cloud radiative forcing is negative, but the cloud radiative forcing is positive in the Arctic, showing a warming effect, except for a short period in mid-summer. Positive cloud-radiative forcing in the Arctic is attributedto the presence of snow and ice with high albedo and the absence of solar radiation during the polar night.展开更多
文摘In this paper the characteristics of surface radiative fluxes and cloud radiative forcing are reviewed with a focus on the Arctic. Three aspects are addressed, including (i) changes in radiation flux over the global surface; (ii) characteristics of surface fluxes in the Arctic; and (iii) characteristics of cloud radiative forcing in the Arctic. The clouds not only significantly reduce the peak summer radiative heating of the surface but also reduce the wintertime radiative cooling at the surface inhigher latitudes. The downward longwave fluxes dominates the incident radiative fluxes in the Arctic during most of the year. Incoming shortwave fluxes are negligible during late fall, winter and early spring, and even during the midsummer the incoming shortwave fluxes are only slightly greater than the downward longwave fluxes. The total net surface radiative flux is negative for most of the year and only positive during midsummer in the Arctic. The global net cloud radiative forcing is negative, but the cloud radiative forcing is positive in the Arctic, showing a warming effect, except for a short period in mid-summer. Positive cloud-radiative forcing in the Arctic is attributedto the presence of snow and ice with high albedo and the absence of solar radiation during the polar night.
