Abstract
The third generation of the radiative flux profile data product, called
ISCCP-FH, is described. The revisions over the previous generation
(called ISCCP-FD) include improvements in the radiative model
representation of gaseous and aerosol effects, as well as a refined
statistical model of cloud vertical layer variations with cloud types,
and increased spatial resolution to 110 km. The new product benefits
from the changes in the new H-version of the ISCCP cloud products
(called ISCCP-H): higher spatial resolution, revised radiance
calibration and treatment of ice clouds, treatment of aerosol effects,
and revision of all the ancillary atmosphere and surface property
products. The ISCCP-FH product is evaluated against more direct
measurements from the Clouds and the Earth’s Radiant Energy System and
the Baseline Surface Radiation Network products, showing some small,
overall reductions in average flux uncertainties; but the main results
are similar to ISCCP-FD: the ISCCP-FH uncertainties remain ≲ 10
Wm-2 at the top-of-atmosphere (TOA) and ≲ 20
Wm-2 at surface for monthly, regional averages. The
long-term variations of TOA, surface and in-atmosphere net fluxes are
documented and the possible transient cloud feedback implications of a
long-term decline of clouds are investigated. The cloud and flux
variations from 1998 to 2012 suggest a positive cloud-radiative feedback
on the oceanic circulation and a negative feedback on the atmospheric
circulation. This example demonstrates that the ISCCP-FH product can
provide useful diagnostic information about weather-to-interannual scale
variations of radiation induced by changes in cloudiness as well as
atmospheric and surface properties.