Environmental Response in Coupled Energy and Water Cloud Impact Parameters Derived from A-Train Satellites, ERA-Interim, and MERRA-2
Academic Article
Overview
Research
Identity
Additional Document Info
Other
View All
Overview
abstract
AbstractUnderstanding the connections between latent heating from precipitation and cloud radiative effects is essential for accurately parameterizing cross-scale links between cloud microphysics and global energy and water cycles in climate models. Although commonly examined separately, this study adopts two cloud impact parameters (CIPs), the surface radiative cooling efficiency Rc and atmospheric radiative heating efficiency Rh, that explicitly couple cloud radiative effects and precipitation to characterize how efficiently precipitating cloud systems influence the energy budget and water cycle using A-Train observations and two reanalyses. These CIPs exhibit distinct global distributions that suggest cloud energy and water cycle coupling are highly dependent on cloud regime. The dynamic regime 500 controls the sign of Rh, whereas column water vapor (CWV) appears to be the larger control on the magnitude. The magnitude of Rc is highly coupled to the dynamic regime. Observations show that clouds cool the surface very efficiently per unit rainfall at both low and high sea surface temperature (SST) and CWV, but reanalyses only capture the former. Reanalyses fail to simulate strong Rh and moderate Rc in deep convection environments but produce stronger Rc and Rh than observations in shallow, warm rain systems in marine stratocumulus regions. Although reanalyses generate fairly similar climatologies in the frequency of environmental states, the response of Rc and Rh to SST and CWV results in systematic differences in zonal and meridional gradients of cloud atmospheric heating and surface cooling relative to A-Train observations that may have significant implications for global circulations and cloud feedbacks.Significance StatementStudying climate change requires understanding coupled interactions between clouds, precipitation, and their environment. Here we calculate two parameters to reveal how efficiently clouds can heat the atmosphere or cool the surface per unit rain. The satellite observations and reanalyses show similar global patterns, but there are some differences in areas of deep convection and low cloud regions. Examination of these parameters as a function of their environment shows that reanalyses cool the atmosphere too much per unit rain in environments with low sea surface temperatures and water vapor. Vertical velocity determines whether clouds heat or cool the atmosphere. Both observations and reanalyses suggest that water vapor is the stronger control on how much clouds heat the atmosphere per unit rain.
