Abstract
Cirrus clouds strongly influence weather and climate processes due to their effects on the radiative balance of the Earth-atmosphere system. In this work, longwave radiative forcing of nighttime cirrus was studied at grid-cell scales covering the regions between 60°S and 60°N. The measurements of CloudSat and CALIPSO were used to obtain the occurrence frequencies of cirrus clouds with different optical thickness, and then the SBDART radiative transfer model was employed to compute the radiative forcing. For the study region, the occurrence frequencies at night time for subvisual (τ ≤ 0.03), thin (0.03 ≤ τ < 0.3), opaque (0.3 ≤ τ < 3), and thick (τ > 3) cirrus types are found to be 7.43%, 9.83%, 8.62%, and 1%; the average occurrence frequency can reach ∼26.89%. Moreover, the mean effective radii are ∼22.87, 19.23, 19.82, 27.6 and 39.18 μm corresponding to total, subvisual, thin, opaque and thick cirrus clouds. We found that average longwave (4–50 μm) radiative effect (LWRE) for nighttime cirrus clouds is ∼17.38W.m − 2 at the top of the atmosphere (TOA) and ∼1.14W.m − 2 at the Earth surface. Finally, the LWRF of opaque cirrus is identified to be the largest contribution to the warming effects at nighttime (∼ 7.76W.m − 2at the TOA, 0.68W.m − 2 at the surface), primarily due to their high fractions and optical thickness, appearing simultaneously. These findings provide valuable references to understanding the role of nighttime cirrus in regulating the radiation field.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
More From: Journal of Quantitative Spectroscopy and Radiative Transfer
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.