TY - GEN
T1 - Cirrus cloud radiative forcing at the top of atmosphere using the nighttime global distribution with the microphysical parameters derived from AVHRR
AU - Katagiri, Shuichiro
AU - Sekiguchi, Miho
AU - Hayasaka, Tadahiro
AU - Nakajima, Teruyuki
PY - 2013
Y1 - 2013
N2 - The radiative effect of cirrus clouds is particularly ambiguous in the climate research. We calculated the global cirrus cloud radiative forcing (CRFci) distributions at the top of the atmosphere (TOA) using the cloud microphysical parameters of effective radius (Re), optical thickness (COT) and the cloud top temperature (CTT) derived from AVHRR nighttime data. The results indicate that cirrus clouds warm the atmosphere, and in particular produce a large warming effect in the tropics. We also computed the dependence of radiative forcing on the effective radius of cloud particles, the optical thickness of the cloud, and the cloud-top temperature (CTT) and determined that cooling effects occur with clouds when their optical thickness is greater than 4.0∼4.5 with a cloud top temperature of 220K and 2.5∼3.0 with a cloud top temperature of 235K. Cloud radiative forcing in April 1987 (El Niño year) and April 1990 (neutral year) were computed, and found that a larger amount of cirrus clouds appeared in the tropics off Peru in 1987 than in 1990. But the globally averaged net cloud radiative forcing was smaller by 0.55W/m2 in 1987 than in 1990. Consequently, the temperature distribution of the oceans has a global effect on atmospheric warming and cooling.
AB - The radiative effect of cirrus clouds is particularly ambiguous in the climate research. We calculated the global cirrus cloud radiative forcing (CRFci) distributions at the top of the atmosphere (TOA) using the cloud microphysical parameters of effective radius (Re), optical thickness (COT) and the cloud top temperature (CTT) derived from AVHRR nighttime data. The results indicate that cirrus clouds warm the atmosphere, and in particular produce a large warming effect in the tropics. We also computed the dependence of radiative forcing on the effective radius of cloud particles, the optical thickness of the cloud, and the cloud-top temperature (CTT) and determined that cooling effects occur with clouds when their optical thickness is greater than 4.0∼4.5 with a cloud top temperature of 220K and 2.5∼3.0 with a cloud top temperature of 235K. Cloud radiative forcing in April 1987 (El Niño year) and April 1990 (neutral year) were computed, and found that a larger amount of cirrus clouds appeared in the tropics off Peru in 1987 than in 1990. But the globally averaged net cloud radiative forcing was smaller by 0.55W/m2 in 1987 than in 1990. Consequently, the temperature distribution of the oceans has a global effect on atmospheric warming and cooling.
KW - Cirrus clouds
KW - Cloud radiative forcing
KW - Ocean-atmosphere interactions
KW - Satellite remote sensing
UR - http://www.scopus.com/inward/record.url?scp=84877857148&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84877857148&partnerID=8YFLogxK
U2 - 10.1063/1.4804867
DO - 10.1063/1.4804867
M3 - Conference contribution
AN - SCOPUS:84877857148
SN - 9780735411555
T3 - AIP Conference Proceedings
SP - 704
EP - 707
BT - Radiation Processes in the Atmosphere and Ocean, IRS 2012 - Proceedings of the International Radiation Symposium (IRC/IAMAS)
T2 - International Radiation Symposium: Radiation Processes in the Atmosphere and Ocean, IRS 2012
Y2 - 6 August 2012 through 10 August 2012
ER -