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Observed linkages between the northern annular mode/North Atlantic Oscillation, cloud incidence, and cloud radiative forcing
Author(s) -
Li Ying,
Thompson David W. J.,
Huang Yi,
Zhang Minghong
Publication year - 2014
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1002/2013gl059113
Subject(s) - climatology , northern hemisphere , north atlantic oscillation , cloud forcing , cloud cover , forcing (mathematics) , troposphere , radiative forcing , extratropical cyclone , atmospheric sciences , environmental science , geology , southern hemisphere , cloud feedback , climate model , climate change , cloud computing , oceanography , climate sensitivity , computer science , operating system
Abstract The signature of the northern annular mode/North Atlantic Oscillation (NAM/NAO) in the vertical and horizontal distribution of tropospheric cloudiness is investigated in CloudSat and CALIPSO data from June 2006 to April 2011. During the Northern Hemisphere winter, the positive polarity of the NAM/NAO is marked by increases in zonally averaged cloud incidence north of ~60°N, decreases between ~25 and 50°N, and increases in the subtropics. The tripolar‐like anomalies in cloud incidence associated with the NAM/NAO are largest over the North Atlantic Ocean basin/Middle East and are physically consistent with the NAM/NAO‐related anomalies in vertical motion. Importantly, the NAM/NAO‐related anomalies in tropospheric cloud incidence lead to significant top of atmosphere cloud radiative forcing anomalies that are comparable in amplitude to those associated with the NAM/NAO‐related temperature anomalies. The results provide observational evidence that the most prominent pattern of Northern Hemisphere climate variability is significantly linked to variations in cloud radiative forcing. Implications for two‐way feedback between extratropical dynamics and cloud radiative forcing are discussed.