Understanding the variability of clear-sky outgoing long-wave radiation based on ship-based temperature and water vapor measurements
Journal article, 2006

High-resolution radiative transfer model calculations with the Atmospheric Radiative Transfer Simulator (ARTS) were used to simulate the clear-sky outgoing long-wave radiative flux (OLR) at the top of the atmosphere. The unique set of radiosonde data collected by the research vessel Polarstern of the Alfred Wegener Institute for Polar and Marine Research during 27 expeditions in the years 1982 to 2003 was used to investigate the sources of clear-sky OLR variability for ocean areas in different climate zones and seasons. For this dataset, tropospheric temperature variations contribute approximately 33 W m -2 OLR variability, tropospheric relative humidity variations 8.5 W m -2 , and vertical structure 2.3-3.4 W m -2 . Of these, 0.3-1.0 W m -2 are due to structures on a vertical scale smaller than 4 km, which cannot be resolved by conventional remote-sensing instruments. It was also found that the poor absolute accuracy of current humidity data in the upper troposphere, approximately 40% relative error in relative humidity, leads to a significant uncertainty in OLR of about 3.8 W m -2 (for a midlatitude summer atmosphere), which should be put in the context of the double CO 2 effect of only 2.6 W m -2 (for the same atmosphere). © Royal Meteorological Society, 2006.


V.O. John

Universität Bremen

University of Miami

S.A. Buehler

Luleå University of Technology

Universität Bremen

A. von Engeln

European Organisation for the Exploitation of Meteorological Satellites

Patrick Eriksson

Chalmers, Department of Radio and Space Science, Global Environmental Measurements

T. Kuhn

University of Cologne

E. Brocard

University of Bern

G. Koenig-Langlo


Quarterly Journal of the Royal Meteorological Society

0035-9009 (ISSN) 1477-870X (eISSN)

Vol. 132 621 2675-2691

Subject Categories

Meteorology and Atmospheric Sciences



More information

Latest update