Global contrail radiative forcing and the impact of diurnal variations of air traffic N. Stuber and P. Forster Department of Meteorology, The University of Reading, Earley Gate, PO Box 243, Reading, Berkshire, RG6 6BB, UK School of Earth and Environment, University of Leeds, Leeds, LS2 9JT, UK Received: 3 August 2006 – Accepted: 6 September 2006 – Published: 25 September 2006 Correspondence to:...

[1] If mitigation of black carbon (BC) particulate matter is accompanied by a decrease in particle number emissions, and thereby by a decrease in global cloud condensation nuclei (CCN) concentrations, a decrease in global cloud radiative forcing (a reverse “cloud albedo effect”) results. We consider two present‐day mitigation scenarios: 50% reduction of primary black carbon/organic carbon (BC/O...

A subset S of initially infected vertices of a graph G is called forcing if we can infect the entire graph by iteratively applying the following process. At each step, any infected vertex which has a unique uninfected neighbour, infects this neighbour. The forcing number of G is the minimum cardinality of a forcing set in G. In the present paper, we study the forcing number of various classes o...

The largest uncertainty in the historical radiative forcing of climate is caused by the interaction of aerosols with clouds. Historical forcing is not a directly measurable quantity, so reliable assessments depend on the development of global models of aerosols and clouds that are well constrained by observations. However, there has been no systematic assessment of how reduction in the uncertai...

[1] The contrail radiative forcing induced by human aviation activity is one of the most uncertain contributions to climate forcing. An accurate estimation of global contrail radiative forcing is imperative, and the modeling approach is an effective and prominent method to investigate the sensitivity of contrail forcing to various potential factors. We use a simple offline model framework that ...

[1] A global estimate of the direct effects of anthropogenic aerosols on solar radiation in cloudy skies is obtained by integrating satellite and ground-based observations with models of aerosol chemistry, transport, and radiative transfer. The models adopt global distribution of aerosol optical depths (from MODIS), clouds, water vapor, ozone, and surface albedo from various satellite climatolo...