7th Framework Programme
     Environmental Flight Planning / Climate Cost Functions     30 Apr 2010

Climate cost functions

Climate cost functions indicate for an emission what is related climate impact if emission is released at that location and that specific time. Hence, such 4-dimensional climate cost functions allow to quantify related climate impact for any given location and time of emission.

How to calculate climate cost functions

Within REACT4C a simulation tool will be prepared in order to calculate the time evolution of the perturbations of the atmospheric composition and cloudiness arising from unit emissions released from aviation (e.g. NOx, H2O) at a high number of latitude-longitude-altitude model grid cells. This analysis will be performed for the archetypical weather situations selected earlier (WP1). Due to a Lagrangian advection scheme ATTILA a very high number of such perturbations can be included within one single model simulation, excluding interaction of the individual perturbations.

Radiative forcing as input to climate cost functions

The radiative forcings (RFs) arising from the unit perturbations will be calculated for each of the perturbations as functions of time. The result will be individual 5-dimensional functions of global (marginal) radiative forcings as functions of time t (after emission), location (longitude, latitude), pressure altitude p and time of emission te, separately for the different types of emissions (NOx, H2O, contrails). Due to the long lifetime and the small perturbation of the background concentrations the RFs from CO2 and CH4 can be derived via box models.

The time dependent RFs will form the input for calculating the 4D (specific) climate cost func-tions. We will concentrate on the incremental integrated RF (if a GWP based emission metric is used) and on the incremental temperature change (if a GTP based emission metric is used). The output will serve as climate/environmental cost functions quantifying impact of CO2, NOx, and H2O emissions, and of contrails (plus potentially contrail-cirrus) for a set of typical weather situations. For illustrative purposes we shall also consider the marginal radiative forcing as cost function.