Ling L. Lim

Flying into the Future: Aviation Emissions Scenarios to 2050

This study describes the methodology and results for calculating future global aviation emissions of carbon dioxide and oxides of nitrogen from air traffic under four of the IPCC/SRES (Intergovernmental Panel on Climate Change/Special Report on Emissions Scenarios) marker scenarios: A1B, A2, B1, and B2. In addition, a mitigation scenario has been calculated for the B1 scenario, requiring rapid and significant technology development and transition. A global model of aircraft movements and emissions (FAST) was used to calculate fuel use and emissions to 2050 with a further outlook to 2100. The aviation emission scenarios presented are designed to interpret the SRES and have been developed to aid in the quantification of the climate change impacts of aviation. Demand projections are made for each scenario, determined by SRES economic growth factors and the SRES storylines. Technology trends are examined in detail and developed for each scenario providing plausible projections for fuel efficiency and emissions control technology appropriate to the individual SRES storylines. The technology trends that are applied are calculated from bottom-up inventory calculations and industry technology trends and targets. Future emissions of carbon dioxide are projected to grow between 2000 and 2050 by a factor in the range of 2.0 and 3.6 depending on the scenario. Emissions of oxides of nitrogen associated with aviation over the same period are projected to grow by between a factor of 1.2 and 2.7.

Integrated decision support system for urban air quality assessment

Abstract Urban air quality is a major concern throughout the world. In the UK, local authorities are now required to improve air quality in their respective area. In most urban areas, emissions from traffic are a major contributor of harmful pollutants such as nitrogen oxides (NOX) and particulate matter (PM). Tools such as transportation and dispersion models are needed to predict any potential atmospheric pollution problems and to test the effectiveness of any air quality action plans. This paper describes a new framework to link existing air quality tools and the implementation of this framework through the development of prototype software IMPAQT (Integrated Modular Program for Air Quality Tools). IMPAQT aims to aid transport or environmental planners by increasing the efficiency of air quality assessments. IMPAQT was applied to several case studies using a countywide transportation model, an advanced atmospheric dispersion model and a desktop GIS. It was used to carry out urban air quality assessments and to test traffic scenarios. The laborious and time-consuming data preparation work involved in air quality studies was completed efficiently and in a shorter time compared with the methodology currently adopted by local authorities.

A review of various strategies for contrail avoidance

A review is given of various contrail avoidance strategies that have been developed since the publication of the Intergovernmental Panel on Climate Change (IPCC) special report on Aviation and the Global Atmosphere. The goal of this review is to provide an overview of the various options for contrail mitigation, to describe the state of the art, and to indicate future directions for research.

Simple Versus Complex Physical Representation of the Radiative Forcing From Linear Contrails: A Sensitivity Analysis

An off-line complex representation of the radiative forcing of linear contrails is applied for the first time to monthly mean 3-D distributions. This representation assumes the same temperature-dependent, spatially and time-varying functions of ice water content and particle size for contrails as for natural cirrus. This complex representation is contrasted with more commonly used simplified setups in which fixed contrail optical depth values [0.1 to 0.3] are prescribed and from which the results show differences covering a factor of 3 assuming fixed or variable contrail layer altitudes. This prescribed range of representative fixed altitudes resulted in differences covering a factor of 2 when the optical depth was also fixed. Prescribing fixed particle sizes also resulted in differences covering a factor of 2 if altitude and optical depth are also fixed. In contrast, the inclusion of the dependence of the contrail ice water content on temperature produced differences of around 20% or less when assuming the same ranges of altitudes and ice particle sizes, resulting in a much improved confidence in the radiative forcing estimates and more accurate spatial and temporal representations of the radiative interaction between contrails and the background meteorology. Assuming a contrail vertical extent of 500 m, a 9 mW m−2 annual mean contrail radiative forcing is estimated, with an uncertainty range between 1 and 23 mW m−2 based on the ice water content’s observed variability.