Share Email Print

Proceedings Paper

The Ångström coefficient as an indicator of non-marine particles in ANAM (Advanced Navy Aerosol Model)
Format Member Price Non-Member Price
PDF $14.40 $18.00
cover GOOD NEWS! Your organization subscribes to the SPIE Digital Library. You may be able to download this paper for free. Check Access

Paper Abstract

The Advanced Navy Aerosol model (ANAM), being a modified version of the Navy Aerosol Model (NAM), is a wellknown engineering tool providing a quick and reasonable estimate of the aerosol extinction in the marine near-surface environment on the basis of simple meteorological input data. The original NAM consists of 3 lognormal distributions, which describe freshly produced marine aerosols, aged marine aerosols (produced elsewhere and advected to the measurement site) and a background concentration of marine aerosols. The ANAM adds a 4th lognormal mode to NAM to account for the largest marine particles. To account for non-marine particles, a special lognormal mode, called "dust mode" was included in NAM. The relative importance of the dust mode versus the marine background concentration is governed by a special input parameter known as the air mass parameter (AMP). Unfortunately, the AMP is ill-defined and the NAM user community has found it difficult to attribute a proper value to the AMP. This inconvenience became even more stressing when NAM was used for assessing aerosol extinction in the coastal zone. To overcome this inconvenience, a new approach is suggested which involves replacement of the AMP by the Ångström coefficient. The advantage is that the latter parameter can be directly measured and has a physical relation to the aerosol size distribution. When the particle size distribution is dominated by small particles, usually associated with pollution, the Ångström coefficients are high; in clear conditions they are usually low. Therefore this parameter is a good tracer of the aerosols originated over land and hence a good replacement for the AMP.

Paper Details

Date Published: 12 August 2009
PDF: 9 pages
Proc. SPIE 7463, Atmospheric Optics: Models, Measurements, and Target-in-the-Loop Propagation III, 74630G (12 August 2009); doi: 10.1117/12.828394
Show Author Affiliations
Jolanta Kusmierczyk-Michulec, TNO Defence, Security and Safety (Netherlands)
Alexander M. J. van Eijk, TNO Defence, Security and Safety (Netherlands)

Published in SPIE Proceedings Vol. 7463:
Atmospheric Optics: Models, Measurements, and Target-in-the-Loop Propagation III
Stephen M. Hammel; Alexander M. J. van Eijk; Mikhail A. Vorontsov, Editor(s)

© SPIE. Terms of Use
Back to Top