The ESA ALANIS Smoke Plumes Project - an Overview
Fisher, Daniel; Muller, Jan-Peter; Yershov, Vladimir
MSSL, UNITED KINGDOM

The Eurasian boreal region is the Earth's largest terrestrial ecosystem, and within its forests, wetlands and peat bogs it contains vast quantities of sequestered carbon. These carbon stocks, if released, have significant potential to alter the Earth's climate. Therefore, effective monitoring of the interactions between them and the atmosphere is of vital importance. Recognising this importance, ESA established the STSE Atmosphere Land Interaction Study over Boreal Eurasia (ALANIS), which comprised three separate science tasks: ALANIS-methane, ALANIS-aerosols, and ALANIS-smoke plumes.

The remit of the smoke plumes project was to assimilate three novel Earth Observation based datasets into the TM-5 land-atmosphere coupled model [1] and to determine what improvement in large-scale forest fire emission dispersion forecasts this integration might achieve. The three datasets comprise: carbon monoxide columns derived from near-real-time IASI retrievals [2]; burnt area and emission data from MERIS and MODIS; and stereo-derived smoke plume masks and injection heights from AATSR [3]. Here we present an overview of the work undertaken in the development of the smoke plume products.

To retrieve smoke plume injection heights from AATSR, a new stereo matching algorithm sensitive enough to detect the fine-scale structure often observed in smoke plumes was developed. The algorithm, referred to as M6, due to a shared heritage with the other M-series matchers [4,5], has been extensively validated against collocated smoke plume injection height data from the MISR and CALIOP instruments. In these inter-comparisons against higher resolution observations, M6 is shown to retrieve smoke plume injection heights to an accuracy of ~1km.

To automatically detect and retrieve smoke plumes, a masking algorithm, which takes advantage of the spectral characteristics of AATSR and the stereo height retrievals, to differentiate between smoke and non-smoke features was developed. The combined stereo and masking algorithms were then used to generate a smoke plume injection height dataset for the study region for the period April-August time period from 2008 to 2011. They are now available from the ALANIS smoke plumes consortium�fs website http://alanis.noveltis.com/ The overall summary of these products will be discussed as well as the issues associated with the narrow orbital swath and infrequent revisit time of AATSR. The potential of ATSR�fs successor, SLSTR, will be described*.

References cited
[1] Krol, M., Houweling, S., Bregman, B., Van Den Broek, M., Segers, A., Van Velthoven, P., ... & Bergamaschi, P. (2005). The two-way nested global chemistry-transport zoom model TM5: algorithm and applications. Atmospheric Chemistry and Physics, 5(2), 417-432.

[2] Clerbaux, C., Boynard, A., Clarisse, L., George, M., Hadji-Lazaro, J., Herbin, H., ... & Coheur, P. F. (2009). Monitoring of atmospheric composition using the thermal infrared IASI/MetOp sounder. Atmos. Chem. Phys, 9(16), 6041-6054.

[3] Fisher, D. N., Muller, J.-P., and Yershov, V. (2012). Automated stereo retrieval of smoke plume injection heights and retrieval of smoke plume masks from AATSR and assessment with CALIPSO and MISR, IEEE T. Geosci. Remote, in press,

[4] Muller, J. P., Denis, M. A., Dundas, R. D., Mitchell, K. L., Naud, C., & Mannstein, H. (2007). Stereo cloud�]top heights and cloud fraction retrieval from ATSR�]2. International Journal of Remote Sensing, 28(9), 1921-1938.

[5] Muller, J. P., Mandanayake, A., Moroney, C., Davies, R., Diner, D. J., & Paradise, S. (2002). MISR stereoscopic image matchers: Techniques and results. Geoscience and Remote Sensing, IEEE Transactions on, 40(7), 1547-1559.

* work supported under ESA ALANIS contract (ESRIN Contract N�-42000230S5/1O/I-LG).