Atmospheric Brown Clouds in the Himalayas: first two years of continuous observations at the Nepal-Climate Observatory at Pyramid (5079 m)

This paper provides a detailed description of the atmospheric conditions characterizing the high Himalayas, thanks to continuous observations begun in March 2006 at the Nepal Climate Observatory-Pyramid (NCO-P) located at 5079 m a.s.l. on the southern foothills of Mt. Everest, in the framework of ABC-UNEP and SHARE-Ev-K2-CNR projects. The work presents a characterization of meteorological conditions, air-mass circulation and atmospheric composition at NCO-P after the first two years of activity. The objective of this paper is to investigate and evaluate the influence on the NCO-P atmosphere composition of the so-called atmospheric brown clouds, i.e. wide polluted tropospheric layers characterised by anthropogenic aerosol optical depth (AOD) greater than 0.3 and absorbing AOD greater than 0.03. Due to the large amount of gases and aerosol particles, these brown clouds have strong impacts on the air quality, visibility and energy budget of the troposphere Due to the large amount of gases and aerosol particles, including black carbon, these brown clouds have strong impacts on the air quality, visibility and energy budget of the troposphere. In the past decade, scientific research has been conducted over the Indo-Asia-Pacific region, where an extensive observation system has been developed within the INDOEX project. This paper, published in one of the most important journals in the field of atmospheric sciences, testifies the involvement of M. Maione in an extremely important research activity of global relevance and dealing with crucial issues such as climate and air quality, and the inclusion in an international and multidisciplinary research groups