The Nepal Climate Observatory - Pyramid (Nepal, 27.95N, 86.82E, 5079 m a.s.l.) has been installed in February 2006 in the high Khumbu Valley, above the timber line in a rocky and mossy environment not far from the base camp area of Mt. Everest. The Observatory is running in the framework of theAtmospheric Brown Clouds Project (ABC) of UNEP, and is part of AERONET network and WMO-GAW program. Since 2010 NCO-P is a global GAW station. The instrument set-up was defined in accordance with “ABC” Project standards (Ramanathan et al., 2006) and includes: (a) a surface ozone analyser, (b) a Multi-Angle Absorption Photometer which measures aerosol light absorption also allowing the determination of the BC concentration in atmosphere, (c) a Differential/Scanning Mobility Particle Sizer to determine the aerosol size distribution from 10 to 500 nm, (d) an optical particle counter to complete the aerosol size distribution till 32 µm also allowing to reconstruction of aerosol mass, (e) a three wavelength integrating nephelometer to determine aerosol total and back scattering coefficients, (f) a sun photometer for measuring the aerosol optical depth, (g) a high volume aerosol sampler for chemical analyses, (h) a “clean” sampling device to collect grab air samples for halocarbons analyses, (i) a pyranometer for measuring the global solar irradiance, (j) a pirgeometer for measuring the downwelling infra-red irradiance, (k) a meteorological unit measuring temperature, pressure, relative humidity, rain, wind intensity and direction.
