In 2008 expedition, at South Col was installed the DMA572 termohygrometer, that was replaced during the 2011 expedition with two DMA672 termohygrometers and one DMA033 thermometer. All these sensors are manufactered by LSI-Lastem (Italy). DMA 672 thermohygrometer is an instrument for measuring temperature and relative humidity and suitable for a continuous measurement in severe environments; in presence of deep thermal and hygrometric ranges with high sun radiant heat. An importatnt feature of this set of sensor is that the thermohygrometric sensitive element is easily replaceable, in order to have a simple and rapid ordinary maintenance and avoiding calibration. The Thermohygrometer has supported a considerable improvement, owing to a deep technical and styling development process: a fan ensures a continuos air change around the sensor in order to eliminate temperature fault caused by radiant heat. Technical characteristics for temperature: Range: -30 to 70°C Sensitive element: Pt100 Class B 1/3 DIN Sensitive element replacement: sensor replacement Accuracy (Repeatability+ Hysteresis): ±0,1°C (0°C) Resolution: n.a. Response time (Sens. Element): 10 s Thermal drift: n.a. Long term stability: <1°C year Operating temperature: -50°÷100°C Technical characteristics for relative humidity: Range: 0 to100% Sensitive element: Capacitive Sensitive element replacement: sensor replacement Accuracy (Repeatability+ Hysteresis): 1,5% (5 to 95%, 23°C) Resolution: 0,12% Response time (Sens. element): 10 s Thermal drift: Max ± 1,5% Long term stability: <1 RH% year DMA033 Thermometer is well-suited for environmental outdoor measurements, with natural or forced ventilation antiradiant shield. Technical characteristics: Range : -40 to70°C Sensitive element: Pt100 1/3 DIN-B Accuracy: ±0,1C (0°C) Repeatability: 1/5 accuracy Electric output: Pt100 ? 1/3 DIN Operating temperature: -40°to 95°C Protection (vertical pos.): IP66

In 2008 at South Col the CombiSD DNA022 sensor (LSI-Lastem, Italy) was installed. During the 2011 expedition, this sensor was replaced with a prototype (LSI-Lastem) to support with another sensor manufactured by VAISALA: WA15D7B. The WA15 is based on accurate sensors installed on a large crossarm. It is designed for demanding wind measurement applications. Three lightweight, conical cups mounted on the cup wheel, provide excellent linearity over the entire operating range, up to 75 m/s. A wind-rotated chopper disc attached to the shaft of the cup wheel cuts an infrared light beam 14 times per revolution. This generates a pulse output from the phototransistor. The output pulse rate is directly proportional to wind speed (e.g. 246 Hz = 24.6 m/s). However, for the highest accuracy, the characteristic transfer function should be used to compensate for starting inertia.

In both 2008 and 2011 expeditions a CM6B Kipp&Zonen radiometer was installed at South Col. This sensor is a first class pyranometer as defined by the World Meteorological Organization. It is suitable for the measurement of solar irradiance on a plane surface (W/m2). It incorporates a 64-thermocouple sensor, which is rotationally symmetrical, housed under K5 domes. A white screen prevents the body of the pyranometer from heating up. The pyranometer is supplied with a spirit level and screws for accurate levelling. CM6B technical data - Spectral range 305 to 2800 nm (50%points) - Sensitivity 9 to 15 ?V/Wm-2 - Impedance 70 to 100 Ohm - Response time 1/e 5 s, 99 % 55 s - Non-linearity <1.5 % (<1000 W/m 2 ) - Tilt error <1.5 % at 1000 W/m 2 - Operating temperature -40 to +90 °C - Temperature dependence of sensitivity _2 % (-10 to +40 °C) - Maximum irradiance 2000 W/m2 - Directional error < _20 W/m2 at 1000 W/m2 - Weight 0.85 kg - Cable length 10 m

The CNR 4 net radiometer measures the energy balance between incoming short-wave and long-wave Far Infrared (FIR) radiation versus surface-reflected short-wave and outgoing long-wave radiation. The CNR 4 net radiometer consists of a pyranometer pair, one facing upward, the other facing downward, and a pyrgeometer pair in a similar configuration. The pyranometer pair measures the short-wave radiation. And the pyrgeometer pair measures long-wave radiation. The upper long-wave detector of CNR 4 has a meniscus dome. This ensures that water droplets role off easily and improves the field of view to nearly 180°, compared with a 150° for a flat window. All 4 sensors are integrated directly into the instrument body, instead of separate modules mounted onto the housing. But are each calibrated individually for optimal accuracy. Two temperature sensors, a Pt-100 and Thermistor, are integrated for compatibility with every data logger. The temperature sensor is used to provide information to correct the infrared readings for the temperature of the instrument housing. Care has been taken to place the long-wave sensors close to each other and close to the temperature sensors. This assures that the temperatures of the measurement surfaces are the same and accurately known. Which improves the quality of the long-wave measurements. Technical Characteristics: Spectral range: 300 to 2800 (short wave) nm Spectral range: 4500 to 42000 (long wave) nm Sensitivity: 5 to 20 µV/W/m² Temperature dependence of sensitivity (-10 ºC to +40 ºC) : < 4 % Response time: < 18 s Non-linearity: < 1 % Operating temperature: -40 to 80 °C Ventilation power (of the optional CNF 4 ventilation unit): 10 W

The USH-8 Ultrasonic Snow Depth Sensor by SOMMER is ideal for the reliable measurement of snow-depth in extreme conditions. The sensor’s principle of measurement deals with the transit-time measurement of an ultrasonic pulse. The sensor transmits several energy-charged pulses to the snow cover and subsequently receives its reflected signals. Based upon the required transit time of the ultrasonic signals, the USH-8 sensor calculates the current snow depth. The processing time of the ultrasonic pulses here is enormously influenced by the air temperature. For this reason, the snow depth sensor also possesses integrated temperature compensation. This takes into account the influence of the air temperature on the processing time of the ultrasonic signals, in the calculation of the snow depth. The calculation takes place in the sensor, so that the output signal provides the already converted snow depth. USH-8 Specifications: Snow Depth Measurement Range of measurement: 0 to 8 m Minimum distance to the maximum expected snow depth: 1 m Accuracy: 0,1 % (FS) Resolution 1 mm Principle of measurement: Ultrasonic (Frequency 50 kHz; Angle of reflected beam 12°) Integrated Compensation of the Air Temperature Temperature sensor: Integrated air-temperature sensor in self-venting radiation shield Range of measurement: -35 to 60 °C Resolution: 0,1 °C Non-linearity: ? 0,15 % Interfaces Analogue: Snow depth measurement 0/4 - 20 mA signal (configurable) Resolution: 12 Bit Max. load: 300 ? Digital: Snow depth measurement; air temperature; quality flag RS 232; serial interface Protocol: Various ASCII formats

At the end of March 2006 a Cimel CE-318 sunphotometer was installed at the Nepal Climate Observatory - Pyramid (NCO-P) within the framework of the Aerosol Robotic Network, AERONET (http://aeronet.gsfc.nasa.gov, EvK2-CNR site). It provides a characterization of aerosol optical and microphysical properties of the air column above the station.

At the Nepal Climate Observatory - Pyramid, aerosol total and back scattering coefficients at three wavelengths (450, 550 and 700 nm) are derived by an integrating nephelometer (model TSI 3563).

Both in 2008 and in 2011 expedition a DPA 007, manufactured by LSI-Lastem was installed at South Col. This broad band radiometers measure electromagnetic radiation intensity in a determined interval of wavelength. Applications often need information about emission in ultraviolet, infrared, and visible spectral band, demanding a more specialized instrumentation.In particular, this model permit to record UVA radiation and work according to the the WMO (World Meteorological Organization) guideline. The sensitive element is aphotodiode with optical filter with interferential deposition in order to improve the spectral transmission. Technical characteristics: Sensitive element: photodiode Spectral range: 315 to 400 nm Range: 0 to 70 W/m2 Response time (s): 0.1 Accuracy: ±12% VL/reading ± 1W/m2 Linearity: <=1%

The sensor’s principle of measurement deals with the transit-time measurement of an ultrasonic pulse. The sensor transmits several energy-charged pulses to the snow cover and subsequently receives its reflected signals. Based upon the required transit time of the ultrasonic signals, the USH-8 sensor calculates the current snow depth. The processing time of the ultrasonic pulses here is enormously influenced by the air temperature. For this reason, the snow depth sensor also possesses integrated temperature compensation. This takes into account the influence of the air temperature on the processing time of the ultrasonic signals, in the calculation of the snow depth. The calculation takes place in the sensor, so that the output signal provides the already converted snow depth. USH-8 Specifications: Snow Depth Measurement Range of measurement: 0 to 8 m Minimum distance to the maximum expected snow depth: 1 m Accuracy: 0,1 % (FS) Resolution 1 mm Principle of measurement: Ultrasonic (Frequency 50 kHz; Angle of reflected beam 12°) Integrated Compensation of the Air Temperature Temperature sensor: Integrated air-temperature sensor in self-venting radiation shield Range of measurement: -35 to 60 °C Resolution: 0,1 °C Non-linearity: ? 0,15 % Interfaces Analogue: Snow depth measurement 0/4 - 20 mA signal (configurable) Resolution: 12 Bit Max. load: 300 ? Digital: Snow depth measurement; air temperature; quality flag RS 232; serial interface Protocol: Various ASCII formats

At Changri Nup station a DMA 572 thermohygrometer was installed in 2010. Temperature sensitive element is a thermoresistance Pt100 type while the humidity sensitive element is a capacitive plate. The sensitive elements are protected from incident solar radiation by a double radiation shield. Sensors for temperature and relative humidity measurements with radiation shield for meteorological uses. Sensors are equipped with a microprocessor. For temperature: Range -30.+70°C Sensitive element Pt100 1/3 DIN-B Accuracy ± 0,1°C (0°C) Hysteresis&Repeatability na Resolution 0,025°C Long term stability -0.04% (after 5 years at 200°C) Calibration uncertainty 0,1°C Response time (T63) Wind speed 0,3-0,5 m/s: 80sec Radiation shield efficiency with respect to forced ventilation sensor (wind 0,5m/s, rad.800 W/m2): +0,6°C For relative humidity: Range: Nom.0..100%, Eff.10..98% Sensitive element Capacitive Accuracy 2,5% (11-90%) 0,6°C (20°C, 50%RH) Hysteresis&Repeatability 0,5% Resolution 0,2% Long term stability -2%/year (at 75%RH) n.a. Calibration uncertainty 0,1°C 1,5% na Response time (T63) Wind speed 0,3-0,5 m/s: 80sec Radiation shield efficiency with respect to forced ventilation sensor (wind 0,5m/s, rad.800 W/m2): n.a. General characteristic: Ventilation: Natural Electric output Jumper locally selectable 2 x 0-20 mA, 4-20 mA, 0-5 V, 1-5 V. 60-300 mV Output signals Output n.1: temperature. Output n.2: RH% or dew point (default RH%) Operating temperature -30°+70°C Sampling rate 1 sec. (default) PC programmable 1..300 sec. N°acquisitions for mobile average calculation: N°1 (default), PC programmable 1..20 acquisitions Load resistance (mA output): DMA570 300 Ohm