EET-3120Sensors and Instruments

Field Trip to Grove School of Engineering’s Optical Sensors Lab

Name of the Student: Faiz RasoolE-Mail: Faiz.Rasool@mail.citytech.cuny.eduDate: 05/07/2015Instructor: Vivian Vladutesc

Department of Electrical & Telecommunication Engineering

On April 30th, 2015 our sensors and Instruments class made a trip to Grove School of Engineering at City College of New York to learn about some sensors and instruments they are using to take measurements for weather, air pollution(Aerosol in air), light absorbed by air particles, light radiations. We had tour to the roof where those instruments were installed and then we went to the lab where they we getting information from those sensors and instruments.

Fig-1. Grove School Of Engineering

Fig-2. Sensors and Instruments Class at roof of Grove School of Engineering

CIMEL Sun Photometer:-

Sun Photometer Instrument, CIMEL Sun Photometer CE318, is #237 in the NASA AERONET (Aerosol Robotic Network.) This microprocessor controlled, stepper motor positioned robot has a two component optical head containing the sun collimator without lens and the sky collimator with lenses and filter wheel. Sun tracking is controlled with a 4-quadrant detector. Data is temporarily stored in memory and once every hour uploaded to NASA via a GOES-E (geosynchronous) satellite uplink.

The instrument directly measures the incoming solar energy at selected wavelengths of 340, 380, 440, 670, 870, 1020 nm, and 936 nm. Light is absorbed and scattered by atmospheric gasses, water vapor and aerosols. The concentration of different atmospheric components can be determined by the attenuation at wavelengths which are strongly absorbed or scattered.

Fig - 3. CIMEL N-237 Fig - 4. CIMEL Taking the Measurement

Microwave Radiometer:-

The instrument measures the microwave radiation emitted from the oxygen molecules and water

vapor in the air and, with the use of statistical methods, determines the temperature and humidity

profiles of the atmosphere from the ground up to 10 km aloft. It measures humidity electrical

sensor that measure the change in resistance due to presence water in air. If there is water on that

sensor it removed by powerful fan but if rain and water is falling continuously then it stop taking

readings.

Fig - 5. Microwave Radiometer

Fig - 6. Data of 05/06/2015 MWR water vapor (g/m 3 )

The Multi-Filter Rotating Shadowband Radiometer (MFR-7):-

The Multifilter Rotating Shadowband Radiometer (MFR-7) measures total, diffuse, and direct irradiance with a broad-band silicon pyranometer and at six wavelengths using sensors with narrow band filters at 415, 500, 615, 673, 870, and 940 nanometers. The full width half maximum width is ten nanometers. The head, where the sensors are located, is thermally stabilized to significantly reduce uncertainties associated with temperature variation. The MFR-7 makes measurements simultaneously across all seven channels. The shadowband enables the instrument to measure the global and diffuse components of solar irradiance and then calculate the beam component. It is used for prediction of UV-B hazards to public, Global climate change, Ozone studies, UV-B and aerosol research and biological effect studies.

Fig - 7. Shadow band Radiometer Fig - 8. Shadow band Radiometer parts

Backscatter Lidar:-

Backscatter Lidar works like a radar. It sends the beam of green Laser in the atmosphere that contains three different wavelengths and it goes upto 15Km in atmosphere and then the attenuation in the signals is measured on the sensors that give the presence of different aerosoles and gases in the atmosphere.

Fig - 9. Leaser wavelengthsplitter

Figure - 10. Sensors and transducers for backscatter Lidar

Ceilometers:-

This instrument also use beam of light or laser to determine the base of clouds. It can be also used to determine the aerosol concentration within the atmosphere. It consist of laser and receiver in the same location. A laser is sent through atmosphere where tiny fraction of the light is scatter by aerosol. The size of particles is similar to the wave length of the laser. A small component of this scatter light is received by the receiver. The receiving time is transformed into a spatial range by using the speed of light.

Figure-11. Ceilomerter

References :-

http://sky.ccny.cuny.edu/#

http://www.hko.gov.hk/aviat/outreach/observation/18th/MicrowaveRadiometer.htm http://www.yesinc.com/products/data/mfr7/