De La Salle University - Manila

LIDAR

SUNPHOTOMETER

Introduction

Research on aerosols is attracting more and more attention in many fields, such as radiation transmission, environmental monitoring, and climate. Some researchers make use of radiosondes to measure the altitude variation of the air pressure, humidity and air temperature with the use of a radio-transmitting instrumented package carried into the atmosphere by a balloon. Others use air samplers to gather sample aerosols, which are later studied using chemical techniques. One of the unconventional methods used in more current researches is called Light Detection and Ranging (LIDAR). Also called Laser Remote Sensing, this method can immediately detect the concentration of certain chemicals such as ozone, water vapor and air pollutants [Robles, 2001]. Another method that is being used in the study of the atmosphere is called Sunphotometry.

Sometimes called as Solar Spectral Radiometry, Sunphotometry is a passive remote sensing technique used to measure the intensity of the solar beam transmitted through the atmosphere using a sunphotometer, which are specialized narrow field-of-view radiometers designed to measure solar irradiance [Rollin, 2000]. Such measurements, made in several narrow bands of ultraviolet, visible, and infrared radiation, provide valuable information on the properties of aerosols and important trace gases such as water vapor and ozone [Mims, 1999]. Using a single technique to study both aerosols and trace gases is often an advantage in understanding their properties and these interactions.