Measurements of pollution in the troposphere (MOPITT) instrument

The earth’s environment is changing through natural and artificial mechanisms. Monitoring these changes on a global basis is becoming an international priority. The troposphere, being the area of the atmosphere which we inhabit, is of great importance although it is extremely difficult to make measurements of this region from space due to the interfering effects of clouds and the nearby surface. However the state of the troposphere, and particularly its chemistry is of considerable and immediate importance. The MOPITT instrument will use the principle of correlation spectroscopy to measure carbon monoxide (CO) amounts at three levels in the troposphere utilising thermal radiation at 4.7/μm, and the total column amount of CO and methane (CH4) using reflected sunlight around 2.3lLim. The required accuracy is 10% for the CO measurements and 1% for the CH4 channels. These figures pose a considerable challenge to the instrument engineering.