Water vapor corrections to mid-infrared photometry

We explore water vapor corrections for the San Pedro Martir mid-infrared photometric system CID. Atmosphere opacity is measured by a 210 GHz radiometer. By using the results of the ATM code, we propose a linear relationship between 210 GHz opacity and water vapor content. This relation allows us to determine the water vapor content in the atmosphere from opacity measurements at the radiometer frequency. We also obtain a relation between water vapor content and mid-infrared opacity by using the MODTRAN 3 atmospheric model. Thus, through the water vapor we obtain a relation that connects millimeter opacity to mid-infrared opacity under clear sky conditions. We tested this relation with measurements made at San Pedro Martir of these two opacities.