In part 2 the cloud patterns seen in imagery are compared to model cloud patterns. The CSC is located at the center of curvature of a partial wall cloud in developing cyclones, and at the center of the eye in mature cyclones. If the CSC is not obvious, a model cloud pattern is selected that compares to the one seen in imagery, and the model s expected CSC is used. The first intensity estimate is made in step 2 by measuring the cloud features related to intensity. This is done when the cloud pattern contains cloud features similar to those in the cloud pattern descriptions listed in steps 2A to 2E. Since these patterns are seen in IR imagery, as well as visual imagery, you should know the importance of IR pictures in tropical cyclone analysis and the major differences with regard to intensity analysis.
Infrared pictures permit tropical cyclone monitoring day and night.
First, thin cirrus clouds, which are normally transparent in visual imagery, are often opaque in IR, thereby obscuring the view of lower cloud features. When the cirrus obscures the boundaries of lower cloud features, no intensity measurements are possible or erroneous ones are taken. This means the CDO size and embedded eye distance measurements cannot be interpreted in unenhanced IR pictures. Second, the low cloud lines used to pinpoint the storm center may not be visible because of the cirrus. With these differences in mind, let us now look at the cloud band pattern types seen in imagery and the type of imagery used to obtain the intensity estimate.