CLOUD HEIGHT EQUIPMENT

Figure 2-37.—OA-7900A/GMQ-10 Converter/Indicator Group consisting of the ID-1939/GMQ-10 digital LED indicator and the CV-3125/GMQ-10 signal converter. Maintenance This equipment requires very little operator maintenance. Maintenance includes cleaning the fan screen on the rear of the converter and keeping external surfaces clean. Refer to the operator’s manual for details. REVIEW QUESTIONS Q36. What does a meteorological transmissometer actually measure? Q37. How do the terms "sector visibility" and "runway visual range" differ with respect to the AN/GMQ-32? Q38. What publication contains criteria and instructions for the use of transmissometers? Q39. How are transmissivity values presented on the AN/GMQ-32 and how are these values converted? Q40. What routine maintenance is normally accomplished by the observer with respect to the AN/GMQ-32? CLOUD HEIGHT EQUIPMENT LEARNING OBJECTIVES: Describe the operation, recorder trace outputs, and maintenance of the AN/GMQ-13 cloud height set. Explain the operation and maintenance of the ML-121 ceiling height projector and clinometers used ashore and at sea. Describe two types of ceiling balloons, how they are inflated, and how they are used to determine cloud height. In this section we will discuss some of the more frequently used types of cloud-height measuring equipment. The AN/GMQ-13 cloud height set (also called the rotating beam ceilometer or RBC), is still the primary cloud-height measuring equipment in use at some shore stations. The AN/GMQ-13 is currently being replaced by the ASOS cloud height detector. Most shore stations also have backup cloud-height measuring equipment, which consists of an ML-121 ceiling light projector and ML-119 clinometer. Aboard ship, an ML-591/U shipboard clinometer is used in 2-29