• Home
  • Download PDF
  • Order CD-ROM
  • Order in Print
ML-121 CEILING LIGHT PROJECTOR
CALCULATORS

Aerographers Mate, Module 01-Surface Weather Observations
Page Navigation
  99    100    101    102    103  104  105    106    107    108    109  
shipboard  clinometer,  used  both  aboard  ship  and ashore. The ML-l19 clinometer is shown in figure 2-44. It is hand-held, whereas the shipboard clinometer is   mounted   on   a   bracket   and   supplied   with   a weatherproof cover; operation is similar. Operation To operate the clinometer, loosen the clutch screw to allow the elevation scale to swing freely. After sighting the light spot on the cloud base, bring the cross hairs to bear on the spot. Then, with the cross hairs on the spot, tighten the clutch screw, and read the elevation angle from the scale to the nearest whole degree. Cloud height  is  calculated  by  multiplying  the  baseline  distance by the tangent of the elevation angle. Normally, a minimum of three readings are used to determine an average. Aboard ship, add the height of the clinometer above the waterline to the calculated distance. Where established premeasured baselines are used, tables for converting  measured  elevation  angle  to  cloud  height may have been previously calculated and may be available.  NAVMETOCCOMINST  3144.1  provides summarized  procedures  for  using  the  shipboard clinometer. Maintenance Maintenance   procedures   for   the   ML-l19 clinometer are described in NA 50-30FR-521 and for the  ML-591/U  clinometer  in  NAVWEPS  50-30FR13, Technical  Manual,  Operation,  Maintenance,  and Overhaul  Instructions  with  Illustrated  Parts Breakdown, (Shipboard) Elevator Clinometer ML- 591/U. Monthly cleaning is recommended, along with inspection  to  make  sure  the  parts  move  freely. Aerographer’s  Mates  are  normally  responsible  for  all maintenance on clinometers. CEILING BALLOONS Ceiling balloon measurements are still a valid procedure  to  determine  cloud  height  when  other methods  fail.  Although  not  routinely  accomplished  at most   Naval   meteorology   and   oceanography detachments, ceiling balloon observations are common aboard ship and at most Marine Corps weather stations. Ceiling balloons are primarily used as a backup method to determine cloud height during the day when ceiling lights  cannot  be  used. Ceiling  balloons  provide  a  reasonable  height determination   up   to   2,000   feet.   Since   heavy precipitation  will  slow  the  ascension  rate  enough  to invalidate   any   measurement,   avoid   balloon measurement during such conditions. The  equipment  required  for  a  ceiling  balloon observation  includes  the  balloons,  balloon  weight  set,  a stopwatch, helium, and a helium regulator with a balloon-inflation nozzle. In this section we discuss the balloons, the balloon-inflation procedure with the weight set, and the method used to determine cloud or ceiling  height. Balloon Types Several different sizes and colors of balloons may be  used  for  ceiling  determination.  The  balloons  are available in both red and black; the red balloons are used for thin cloud cover or on hazy days, while the black balloons  are  used  for  all  other  cloud  conditions. Although the standard ceiling balloons are the lo-gram balloons, 30-gram balloons provide a faster ascension rate  and  are  preferable  for  use  during  high-wind conditions. Use of the slower ascending, lo-gram balloon during high winds may result in the balloon being carried out of sight horizontally before it reaches Figure  2-44.—ML-119  clinometer. the cloud layer or ceiling. 2-34







Western Governors University

Privacy Statement
Press Release
Contact

© Copyright Integrated Publishing, Inc.. All Rights Reserved. Design by Strategico.