Q34. Q35. Q36. Q37. During a Pibal observation, how are true wind direction and speed computed? Which  publication  contains  detailed  information on conducting Pibal observations? What software package contains a program fur automatic   computation   of   Pibal   observation data? What color Pibal balloon is normally used when the sky is clear? UPPER-AIR  REPORTING  CODES LEARNING   OBJECTIVES:   Recognize   the applications   for   upper-air   observation reporting  codes. Identify  the  observation location   and   time   in   an   upper-air   report. Identify   the   standard   upper-air   observation times. Upper-air  codes  are  designed  to  allow  transmission of a large amount of data using only a small number of characters.   The   numerically   coded   data   allows   the report to be decoded by a weather person in any country, regardless of the language spoken. More importantly, this  numerically  coded  format  can  be  readily transmitted  by  computer.  These  codes  may  be  easily loaded into computer programs that analyze the upper- air  data,  plot  graphical  displays,  and  then  calculate probable  changes  in  the  reported  conditions.  The resulting information serves as an invaluable forecast aid. Fleet   Numerical   Meteorology   and   Oceanography Center,  and  to  the  National  Weather  Service's environmental   prediction   system   at   the   National Meteorological  Center.  Navy  and  Marine  Corps observers  must  be  able  to  decode  all  upper  air observation codes. And, as stated earlier, they must be able to encode, or verify, the MRS computer encoding of the various forms of the TEMP code. IDENTIFYING   MESSAGE   CODE   FORM Nearly all coded upper-air-report messages contain a four-letter code identifier as the first group of the first line  of  data.  All  upper-air  codes  except  the  AMDAR code have a common format for the data identification line.  As  encoded  for  transmission,  identification  data appears in the first line of the message. The symbolic format for the identification data groups is as follows: M_iM_iM_jM_j  YYGGI_d  IIiii  (land  stations) o r M_iM_iM_jM_j  D.  .  .  .D  99L_aL_aL_a  Q_cL_oL_oL_oL_o MMMU_LaU_Lo   (h_Oh_Oh_Oh_Oi_m) (ship/aircraft/mobile  land  stations) The  first  group,  M_iM_iM_jM_j,  is  found  in  nearly every  international  coded  report,  and  is  the  code identifier. The  M_iM_i  identifies the code type. See the second column of table 1-7. The M_jM_j identifies which part of the multi-part upper-air reports is contained in the section of the report: AA for Part A, BB for Part B, and  so  forth.  If  all  of  the  observed  data  is  routinely distributed  as  a  single  message,  such  as  the  CODAR report, the M_jM_j is encoded XX. The first group of the coded report also contains the observation time and the location  of  the  sounding. IDENTIFYING  OBSERVATION  TIME  AND LOCATION The   WMO   has   established   standard   times   for conducting  upper-air  observations:  they  are  the synoptic  hours  of  0000Z,  0600Z,  1200Z,  and  1800Z. Most  balloon  releases  actually  take  place  30  to  45 minutes  before  these  times  so  that  the  scheduled observation time actually occurs near the middle of the observation. Because  of  time,  personnel,  and  budget considerations,   most   stations   do   not   conduct observations at each of the synoptic hours. If only two upper-air soundings are taken per day, they are taken at 0000Z  and  1200Z.  If  only  one  upper-air  sounding  is conducted,  it  is  taken  at  0000Z  or  1200Z,  whichever time  is  closest  to  local  sunrise. Reports of conditions measured during any of the various  upper-air  observations  are  normally  encoded  in WMO   international   codes   for   dissemination. International   upper-air   observation   reporting   codes were established by the WMO to allow all countries of the  world  to  exchange  data.  Because  there  are  many different  types  of  upper-air  observations  conducted each day, several similar codes are in use to efficiently report  the data collected. Table 1-7 shows the different types of upper-air observations conducted, the types of data observed and reported, and the WMO International code form used to format the report. Reports received in these codes are routinely used by  weather  personnel  for  routine  aviation  support, weather-forecasting  support,  and  as  input  for  TESS. Additionally, these observations provide primary input to the Navy’s environmental prediction system at the 1-20