ships, aircraft, and submarines all use the same code. Surface  ships  and  some  aircraft  must  take  a  surface weather  observation  at  the  same  time  the  BT observation   is   made. As an Aerographer’s Mate, you will be required to encode  or  at  least  review  bathythermograph  data  for dissemination.  Besides  its  immediate  operational  use, BT  data  will  also  be  used  to  develop  oceanographic historical data bases. Therefore, it is imperative that a quality   control   check   be   conducted   prior   to transmission   of   the   data. Additional   information   on   conducting   and encoding  bathythermograph  observations  is  contained in  OPNAVINST  3141.1,  Collection  and  Reporting  of Bathythermograph  Observations,  and  in  NAVMET- OCCOMINST  3140.1,  United  States  Navy  Meteoro- logical and Oceanographic Support System Manual. The symbolic format of the BATHY code is shown in table 2-2. The  bathythermograph  code  is  sent  as  a  single message composed of four sections of data.  In table 2-2, groups in parenthesis are optional. Section 1 contains identification  data  and  may  contain  meteorological data;   section   2   contains   the   instrumentation   and recorder type, and the depth/temperature information; section   3   reports   water   depth   and   surface   current (optional);  and  section  4  is  the  ship  or  ocean  station identifier. IDENTIFICATION  DATA The  identification  data  section  contains  the mandatory  data  identifier;  the  year,  month,  and  day group;  the  actual  time  of  the  observation;  a  latitude  and longitude   group;   and   the   optional   wind   and   air temperature groups. The first group in section 1 is the data identifier, which is reported as "JJYY" for all ship, aircraft, and submarine BATHY observations. A  group  not  seen  in  many  other  codes  is  the YYMMJ. The YY is the UTC day of the month, while Table 2-2.—Symbolic Format of WMO Code FM 63-X BATHY MM is the month in two digits, and J is the last digit of the  year.  For  example,  "JJYY  22037"  indicates  that  a BATHY  observation  was  taken  on  the  22d  day  of March,   1997. The  time  of  the  observation  is  encoded  in  group GGgg/  in  UTC.  The  GG  is  the  hour,  and  gg  is  the minutes  after  the  hour.  When  the  code  is  transmitted with  depth  and  temperature  reported  in  metric  units (meters and degrees Celsius), the time is followed by a slant. If the operator is unable to convert observations from English units to metric units, the slant is changed to a 9. Navy bathythermograph operators will normally convert   from   English   to   metric   units. The  latitude  and  longitude  of  the  observation  are reported in two groups, Q_cL_aL_aL_aL_a and L_OL_OL_OL_OL_o. The Q_c is the quadrant of the globe using WMO code table 3333 (see appendix III); L_aL_aL_aL_a is the latitude in degrees and minutes; and L_oL_oL_oL_oL_o is the longitude in degrees and minutes. This is the only code routinely used that reports latitudes and longitudes in degrees and minutes.  All of the other codes report in degrees and tenths of a degree. The  optional  wind  group,  i_uddff,  is  reported  by most  surface  ships,  but  need  not  be  reported  by submarines   and   aircraft.   The   group   starts   with   an indicator for wind speed, i_u, found in WMO code table 1853. This is not the same indicator used for wind speed in the land and ship Synoptic codes (WMO Code 1855). Navy  ships  use  only  code  figure  3  to  indicate  winds measured  in  knots  in  the  bathythermograph  code.  Wind direction is reported in hundreds and tens of degrees in dd, and speed is reported to the nearest whole knot in ff. NOTE:  Instructions  accompanying  the  log  sheet state that i_u should be encoded as a "0" (wind speed in meters)  or  a  "1"  (wind  speed  in  knots).  In  the  coded message,  only  a  "3"  (uncertified  wind  measuring instruments used) should be encoded as the first digit of the  wind  group. SECTION CODE  FORM 1 JJYY  YYMMJ  GGgg/  or  (GGgg9)  Q_cL_aL_aL_aL_a L_oL_oL_oL_oL_o (I_uddff) (4s_nTTT) 2 8888Kj I_XI_XI_XX_RX_R Z_OZ_OT_OT_OT_O . . . . . Z_nZ_nT_nT_nT_n 999zz   Z_nZ_nT_nT_nT_n (ooooo) 3 (66666  1Z_dZ_dZ_dZ_d  k₅D_cD_cV_cV_c) 4 D. . . .D or 99999 A₁b_wn_bn_bn_b Ships  should  also  report  the  optional  outside  air temperature in group 4s_nTTT. The 4 is the temperature indicator; s_n is the temperature sign (0 for positive or zero, and 1 for negative temperatures); and TTT is the air temperature to the nearest tenth degree, usually in degrees   Celsius. This   group   is   not   reported   by submarines and aircraft. Shipboard  bathythermograph  operators  should report both wind and air temperature, and insert these code groups between data groups 5 and 6 on the form. 2-15