Since  all  observations  are  entered  into  the  climatic  data base, errors on the observation form should be corrected even if discovered too late to provide timely and accurate information to aircraft and ships. You should correct errors in the following three ways: If an error has not been transmitted, erase and reenter data correctly. If an error is discovered after transmission, line out the error, enter the correction in red, transmit the correct data, and then enter the correction time, which is the time of transmission of the corrected  data. If an error has been transmitted but superseded with a later observation, simply line out and enter the correction in red. See  NAVMETOCCOMINST  3141.2  or NAVMETOCCOMINST 3144.1 for additional details on entering corrected data. To help reduce errors, all data  should  be  reviewed  by  another  qualified  observer. Most sites have an established quality control person who  routinely  reviews  the  observation  forms.  Other than the observer, the quality control person is the only individual who may be authorized to make corrections to an observation record. MAILING OF RECORDS At the end of each month, the original observation forms   are   forwarded   to   the   Fleet   Numerical Meteorology   and   Oceanography   Detachment, Asheville, North Carolina. Refer to NAVMETOC- COMINST  3141.2  or  NAVMETOCCOMINST  3144.1 for detailed information on mailing observation forms. Additional  information  is  also  contained  in NAVMETOCCOMINST  3140.1,   U.S.  Navy Meteorological and Oceanographic Support System Manual,  and  FNMODASHEVILLENOTE  3140, Procedures for Submitting Meteorological Records. The observation forms are microfiched at Asheville, and the information is included in the National Climatic Records data base. Duplicate copies of the observation forms may be retained on board until no longer needed; however, most sites retain the duplicate copies for at least 1 year. After recording the observation, it must be encoded for  local  and/or  longline  (regional  or  national) dissemination. In the next section, we will discuss the codes used for dissemination purposes. REVIEW QUESTIONS Q6. How  should  missing  data  be  indicated  on observation  forms? Q7. What is the primary purpose of collecting and transmitting  weather  data? Q8.   How is an observation error corrected on an observation form after the observation has been transmitted? Q9. Where are observation forms mailed at the end of each month? SURFACE AVIATION WEATHER – METAR/SPECI  CODE LEARNING  OBJECTIVES:  Identify  the applications of the format of the METAR and SPECI codes. Describe the elements of the METAR and SPECI codes and define the meaning of each element. The METAR code is an International Observation code used to record and disseminate routine surface aviation weather observations. The SPECI code is a related  International  code  used  to  record  and disseminate  selected  surface  aviation  weather observations  marking  significant  changes  in  the weather conditions. It is used to supplement the hourly observations in the METAR code. The METAR and SPECI codes discussed in this section are used by all Navy and Marine Corps activities worldwide and are a modified version of the WMO METAR and SPECI codes used by most of the other countries in the world. As  previously  mentioned,  the  primary  reference manuals for Navy and Marine Corps activities are NAVMETOCCOMINST 3141.2 and NAVMETOC- COMINST 3144.1. You, as an observer, must be thoroughly  familiar  with  these  instructions.  We  will now discuss the encoding of the individual elements of a METAR  observation. TYPES OF OBSERVATIONS In  METAR,  there  are  only  two  types  of observations: Routine  observations  (METAR)—routine observations,  taken  each  hour  on  the  hour.  The observation time is noted when the last element was 3-5