VOS Communications Problems and Errors World Meteorological OrganizationIntergovernmental Oceanographic Commission of UNESCO Ship Observations Team ~ integrating and coordinating international ship-based observing programmes for JCOMM ~ SOT-IV April 2007, Geneva, Switzerland Sarah North

Page 2© Crown copyright 2007 SOT IV - VOS Communications Problems and Errors This report addresses coding and transmission errors that have been noted for observations sent via Goonhilly Inmarsat LES Approx 300 observations each month are being rejected by the Met Office’s observation handling software Manual intervention is possible to correct some of these coding errors. However, because resources are limited, many of these errors are not followed up. It is understood that similar coding and transmission problems are being encountered by other NMS that host Inmarsat LES

Page 3© Crown copyright 2007  BBXX or call sign not included in message.  Empty transmissions with no data.  Using 4 figure dew point groups.  Sending phenomena reports or other general messages via Special Access Code 41  Variable group lengths – e.g a 6 figure longitude group, and other 1,2,3,4 and 10 figure groups  Using /’s between groups  Late date/time groups.  Use of O instead of 0  Using 6 figure date/time group – reporting month, day and hour, and omitting the wind indicator.  Using 7 figure date/time group, possibly month being added to beginning of group.  Message sent in Hex with no BBXX.  Adding an extra space in one of the 5 figure groups  Using 6 and 4 figure groups and missing temperature and dew point group  Putting in 6 figure groups (mainly extra / in the 8 group)  Missing out a space between 7 and 8 groups and adding a space in the 8 group (e.g ///).  Messages being received as 10 figure groups.  Invalid KKKK group added at end of message. SOT IV - VOS Communications Problems and Errors Typical rejections …

Page 4© Crown copyright 2007 Number & Percentage of Rejections November 2006 and January 2007 SOT IV - VOS Communications Problems and Errors

Page 5© Crown copyright 2007  Quality controls in electronic logbooks (TurboWin, SEAS etc) will increasingly help to reduce the problem  Whilst we have an abundance of monitoring feedback systems for observation quality problems, there is no formal mechanism for feeding back coding or transmission errors to PMOs or observers  Subject to resources, NMS could perhaps issue details of errors via the PMO and VOS mailing lists run by JCOMMOPS  Some NMS may be able to establish data processing software systems to automatically relay rejected messages back to the VOS focal points What can be done to resolve this ongoing problem? … SOT IV - VOS Communications Problems and Errors SOT to provide guidance, as appropriate…