Introduction.

Many people have many different ways of achieving different goals. Like the observers participating in the VOS programme, we are all prone to adapt to routine behavour. This enables us to achieve our aim with less effort, but dangers lure around the corners. Errors, once adopted, are hard to change. This goes especially for those errors that are not corrected in time, and are made over long periods of time. Unfortunately the PMO has only limited access to those that are making weather observations at sea. The occasional rendevous in port, is usually not long enough to go into lengthy detail about the quality of the observations. In many occasions it is not clear who is responsable for errors occuring in the observations. Promptly feedback is nessecary but costly in manpower and communication.

Therefor we tried to give a little more insight in the most commonly occuring errors that are made in Ships' observations format (Fm13). Although we have supplied our Dutch VOS fleet with Turbo program, many handmade observations still reach us through LES 12, Burum. It will take time to equip the entire VOS fleet with the Turbo program. In the mean time a lot of corrections have to be made in the manual observations.

The observations are sent to us from Burum (station 12) and automaticly checked. Common errors are corrected automaticly. If not, the PMO gets to see the erroneous nessages and he decides if this error is recurring (feedback to ship) or the error is just a mistake (no feedback to ship necessary).

The errors you will find here are all examples of obs's send to us. We changed the call signs, as these examples are for educational purposes only.

Obs's with text.

41

From: MV ERROR

To: Metoffice MyCountry

BBXX ERROR 10003 99354 70123 41/98 43024 10165 20129 40170
52005 70111 84/// 22243 00170 20504 330// 41008 80145

BRGDS

NNNN

On many occasions a layout is used from the Telex Over Radio period. The message starts with 41 as indication that this message was sent using special access code 41. The sender and receiver are in the header of the message. The message is not closed with character = (end of observation) but instead BRGDS is used to confirm the politeness of the master and his crew. Our automatic system can detect the obs from BBXX to =, but as no = character is found BRGDS is seen as erronous information and the observation is rejected.

It may be superfluous to state that all info, but from BBXX to =, is discarded of in the distribution of the obs. The correct format to transmit this obs should be:

BBXX ERROR 10003 99354 70123 41/98 43024 10165 20129 40170
52005 70111 84/// 22243 00170 20504 330// 41008 80145=

8 Bits Code Format.

Many vessels use the Amver Seas Program to make and distribute their observations. Although only LES's Aussaguel (FR) and Santa Paula and Southbury (USA) are equipped to deal with this information, many ships use this program to transmit their observation to other LES's in the region. The difficulty in receiving and handling observations made with this program lies in the fact that the code format generated by this program is in 8 bits format. We receive these observations from Burum (Station 12) in a format that we cannot read. We have no possiblity to convert the message from 8 bits to 7 or 5 bits, which we can handle.

Seas with Datanetnumber are solely to send to Santa Paula (201-POR), Aussaguel (121-AOR/E and 321-IOR) and Southbury (001-AOR/W and 101-AOR/E)

We are not sure how other LES's and Meteorological institutes tackle this issue, but we know for sure that many vessels transmit their weather observations this way.

If we come across an 8 bits coded message, the ship is contacted and asked either to change the code format or use a LES that can handle this type of messages.

This is an example of an 8 bits coded message received through Burum (station 12):

QkJYWCBVQ0FCIDAzMTIwIDk5Mjg1IDcwMzkwIDQxNTk4IDgwOTExIDEwMjEw

IDQwMTU5DQo1MzAwNyA3MjA1NSA4ODQ0KyAyMjI1MiAwMDE5MCAyMDcw

NSAzMTIwMCA9DQoNCg0KDQoNCg0KDQoNCg0KDQoNCg0KDQo=

Missing elements.

One of the most occuring errors is to leave out groups that are obligatory in ships obs FM13. One can leave out nearly all groups (BBXX ERROR 99100=) or leave out groups that are essential to the obs but have nothing to do with the weather (like BBXX, Callsign, time/date of the obs, position of the vessel, direction and speed of the vessel and the character = to end the message). These groups are essential, without them it is much harder to make use of the observation, it can even render the observation worthless.

On many occasions these errors are mistakes and are easily corrected by the observers themselves. If particular groups or elements are missing, the valuable meteorological information cannot be used.

Many observators tend to forget the obligatory groups 3//// 4//// 5//// at he end of the obs. As there is no more meteorological information to give in the observation, the tendency is to close it after the last group (2PwPwHwHw = group with Period and Height of wind waves).

Sometimes one encounters groups that are not allowed (like 6//// giving amount of rainfall) or groups that have a national background and are not recognized. Please find the missing element in this obs:

BBXX ERROR 10004 99223 70192 /2698 10618 10222 20182 40205 54005
70100 81008 02222 20201 33204 40603 50403 80195= (see wrong content for solution)

 

Wrong content

Often messages that are no weather observation at all, are send to LES's using special access code 41. AMVER is one of the most erroneously sent message that are received at our Meteorological Institute. Most likely this has to do with the conjuncture in AMVER Seas program (see 8 bits code), where weather observations and teh AMVER message are transmitted to the same address using the same program. Observers should be careful where to, and in what format they send their observations. Check if the LES you use is capable to handle the format that you use. One hazardous thing is the fact that it is not at all clear which LES's are capable and authorized to handle special access code 41. Repeatedly the Inmarsat providers are asked to be more transparant in this case but to no avail as yet. To make things more complicated, not all LES's use standard format 41. Notably Eik (NO) uses code 61 as special access code for ships observations.

All types of messages reach our desks. Often messages from the captain to their offices or to shiphandlers, sometimes quite private messages that are sent using special access code 41. In some occasions the message is forwarded when the importance is evident.

Besides the miscommunication, the element of costs also takes effect. All messages sent by special access code 41 are paid by the receiving national meteorological service. In order to keep our costs limited we encourage observers to be cautious with the use of code 41. Their message may not reach it's destination and we have to pay for information that we do not want.

(answer to question missing elements: group 222DsVs is missing!)

Common errors.

Common errors are:

Groups contain 4 or 6 digits where 5 are allowed.

++ or \\ are given when // should be used.

Date/time: 24 hours the same day should be 00 hours the next (23241 => 24001)

Windindicator (0,1,3 or 4) contains non existing number (2, 5, etc).

Groups carry the wrong identification number

Sometimes 2 observation are given in one message (bulletin). Please do seperate the observations and send them separately. This way old observations are valuable for climatological purposes. Two observations in one message are not recognized as a proper message and both of them will be rejected.