Naval Oceanographic Office Profiling Drifters

Naval Oceanographic Office
Profiling Drifters

Introduction
Automatic data processing & web-page generation
Reliability statistics
Argos Data Telemetry
GTS publication of float profiles
Contact Information

Introduction

Welcome to the Web Site for the Naval Oceanographic Office profiling drifter study.

Automatic data processing, data distribution, & web-pages generation

This web site contains thousands of dynamic objects that must be updated as new data become available. Examples include postscript files, jpeg images, tables, HTML files, hydrographic profile data, and data distribution services. These objects are automatically generated or maintained in quasi-real-time by an extensible system of autonomous software. Consequently, maintaining this web site requires no regular manual intervention.

Reliability Statistics

The reliability of the floats can be measured in terms of the number of profiles expected during a specified time period as compared to the number actually executed. These statistics are presented in the following table (updated daily).

Profiling Drifter Reliability

Profiler Reliability Statistics for the period from Jan 01 00:01 GMT 2000 to Sep 05 00:08 GMT 2018.
Group	Size	Profiles Executed	Profiles Expected	Reliability (%)
APEX180	14	1180	8750	13.5
APEX260	72	10985	52488	20.9
APF7	14	1180	8750	13.5
APF8	72	10985	52488	20.9
Total	86	12165	61238	19.9

Note: Floats 341 and 356 have been excluded from the above statistics for the following reasons:

The deployment parachute for float 341 was observed to prematurely detach (in mid-air) from the instrument. The float failed to execute its first profile and is presumed to have been destroyed on impact with the water. Since the failure of this instrument is known to be unrelated to instrument reliability then this float has been excluded from calculations of reliability statistics.
The deployment vehicle for float 356 was observed to prematurely (in mid-air) separate from the instrument. The float failed to execute its first profile and is presumed to have been destroyed on impact with the water. Since the failure of this instrument is known to be unrelated to instrument reliability then this float has been excluded from calculations of reliability statistics.

Argos Data Telemetry

The data are recovered from the floats via the Argos system. These floats spend 7 to 8 hours transmitting on the surface with one message transmitted every 46 to 54 seconds. This means that each float transmits from 470 to 530 messages for each profile. Most of these transmissions are lost because no satellite happens to be overhead. In fact, telemetry statistics below show that only 7 to 10 percent of these messages are transmitted when a satellite is overhead. Some statistics have wider appeal and we have collected several of them in the table below (updated daily). All of these statistics were computed on a per-profile basis.

Float Id: A unique 3 digit identifier assigned to each float.
Number of Profiles: The number of profiles the float has executed so far.
Incomplete Profiles: The number of profiles that have an incomplete Argos message set. This condition results in a missing segment of data in the profile plots. The accompanying percentage gives the ratio of the Incomplete Profiles to the Number of Profiles.
Satellite Passes: The average number of times that a satellite passed overhead while the float was on the surface.
Messages Expected: This is the average number of messages that should have been received when satellites were overhead. If two or more satellites are overhead simultaneously then each transmission was multiply-counted. The number of messages expected for a given satellite pass is determined from the Argos data stream by counting the number of messages received and adding the number of messages missing. Due to averaging and rounding effects, these entries in the table below may not add up exactly.
Messages Received: This is the average number of messages that were actually received by satellites (without regard to the CRC check). The accompanying percentage gives the average ratio of the messages received to the messages expected.
Messages Missing: This is the average number of messages that were transmitted while a given satellite was overhead but that were not received by the satellite. These are detected in the Argos data stream by gaps in time and message number. The accompanying percentage gives the average ratio of the messages missing to the messages expected.
Good Messages: This is the average number of messages received that passed the CRC check. The accompanying percentage gives the average ratio of the good messages to the messages received.
Bad Messages: This is the average number of messages received that failed the CRC check. The accompanying percentage gives the average ratio of the bad messages to the messages received.
Telemetric Efficiency: This measures the average rate of successful transmission when satellites are overhead. It is the average ratio of the number of good messages to the number of messages expected.

Naval Oceanographic Office Profiling Drifter ARGOS Receipt Statistics

As of 00:41 GMT on Sep 09, 2010				Average Per-Profile Statistics for ARGOS Data Telemetry
Float Id	Profiles Executed	Incomplete Profiles		Satellite Passes	Telemetric Efficiency	Messages Expected	Messages Received		Messages Missing		Good Messages		Bad Messages
0339	7	0	0.0%	2	63%	27	23	85%	4	15%	17	75%	5	25%
0340	28	1	3.6%	4	67%	56	48	85%	8	15%	38	79%	10	21%
0341	1	0	0.0%	1	0%	1	1	100%	0	0%	0	0%	1	100%
0342	112	2	1.8%	6	55%	79	50	75%	29	25%	37	74%	13	26%
0343	59	2	3.4%	6	61%	76	61	83%	15	17%	45	74%	15	26%
0350	1	0	0.0%	3	42%	24	24	100%	0	0%	10	42%	14	58%
0351	24	0	0.0%	8	64%	107	91	86%	15	14%	68	74%	24	26%
0352	125	0	0.0%	8	65%	102	85	84%	17	16%	66	77%	19	23%
0353	1	0	0.0%	1	91%	11	11	100%	0	0%	10	91%	1	9%
0354	105	0	0.0%	9	47%	107	82	76%	26	24%	51	62%	30	38%
0355	106	1	0.9%	10	38%	113	77	68%	37	32%	43	56%	34	44%
0356	1	0	0.0%	0	0%	0	0	0%	0	0%	0	0%	0	0%
0357	60	0	0.0%	8	36%	96	63	66%	33	34%	35	55%	28	45%
0358	92	3	3.3%	11	35%	126	75	60%	51	40%	45	59%	30	41%
0359	239	2	0.8%	14	55%	221	148	74%	73	26%	111	74%	37	26%
0360	233	2	0.9%	15	47%	203	133	69%	70	31%	93	68%	41	32%
0627	328	16	4.9%	11	38%	153	78	67%	75	33%	45	57%	33	43%
0628	141	2	1.4%	10	45%	108	81	75%	28	25%	49	60%	32	40%
0629	202	7	3.5%	10	44%	94	65	70%	28	30%	40	62%	25	38%
0630	372	2	0.5%	11	48%	126	94	76%	32	24%	60	64%	34	36%
0672	146	0	0.0%	8	77%	122	107	88%	14	12%	93	87%	14	13%
0673	334	0	0.0%	8	72%	124	107	86%	17	14%	89	83%	18	17%
0674	10	0	0.0%	8	68%	102	94	92%	7	8%	74	74%	21	26%
0675	1	0	0.0%	1	67%	3	3	100%	0	0%	2	67%	1	33%
0676	1	0	0.0%	1	92%	13	13	100%	0	0%	12	92%	1	8%
0677	1	0	0.0%	0	0%	0	0	0%	0	0%	0	0%	0	0%
0678	202	0	0.0%	9	73%	122	107	88%	15	12%	89	83%	18	17%
0680	48	0	0.0%	9	66%	123	103	85%	19	15%	81	78%	22	22%
0681	218	0	0.0%	9	70%	125	109	87%	16	13%	88	81%	21	19%
0682	152	2	1.3%	8	68%	75	60	91%	16	9%	47	75%	12	25%
0683	390	0	0.0%	9	67%	137	115	84%	22	16%	91	79%	24	21%
0684	450	1	0.2%	9	66%	135	107	82%	28	18%	86	80%	21	20%
0685	313	1	0.3%	9	72%	123	104	88%	18	12%	86	82%	18	18%
0702	92	1	1.1%	10	47%	111	83	75%	28	25%	52	63%	31	37%
0703	69	0	0.0%	8	55%	79	60	83%	18	17%	40	66%	20	34%
0704	65	1	1.5%	10	54%	110	84	76%	26	24%	60	71%	24	29%
0706	52	0	0.0%	10	49%	110	85	77%	25	23%	55	63%	30	37%
0720	53	0	0.0%	9	49%	91	67	73%	24	27%	46	67%	21	33%
0884	56	2	3.6%	14	64%	218	152	81%	66	19%	120	79%	32	21%
0954	26	0	0.0%	10	75%	132	117	88%	15	12%	99	85%	18	15%
0955	307	1	0.3%	10	70%	138	117	85%	21	15%	96	82%	21	18%
0956	159	0	0.0%	10	71%	128	110	87%	17	13%	90	82%	20	18%
1069	254	8	3.1%	10	50%	84	63	75%	21	25%	41	66%	21	34%
1070	5	2	40.0%	7	44%	55	38	74%	17	26%	23	58%	15	42%
1071	122	6	4.9%	11	49%	94	71	76%	23	24%	46	65%	25	35%
1072	254	4	1.6%	10	47%	72	52	82%	20	18%	31	58%	20	42%
1073	153	3	2.0%	11	50%	121	76	76%	46	24%	50	65%	25	35%
1131	255	0	0.0%	9	69%	121	104	86%	17	14%	83	80%	21	20%
1132	254	1	0.4%	9	66%	120	102	85%	18	15%	79	77%	23	23%
1133	140	1	0.7%	11	72%	175	118	89%	57	11%	96	81%	22	19%
1134	97	0	0.0%	11	74%	133	117	88%	15	12%	98	84%	19	16%
1135	179	0	0.0%	9	68%	122	105	86%	17	14%	82	78%	23	22%
1136	59	0	0.0%	10	75%	137	121	88%	16	12%	103	85%	18	15%
1137	255	2	0.8%	8	63%	108	88	82%	20	18%	68	77%	21	23%
1138	17	0	0.0%	8	80%	98	91	94%	7	6%	78	85%	13	15%
1213	3	1	33.3%	10	54%	114	92	67%	22	33%	78	74%	15	26%
1214	241	0	0.0%	14	62%	177	145	82%	32	18%	111	76%	34	24%
1220	136	2	1.5%	10	51%	88	60	77%	28	23%	40	67%	20	33%
1221	254	11	4.3%	10	45%	89	62	72%	27	28%	39	62%	23	38%
1222	80	0	0.0%	11	54%	94	72	77%	22	23%	51	70%	22	30%
1223	71	0	0.0%	11	58%	90	74	82%	17	18%	53	71%	21	29%
1224	255	1	0.4%	8	70%	116	99	86%	17	14%	80	81%	19	19%
1225	1	0	0.0%	4	83%	60	60	100%	0	0%	50	83%	10	17%
1269	255	0	0.0%	8	72%	111	96	86%	15	14%	80	83%	16	17%
1283	106	0	0.0%	9	63%	112	98	88%	14	12%	70	72%	28	28%
1284	50	0	0.0%	9	49%	118	84	71%	34	29%	56	68%	27	32%
1293	10	0	0.0%	10	74%	123	110	90%	13	10%	90	82%	20	18%
1319	55	0	0.0%	9	49%	116	80	70%	36	30%	55	69%	25	31%
1501	31	0	0.0%	12	46%	102	81	80%	21	20%	47	57%	35	43%
1502	59	2	3.4%	49	23%	231	213	90%	18	10%	36	26%	177	74%
1503	71	0	0.0%	11	49%	86	67	79%	18	21%	42	62%	26	38%
1504	6	1	16.7%	15	60%	114	92	84%	22	16%	66	72%	26	28%
1505	18	2	11.1%	29	30%	198	105	78%	93	22%	54	40%	51	60%
1628	231	2	0.9%	11	52%	156	106	71%	50	29%	78	73%	28	27%
1629	171	1	0.6%	10	56%	134	99	74%	36	26%	75	76%	24	24%
1771	14	1	7.1%	7	56%	180	77	74%	103	26%	58	75%	20	25%
1772	128	1	0.8%	10	46%	129	87	68%	42	32%	59	67%	28	33%
1773	216	8	3.7%	9	39%	108	68	63%	40	37%	42	61%	27	39%
1774	106	16	15.1%	10	34%	119	71	61%	48	39%	40	55%	31	45%
1775	14	1	7.1%	10	66%	129	100	81%	29	19%	81	82%	19	18%
1796	206	0	0.0%	13	66%	133	116	87%	17	13%	89	76%	27	24%
1797	254	0	0.0%	12	50%	135	96	72%	39	28%	67	69%	29	31%
1798	255	5	2.0%	10	46%	128	85	68%	43	32%	58	68%	27	32%
1799	255	2	0.8%	11	56%	149	110	74%	40	26%	83	75%	27	25%
1800	207	43	20.8%	12	40%	114	72	66%	42	34%	44	60%	29	40%
1801	258	3	1.2%	15	49%	219	139	69%	80	31%	100	71%	39	29%
1803	262	3	1.1%	13	51%	211	133	69%	78	31%	100	75%	32	25%
2096	55	0	0.0%	8	58%	111	83	76%	28	24%	64	77%	19	23%
2097	41	2	4.9%	8	61%	144	82	76%	61	24%	66	80%	16	20%
2098	248	18	7.3%	9	39%	95	61	64%	35	36%	37	61%	23	39%
2099	245	18	7.3%	9	34%	109	65	60%	44	40%	37	56%	28	44%
2100	40	4	10.0%	8	52%	115	81	74%	34	26%	57	70%	23	30%
2101	407	16	3.9%	14	42%	184	114	64%	70	36%	76	65%	38	35%
2102	46	1	2.2%	13	44%	182	114	66%	68	34%	76	66%	38	34%
2103	426	16	3.8%	13	43%	168	104	66%	64	34%	67	64%	37	36%
2104	82	3	3.7%	13	41%	188	115	63%	73	37%	75	64%	40	36%
2105	256	10	3.9%	14	39%	187	112	62%	74	38%	71	62%	41	38%
2281	71	10	14.1%	13	36%	158	93	65%	65	35%	51	55%	41	45%
2882	17	4	23.5%	12	41%	166	97	62%	69	38%	64	66%	32	34%
2883	195	71	36.4%	13	33%	191	97	59%	93	41%	55	55%	42	45%
2884	185	8	4.3%	10	57%	125	88	75%	37	25%	70	76%	18	24%
2885	254	42	16.5%	13	42%	210	120	63%	90	37%	82	67%	37	33%
2886	143	71	49.7%	11	34%	149	76	60%	73	40%	43	56%	33	44%
2903	226	29	12.8%	9	37%	100	56	67%	45	33%	31	55%	25	45%
2904	1	0	0.0%	0	0%	0	0	0%	0	0%	0	0%	0	0%
2905	209	53	25.4%	9	33%	117	67	60%	49	40%	37	55%	30	45%
2906	164	46	28.0%	9	33%	106	62	59%	44	41%	35	55%	28	45%
2907	1	0	0.0%	0	0%	0	0	0%	0	0%	0	0%	0	0%
2908	42	12	28.6%	8	30%	105	59	60%	47	40%	29	49%	30	51%
2909	192	37	19.3%	9	34%	116	68	61%	48	39%	38	56%	30	44%
3719	151	1	0.7%	15	47%	274	151	58%	123	42%	121	80%	29	20%
3899	54	2	3.7%	17	49%	318	193	62%	125	38%	155	80%	38	20%


Ensemble Average:			4.7%	10	52%	120	85	74%	34	22%	60	66%	25	30%
Standard Deviation:			9.3%	5	18%	55	37	18%	27	12%	29	18%	18	14%

Publication of Profiles to the Global Telecommunications System (GTS)

The profiles from these floats are published in quasi-real-time via the GTS system using TESAC/KKXX format. Each float is assigned a unique WMO identifer that can be found on our Present Status web page. The status of each profile with respect to GTS publication is also available on our GTS Status web page.

Quality control of profile data is managed automatically by a QC module that is integrated into the GTS publication software. Each profile must pass a number of quality control criteria in order to be published via GTS. If even a single observation in the profile violates any of the criteria then publication of the entire profile is inhibited. The following criteria are used to inhibit publication of rejected profiles.

A profile that is older than 30 days will be rejected as required for GTS publication.
A profile that does not have a valid location fix will be rejected as required for GTS publication. This might happen if ARGOS reception is poor.
A profile with a gap between adjacent observations that exceeds 300 decibars will be rejected. A profile with the shallowest observation deeper than 300 decibars will also be rejected. This is to maintain reasonable accuracy in the pressure to depth conversion calculation as required for GTS publication. This might happen if ARGOS reception is poor.
A profile with an observation where the pressure is reported to be less than zero or greater than 3000 decibars will be rejected as indicative of a pressure sensor problem or malfunction.
A profile with deepest observation less than 50 decibars is rejected. For example, this might happen if the float drifts into shallow water or becomes entangled in mats of surface-drifting seaweed.
A profile with pressures that are not monotonic will be rejected. This is intended as a general criterion that a properly collected profile should satisfy.
A profile with fewer than 5 observations will be rejected. This is intended as a general criterion that a properly collected profile should satisfy.

This list is exhaustive in the sense that any profiles that do not violate these criteria will be published via GTS. In the absence of established GTS quality control criteria, the approach of caveat emptor has been assumed with respect to the hydrographic data.

Contact Information: Please note that the data and material on this web site are the property of the Naval Oceanographic Office. Questions concerning the information available here can be addressed to the principal investigator, Dr. Charles Horton, (email: hortonc@navo.navy.mil).

This web site was developed and is maintained by Dana Swift (email:swift@ocean.washington.edu) of the University of Washington, Seattle, Washington.

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