Naval Oceanographic Office
Profiling Drifters

Table of Contents

  1. Introduction
  2. Automatic data processing & web-page generation
  3. Reliability statistics
  4. Argos Data Telemetry
  5. GTS publication of float profiles
  6. Contact Information
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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 Oct 30 00:17 GMT 2014.
Group Size Profiles Executed Profiles Expected Reliability (%)
APEX180 14 1180 8750 13.5
APEX260 72 10985 51237 21.4
APF7 14 1180 8750 13.5
APF8 72 10985 51237 21.4
Total 86 12165 59987 20.3

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

  1. 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.
  2. 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.

Naval Oceanographic Office Profiling Drifter ARGOS Receipt Statistics
As of 00:26 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 203 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 255 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 255 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 137 2 1.5% 10 51% 88 60 77% 28 23% 40 67% 20 33%
1221 255 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 37% 188 105 78% 83 22% 54 47% 51 53%
1628 232 2 0.9% 11 52% 156 106 71% 50 29% 78 73% 28 27%
1629 172 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 129 1 0.8% 10 46% 129 87 68% 42 32% 59 67% 28 33%
1773 252 9 3.6% 9 39% 105 66 64% 39 36% 41 61% 26 39%
1774 106 16 15.1% 10 34% 119 71 61% 48 39% 40 55% 31 45%
1775 14 1 7.1% 9 67% 114 93 82% 22 18% 75 81% 18 19%
1796 207 0 0.0% 13 66% 133 116 87% 17 13% 89 76% 27 24%
1797 256 0 0.0% 12 50% 136 96 72% 39 28% 67 69% 29 31%
1798 255 4 1.6% 10 46% 128 85 68% 43 32% 59 68% 27 32%
1799 256 2 0.8% 11 56% 149 110 74% 40 26% 83 75% 27 25%
1800 209 43 20.6% 12 41% 98 68 69% 31 31% 41 60% 27 40%
1801 258 3 1.2% 12 51% 160 110 71% 50 29% 79 72% 31 28%
1803 262 4 1.5% 10 55% 143 103 72% 39 28% 78 76% 25 24%
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 249 19 7.6% 9 39% 95 61 64% 35 36% 37 61% 23 39%
2099 249 18 7.2% 9 34% 108 64 60% 44 40% 37 56% 28 44%
2100 40 4 10.0% 7 51% 86 64 77% 21 23% 46 67% 19 33%
2101 407 21 5.2% 11 44% 138 93 67% 45 33% 62 66% 31 34%
2102 46 1 2.2% 11 45% 132 91 69% 41 31% 61 66% 31 34%
2103 428 15 3.5% 10 46% 116 82 71% 34 29% 53 65% 29 35%
2104 82 3 3.7% 11 43% 139 92 66% 47 34% 61 65% 32 35%
2105 256 12 4.7% 11 41% 136 89 65% 47 35% 56 62% 33 38%
2281 71 11 15.5% 11 38% 118 78 67% 40 33% 43 56% 35 44%
2882 17 4 23.5% 11 44% 136 91 66% 45 34% 60 66% 31 34%
2883 195 72 36.9% 12 35% 154 90 62% 64 38% 51 56% 39 44%
2884 256 8 3.1% 9 59% 96 74 76% 22 24% 58 77% 16 23%
2885 255 42 16.5% 12 48% 155 105 69% 50 31% 73 69% 33 31%
2886 143 73 51.0% 11 36% 119 73 63% 46 37% 41 56% 32 44%
2903 248 29 11.7% 8 37% 95 53 68% 41 32% 30 55% 24 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 226 41 18.1% 9 34% 118 67 61% 52 39% 38 57% 29 43%
Ensemble Average: 4.8% 10 52% 110 81 75% 29 21% 57 66% 24 30%
Standard Deviation: 9.4% 5 18% 45 34 18% 19 11% 27 18% 17 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.

  1. A profile that is older than 30 days will be rejected as required for GTS publication.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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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