Hokkaido University / University of Washington
Profiling Drifters

Table of Contents

  1. Introduction
  2. Automatic data processing & web-page generation
  3. Reliability statistics
  4. Argos Data Telemetry
  5. Deployment locations for the Okhotsk Sea profiling drifters
  6. Contact Information
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Introduction

This site contains data from an international program to explore the Okhotsk Sea, sponsored jointly by Japan, Russia, and the US. Most of the profiling floats shown on this site (numbers 280-283) are Japanese floats that were prepared at the University of Washington in the US. One of the floats (number 226) is a US float prepared at UW and deployed in the Japan Sea as part of the US Japan/East Sea initiative. All of these floats were deployed from the Russian research vessel Professor Khromov, operated by the Far East Regional Hydrometeorological Research Institute in Vladivostok, Russia. Web support for these floats is provided by the University of Washington. We are grateful to the National Science Foundation and the Office of Naval Research in the US, and to the Science and Technology Agency and CREST in Japan for providing support for this project.

This project is designed to examine the circulation of the Okhotsk Sea, its interaction with the climate of the Northwest Pacific region, and the effect of the Okhotsk Sea on circulation and water masses of the North Pacific Ocean. As part of this project three cruises were conducted jointly by Japan, Russia, and the US using the Professor Khromov, in 1998, 1999, and 2000. During these cruises CTD data were obtained at a large number of stations in the Okhotsk Sea, moored data were collected from nearly 20 sites, and chemical tracer and meteorological data were obtained. The four Japanese profiling drifters shown on this site were deployed during the June 2000 cruise of the Professor Khromov, for the purpose of examining the flow of dense water, produced on the northwest Okhotsk shelf in winter, in the East Sakhalin Current. It is hoped that the data from these floats will show the pathways of this water, thought to potentially be the source waters of North Pacific Intermediate Water, between the northern Okhotsk Sea and the N. Pacific Ocean. The US float was deployed in the Japan Sea in August of 1999, and some profiles from the US float can also be found on the US Japan/East Sea Profiling Drifter web site.

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 Dec 11 12:01 GMT 1999 to Mar 27 12:03 GMT 2009.
Group Size Profiles Executed Profiles Expected Reliability (%)
APEX260 17 1324 2073 63.9
APF5 4 190 288 66.0
APF8 14 1145 1734 66.0
APF9 3 179 339 52.8
Apf9a 1 21 145 14.5
Apf9i 2 158 194 81.4
Lithium 2 158 194 81.4
R1 4 190 288 66.0
Total 21 1514 2361 64.1

Argos Data Telemetry

The data are recovered from the floats via the Argos system. These floats spend 9.5 hours transmitting on the surface with one message transmitted every 84-90 seconds. This means that each float transmits from 380 to 410 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.

Hokkaido University / University of Washington Profiling Drifter ARGOS Receipt Statistics
As of 12:02 GMT on Sep 04, 2018 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
0280 19 0 0.0% 8 78% 62 57 92% 5 8% 49 84% 8 16%
0281 153 5 3.3% 7 74% 54 43 87% 11 13% 37 84% 7 16%
0282 119 13 10.9% 8 70% 53 45 86% 7 14% 37 82% 8 18%
0283 48 2 4.2% 5 81% 36 34 93% 3 7% 29 87% 4 13%
0655 56 0 0.0% 15 58% 120 96 80% 24 20% 71 72% 26 28%
0656 228 8 3.5% 12 62% 97 78 80% 19 20% 60 76% 18 24%
0657 34 0 0.0% 16 65% 114 94 82% 20 18% 74 78% 20 22%
0658 154 4 2.6% 9 64% 85 70 82% 15 18% 55 78% 15 22%
0659 66 1 1.5% 12 64% 99 80 83% 18 17% 61 76% 20 24%
0660 199 2 1.0% 14 63% 141 106 81% 35 19% 83 78% 23 22%
0661 214 3 1.4% 19 65% 149 122 82% 27 18% 97 79% 24 21%
0869 30 2 6.7% 14 63% 149 119 80% 30 20% 97 80% 22 20%
0870 164 5 3.0% 13 64% 136 109 80% 26 20% 87 80% 22 20%
0871 181 2 1.1% 15 57% 152 118 77% 34 23% 88 74% 29 26%
0968 26 4 15.4% 16 54% 321 135 72% 187 28% 101 74% 34 26%
0969 48 0 0.0% 17 65% 267 214 81% 52 19% 171 80% 44 20%
0970 71 0 0.0% 17 63% 251 197 79% 54 21% 158 80% 39 20%
0971 57 2 3.5% 15 57% 164 124 75% 40 25% 94 76% 30 24%
Ensemble Average: 3.2% 13 65% 136 102 82% 34 18% 81 79% 22 21%
Standard Deviation: 4.1% 4 7% 77 48 5% 41 5% 38 4% 11 4%

Contact Information: Please note that the data and material on this web site should not be used or quoted without the permission of the principal investigators. Questions concerning the information available here can be addressed to Professor Masaaki Wakatsuchi of Hokkaido University, (email: masaakiw@soya.lowtem.hokudai.ac.jp).

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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