Hokkaido University / University of Washington
Profiling Drifters
- Introduction
- Automatic data processing & web-page
generation
- Reliability statistics
- Argos Data Telemetry
- Deployment locations
for the Okhotsk Sea profiling drifters
- Contact Information
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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.
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.
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 |
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.
- 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.
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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