JOINT ARCHIVE FOR SEA
LEVEL
DATA REPORT: May 2007
By
Mr. Patrick C. Caldwell
National Coastal
National Oceanographic
World Data Center-Silver Spring, Oceanography,
National Environmental Satellite Data and Information Service,
National Oceanic and Atmospheric Administration
and
Dr. Mark A. Merrifield
and Technology,
Joint Institute for Marine and
Atmospheric Research, and
University of
JIMAR CONTRIBUTION NO.
07-365
DATA REPORT NO. 20
Abstract
The Joint Archive for Sea Level (JASL) is a collaboration between the University of Hawaii Sea Level
Center (UHSLC) and the World Data Center-Silver Spring (WDC-SS) for
Oceanography, which is co-located at the US National Oceanographic Data Center.
The JASL is based at the UHSLC and grew
out of the need for data management support of the Tropical Ocean Global Atmosphere
(TOGA) Sea Level Center, founded by Dr. Klaus Wyrtki in 1985 at the
Contents
Page
1 HISTORY 4
2 DATA
HOLDINGS MARCH 2007 6
3 DATA
REQUESTS 13
3.1 Anonymous FTP
3.2 World Wide Web
3.3 Sea Level CDROM
3.4 Direct Requests
ACKNOWLEDGEMENTS 16
REFERENCES 16
APPENDICES 17
A
STATION LISTS
A.1 2007 Submission
to the
A.2 New Series
A.3. Updated Series
A.4. Series
with 2005 Data
A.5 Series Extended Backwards
A.6. Replaced
Years within Series
B
ORIGINATORS 33
1 HISTORY
Over the past few decades, the scientific
community has become increasingly interested in the predictability of climate. Consequently, the World Climate Research
Programme (WCRP) was created by the World Meteorological Organization (WMO) and
the International Council of Scientific Unions (ICSU) with the objective to
determine the extent of climate predictability and of man's influence on
climate.
A key activity of the WCRP in the 1980s was
the Tropical Ocean Global Atmosphere (TOGA) Project, which was organized with
the joint support of the ICSU's Scientific Committee on Oceanic Research (SCOR)
and the Intergovernmental Oceanographic Commission (IOC) of UNESCO. A major component of the plan was to monitor
the global atmosphere and the upper layers of the three tropical oceans during
the ten-year period of 1985-1994. Existing meteorological and oceanographic
observation systems
were maintained and new networks were installed. These observations along with available
historical data have provided a description of the ocean-climate system and its
variability from sub-seasonal to inter-annual scales and have served as the
basis for studies of oceanic and atmospheric dynamics and for model input and
verification. A
secondary goal was to encourage the continuation of an indefinite observational
oceanic and atmospheric monitoring system.
An important parameter of the ocean
monitoring system is sea level. The TOGA
program required daily sea level values with an accuracy of 2 cm. Sea level measurements have been made
throughout the world by various national agencies, local ports authorities, and
research organizations, but a centralized archive of daily data did not exist. In order to concentrate the efforts of
acquiring, processing, and archiving the sea level data, the
The UH pursued the duel responsibilities of
maintaining a large sea level network and serving as a scientific data center. In the late 1980s, the UH increased the number
of sites in the Pacific and expanded into the
The UHSLC presently operates the Joint
WMO/IOC Commission for Oceanography and Marine Meteorology (JCOMM) Sea Level
Program in the Pacific and the GLOSS `Fast-Delivery'
As the quantity of data collected by the
TOGA SLC increased during the mid 1980s, assistance with data management was
provided by the United States (US) National Oceanographic Data Center (NODC), co-located
with the World Data Center-Silver Spring (WDC-SS) for Oceanography, with the establishment in
1987 of the Joint Archive for Sea Level (JASL) at the UH. The JASL supplements the UHSLC with
acquisition, quality review, data documentation, and archival of sea level
values from contributing agencies. The
proximity of JASL staff to the sea level experts at UH ensures a research data
set of the highest quality, while the NODC lends its skills in data management
to aid in timely turnaround of concise, standardized, well-documented data to
the scientific community. The JASL is
the primary avenue of acquisition of finalized data sets and annually requests
data contributions from agencies around the globe. The JASL promotes the creation of high quality
data sets by offering a sea level processing package (
The first seven years of the TOGA SLC were
dedicated to collection of data from the Pacific and
operate and most of the collaborative agencies continue to provide sea level
data on a regular basis. Over the past
decade, the JASL has requested finalized, quality-controlled hourly data from
agencies which maintain gauges at oceanographically important high latitude
sites, such as those of the WOCE, CLIVAR, or GLOSS networks. Many of these sites have served as ground
truth stations for the joint US/France TOPEX/POSEIDON altimetry program (Mitchum,
1994) and continue to serve on follow-up altimeter missions. The JASL has also
focused attention on data rescue by obtaining paper records, overseeing the
digitization, and performing quality control (
This data report describes the present data
holdings at the JASL and highlights new and updated series. Methods of acquisition,
quality control, and assessment have been documented (Caldwell and Kilonsky,
1992; Kilonsky and Caldwell, 1991) and will not be elaborated upon in this
text.
Figure 1. As of May 2007, 558 series have been
contributed to the JASL from over 60 agencies representing over 70 countries.
The symbols note the May 2007 status relative to March 2006.
2 DATA HOLDINGS MAY 2007
The JASL prepares scientifically valid data
sets of hourly, daily, and monthly values which are submitted annually to international
data banks and are made readily available in a more timely fashion through the Internet.
As of May 2007, 558 series with 11,460 series-years (Appendix A.1) of quality-assured
data have been submitted to the WDC-SS, US NODC, the Permanent Service for Mean
Sea Level (PSMSL), and the CLIVAR `Delayed-Mode'
Center (BODC).
Over the past year, 18 new series with 373
series-years (Appendix A.2) have been added to the JASL. The locations are depicted as blue triangles
in Figure 1. New series were made
available in
Figure 2. Cumulative site-years by
ocean depicting growth of the data holdings. The total holdings have increased by 8% relative to 2006.
Over the past year, the JASL updated 156
existing series with 438 site-years (Figure 1 and Appendix A.3), which includes
91 site-years extended backwards and 347 site-years forward in time. The JASL
set now includes 161 series with 2005 data and 49 with 2006 (Appendix A.4). Most of these are affiliated with the GLOSS
Fast-Delivery System of the UHSLC. Since
March 2006, the total number of new and updated site-years in the archive has
increased by 8% (Figure 2).
In support of the GLOSS, which presently consists
of 290 Core Network stations, the JASL added 12 sites since 2006 bringing the
total GLOSS holdings to 232, or 80% of the total. This increases the GLOSS holdings to 6,870 station-years. Of the 171 stations identified in the Global
Climate Observing System (GCOS), the JASL presently holds 141 sites, or 83%. The
abundance of data is possible through the generous contributions of over 60
agencies representing over 70 countries (Appendix B).
The meridional distribution of the data
holdings is shown in Figure 3 which depicts the highest concentration of sites
in the northern hemisphere. Since 2006, updates were made in most latitudinal
zones. Historically the holdings at the JASL focused on the tropics and subtropics
as a reflection of the TOGA program. Since
1995, holdings at high latitude stations have steadily increased as WOCE
stations were received, GLOSS sites were sought, and NOAA-NOS continental
locations were acquired. Since 2006, the
largest increase of new sites and years is in Europe (Appendix A.2), explicitly
in
The spatial distribution by site of the
series lengths is depicted in Figure 4. This shows the excellent space and time
coverage of the tropical Pacific, the Japanese and Chinese coasts, and selected
sites in South, Central, and
The series are of variable length (Figure 4)
with the greatest concentration between 5 to 15 years (Figure 5). However, the number
of series with records longer than 30 years has expanded to 115, while 31 sites
have series greater than 60 years. Most of the longest series are from the
NOAA-NOS continental
Figure 3. Distribution
of site-years by latitude and growth relative to March 2006.
Figure 4. Lengths
of the time series as of May 2007. The size of the circle represents the
length of the series. The majority of the record lengths are between 5 and 15
years.
The temporal coverage of the sea level
records is depicted well in Figure 6. This shows the dominance of data
availability starting in the 1980s, mostly a reflection of the TOGA program.
The WOCE, CLIVAR, and GLOSS programs have supported continued international
data exchange into the 1990s. The figure also depicts the typical time lag from
collection to public dissemination, which is on the order of a few years.
Since 2006, the JASL has extended 3 series
backwards for a total of 91 site-years (Appendix A.5). This has been made possible by data rescue at
various agencies. Existing years in the
JASL archive have also been replaced since 2004 when necessary. A summary of actions is given in Appendix
A.6. The Bureau of Meteorology (BOM,
historically the National Tidal Facility) updated the
Figure 5. Lengths (years) of the time series. A majority of the record
lengths are less than 30 years long; however, 115 series have record length
greater than 30 years, while 31 series have length greater than 60 years.
Figure 6. For each year, the number of series with data for that year are depicted by
ocean. The data availability increases rapidly in 1984 through efforts of the
TOGA program. The drop-off for recent years represents the lag in obtaining
finalized updates from the originators.
Pursuit of data rescue continues at the
JASL (Appendix A.7) although this year there were no
new series digitized at the JASL. In
recent years, significant historic holdings have been added.(
Several unique sites have multiple
independent series due to reference levels that have not been linked from one
time span to the next. In several cases, a series was broken into multiple
segments at the point of a reference level shift. For the given site, if new
time span(s) that were not linked to the reference level of the existing series
were added, then a separate series was established. The filename of each site with
multiple series is appended by letters and the filenames are ordered
chronologically (i.e. the earliest data is version A, e.g.
extended backwards and the new span is not linked to the same reference level.
This year, Instituto Espanol de
Oceanografia provided a quality-controlled time series for Ceuta, which had
previously been broken into segments Ceuta-A, Ceuta-B, Ceuta-C, and Ceuta-D. The new series is simply
3 DATA REQUESTS
Hourly, daily, and monthly data constitute
the permanent archive of sea level. The archive is presently composed of 558
sites for 11,460 site-years. The success of the sea level archive is possible
through the generous contributions of many data collecting agencies around the globe.
The data and quality assessments are stored digitally on the hard disk of computers
at the UH and on various backup media. On an annual basis, the data sets and
documentation files are submitted to the World Data Center-SS for oceanography,
which ensures the archival for posterity, assures widespread advertisement of
the data availability, and allows easy access for the scientific and public
communities.
Data are available from a variety of
sources: an anonymous FTP account, a World Wide Web site, on CDROM, or directly
from the WDC-SS or JASL on the transfer media of choice. From March 2006 –
February 2007, 8,660 requests have been serviced consisting of 2,661,276
series-years for 140,139 series through anonymous and hands-on transfers at the
JASL and UHSLC.
3.1 Anonymous
FTP
The Joint Archive for Sea Level has
available the research quality sea level data set of hourly, daily, monthly values
on its ``anonymous'' FTP account.
For those on Internet, the account may be
accessed by typing:
ftp://ilikai.soest.hawaii.edu/rqds
or directly following these instructions:
ftp ilikai.soest.hawaii.edu
user: anonymous
password: please enter your Internet address
cd rqds
Once you have successfully logged on,
please see the README file for information and instructions. The ASCII data
files in the JASL final archive format are within a subdirectory named ``rqds''
and are organized by ocean. This FTP account contains the most recent holdings of
the JASL data set for series that have been quality controlled and documented.
Since March of 1998, hourly data have been
made available through FTP to complement the daily and monthly values which have
been maintained online since 1994. The hourly data files are grouped by year, then compressed using Info-Zip into a single file per time
series. The Info-Zip web site is at http://www.cdrom.com/pub/infozip and the
software can be directly downloaded from ftp://ftp.cdrom.com/pub/infozip/.
This freeware zip utility is compatible to most platforms and operating
systems.
The hourly, daily, monthly, and document
files are updated a few times a year as new sets are added to the final
archive.
3.2 World
Wide Web
In December 1994, the World Wide Web site
for the UHSLC came online. It provided pointers to the data holdings of the
UHSLC anonymous FTP area using simple lists of sites. In February 1996, the web
site was upgraded with a modified geographical information system that allows
one to select data and metadata for sites from global and regional maps. In March
of 1998, the hourly data were made available as well.
The URL for this site is:
http://uhslc.soest.hawaii.edu
3.3 Sea
Level CDROM
A
CDROM was prepared by the JASL in May 2007 to facilitate data
dissemination. It contains data and this
report. The complete archive of hourly,
daily, and monthly values is included.
Requests for a copy can be sent directly to the JASL.
3.4 Direct
Requests
The sea level holdings are available on a
variety of storage media or through FTP transfer on Internet directly from the
WDCA or UHSLC. In 2002, Fast Delivery
UHSLC and JASL data were made available in the WOCE Global Data Version 3.0 DVD
set. For a copy, send requests to:
The
World Data Center-SS for Oceanography
c/o NOAA/NESDIS/NODC
User Services E/OC1
SSMC3, 4th Floor
phone: 301-713-3277 or -3278
fax: 301-713-3302
email: services@nodc.noaa.gov
WWW: http://www.nodc.noaa.gov
Some stations may have unresolved problems.
These data are retained at the UH Sea Level Center and may be obtained on a
case-by-case basis. Questions concerning the data and preparation should be
directed to:
Joint
Archive for Sea Level
Dept. of Oceanography
phone: 808-956-4105
fax: 808-956-2352
email: caldwell@hawaii.edu
WWW: http://ilikai.soest.hawaii.edu/jasl.html
ACKNOWLEDGEMENTS
We are deeply
appreciative to the technicians, tide station operators, digitizers, data
processors, coordinators, principle investigators, data managers, division
chiefs, and directors of the many agencies who have made possible the
collection and processing of the raw data and the contribution of the finalized
data to the Joint Archive for Sea Level. The UHSLC support of this report and
the WDC-SS posterity archive is funded by NOAA Cooperative Agreement
NA17RJ1230. The views expressed herein are those of the authors and do not
necessarily reflect the view of NOAA or any of its sub-agencies.
REFERENCES
Caldwell, P.,
and B. Kilonsky, 1992. Data processing and quality control at the
Caldwell, P. 2003. NOAA support
for global sea level data rescue. Earth
System Monitor, Vol. 14, No. 1, Fall 2003. pp. 1-5.
Levitus,
S., R. Gelfeld, M. E. Conkright, T. P. Boyer, D. Johnson, T. O?Brien, C. Stephens,
C. Forgy, O. Baranova, I. Smolyar, G. Trammell, R. Moffatt, 2000: Results of the NODC and IOC Data Archaeology
and Rescue projects. Key to Oceanographic Records Documentation No. 19,
Kilonsky, B.
J. and P. Caldwell, 1991. In pursuit of high- quality
sea level data. IEEE Oceans Proceedings. Vol. 2, October 1-3, 1991.
Mitchum, G. T., 1994. Comparison of TOPEX sea surface heights and tide
gauge sea levels. Journal of Geophysical Research,
Vol. 99, No. C12, pp. 24541-24553.
UNESCO, 1993. IOC Training Course for
the
UNESCO, 1995. IOC/GLOSS-GOOS
Training Workshop on Sea-Level Data Analysis. Geodetic and Research Branch, Survey of
APPENDICES
A. Station Lists
A.1 2007 Submission to the
May 24, 2007
GLOBAL
# Series: 558
# Site-years: 11,460
GENERAL INFORMATION FOR DESIRED STATIONS:
Update: May 24, 2007
# Series = 292
# Site-years = 6428
Notes on columns:
CI: Completeness index or
percentage of data span without missing data.
QC-YEARS: years which have
received quality control.
JASL TOGA GLOS STATION COUNTRY LAT
LONG QC-YEARS CI
001A Pxxx 115 Pohnpei-A Fd St Micronesia 06-59N 158-14E 1969-1971 100
001B Pxxx 115 Pohnpei-B Fd St Micronesia 06-59N 158-15E 1974-2004 98
002A Pxxx 113 Tarawa-A,Betio Rep. of
002B Pxxx 113 Tarawa-B,Bairiki Rep. of
002C Pxxx 113 Tarawa-C,Betio Rep. of
002D Pxxx 113 Tarawa-D,Betio Rep. of
003A Pxxx 169 Baltra-A
003B Pxxx 169
004A Pxxx 114
004B Pxxx 114 Nauru-B Rep. of
005A Pxxx 112 Majuro-A Rep. Marshall I. 07-06N 171-22E 1968-1999 92
005B Pxxx 112 Majuro-B Rep. Marshall I. 07-07N 171-22E 1993-2006 97
006A Pxxx xxx Enewetok-A Rep. Marshall I. 11-26N 162-23E 1951-1971 98
006B Pxxx xxx Enewetok-B Rep. Marshall I. 11-26N 162-23E 1974-1979 94
007A Pxxx 120 Malakal-A Rep. of
007B Pxxx 120 Malakal-B Rep. of
008A Pxxx 119
008B Pxxx 119
009A Pxxx 066
009B Pxxx 066
010A Pxxx 065 Rabaul
011A Pxxx 146 Christmas-A Rep. of
011B Pxxx 146 Christmas-B Rep. of
012A Pxxx xxx Fanning-A Rep. of Kiribati 03-54N 159-23W 1957-1958 88
012B Pxxx xxx Fanning-B Rep. of
012C Pxxx xxx Fanning-C Rep. of
013A Pxxx 145 Kanton-A Rep. of
013B Pxxx 145 Kanton-B Rep. of
014A Pxxx 107 French Frigate
015A Pxxx 140
015B Pxxx 140 Papeete-B
016A Pxxx 138 Rikitea
017A Pxxx xxx Hiva Oa French Polynesia 09-49S 139-02W 1977-1980 75
018A Pxxx 122
018B Pxxx 122
019A Pxxx 123
021A Pxxx 176 Juan
Fernandez-A
021B Pxxx 176 Juan
Fernandez-B
022A Pxxx 137 Easter-A
022B Pxxx 137 Easter-B
022C Pxxx 137 Easter-C
023A Pxxx 139 Rarotonga-A
023B Pxxx 139 Rarotonga-B
024A Pxxx 143 Penrhyn
025A Pxxx 121 Funafuti-A
025B Pxxx 121
026A Pxxx xxx
027A Pxxx xxx
028A Pxxx 118
028B Pxxx 118 Saipan-B N. Mariana Is. 15-14N 145-45E 1978-2003 93
029A Pxxx 117 Kapingamarangi Fd St Micronesia 01-06N 154-47E 1978-2003 93
030A Pxxx xxx
031A Pxxx 142 Nuku Hiva
033A Pxxx 069 Bitung
034A Pxxx 161 Cabo San
Lucas
035A Pxxx 177 San Felix
036A Pxxx 160 Guadalupe
038A Pxxx 125 Nuku'alofa Tonga