WORLD METEOROLOGICAL ORGANIZATION
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RA I/TCC-21/Doc. 6.1(1)
(25.VIII.2015)
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RA I TROPICAL CYCLONE COMMITTEE
FOR THE SOUTH-WEST INDIAN OCEAN
TWENTY-FIRST SESSION
ITEM 6.1
ST DENIS, LA REUNION
28 SEPTEMBER – 2 OCTOBER 2015
Original: ENGLISH
REVIEW OF THE TECHNICAL PLAN AND ITS
IMPLEMENTATION PROGRAMME
Meteorological Component
Surface-based subsystem
(Submitted by the Secretariat)
Summary and Purpose of Document
This document provides information and proposals related to various aspects of
the meteorological component to assist the Committee in its review of this
component of its Technical Plan, which is aimed at strengthening the tropical
cyclone forecasting and warning system.
ACTION PROPOSED
The Tropical Cyclone Committee is invited to:
(a)
Note the information given in this document and that provided by participants at the
session;
(b)
Review the meteorological component of its Technical Plan and its Implementation
Programme taking into account information provided in this document; and,
(c)
Decide on further action to be taken to support meteorological observation.
____________
Reference:
Technical Plan
RA I/TCC-21/Doc. 6.1(1), p. 2
6.1
METEOROLOGICAL COMPONENT (GLOBAL OBSERVING SYSTEM)
REGIONAL BASIC SYNOPTIC NETWORK (RBSN)
6.1.1.
The Regional Basic Synoptic Network (RBSN), being a minimum regional
requirement to permit members to fulfill their responsibilities within the WMO World Weather
Watch (WWW) Programme, continued to provide a fundamental basis for weather analysis and
forecast and for tropical cyclone warning services in Region I. Overall, the countries of the
region are contributing to the implementation of the RBSN (August 2015) by operating a total of
782 surface and 81 upper-air synoptic stations of which 234 surface + 19 upper-air synoptic
stations are located in countries in the area of the RA I Tropical Cyclone Committee. The details
of the observational programmes provided by these stations are given in Weather Reporting
(WMO-No. 9, Volume A), and available on the WMO website at
http://www.wmo.int/pages/prog/www/ois/ois-home.html.
6.1.2.
The quarterly Integrated WWW Monitoring (IWM) exercise of the operation of the
WWW provides information on the performance level of the observing and telecommunications
systems. A summary of the analysis following the results of the monitoring carried out during the
intersessional period, showing the availability of the SYNOP and TEMP reports from the RBSN
stations in the area of the RA I Tropical Cyclone Committee, is provided in the table below. It
should be noted that while a number of surface stations had slightly increased between 2011
and 2014, that the overall percentage of the SYNOP reports received had shown a small
decrease. However, a number of upper-air stations as well as the overall percentage of TEMP
reports received had shown a significant decrease during this period; see the details in the table
below. The community should be alarmed by this trend and decide on actions to rectify the
situation, including implementation of alternative cost-effective observing systems; see sections
6.1 to 6.1.6.
RBSN stations in the area of the RA I Tropical Cyclone Committee
Quarterly Integrated WWW Monitoring (IWM) of the Operation of the WWW, availability of
SYNOP/TEMP data at MTN Centres
(Period July 2010 – April 2011 and July 2013 – April 2014)
Country/Area
Botswana
Comoros
French Islands
Kenya
Lesotho
Madagascar
Malawi
Mauritius
Mozambique
Namibia
Seychelles
South Africa
Swaziland
Tanzania
Zimbabwe
Total
Number of surface stations / (%) of
SYNOP reports received
2011
2014
12
2
8
18
3
26
2
6
15
15
3
87
1
16
17
231
61%
95%
98%
63%
3%
49%
19%
91%
39%
46%
32%
84%
45%
49%
53%
66%
15
2
8
11
3
26
2
6
27
15
3
82
1
15
18
234
51%
86%
55%
74%
15%
54%
44%
92%
30%
71%
64%
94%
47%
82%
52%
61%
Number of upper-air stations / (%) of
TEMP reports received
2011
2014
5
3
2
2
1
2
3
1
10
3
2
34
1%
39%
20%
70%
0%
26%
0%
28%
28%
4%
7%
20%
4
2
1
2
1
1
2
1
1
3
1
19
0%
23%
33%
32%
0%
6%
0%
40%
84%
8%
3%
15%
RA I/TCC-21/Doc. 6.1(1), p. 3
6.1.3. Sustainability of basic networks in some parts of the region and the low availability of
data from those networks remain an issue of concern which emphasizes the need to further
strengthen basic networks, especially those in developing and the least developed countries.
For more details on the Integrated WWW Monitoring (IWM) results, see
http://www.wmo.int/pages/prog/www/ois/monitor/index_en.html.
AIRCRAFT OBSERVATIONS
6.1.4. The aircraft-based observing system, comprising the AMDAR observing system1
supplemented by aircraft observations derived from ICAO systems, now produces nearly
800,000 upper air observations per day on the WMO GTS, with the AMDAR system contributing
the vast majority and around 770,000 observations from 38 participating airlines and a global
fleet of around 4500 aircraft. This critical sub-system of the WMO Integrated Global Observing
System produces both upper tropospheric enroute and vertical profile (from AMDAR aircraft at
airport locations) high quality, upper air temperature and wind data, that continues to
demonstrate a significant positive impact on global, regional and high resolution NWP and other
forecasting and meteorological applications. With the advent and scientific validation of the
Water Vapour Sensing System, WVSS-II, for jet aircraft, there is a growing number of aircraft
(currently 127 aircraft, chiefly providing data over the US) operationally providing vertical profiles
of high quality atmospheric moisture data. This means that AMDAR can now be considered as a
complete upper air sounding system providing a high quality and high impact supplement to
radiosonde data. Also, given its comparatively significantly lower establishment and running
costs2, AMDAR might be considered as an alternative to radiosondes when resources and/or
technical capabilities of countries are limited.
6.1.5. Since the previous TCC session, little has changed in regard to the status of aircraftbased observations and AMDAR data coverage over RA I. The South African AMDAR
Programme is still the sole AMDAR Programme in the region, with an increased fleet of 56
South African Airways aircraft, now providing around 5000 upper air observations, including
around 100 vertical profiles per day on the GTS. The coverage over the region is supplemented
by voluntary and contracted contributions from EUMETNET via the E-AMDAR programme,
which provides additional vertical profiles over a limited number of airports throughout Africa.
The figure below, showing a filtered coverage map from March 2015, with vertical profile
locations indicated in red, illustrates the limited coverage over Africa and the potential for
significant growth of AMDAR implementation when compared with other areas of the globe.
6.1.6. CBS, through its Expert Team on Aircraft Based Observing Systems, is endeavouring
to collaborate with Regional Association I and its Members in the development of new AMDAR
programs in Africa in cooperation with partner organizations and the aviation industry. The
association, at its recent session and regional conference in Cabo Verde (February 2015),
received a presentation on the benefits of and potential for AMDAR development in Africa.
Additionally, a draft Aircraft Based Observations Regional Implementation Plan (A-RIP) for
Africa was submitted to the session as an information paper. The session agreed that a regional
working body for AMDAR might take on the role of coordinating and overseeing further
development of the aircraft-based observing system. A Regional Workshop on AMDAR was
held in Nairobi, Kenya over 25-26 June 2015, and another is planned to take place in
Casablanca, Morocco in December 2015. Growth and enhancement of the AMDAR programme
within Africa would be expected to have a significant additional positive impact on tropical
cyclone forecasting and monitoring skills and applications of RA I Members.
1
http://www.wmo.int/pages/prog/www/GOS/ABO/AMDAR/
See WIGOS Technical Report 2014-1, The Benefits of AMDAR Data to Meteorology and Aviation at:
http://www.wmo.int/pages/prog/www/wigos/technical_reports.html
2
RA I/TCC-21/Doc. 6.1(1), p. 4
WEATHER RADAR SYSTEMS
6.1.7. The Turkish State Meteorological Service (TSMS), in consultation with CBS and CIMO
has taken the lead in developing and establishing an online database of world weather radars
based on the data gathered in a 2009 questionnaire on weather radars. In 2012, the TSMS
undertook to maintain the WMO Radar Database (WRD)3 on behalf of WMO Members in an
operational capacity. In September 2011, the Secretariat wrote a letter to WMO Members
requesting that all Members either operating or intending to operate weather radar systems in
support of the WWW Programme, should nominate a Weather Radar Focal Point who would
have responsibility for seeding and maintaining the weather radar metadata within the WMO
Radar Database (WRD). The WRD has now become a very important source of weather radar
systems metadata and online data availability and will be the source of information for observing
systems capability analysis under OSCAR. In addition to providing statistical and operational
information on WMO Member weather radar, the WRD will in the future be important to assist in
and facilitate the process of international exchange and sharing of weather radar data in support
of meteorological applications. WMO encourages all Members to support and maintain the
WRD. Expansion of radar network within Africa would be expected to have a significant
additional positive impact on tropical cyclone forecasting and monitoring skills and applications
of RA I Members.
MARINE AND OCEAN METEOROLOGICAL OBSERVATIONS
6.1.8. The Observations Programme Area (OPA) work plan of the Joint WMO-IC Technical
Commission for Oceanography and Marine Meteorology (JCOMM) is aligned with the ocean
chapter of the GCOS Implementation Plan for the Global Observing System for Climate in
support of the UNFCCC (GCOS-138 in its 2010 update). The implementation goals provide
specific implementation targets for building and sustaining an initial global ocean observing
system representing the climate component of the Global Ocean Observing System (GOOS)
3
http://wrd.mgm.gov.tr/default.aspx?l=en
RA I/TCC-21/Doc. 6.1(1), p. 5
and the ocean component of the Global Climate Observing System (GCOS). Although the
baseline system proposed under the implementation goals was designed to meet climate
requirements, non-climate applications, such as NWP, tropical cyclone prediction, global and
coastal ocean prediction, and marine services in general, will be improved by implementation of
the systematic global observations of Essential Climate Variables (ECVs) called for by the
GCOS-138 plan.
6.1.9. The Fourth Session of the joint WMO-IOC Technical Commission for Oceanography
and Marine Meteorology (JCOMM, Yeosu, Republic of Korea, May 2012) has updated the
implementation goals for its Observations Programme Area (OPA) according to the latest
developments with regard to (i) the outcome and recommendations from the OceanObs’09
Conference; (ii) the outcome of the Third World Climate Conference (WCC-3); and (iii) nonclimate requirements arising from the CBS Rolling Review of Requirements, including
Statements of Guidance and gap analysis. Implementation of marine observing network in the
region is realized thanks to role of WMO Members, including with support from Members in the
region. Globally, the ocean in situ observing system is now 67% implemented although no
substantial progress according to the completion targets has been noticed in the last few years.
All data are being made freely available to all Members in real-time. Tropical oceans provide for
an important heat engine of global climate and weather patterns, and the Tropical moored buoy
arrays and the Argo profiling float programme provide essential upper ocean thermal data from
that perspective. These data complement other existing satellite (e.g. sea level) and in situ
observations in the region. All data are being made freely available to all Members in real-time.
Completion will require substantial additional yearly investment by the Members/Member
States, including in WMO Regional Association I.
6.1.10. The global surface buoy network coordinated through the Data Buoy Cooperation
Panel (DBCP) is now essentially complete and being sustained (1499 global units in June
2015). The technical problems with regard to the drifter life-times and their drogues that have
been noted since 2011 have been addressed, and the robustness of the drifters increased..
Efforts are being made to increase the number of those drifters reporting sea level pressure
(765 global units in August 2015). Regions such as the Equatorial Atlantic, Equatorial Indian,
and the Southern Ocean appear relatively data sparse. Barometer drifters are currently not
being deployed in the tropical regions. Cost-effective technology exists for surface drifters
equipped with thermistor strings and designed to be deployed in tropical cyclone
conditions. However, no such drifters are being deployed operationally in area of interest from
the Regional Association.
6.1.11. The Argo profiling float programme reached completion in November 2007 and is now
providing essential Upper Ocean thermal and salinity data for Tropical Cyclones research,
monitoring and forecast activities. 3881 floats were operating worldwide in June 2015 but the
core mission targets are just recently reached (3000 floats operating 60N/60S, no marginal
seas), as some floats are operating a pilots in non-core regions. Argo is in active discussions
with the community to evolve its original core design and sampling to meet increasing needs
and exploit technological advances. Pilots continue in the sea ice zone, near surface sampling,
chemical and optical sensors and in special areas with enhanced array density. A possible
future ‘Global Argo’ might involve over 4000 active floats. Argo is still short of requirements in
the far Southern Ocean. Regions such as the Eastern Equatorial Pacific Ocean, and the
Caribbean Sea appear poorly covered. Efforts are necessary to ensure adequate geographical
coverage and ensure sustainability of the array (requiring around 800 new floats each year).
While over 20 nations deploy Argo floats, the program is still overly dependent on a small
number of national programs and thus Argo must strive to increase contributions from a larger
number of nations. 90% of Argo profiles reach the GTS within 24 hours of collection and efforts
to reduce delays in the GDACs data distribution are increasing their timeliness. Most Argo data
centres are meeting the requirements for throughput of delayed-mode quality control. Argo is
regularly auditing the data stream for consistent formatting, pressure bias removal, consistency
with altimetric data, and for outliers in the real-time data stream. The profiling float technology is
evolving and new generations of instruments are emerging. Their long term performance will not
RA I/TCC-21/Doc. 6.1(1), p. 6
be known for several years and diligence in monitoring the array performance is required. The
increase in the use of high-bandwidth satellite communications is driving a change in the Argo
data set from relatively low vertical (50-70 points) to high (~500 points) vertical resolution, and
more accurate surface location. . Around 33% (>1,200 floats) of the array is now delivering
highly vertically resolved (2db) profiles. Pilot deployments of bio-optical-geochemical sensors
and ice-avoidance capabilities continue. Several groups are developing and field testing “deep
floats” (4000m and below). The evolution of Argo to pursue new and additional missions is
being discussed at various workshops and by the Argo Steering Team. Regions of interest to
RA-I such as the Gulf of Guinea, the Mozambique Channel, and West of the Somali Basin
appear poorly covered. Efforts are necessary to ensure adequate geographical coverage
and ensure sustainability of the array (requiring around 800 new floats each year).
6.1.12. The Tropical Pacific Ocean moored buoy array (TAO/TRITON) is now complete, and
salinity is available nearly on every mooring site. The Pilot Research Moored Array in the
Tropical Atlantic (PIRATA) moored array is now also complete with 18 operational sites. The
Research Moored Array for African-Asian-Australian Monsoon Analysis and Prediction
(RAMA) is still developing in the Indian Ocean to complete coverage of the tropical
oceans - the heat engine of global climate and weather patterns. RAMA consists of a basin
scale network of 46 deep ocean moorings that provide essential data to complement other
existing satellite and in situ observations in the region. 34 (i.e. 74%) of the 46 RAMA sites have
now been deployed and are maintained. The primary data telemetered in real time from surface
moorings in the arrays are daily or hourly mean surface measurements (wind speed and
direction, air temperature, relative humidity and sea surface temperature and salinity) and
subsurface temperatures. Moorings provide optional enhanced measurements, which include
precipitation, short and long wave radiation, barometric pressure, salinity, and ocean currents.
These enhancements provide heat, moisture and momentum flux measurements at 5 Tropical
Indian ocean moorings. High temporal resolution (10-min or hourly) measurements are available
in delayed mode. Daily average data return for the period 1 July 2013 through 30 June 2014
was 38% for TAO, 84% for TRITON, 86% for PIRATA and 54% for RAMA. Abnormally low TAO
data return was in large part due to vandalism on the data buoys, and difficulties to assure
maintenance due to the cost of ship time, and piracy (Pacific Ocean).
6.1.13. Voluntary Observing Ships (VOS) provide for valuable marine meteorological
observations in the region. Globally, in March 2015, about 30 countries were recruiting a total of
3,045 active VOS. However the tropical regions, and the southern ocean remain relatively
data sparse. Efforts are being made to increase the number of Automatic Weather Stations
installed on ships to improve real-time reporting for weather forecasting and climate. VOSClim
class vessels are delivering high quality observational data for climate related applications. The
number of active VOSClim and VOSClim Automatic Weather Station (AWS) ships now stands
at 498 ships, i.e. 16% of the operational VOS fleet (22% compared to the target of 25% if
counting ships that had submitted more than 5 pressure observations per month). On average,
in excess of 100,000 VOS reports are distributed on the GTS per month worldwide,
predominantly in the Northern Hemisphere.
6.1.14. The Ship of Opportunity Programme (SOOP) addresses both scientific and operational
goals for building a sustained ocean observing system with oceanographic observations mainly
from cargo ships. It provides for valuable upper ocean thermal data through 29global high
resolution and frequently repeated Expendable Bathythermograph (XBT) lines now fully
occupied (target is 50 lines). Globally, XBT observations currently provide approximately 20,000
profile data (target is 30,000 units), or 15% of the global temperature profile observations,
making them a key component in the data set to assess global ocean heat content. A large
number of XBTs deployed by non-US agencies are the result of donations from the US (NOAA),
thereby making the operation highly dependent on the continuing support of one single
institution. International collaboration is key to the success to the implementation of the
XBT network, where the operations are related to ship recruiting, deployment of probes,
data transmission, data quality control, and archiving. Some ships are also transmitting
RA I/TCC-21/Doc. 6.1(1), p. 7
Thermosalinograph (TSG) data, most of which are operated by French institutions and by the
US/NOAA research and SOOP fleet.
6.1.15. The Global Sea Level Observing System (GLOSS) has expanded beyond the original
aim of providing tide gauge data for understanding the recent history of global sea level rise and
for studies of interannual to multi-decadal variability. Tide gauges are now playing a greater role
in regional tsunami warning systems and for operational storm surge monitoring. The GLOSS
tide gauge network is also important for the ongoing calibration and validation of satellite
altimeter time series, and as such is an essential observing component for assessing global sea
level change. The number of sea level stations reporting to the GLOSS Data Centres has
increased markedly over past last ten years, particularly for stations that report in near real-time.
About 70% of the GLOSS Core Network (GCN) of 290 stations can be considered operational in
August 2015, and there are focused efforts to address the remaining 30% of stations not
currently on-line. In order to close gaps in the GCN there is a need for international
support for equipment and training. About 150 of the GCN stations have installed co-located
continuous GNSS stations for vertical land motion rates. GLOSS continues to advocate for
installation of c-GNSS stations near all GCN stations. Not all of these stations have geodetic
ties between the GNSS stations and the tide gauges that allow determination of absolute
ellipsoidal heights and GLOSS needs to continue to develop these links.
6.1.16. TCC members are invited to explore enhanced contributions of WMO Members in
the region in support of the implementation of the buoy networks in the South Western
Indian Ocean. Of particular interest is the provision of ship time to assist in the
deployment and servicing of RAMA buoys, and for the deployment of drifters and XBTs.
Members interested to contribute are invited to contact the Technical Coordinator of the
Data Buoy Cooperation Panel (DBCP), Ms Champika Gallage (cgallage@jcommops.org).
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