Report -CBS/IOS Expert Team on Requirements and Implementation
Geneva, Switzerland, 22-25 June 2010
Official photo of meeting participants
For the agenda and links to the documents
please go to the link at:
The HMEI attendees of this meeting were:
Christine Charstone, HMEI Administrator and Jorma Islander from Vaisala.
The full list of participants will be available
in annex 1 of the Final Report.
The WMO Final Report of the meeting is available from:
This HMEI report is not intended to be definitive, but
highlights items considered of interest for HMEI Members.
Working documents listed against items in this report are not
the final decisions of the ET-AWS, rather the final decisions can be
seen in the Final Report of the meeting.
Opening of the Meeting
The meeting was opened with a welcome from the Director of
the Observing and Information Systems Department, Dr. Wenjian Zhang. Dr
Zhang welcomed the various participants and stressed the importance of
the work of this ET. Particularly in light of the growing use of AWS in
weather and climate services. HMEI was specifically welcomed to the
session with the importance of feedback to and input from the
Report of the Chairman of ET-AWS - Doc. 2
Mr Monnik noted for the meeting the requirements and requests
from the previous CBS session, WMO CBS-XIV, which were relevant
to this ET, this included requests for continued work work on
Metadata and BUFR descriptors and standardization issues.
CBS adopted the: Revised functional specifications for automatic
weather stations, and the: Basic set of variables for a standard
automatic weather station for multiple users. (See
the Chairman's Report, pages 4 and 5, for an outline of these)
Also the previous CBS noted that there was no ET working on the
operational and implementation issues for AWS; therefore this
ET-AWS has had its brief expanded to include these issues and
its title changed to include "Implementation of AWS Platforms".
Also new Terms of Reference for the ET-AWS were created.
The changes to the members of ET-AWS are noted in the chairman's
The Chairman further noted that it is proposed that the AWS
network be used to support the calibration of Space-based
The proposed work for the ET-AWS during this next intersessional
period will be:
Address requirements for integration, interoperability,
standardization and homogeneity of the WIGOS concept through
enhancing existing WMO documentation;
Monitor and update AWS Functional Specifications (FS) for
all WMO-related Programmes including updating basic set of
variables to be reported by a standard AWS for multiple
Review of BUFR descriptors and BUFR templates for variables
measured by AWS;
Further development of AWS metadata catalogues;
In consultation with ET-SUP and ET-SAT, investigate the
potential for AWS to contribute to the calibration and
ground truth of space-based observations;
Develop the requirements and standards for a basic, robust
AWS suitable for less developed and remote areas in
consultation with manufacturers and WMO member countries;
Develop requirements for new data types from AWS sensors in
consultation with ET-DRC ;
Monitor advances in AWS technology and develop standards for
integration into AWS networks.
Contribution of ET-AWS to WIGOS (WMO Integrated Global Observing
System) - Doc. 3, Rev 2
Dr Igor Zahumensky presented this document which
updated the meeting on the WIGOS and WIS (WMO Information
System) progress and the WIGOS need for a coordinated and
sustainable system of observing systems, ensuring
interoperability between its component systems.
This need for interoperability of measurement data means
that, for example, there is a need for data from various
observing systems (i.e. surface measurements and space-based
sensing data) are compatible and interchangeable.
From discussion of this document it was clarified that the
interoperability of data would be achieved through the following
recommendations from WMO guidelines and traceability back to ISO
standards. These standards and guidelines will continue to be
refined and developed.
Presentation on WIGOS Demonstration Project in Morocco
This presentation shared the experiences of the Moroccan
Met. Service (a Regional Instrument Center (RIC) for Africa)
with implementing WIGOS, including issues related to standards
and calibration; Morocco being an African center for
AWS Functional Specifications - Doc. 4 (see
This document looks at an additional set of variables proposed
at the 5th session of this ET by representatives of other WMO
Technical Commissions (TCs). However due to the lack of clear
definitions and the absence of a well defined ranges and
reporting resolution, the Expert Team had postponed the
consideration of some variables including "freshwater salinity",
"freshwater conductivity", "(net) heat flux" and “Slant Path
Visual Range (SVR)" in order to conduct further investigation on
the needed requirements. Propositions for these variables are
presented for discussion in this document. The team made an item
for the work plan for creating a recommendation on these.
Furthermore, the Expert Team requested OPAG-ISS to cooperate as
needed with guidance in the development of BUFR descriptors of
all variables considered. Detailed information on the BUFR
descriptors is given in document 10.1 submitted by Dr Eva
Functional Specifications (FS) and BUFR descriptors of AWS will
be looked at by other WMO Technical Commissions for validation.
was further requested that HMEI member manufacturers be asked to
review the FS as they become available and give feedback on their
feasibility from a manufactures' view point to the ET.
During the discussions on AWS requirements, maintenance problems
and challenges and also problems with various instrument designs
was raised. It was suggested that documentation, freely
available (perhaps via the Internet), that would give feedback
on problems that users find with various instruments generally
or suggestions for amendments, would be a valuable tool for
users and manufacturers.
Requirements for AWS to contribute to the Calibration and
Ground Truth of Space-based Observations - Doc. 6
It was noted that:
It is now possible for AWS systems to be temporarily aligned
with satellite overpasses.
BUFR format data on the GTS can transmit a larger amount of
data than an alpha numeric format.
There are more sensors that can now be added to AWS that
will make ground truthing of space based observations more
There are problems with the differences of resolution and
area scale between point in-situ AWS observations and the
observations that are space-based, when looking at using AWS
measurements for calibration and ground truthing of
The WMO Space Programme representative, Jerome Lafeuille
(Chief, Space-based Observing System) informed the meeting that
calibration of Spaced-based observations was not seen as
particularly useful by the Space Programme. However validation
of space -based observations was seen as potentially useful,
using AWS networks, particularly high quality stations such as
reference stations could be used. Cooperation between the ET-AWS
and the WMO Space Programme ETs to define the variables and
parameters for this should be looked at.
Charpentier, (Scientific Officer, Observing Systems Division)
noted that the WMO Marine Programme was already looking at
this kind of calibration cooperation between the marine buoy
observing network and the space-based observations.
It was noted that there are many potential sources, beyond
the met services, of AWS data/observations. Addressing this
It was suggested that the HMEI Secretariat approach its
members regarding the supply of instruments for specific
geophysical parameters. It was pointed out by the HMEI
representative that the buyers/users where in fact the ones
who specified these AWS and networks and thus best fitted to
know the geophysical parameters being used in their
networks. However the HMEI Secretariat expressed its
willingness to pass this request on to the next meeting of
its members and/or Council to discuss the feasibility of
providing this information.
Automation of Surface Observations - 'Development of
Guidelines and Procedures for the Transition from Manual to
Automatic Weather Stations" - Doc. 7 (see
The draft guidelines in this paper were developed by the
CIMO-ET on Surface Technology and Measurement Techniques and
presented by Mike Molyneux from the UK Met Office. It documents
the issues and procedures that the UK Met Office encountered and
used in the change of their network from Manual Weather Stations
to almost entirely AWSs. It was decided that the value of this
document was such that it be prepared for publication and
published as a WMO Technical Document.
AWS Metadata Catalogues - Doc. 8 (see
Rodica Nitu submitted and presented this document. Ms Nitu has
reviewed the catalogue values from the 4th session of this
ET-AWS to identify omissions and necessary amendments. There was
some discussion as to what information should be included in
real time metadata, in comparison with non-real time metadata.
There is list of approved metadata published in Part 3, Appendix
3.III of the
Guide to the GOS (see here)
It was recommended that the humidity BUFR table descriptors need
to be extended.
A need was seen to identify missing sensor types. Appropriate
ETs would need to designate the metadata for these.
The challenge of getting users such as the met services to
implement and provide metadata was also seen as an important
issue to be resolved.
BUFR Descriptors Related to AWS Doc. 10.1 (see
Dr Eva Cervená and Mr Rabia Merrouchi have reviewed the BUFR
descriptors presented in this document. Dr Cervená presented
the findings and asked for input and clarifications from the
meeting for a number of descriptors. The document with the
revisions will be an appendix of the final report of this
Advances in AWS Technologies Docs. 11.1 (see
the document here) & 11.2 (see
Rodica Nitu presented this item point. These
documents look at still relevant advances noted in the previous
version of this report as presented at the last ET-AWS, plus the
newest advances and points about AWS.
Noted from the reports:
AWS have become extensively used and the costs in themselves
of AWS have gone down;
However the running costs have increased often in relation
to a NETWORK of AWSs (especially where expectations for the
uses of the AWS goes beyond its original intention) ;
Most AWS are now made by private industry manufacturers,
rather than systems being made in house by met services;
Advances mainly have been in the low end of AWSs rather
than the high end technologies;
Most manufactures have a reasonably low cost AWS. However
they are not always producing the best input of data into
networks, although they are useful in some situations
for basic use, but do have significant drawbacks often in
the way they stand and are setup;
The most persuasive selling point for some low cost AWS is
its apparent ability to manage the data for the user, and
they are used in, for example, emergency services,
forestry and so forth.
The ability of sensors to have internal diagnostics has
increased the facility for maintenance and lowering related
Advances in sensor development have slowed as there has been
a reduction in budgets for met services.
For some remote areas, where power is not available, sensors
for “visual observation” or for observation in
harsh conditions (i.e icing) cannot be used, as they need
more power than a solar panel provides and
infrastructure costs become too high.
Quality of measurements from AWS is generally increasing,
but there are ongoing requirements for regular maintenance
to ensure this (see points 1.6 & 1.7 of the document).
There is a need for the algorithms applied to AWS be known
i.e. by parameter, the real time quality control algorithms
used, and whether the algorithms are documented and
published (see items 2.4 & 2.5 of the document for the full
There was a perceived need for WMO and CIMO to be very
proactive in letting WMO members know that for AWS to be of
sufficient quality it must meet the WMO recommendations.
It was suggested that perhaps WMO members should first get
an AWS objectively tested to establish if it does fit the
The China met service has guidelines for AWS, it was
requested that these guidelines be translated into English
for this ET to see.
The Netherlands met service also has guidelines available
for AWS on their website at:
http://www.knmi.nl/samenw/hawa/ then see the link to
It was suggested that a recommendation from ET-AWS be made
that CIMO should look at having an Intercomparison of AWS.
It was suggested that CIMO could look at a certain level of
standardization for some aspects of AWS, in collaboration
with the ISO, to help with the large variability of AWS and
the high turnover of the instruments involved.
It was suggested that this ET-AWS should produce a Technical
Report (TC) with information on transition from manual to
automatic weather stations and information on the new
technologies in automatic weather stations. (This would need
to be an ongoing dynamic publication with update from ET-AWS
The Marine Observations representative noted that satellite
technologies for very remote areas has issues to do with
tariffs and data user requirements that need to be addressed
as there are no guidelines to cover this. JCOMM is going to
have a forum about this in relation to WIGOS (WMO Integrated
Global Observation Systems) and will look at including
others communities using AWSs needing satellite
communication of data.
'Standardization' of certain elements from the CIMO guide in
relation to AWS was discussed; the process of items becoming
ISO standards is a formulaic one, which takes a certain
time, however WMO with its new agreement with ISO to be a
standard setting body makes relative fast tracking of its
HMEI noted points of interest on AWS in use and the work of
Jorma Islander from HMEI suggested that because not all
users were in a position to test AWSs qualities for
themselves until the product was purchased and in operation,
perhaps WMO could put in place some kind of a certification
system. Some met. services already carry out some forms of
certification of met instrumentation and equipment.
The HMEI Secretariat supported the idea of Jorma's point:
that what are commonly call AWS, which are instruments
"systems" in themselves ( but with various options of which
sensors are used and which parameters are measured attached
to them) and which can subsequently be in different
situations, are now becoming more and more in use. For want
of a better word these shall here be referred to as "AWS systems".
These "AWS systems" come in all qualities and sizes and
configurations and prices, wherein lies the problem.
For instance the China representative at the meeting
informed HMEI that China has 30,000 of these "AWS systems"
type installations compared to the other type of AWS (as are
commonly in use in the UK Met Office network, which are AWSs
with instruments that are configured similarly to a manual
station, but which is automatic in its data collection and
The Indian representative at the meeting also gave
HMEI figures for its use of the AWS systems" (each with
various multiple optional sensors). India has 425 of these
"AWS systems" with an extra 250 of these type to be
installed by the end of 2010. By contrast India has only
approx. 100 of the type of Automatic Weather Station which
is mainly used in the UK Met.
The UK Met Office network has approx. 200 AWS of all types,
but only 10% of these are of the "AWS systems" type (which
is noted as in the majority for China and India).
The above figures seem to indicate a disparity between the
main types of AWS that the UK met service currently has and
those of the China and India met services. Does this reflect
a general disparity between what the countries that are
"well off" use for their AWSs and the type of AWSs other
countries are using?
The importance between these differences is important for
Jorma Islander's point, because Jorma wanted to have a
method of assessment of the "AWS systems" in use. This is
because the "AWS systems" are more and more commonly in use
even in met services, but there is NO way of knowing how
they perform or how their sensors perform as they are
configured in these circumstances. This is a problem that
African countries often bring up in the WMO Executive
Council and Congress,
HMEI would be interested to see some way for WMO/CIMO to
specify the requirements for such "AWS systems" and have
guidelines on the configuration for "AWS systems", in order
that users can have a clear idea of how to select these
"systems" for procurement purposes.
BUFR Templates for Representation of AWS Data - Doc 10.2 (see
The work was recognized of HMEI
member, IBL Software Engineering with the Expert Team on Data
Representation and Codes, in bringing sequence 3 07 091 ( 3 07
091 (BUFR template for surface observations from one-hour period
with national and WMO station identification) and the
descriptors 0 01 101, 0 01 102 and 3 01 089 (BUFR or National
station identification) to pre-operational status and then
operational implementation as from 4 November 2009 by the
The list of WMO recommended BUFR templates/descriptors relevant
for AWS are listed in this document.
ET-AWS 6 Recommendations and Work Plan
The list of recommendations and the work plan from Annex X of
the Final Report of this meeting
is available here.
Recommendations in the work plan relevant to HMEI were:
Updates of AWS Functional Specifications (FS) for all
WMO-related Programmes to be reviewed by several WMO bodies
and also HMEI.
In regard to developing a basic, robust AWS which takes
advantage of technological advances AWS suitable for remote and extreme climate conditions, review challenges, solutions
and advances in liaison with HMEI.
Close of Meeting
The meeting was closed 3.15pm Friday 25 June 2010.