Report -CBS/IOS Expert Team on Requirements and Implementation AWS Platforms,
Geneva, Switzerland, 22-25 June 2010

For the agenda and links to the documents please go to the link at: http://www.wmo.int/pages/prog/www/OSY/Meetings/ET-AWS6-2010/DocPlan.html

 

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: http://www.wmo.int/pages/prog/www/OSY/Reports/ET-AWS-6_Geneva_2010_REV.doc

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 manufacturing sector.

Report of the Chairman of ET-AWS - Doc. 2 (see document here)
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 report.

The Chairman further noted that it is proposed that the AWS network be used to support the calibration of Space-based observations.

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 users;

• 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 calibration.

AWS Functional Specifications - Doc. 4 (see document here)
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 Červená (see document here).

Functional Specifications (FS) and BUFR descriptors of AWS will be looked at by other WMO Technical Commissions for validation.

It 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 realistic.

• 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 space-based observations.

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.

Etienne 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 document here)
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 document here)
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 document here)
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 meeting.

Advances in AWS Technologies Docs. 11.1 (see the document here) & 11.2 (see document here)
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 costs.

• 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 considerations noted).

In discussion:

• 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 WMO requirements.

• 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 downloads.

• 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 as appropriate).

• 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 propositions possible.

HMEI noted points of interest on AWS in use and the work of ET-AWS:

• 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 transmission).
  
  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 document)
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 CBS-XIV.

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.