HMEI Report of the
ET on Remote Sensing Upper-Air Technology and Techniques
14-17 March 2005 in Geneva, Switzerland.

Welcome by WMO Assistant Director

Introduction by Mr. Drombrowsky Co-Chair of this ET
This first meeting to be concerned with defining and identifying the skills and interests of the ET members so that areas can be identified to be addressed in accordance with the key elements of the tasks for the ET as outlined by the CIMO 13 and to be completed in time for CIMO 14. 

Introduction by Dr John NASH Co-chair, OPAG UPPER-AIR
With Lightning, Wind profilers, GPS water vapor, systems now available, the importance was outlined of coordination globally and COMPATIBILITY of these systems to be defined and organized at WMO level Also integration of the types of different parameters measured.

Report from Dr. Alexei Ivanov Chairman of this ET
Defined the activities of the ET and invited team members to use this information in their discussions and in formulating their work plan and future activities.

Particular mention was made of Radio Frequency issues.

It was mentioned that the issue of liaison between CBS and CIMO is seen as important to resolve.

Also mentioned as important was the issue of climate requirements and liaison between the GCOS and the aims and recommendations of this ET group.

GPS Water Vapor Measurements Report by Siebren de Haan
Discussions after report:
Does GPS over estimate summer water vapor level compared to Radiosonde? (Switzerland, Prof. Richner)

GPS and Radiosonde Vaisala’s RS 80 seem in fairly close agreement (Japan, Dr. Ishihara)

The different results from different Intercomparison/research projects need to be brought together to try to find out the true values and accuracies in this issue (UK, Dr. Nash)

The stringent demands of the Climate community currently being defined need to be taken into consideration, and the climate community will certainly require a resolution of the accuracy issues (USA, Mr. Drombowsky).

Operational affordability of the GPS network is something for which this ET could try to develop some useful recommendations - from this ET’s members’ countries experiences (Dombrowsky, Nash, Ivanov).

Report on NOAA GPS Meteorology by Mr. Drombrowsky
Mr. Drombowsky stressed that information from GPS was and for the near future would continue to be complimentary to traditional radiosonde data.

The issue of the accuracy to which measurement of parameters or parameters/equipment should achieve was raised. It was noted that CIMO had guidelines for accuracy regardless of the equipment used. It was also noted that this had been an issue and the BUFR code for it had been dealt with at the WMO CBS Expert Team on Requirements For Data From Automatic Weather Stations -3rd Session, July 2004 and similar agreement was perhaps needed for GPS.

Report on GPS Meteorology at Japan M.A. by Dr Masahito Ishihara
Japan has wide research being done there, very potentially important for their thunderstorm and typhoon activity, however they need more coverage over the ocean (although very good land coverage). Currently there work is not real time.

Report on Preliminary Results of GPS real time processing using Bernese V software by Dr. Nash
Using the Bernese V software the GPS and Radiosonde methods (UK collocates all GPS and Radiosonde measurements) of measurement of Water Vapor are again seen as very much complimentary rather than one or other being more accurate/reliable. So the two systems run in sync look to be the way to go to improve the models.

Evaluation of GPS Precipitation Water over Canada and the Global IGS Network by Dr Paul Joe
This was a non real time study. Benefit was most noted for forecasting heavy precipitation events.

Operational use of Wind Profilers in USA by Mr. Dombrowsky
Although these are not technically considered operational per se, the wind profiler has proved a useful tool for verification of accuracy of tornado forecasting and for heavy snow events.

NOAA has however had problems with RASS because of the noise created by the system and its unpopularity with the public, unless sited in more remote areas.

Complimentary systems with Radiosondes again looks to result in the best forecasting results; although economic considerations in the US administration could cause a pressure for some sites to replace radiosonde readings with the (cheaper) GPS technologies even if the accuracy is reduced somewhat.

Dr. Nash noted that the rising costs of Wind Profilers could become an issue as they could become too expensive to be afforded by the Met Services.

Operational Aspects of Wind Profilers in Germany by Dr Dirk Engelbart

Report from India by Mr Bhukan Lal
Verbal statement on India’s wind profiler use.

Wind Profilers - Germany by Dr Engelbart
RASS wind profilers used in two centres in Germany. There were successful improvements in forecasting. These systems are good as complimentary to Radiosondes.

Problems were mentioned with regard to siteing. Wind turbines, particularly as these items increase in height, can cause problems as well as other clutter issues.

Dr Nash stressed that issues of clutter and the correct siteing of all the systems needs to always be considered, he noted problems in France where the site was under a main crossing of flight corridors.

Dr Drombowsky noted that the siteing of all meteorological equipment needed to be more carefully considered.

Wind Profiler Network Japan by Dr. Ishihara
31 wind profilers are being operated as a meso-β scale upper-wind observation network WINDAS in Japan.

Japan found data from wind profilers they have installed equal in accuracy to Radiosonde data.

Wind data obtained from WINDAS has been since 2002 assimilated in the numerical weather prediction models of Japan Met Agency (4-D variational data assimilation scheme built in the weather forecast models of JMA), wind profiler data of U.S. and Europe also used.

Severe rainstorm predication generally considerably improved by inclusion of wind profiler data.

Wind Profiler radar in China by Mr. Guan Hong
Good results from the experimental performances, therefore 30 operational wind profilers will be installed soon in China.

Vaisala Presentation by Martti Husu
This was a presentation on the benefits that Wind Profiles can bring to Weather Forecasting.

Benefits stated where: more data; accurate data; complimentary data; more frequent forecasts; can be used for calibration of numerical forecast model output in real-time.

Wind Profilers and Canada by Dr. Joe 
Canada is using profilers and also uses profiler data from the NOAA network.

Report on Wind Profilers, Data Availability and Quality Dr. Dominique Ruffieux from Meteo Swiss

Technical Presentation: Wind profiler, a useful tool for NMHS by Dr. Ruffieux

Presentation by Dr. Hans Richner from Atmospheric and Climate Science in Switzerland
Technical presentation on quality research on RASS and SODAR which Dr. Richner sees as they way of the future.

Presentation by Dr. Richner
Dr. Richner stated that:

 Radiosondes are “old” and “outmoded” technology.

C band radar is under threat, as the band will not be protected against other usage.

Wind Profilers frequencies also not safe.

Pulsed systems (meteorological radars and wind profilers) have problems because the spectrum/bandwidth is too wide in today’s world.

Difference between the bandwidth needed to be used and the bandwidth affected by the equipment should be as narrow as possible in order for efficient use of allocated bandwidth and the ability to protect ones bandwidth from outside usage.

Ultra Wide Band Systems (UWB Systems).

Constantly changing transmission frequencies (AWAKs use them) they are “invisible” and unable to be easily tracked resulting in secure radio links, also used for collision prevention car systems so cars do not interfere with each other’s systems on the road.

With UWB Systems 23.6 to 24 GHz is a range affected, which is also where the water vapor lines are detectable. The man made “background noise” thus adversely effects meteorological observations.

In Europe the UWB Systems will be allowed to use this frequency only until 2013. But in any case only in expensive cars and only be taking up 7% of the band. Japan has decided not to take up this frequency range. USA this range is still being disputed.

Dr. Richter’s conclusion is that this frequency range must be protected. Essential frequencies for passive meteorological sensing should be protected and others should be prioritized and compromises should be reached with methods of sharing.

Within ITU the Steering Group Radio Frequency Committee (SG RFC) experts are brought together, solutions are proposed, the continually changing uses of the spectrum are kept track o, and representation to the decision makers (the Member Countries of ITU) is made.

Note was made that the Galileo satellite had necessitated the withdrawal of the RS 80 radiosonde from Vaisala and its replacement by the RS 92. This was because of the interference from the satellite and the RS 80.

Unstable frequency from Radiosondes has at times been an issue. HMEI stated it would like to be kept informed by the Experts and National Weather Centres of their knowledge of these kinds of issues in order that HMEI can communicate these concerns to the manufacturing community.

Report on Weather Radar in Canada by Dr. Joe
Expanding and upgrading of the Canadian Weather Radar Network took place – 1997 to 2003.

Network now consists of 31 Doppler radars, up from 20. The network uses Magnatron radar transmitter. The radar networks is of in-house design and build as is the processing software, from expertise in the National and Regional Canadian Meteorological Centres and Research Offices and Universities Researchers.

Canada too has had problems with interference from radio “noise”.

BUFR and Radar:
Canada will be using BUFR coding for their radar data, but there are issues they need to solve with the implementation of this.

China New Generation Weather Radar Project (CINRAD) by Mr. Hong
China is to construct 158 CINRAD sites, 74 were already constructed and operational by end 2004 and 41 sites are currently being installed. This network consists of 3 types of S band radars and 4 types of C band radars. CINRAD has provided China with significant useful data on weather systems such as, typhoons, cold fronts, convergence lines, hail cloud and tornados.

Doppler Radar for Upper-air Observations in Japan by Dr. Ishihara
JMA currently has 20 conventional radar sites, 18 Doppler radars for airport weather and 1 Airport Weather Surveillance radar site.

Upon examination JMA has considered Doppler radars effective for NWP and monitoring of severe weather forecasting. JMA will replace conventional radars with Doppler radars to start an operational Doppler radar network for NMP in 2006.

Data quality control identified as the most important issue for effectiveness of Doppler radars, for weather services operation.

Report from the Met Office on Limitations of ATD for Lightning Detection near the UK by Dr. Nash
ATDNET has outstations currently in Europe, UK, Iceland, and Switzerland.

This network can be compared against long-range research systems: TOGA over Australia and New Zealand in Southern Hemisphere and Zeus.  

ATD can also be compared for Climatology against US satellite systems.

These comparisons enable new long-range outstations for ATDNET to be proposed in order to improve the Climatological sensitivity of ATDNET.

ATDNET is complementary to satellites in this area

ATDNET will be upgraded to improve detection efficiency over Europe.

Long-range detection of ADTNET will be expanded to cover Africa, with better location accuracy than currently available.

Location accuracy is to be improved over South America.

Met Office is willing to collaborate with other Met services to extend coverage globally.

Report on the Operational Use of Lightning Detection Methods in Brazil by Dr. Reinaldo Silveira
Dr. Silveira acknowledged HMEI’s support in contacting lightning manufacturers for information on lightning networks. Information was received from TOA and Vaisala.

Brazil has many regional networks, but gaps over many regions and over oceans (Asia, Africa are lacking).

There is a requirement for operational standards and inter-comparison between different systems. A presentation from TOA was shown to the meeting, including the technology used. The question was posed, should flash or stroke or both be detected?

Report on the AMS Lightning Conference by Martti Husu
This conference had over 60 papers and lots of material available. The conference will now be yearly.

John Nash noted that the only free data comes from the UK system, which is a long-range system at 10 kHz, but other countries have propriety restrictions on their regional data which is at a higher frequency, usually about 100 kHz to restrict long range interference.

Report on Lightning Detection Efficiencies and Accuracy Determination by Mr. Husu from Vaisala
This report discussed lightning towers and rocket borne lightning investigations. It also discussed video camera investigations, which are mainly conducted in the US.  Network inter-comparisons where noted as becoming very important as more networks are implemented.

Dr. Nash commented that what the user requirements are is a relevant question to which the answer is not really known. For instance NWP only needs 10 km, which is much less than what regional systems provide. Meteorologists are more interested in not missing a storm, rather than knowing the number of flashes. Most systems cannot confirm this, they are more interested in accuracy and the number of flashes, which is what electricity utilities require, not what meteorology requires.

Mr. Husu also reported on a long-range lightning detection network operating in North America.  This is a storm level detection network, rather than a flash detection network, as only about 20 percent of flashed are counted. This augments IR satellite imagery in differentiating convective storms from non-convective activity. 

Discussions resulted on how lightning detection influences NWP, and how is it assimilated into models, and how difficult this is. There was some skepticism as to whether this is possible at the moment.

Report on Lightening Detection and Other Weather Networks in India by Mr Lal
RASS system installed at Pune 2 years ago and operates well.

Plans to develop a lightning detection network.

IMD has 26 X band weather radars and 10 S band cyclone radars.

There is a current plan to replace all S band radars with Doppler radars, 3 have been done, and the fourth is happening now. More radars will be installed to fill gaps, 18 in total. Manufacturers are Gematronik and IRSO.

India has a pilot balloon network of 38 stations, which is planned to be updated with wind profilers.

India plans to upgrade its radiosonde network.

Report on Lightning Detection in Japan by Dr. Ishihara
JMA has a lightning detection network of 29 detection stations, based on SAFIR technology.

Integrated Profiling Systems and other Upper-air Measurement Techniques by Dr. Nash
There was a description of COST 720 – Integration observing systems for upper-air technology.

Dr. Nash described work on a 78 GHz cloud radar experiment. This seems to give as good results as an expensive 35 GHz pulsed cloud radar.  There are still some inherent problems with cloud radar systems, which manufacturers are investigating. 

It was reported that Japan has done an investigation of a 35 MHz system to detect and forecast sea fog.

Dr. Joe stated that giving drop size distribution could be very useful for fog investigation. But John stated that these systems do not do that.   

It was noted that the 78Mhz band is meant for car radars, and so 78MHz will not be used in the future, but will move to 94 GHz, which is an allocated satellite band and is also able to be used by these cloud radars. So the two frequencies that will be used operationally will most likely be 35 GHz and 94 GHz.

Integrated Profiling Systems and Other Upper-Air Measurement Techniques in Russian Federation by Dr. Eugeny Kadygrov
Microwave Temperature Profilers:
- Applications for Urban Climate Investigation
-16 operational systems installed in the Russian Federation
-Russia has bought three Metek sodars this year for installation in Moscow
-Temperature profiles from the scanning microwave profiler currently achieve 600 meters, and there are plans to reach 1km
-The technology was developed for space and has been changed to operate from earth surface. 

Also discussed LIDAR systems that are used in Russia.

Dr. Nash questioned the accuracy obtainable from microwave profilers. From his experience accuracy is not high, and not easily reproducible.

WINPROF Presentation by Dr. Engelbart
A consortium of several European countries is working on a wind profiler network and system , WINDPRF, which is being developed under the framework of COST 76.

Most countries have Vaisala wind profilers. BUFR code has been developed for the network. The network has up to 21 wind profilers and two sodars transmitting to the processing hub in Exeter. Also 23 Doppler radar wind profilers contribute to the network. It is a combination of a research system and an operational system.

Dr. Nash advised that one more wind profiler will be installed on the Isle of Man, making in total a UK network of 6 wind profilers.

Presentation on Cost Action 720 by Dr. Engelbart

Report on Integrated Systems in Canada by Dr. Joe
Four major integrated projects are running in Canada, including CMOST, AIRS, Cloudsat.

The four projects have a multitude of instruments that have to be integrated in order to produce system results. For instance, AIRS is involved with measuring ice and snow, and there are about 10 different types of instruments, both on the ground and on aircraft, that contribute to the final results.

Resulting Work Plan from this ET

Experts were nominated for the Work Plan items, to prepare input for CIMO XIV in February 2007.

HMEI will assist in item 2 -Radar, item 4- Lightning and item 6-Radio Frequency issues.