Chapter 1: Introduction

Peter Lynch, Project Leader

The HIRLAM Project is a cooperative project for development of NWP models. The primary goal is to develop computer models for analysis and prediction which are state-of-the-art. These models are used as the basis of operational short range predicition in the participating institutes.

The HIRLAM 4 Project commenced on 1 January, 1997 and ran for three years, finishing on 31 December, 1999. The framework for the Project was a Memorandum of Understanding signed by the participating Meteorological Institutes. Overall responsibility for the Project rested with the Management Group, and the work organized in sub-projects, each with a coordinator. The research and development work was specified in a detailed Scientific Plan, which was revised annually.

This report summarizes the activities and achievements of the HIRLAM 4 Project over the period 1997-1999.

Memorandum of Understanding

The central purpose of the HIRLAM 4 Project was to provide participating weather services with the best possible numerical analysis and prediction system for short-range, high-resolution forecasting. To achieve this overall goal, several key requirements were identified in the MoU: The Members of HIRLAM 4 were the participating meteorological institutes: The French Meteorological Service (Météo-France) had a cooperation with the HIRLAM 4 Project, and participated in research related to several of the HIRLAM 4 Sub-projects.

The HIRLAM Council comprised the Directors of the participating meteorological institutes, including Météo-France. Overall authority for the Project was vested in the Council. The Council met seven times during the course of the Project.

The HIRLAM Advisory Committee (HAC) consisted of a representative from each of the Members, including Météo-France. HAC held six meetings during the Project. The Scientific Plan was prepared in accordance with the HIRLAM Advisory Committee guidelines and after consultation with the participating scientists.

Major Achievements of the Project

The major highlights of progress in research and development are identified here. Fuller details are given in the following sections.

The development of a variational data assimilation system was a major focus of research in the Project. A series of parallel data assimilation and forecast experiments were carried out to compare the performance of 3D-Var and OI. Forecasts based on 3D-Var assimilation were consistently better than the forecasts based on the OI assimilation. Development work in 4-dimensional variational data assimilation (4D-Var) continued with increased emphasis. The target for the Project was to demonstrate the technical feasibility of running 4D-Var operationally. The main highlights in data assimilation were:

Significant improvements to the forecast model were made over a wide range of areas. A list of the main changes in the reference system is given at the end of this chapter. The main highlights in this area are: A large number of improvements to the HIRLAM System have been implemented, many of them substantial in nature. These have lead to significant benefits in the HIRLAM reference system. Major system developments include: Finally, a vast number of minor code corrections were made. As a result, substantial improvements were achieved in operational forecasts produced by the HIRLAM System. A small sample of verification scores appears below.

Meetings Programme

An intensive programme of Meetings and Workshops was organized during the Project. Once each year there was an All-Staff meeting, where a large proportion of the HIRLAM staff participated. A full list of meetings is attached in Annex 1.

The first All-Staff Meeting of the Project was held in Dublin on 19-21 March, 1997. There were 29 participants. A full report of the meeting appeared in Newsletter No. 27. The 1998 All-Staff Meeting was held at Lysebu, Oslo, on 4-6 May. It was attended by 39 scientists. A report can be found on HEXNET, the HIRLAM extranet, and in Newsletter No. 31. The 1999 All-Staff Meeting was held on 15-17 March in De Bilt. There were 42 participants, making it the largest and, arguably, most successful, such meeting so far. A full report can be found on HEXNET and in Newsletter 33.

There were twenty-one Management Group meetings during the three-year period. Reports of Management Group meetings were made available to all scientists on HEXNET. The Management Group also carried out a programme of visits to the member countries during the course of the Project.

A large number of exchange visits took place during the period, in connection with research cooperation. A complete list is attached in Annex 2.

Publications

Nine issues of the HIRLAM Newsletter were published during the Project. The standard of production of the Newsletter was enhanced considerably. Sixteen HIRLAM Technical Reports and three major Workshop Proceedings were issued during the period. A good number of other publications produced within the Project, or directly related to it, are also listed in Annex 3.

Administration

The Project was managed by the Management Group which, as of January, 1997 was Due to pressure of other work, Sigbjørn Grønås was obliged to withdraw from the Group in mid-Summer, 1997. Bent Hansen Sass took over as Deputy Leader (Modelling) in September of that year. The Project Management Group, as of December, 1999 was as follows:

The staff complement of the Project is equivalent to 22 scientists. The total hours worked during the year, as reported from the member institutes, were monitored by the Project Leader, and were well in excess of the minimum levels specified in the Memorandum of Understanding.

Access to the ECMWF Computer System for research and development work was arranged through the provision of resources for a Special Project.

The HIRLAM Secretariat consisted of the Project Leader with supporting secretarial assistance provided by Met Éireann. The expenditure on the Project was in accordance with the budget, which was agreed annually by Council.

Sample Verification

Verification of the operational forecasts, from the seven centres where the HIRLAM model forms the basis of operations, are produced routinely. A selection of these scores has been collected each year for the period January/March, and they have been reviewed in HIRLAM Newsletters. Here we present a small sample of scores generated by the HIRLAM model run at Met Éireann in Dublin.

The figure shows the annual average scores for 24-hour forecasts of wind speed, pressure and temperature for each year of the HIRLAM 4 Project. Left panels are scores using the EWGLAM list of 55 stations over Europe. Right panels show scores using 12 Irish synoptic stations. It is clear from the figures that there has been a clear trend towards higher accuracy over the period of the Project. Over Ireland, the region most critical for local operations, forecasts of all surface parameter forecasts have improved consistently over the three-year period.

A wealth of evidence from other operational centres confirms that there have been significant enhancements to the quality and accuracy of operational forecasts as a result of assimilation and modelling developments during the HIRLAM 4 Project.

Figure: Annual Trends in Forecast Skill






Detailed Research Progress Report

The Scientific Plan was divided into three sections, dealing with Data Assimilation, Modelling, and System Management. Progress in each area is summarized here. Fuller details are found in the following Chapters, written by the Management Group members.

A comprehensive report by Nils Gustafsson on analysis appears below in Chapter 2. A full account of progress in the area of Modelling, written by Bent Hansen Sass, follows in Chapter 3. The developments in Systems Management and Embedding are described by Gerard Cats in Chapter 4.

1. Data Assimilation and Data

Development of a variational data assimilation system was a major focus of research in the Project. In fact, research on this had already begun in 1995. One of the principal arguments for variational assimilation is the feasibility of utilizing a wide range of non-conventional observations, such as radar and satellite data. Moreover, by applying 4-dimensional variational data assimilation (4D-Var), it is possible to include the time dimension explicitly.

Most data assimilation efforts during the HIRLAM 4 project were devoted to the development and testing of the HIRLAM variational data assimilation, and substantial progress was made. The HIRLAM 3D-Var and 4D-Var software system (HIRVDA) has been developed within a carefully coordinated research programme involving staff from several participating institutes. By the end of the Project, the superiority of the 3-dimensional variational data assimilation (3D-Var), in comparison with OI, had been demonstrated through parallel tests run over several months. Pre-operational tests during the first year of HIRLAM 5 are likely to bring 3D-Var into the operational HIRLAM reference system.

The HIRLAM variational data assimilation software package, HIRVDA, was developed to allow for the inclusion of radar and satellite data, TOVS profiles and ground-based GPS data. In addition, the technical feasibility of applying 4D-Var operationally was demonstrated by a series of experiments. Thus, the main 4D-Var objective was achieved.

Research efforts have also involved progress in soil and surface parameter data assimilation, development of flow-dependent analysis structure functions, and the improvement and maintenance of the OI based reference scheme.

At the commencement of the Project, the data assimilation of the reference HIRLAM system was based on analysis by Optimum Interpolation (OI) and initialization by a non-linear normal mode method. Towards the end of the period, a digital filter initialization was introduced, following extensive testing.

1.1. Variational data assimilation

1.1.1 Three-dimensional variational data assimilation (3D-Var)

Significant progress was achieved with regard to development of advanced 3D-Var structure functions, based on generalized linear balance constraints. The new structure functions have been tested and compared with the standard version structure functions in a parallel run. The results indicate a marginal positive impact.

The HIRLAM 3D-Var, and also the 4D-Var, have been developed with an incremental formulation. This allows for exploitation of advantages of both the spectral and grid-point model versions. Parallel assimilation and forecast experiments have shown that this incremental formulation performs satisfactorily.

The software package for handling observational data (OBSPROC) in the Comprehensive Memory Array (CMA) format, has been adapted for use in the HIRLAM 3D-Var. Documentation of the CMA system was carried out in collaboration with ECMWF. A software package for observation screening, including quality control and data thinning, was developed and tested. A general set of observation operator subroutines for treatment of conventional data has been developed. Non-linear, tangent-linear and adjoint versions of the observation operators were written. A general software framework for inclusion of remote sensing data was developed.

An optimized 3D-Var (and 4D-Var) software package, prepared for parallel computers with explicit message passing between the processors, was developed. Tests on both shared memory and distributed memory machines were carried out successfully.

A series of parallel data assimilation and forecast experiments were carried out to compare the performance of 3D-Var and OI. The results of the tests carried out in SMHI and DMI indicated that the forecasts based on 3D-Var assimilation were consistently better than the forecasts based on the OI assimilation. A sample of verification scores from Lindskog et al. (2000) for mean sea level pressure and 2 meter temperature may be found in Chapter 2 of this Report.

Single observation impact experiments have been done to validate the efficiency of the background error constraint to spread the observed information in space. These experiments confirmed the possibility of applying non-zero lateral boundaries during 3D-Var.

A different approach for handling the background error constraint, using a simple matrix transform within physical space to avoid the inversion of the back-ground error covariance matrix, has been investigated. This has been shown to work satisfactorily in a simple context.

1.1.2 Four-dimensional variational data assimilation (4D-Var)

Development work in 4-dimensional variational data assimilation (4D-Var), which started in 1995-96, continued with increased emphasis during the HIRLAM 4 project. The target for the Project was to demonstrate the technical feasibility of running 4D-Var operationally.

The development work for one of the critical 4D-Var components, the adjoint physics, advanced significantly during the Project. The strategy of using full physics in the adjoint package was chosen for the first phase of the 4D-Var development. The tangent linear and adjoint models of a complete physics package (HIRLAM reference version 4.2) have been coded and a code verification has been made. Some preliminary sensitivity experiments using the full adjoint physics were performed and results were encouraging.

As an alternative to full physics, the regularized and simplified physical parameterization schemes of Météo-France have also been considered for inclusion in the HIRLAM 4D-Var. For this purpose, an interface to the Météo-France physical parameterization package was been developed and tested.

The adjoints of the lateral boundary relaxation scheme have been coded and tested. The experiments indicated that there is a possibility to control lateral boundary conditions within the framework of 4D-Var by the aid of observations inside the model integration area.

A weak digital filter constraint has been included as an option in the HIRLAM 4D-Var software. The digital filter constraint enters as an extra term in the cost function to be minimized. This constraint was tested and compared with the standard non-linear normal mode initialization constraint in connection with the technical demonstration of the HIRLAM 4D-Var. The weak digital filter constraint appeared to perform satisfactorily.

A technical demonstration of the feasibility of running 4D-Var operationally was carried out during autumn 1999. The experiment was run for a 4 day period without any problems. Forecast verification scores were comparable to the corresponding 3D-Var verification scores.

1.2. Flow-dependent Analysis Structure Functions

An efficient and simple way to introduce flow-dependent analysis structure functions is to use flow-dependent coordinate transformations. This idea has been developed and tested successfully at DNMI using a successive correction system. A parallel test using the HIRLAM 50 km system at DNMI was carried out. A systematic reduction of the RMS errors of geopotential was found. On the basis of those results, the method was made operational in the 50 km model at DNMI from May 1997.

Possible strategies for performing the coordinate transformation in the 3D-Var scheme were investigated, and in particular the possibility of performing the transformation in the spectral domain.

1.3. Development and Maintenance of Optimum Interpolation (OI) Analysis

Substantial efforts were required to ensure that the reference OI system continued to perform satisfactorily. This is absolutely essential, as the OI system is used in all the seven centres where HIRLAM is run operationally. A full description of OI work is found in Chapter 2.

Initial development of a distributed memory parallel version of the OI analysis, using MPI for communication, was undertaken by John van de Vegte at KNMI. A parallel version using the SHMEM message passing library was developed at SMHI in collaboration with SGI/Cray. This was modified by SGI/Cray in collaboration with DWD, to use the MPI library. Later, preliminary work to adapt this for the HIRLAM reference OI system was started but, in view of the impending availability of the 3D-Var assimilation system, further work was suspended.

The impact of the additional FASTEX radiosonde observations on the HIRLAM data assimilation and forecasting system was tested in a 2 week parallel run. Averaged over the whole period, the impact is consistently positive, especially on upper model levels.

1.4. Soil moisture analysis

An improved soil moisture assimilation scheme was developed and is an integrated part of the ISBA scheme that has been put into operational use at Météo-France.

1.5. Assimilation of moisture and cloudiness information

Results from the MetCast system for cloud forecasting in the very short range at KNMI have been published in a HIRLAM Newsletter article. MetCast has been made operational at the KNMI.

Some testing of a nudging technique for nowcasting purposes have been done at SMHI, using cloud information mainly from satellite information. The nudged forecast has been digitally filtered in order to get the initial state for nowcasting. The differences between the cloud fields in the nudged forecast and the original forecast are small over most of the area, but significant in some places.

1.6. Assimilation of remote sensing data

Progress has been made on assimilation of TOVS retrievals, produced by the 1D-Var package, and in assimilation of scatterometer winds. With hindsight, it is clear that the HIRLAM 4 Scientific plan was over-ambitious with regard to the assimilation of remote sensing data. However, substantial progress on variational data assimilation (3D-Var and 4D-Var) will now make developments in the use of remote sensing data easier to achieve.
1.6.1. Satellite sounding data (TOVS and ATOVS).
Development efforts with regard (A)TOVS data assimilation have been strengthened during the HIRLAM 4 project and several countries have initiated projects on this topic, partly with support from external sources. Coordinated efforts are now being undertaken at FMI, INM, KNMI, SMHI, IMO and DNMI.

The TOVS 1D-Var sounding retrieval package was implemented and tested in the HIRLAM system. The temperature and humidity profiles retrieved in this way are assimilated into the HIRLAM OI assimilation system. A systematic improvement due to the assimilation was observed in verification scores.

1.6.2. Satellite Scatterometer Winds.
Impact experiments with HIRLAM and tandem ERS-1 and ERS-2 scatterometer wind data have been done. The tandem winds clearly have a beneficial effect, but single scatterometer data does not yield significant improvement. The improved scatterometer processing, PRESCAT, is being included in the HIRLAM system.
1.6.3 GPS Data
At DMI, assimilation tests have been performed using retrieved GPS temperature profiles within the HIRLAM OI framework. DMI is also involved in an EU project for near real-time delivery of Zenith Total Delays derived from ground based GPS measurements. SMHI is involved in a project to assimilate the total delay of GPS satellite to earth signals in order to improve moisture fields. INM is investigating the possible benefit of GPS Zenith Total Delays in NWP. No real-time space-based GPS data is being received currently and no data assimilation of these data is performed at this time.
1.6.4 Other Data
At INM, locally received AVHRR data are used in an optimum interpolation scheme to generate analysed SST fields for the forecast model. The verification scores of surface parameters show a significant benefit of this analysis, mainly over Ireland, England, Spain and Portugal. NOAA SST data are being evaluated for implementation in HIRLAM at KNMI.

The NWP SAF (Satellite Application Facility) started on 1 January 1999. Requirements for satellite data processing within HIRLAM were discussed and agreed during a meeting held in Noordwijk aan zee in November 1999 (see Newsletter 34).

2. Model Developments

Introduction

This is a summary of the report on Modelling written by Bent Hansen Sass which appears in Chapter 3 below. A comprehensive range of modelling activities have been undertaken during the Project. These have lead to significant benefits in the HIRLAM reference system. A full list of the Model Upgrades is given at the end of this chapter.

2.1. Physics

2.1.1. Turbulence parameterization

During the initial phase of the Project a non-local first order turbulence scheme was implemented in the HIRLAM reference system. Extensive evaluation showed that improved overall performance was achieved with this scheme. However, it also had certain short-comings. Therefore, attention was directed to the implementation of a higher-order scheme. Two candidates with turbulent kinetic energy (TKE) as a prognostic variable, were evaluated, the `CBR' scheme (Calvo and Cuxart 1998, Cuxart et al., 1999), and the K-epsilon scheme (Perov and Gollvik 1996).

Extensive experimentation and validation of 3-dimensional case studies and parallel runs with the turbulence schemes was carried out. On the basis of the results, it was decided that the CBR scheme should become the reference turbulence scheme. The new scheme significantly alleviates an old model problem of filling of old cyclones over Northern Europe.

2.1.2. Surface processes

The drag coefficients were revised to make the parameterized fluxes more realistic. After successful 3-D parallel runs it was decided to implement these modifications along with improved diagnostic formulae for temperature, humidity and wind speed in the unstable planetary boundary layer.

The HIRLAM version of the ISBA scheme was recoded to improve its structure and facilitate collaboration with Météo-France. Several tests were carried out with the new scheme. It had not reached a state of readiness for operational implementation by the end of the Project. The final tests, including the new climate generation scheme, soil moisture assimilation and the latest version of the ISBA scheme, and also the improved surface flux computations over sea, will be carried out in the HIRLAM 5 project prior to implementation as a new HIRLAM reference.

2.1.3. Clouds and Condensation

In early 1998, the Tiedtke mass flux convection scheme, together with the HIRLAM 3 condensation code. was implemented in the reference model. However, the performance of the scheme was not entirely satisfactory. A `CAPE' closure was implemented and tested, with encouraging results. In parallel, a recoded condensation scheme was developed, in an effort to alleviate reported problems. This scheme, called STRACO, was introduced in the reference system, following comprehensive parallel testing.

A review on the subject of cumulus parameterization in regional forecast models (Bister, 1998) recommended the Kain-Fritsch scheme for parameterization of convection as a good candidate for a high resolution HIRLAM. Encouraging results have been reported with the Kain-Fritsch scheme in a preliminary study of a tropical cyclone (Hurricane `Flo').

At the end of 1999, the Rasch-Kristjánsson scheme had been run together with Tiedtke mass flux scheme and with the HIRLAM version of the Kain-Fritsch scheme in the framework of HIRLAM 4.6. More work is needed to test the Rasch-Kristjánsson scheme and the Kain-Fritsch convection parameterization, in particular with regard to the cloud parameterization.

2.1.4. Radiation

An improved version of the HIRLAM radiation scheme was developed and tested during HIRLAM 4. The treatment of clouds was improved by parameterizing an effective radius describing the size of cloud droplets and ice crystals. A parallel run with the new scheme gave results comparable to the reference model. Further testing was under way at the end of the Project.

2.1.5. Physiography

A major development of the climate generation system has taken place, using an efficient, machine-independent format, the Hierarchical Data Format (HDF). New basic global data sets have been employed. The new climate generation has been implemented in the HIRLAM reference system. Tests with the ISBA surface parameterization scheme are under way.

2.1.6. Other Physics Work

In the current HIRLAM system, the momentum drag is parameterized from an effective roughness length. A gravity wave drag parameterization (GWD), is under consideration. The disadvantages of not having a GWD parameterization have apparently decreased with the implementation of the CBR TKE scheme.

Filtering of orography has been shown to reduce numerical noise including precipitation features in hilly terrain.

Preliminary experiments with physics computations in a coarse grid have indicated some possible advantages. Recommendations from the Workshop on high resolution modelling support further research in this area.

Progress has been made to update the interface to the Arpege/Aladin Physics Package. This work is important for developing and testing code for 4D variational data assimilation.

Work on the ECMWF Physics Package started towards the end of the Project.

2.2. Numerics

2.2.1. Time integration methods

Substantial progress has been made with development of the semi-Lagrangian scheme. The method for computing the departure point in trajectories has been improved. This has the effect of reducing the generation of numerical noise on the smallest scales. Also, some significant programming errors have been detected and corrected. The combined effect of the changes is a substantial improvement compared to the previous version of the scheme. This has been indicated by extensive testing. Bias problems in geopotential height seen in earlier versions have been greatly reduced. The new scheme is destined to become the default HIRLAM code as soon as remaining coding problems (associated with the MPP code) have been solved

2.2.2. Lateral Boundary Condition

A systematic approach to study and improve on the treatment of the lateral boundary conditions began in HIRLAM 4.

A proposal for additional model runs at ECMWF to provide improved boundary conditions has been approved by the ECMWF Council. It is expected to become operational during 2000, and should result in significant improvements in the accuracy of limited-area forecasts based on the HIRLAM System.

2.2.3. Non-hydrostatic equations

In view of the expected increase in model resolution over the next few years, the issue of non-hydrostatic modelling will become increasingly important. Work on development of a non-hydrostatic version of HIRLAM has continued by the Tartu group. The precise approach to be adopted for future HIRLAM systems is still open.

2.2.4. Digital filter initialization

A digital filter initialization scheme was implemented and tested in the HIRLAM reference system in 1999. The filter is more efficient that NNMI in removing spurious high frequency noise. In a parallel run using FASTEX data, the scores produced by the digital filter initialization were significantly better than those of the reference run.

2.2.5. Other Model developments

A spectral HIRLAM model version has been maintained, and has been used in the context of 4D variational data-assimilation.

A stretched grid version of HIRLAM has been coded, in collaboration with the Hitachi Dublin Laboratory. The preliminary experiments have been encouraging. The method needs to be further tested on large model domains.

3. System Management and Embedding

Introduction

This is a summary of the report on the HIRLAM System, written by Gerard Cats, which appears in Chapter 4 below. A large number of improvements to the HIRLAM system have been implemented, many of them substantial in nature. These have lead to significant benefits in the HIRLAM reference system.

Meteorological improvements were obtained with the implementation of the following model upgrades:

The technical aspects of the implementation were taken care of by the System Management group. These included writing the technical documentation and making that accessible over the HEXNET.

The extranet system, HEXNET, has been introduced and developed for use in HIRLAM. It has proved invaluable for communications and for documentation. Its content and use are growing rapidly. An ftp server has also been provided for HIRLAM. The cooperation and support of KNMI in the development and maintenance of these systems is gratefully acknowledged.

A large number of technical improvements to the reference system were made during the Project. Utilities to facilitate local installation were developed. The HIRLAM System was modified to make it `Millennium-proof'. Performance of the system on a range of hardware architectures was improved.

A `Version Control' mechanism was introduced to facilitate numerical experimentation. A diagnostics package was added to the system. The verification package was extended. A Java-based browser has been developed for use with the HIRLAM Fortran code.

The system was adapted to allow for the 50 and 60-level ECMWF model. HIRLAM can now also run from products of the European Re-Analysis project. A facility has been introduces to ensure that the system adjusts automatically when a new orography field is introduced by ECMWF.

Finally, a vast number of minor code corrections have been made. As a result, substantial improvements have been achieved in operational forecasts produced by the HIRLAM System. Comparative objective verification of operational forecast systems confirms this.

3.1. Enhancement of efficiency of the reference system

In collaboration with EMCWF staff, a system was designed to run the reference system over an inhomogeneous network of computers. The system is based on the principle that it should be compatible with SMS, the Supervisor Monitor Scheduler, used by ECMWF and some HIRLAM member states. To this end, ECMWF staff wrote a simulator of SMS, with reduced functionality. It is now possible to run the system distributed over SGI and Fujitsu to improve throughput.

3.2. Post-processing and verification

The current HIRLAM code incorporates a system for the verification of surface variables and model verification, following the guidelines of the European Working Group on Limited Area Models, EWGLAM. This system provides a crude indication of performance and allows for a broad comparison of HIRLAM with competing limited area models. A meeting was held in De Bilt in 1999, to determine the requirements of a new verification system. Work has begun on implementing the recommendations of that meeting. This work will be continued. In particular, methods are required for verification of model behaviour in extreme events.

3.3. Model diagnostics

A comprehensive diagnostics package was implemented in the HIRLAM reference model. Its memory requirements are big, and hence the package was made optional: it can be switched off in operational runs, and activated as required. The package has already proven its use by indicating inconsistencies in the turbulence scheme.

3.4. Parallelization

At the beginning of HIRLAM 4, the OI analysis scheme and the forecast model were coded for parallel execution on shared memory machines. During HIRLAM 4, code to run the OI scheme on a distributed memory machine, using MPI for communication, was developed.

The forecast model was recoded to allow parallel execution on distributed memory systems. The current code performs very well on shared memory machines, and on distributed memory machines using the `SHMEM' paradigm. MPI code has also been developed. Initial results indicate that there is considerable room for improvement.

3.5. Documentation

In order to facilitate communication in the HIRLAM project, an extranet for HIRLAM, the HEXNET, has been put in place. HEXNET has grown into a powerful means for communication. Much of the documentation that exists for HIRLAM has been made available on HEXNET.

The current version of the graphical user interface (GUI) for HIRLAM allows selection of a geographical areas for defining a HIRLAM run and for displaying results. Further development will be required to make the GUI ready for release.

Version 1 of a code browsing system has been released. Version 2 became ready just before the end of the Project, but some work needs yet to be done to facilitate its local installation.

Main Forecast Model Upgrades.

Below is an overview of the main model upgrades which were introduced during the Project. A more comprehensive list is kept on HEXNET.

HIRLAM 4.1.0; released 16 Feb 1998.
The main model changes between 4.1.0 and 2.7.16 are:
- Holtslag (non-local) vertical diffusion
- Mass-flux scheme in Sundqvist

HIRLAM 4.1.1; released 9 March 1998
Introduce non-dimensional diffusion coefficients, to result in automatic scaling of horizontal diffusion with horizontal resolution.

HIRLAM 4.2.0; released 15 June 1998
Use the STRACO condensation scheme by default.

HIRLAM 4.3.1; released 30 November 1998
Revised boundary relaxation of cloud condensate.

HIRLAM 4.3.5; released 9 March 1999
Upgraded semi-Lagrangian and mass-flux schemes

HIRLAM 4.4.0; released 22 April 1999
Massively parallel forecast model code.

HIRLAM 4.4.3; released 8 June 1999
DMI physics upgrade
- improved surface fluxes over sea
- upgrades to STRACO scheme (scale dependent formulations)
- improved diagnostics of near surface parameters in the unstable boundary layer.

HIRLAM 4.5.0; released 31 August 1999
CBR scheme, diagnostics package, options array, code corrections.

HIRLAM 4.6.0; released 13 September 1999
Semi-Lagriangian advection upgrade (option)

HIRLAM 4.6.3; released 25 October 1999
Move to DFI initialization;

HIRLAM 4.7.0; released 13 December 1999
New climate generation package - improved orography.

HIRLAM 4.7.1; ( January 2000 )
Updates to the HIRLAM radiation scheme (effects of parameterized size of cloud hydrometeors).

Remainder of Report

The following three chapters, written by members of the HIRLAM Management Group, give a very detailed account of work undertaken in the areas of assimilation, modelling and system management: Note: Remaining sections not accessable from here. Please apply to Peter.Lynch[.AT.]met.ie

Chapter 2: Data Assimilation and Data, by Nils Gustafsson.
Chapter 3: Model Developments, by Bent Hansen Sass.
Chapter 4: System and Embedding, by Gerard Cats.

The report also contains three Annexes:

Annex 1 contains a list of HIRLAM 4 Meetings.
Annex 2 is a selected list of Exchange Visits during the Project.
Annex 3 is a list of HIRLAM and related Publications.




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