Home page of Zahari Zlatev (click here to see shortened version in Bulgarian)




Zahari Zlatev (Захари Златев)

Department of Environmental Study

Aarhus University 
Frederiksborgvej 399, P. O. Box 358 
DK-4000 Roskilde, Denmark




E-mail address: zz@dmu.dk or Zlatevi@adslhome.dk  
Web-sites: http://www.dmu.dk/AtmosphericEnvironment/staff/zlatev.htm


Biographical data


Born in Dobrich, Bulgaria (at that time Dobrich was a Romanian town)


Finished a secondary school (gymnasium) in Dobrich


MSc in Mathematics (special subject: Numerical Analysis), University of Sofia, Bulgaria 


PhD in Numerical Analysis, Sct. Petersburg University, Russia (then Leningrad, USSR)


Research Fellow (Institute of Numerical Analysis, Technical University of Denmark)


Assistant Professor (Mathematics Institute, University of Copenhagen) 


Assistant Professor (Institute of Mathematics and Statistics, Royal Veterinary and Agricultural University, Copenhagen, Denmark)


Associated Professor (Computer Science Department, University of Aarhus, Denmark)

After 1980

Senior Researcher, now emeritus, at the Department of Environmental Science, University of Aarhus, Denmark (the name of the institution changed several times, but the members of the staff remained practically the same; one of the former names was National Environmental Research Institute, NERI).

Sabbatical year

Senior Computer Science Researcher in the Centre for Supercomputing Research and Development (CSRD) at the University of Illinois at Urbana-Champaign (Illinois, USA)


Running (participated in five half marathons in Copenhagen (2015, 2016, 2017, 2018 and 2019).



Historical Studies: resulted in five fiction books treating some events from the Bulgarian history, which took place many years ago. The main characters in these books are Bulgarian rulers from the dynasty Dulo (the first Bulgarian dynasty for which some reliable messages in medieval chronicles have been found found). These books, written in Bulgarian and edited by Nadia Deleva, were published by TRUD Publishing House Ltd (Sofia, Bulgaria).


2009: Received the medal “Marin Drinov” from the Bulgarian Academy of Science for achievements in the areas of Numerical Analysis, Scientific Computing, Environmental Modelling and Influence of Climate Changes on Pollution Levels as well as for a successful collaboration with many Bulgarian scientists.

2019: Received a second medal from the Bulgarian Academy of Sciences.


Profesional Societies


I was a member for several other societies while I was still active researcher.






Major Fields of the Research Investigations


Scientific achievements



Click here to see information about monographs, proceeding volumes and special issues

Click here to see the publications with most citations (according to Google)

Click here to see the list of all scientific publications



·       Computing Reviews (http://www.reviews.com)

·       Mathematical Reviews (http://www.ams.org/mresubs)




  • ACM Transactions on Mathematical Software
  • Atmosphere and Ocean
  • Atmospheric Environment
  • BIT
  • Computers and Mathematics with Applications
  • Computing
  • Computing and Visualization in Science
  • Environmental Modelling and Assessment
  • Environmental Science and Pollution Research
  • International Journal of Environment and Pollution
  • Journal of Atmospheric Chemistry
  • Journal of Computational and Applied Mathematics
  • Journal of Computational Physics
  • Journal of Geophysical Research
  • Numerical Linear Algebra with Applications
  • Parallel Computing
  • Parallel Algorithms and Applications
  • SIAM Journal of Scientific Computing
  • Tellus

AOT40 Ozone Levels in Europe. High AOT40 levels are harmful for crops. In the light green areas, the pollution levels are under the critical value of 3000 ppb.hours). In the dark green areas, the critical level is exceeded up to two times. In the yellow areas the critical level is exceeded from two to three times. In the orange areas the critical level is exceeded from three to four times. In the most polluted areas of Europe, the red areas, the critical level is exceeded by more than four times. The results are obtained by running the Unified Danish Eulerian Model (UNI-DEM), discretized on a (96x96) grid, i.e. by using  (50 km x 50 km) grid-squares, over a space domain covering the whole of Europe together with parts of Africa, Asia and the Atlantic Ocean.

Organizer of workshops and mini-symposia at international conferences

·       Four workshops (1992, 1993, 1995 and 1996)

·       NATO ARW (Advanced Research Workshop) in Sofia (Bulgaria) 1998

·       Twenty-five mini-symposia at international conferences: Stanford (California, USA), Hamburg (Germany), Toronto (Canada), San Francisco (USA), Czestochowa (Poland), Copenhagen (Denmark), Limassol (Cyprus) and many times in different Bulgarian sites.


Courses given at foreign universities



Short information about the Unified Danish Eulerian Model


The development of the Unified Danish Eulerian Model (UNI-DEM) was started in 1980. Many colleagues from the Department of Environmental Science and the Technical University of Denmark contributed in the efforts to make this model more flexible and more efficient: first and foremost, Jesper H. Christensen, Jørgen Brandt, Carsten Ambelas Skjøth, Per Grove Thomsen, Jerzy Wasniewski and Claus Bendtsen. Several scientists from the Bulgarian Academy of Sciences (Krassimir Georgiev, Ivan Dimov, Tzvetan Ostromsky) have also very essential contributions, mainly for improving the numerical algorithms and the parallel performance.


The geographical spatial domain of UNI-DEM contains the whole of Europe and some of its surroundings (see the plot given above).


The model is three-dimensional and can be run on several different horizontal scales. The spatial discretization obtained by applying 480 x 480=230400 horizontal grid-points is the finest one. The number of the used in this case (10 km x 10 km) horizontal sells is 230400. Ten non-equidistant vertical layers are used in all versions of the model. This means that the semi-discretized model contains a system of 2304000 which was usually run over a one-year time-interval by using a stepsize of 30 seconds. These short details explain the enormous computational difficulties which have to be overcome. Much more information about UNI-DEM can be found in the monograph: Z. Zlatev and I. Dimov: “Computational and Numerical Challenges in Environmental Modelling”, Studies in Computational Mathematics. Vol. 13, Elsevier, 2006.   


Different scenarios have been developed and used to study effects of climatic changes on high pollution levels, which might be harmful for plants, animals and human beings: more details can be found for example in Z. Zlatev: “Impact of future climate changes on high ozone levels in European suburban areas”, Climatic Change, Vol. 101, No. 3-4, (2010), pp. 447-483.


Pollution levels in Hungary were studied together with scientists from the University of Budapest (Ágnes Havasi and István Faragó).


Pollution levels in England and the North Sea were studied together with either Roy M. Harrison from the University of Birmingham or Vassil Alexandrov from the University of Reading as well as with some of their co-workers.


Pollution levels in Bulgaria and in the Balkan Peninsula were studied together with scientists from the Bulgarian Academy of Sciences (Ivan Dimov, Krassimir Georgiev, Tzvetan Ostromsky, Dimiter Syrakov and Kostadin Ganev).


The group of Ivan Dimov from the Bulgarian Academy of Sciences (first and foremost, Tzvetan Ostromsky, Rayna Georgieva, Venelin Todorov) used furthermore the model in different sensitivity studies.


UNI-DEM was used in two comprehensive studies of European large-scale air pollution models within the project EUROTAC-2. The first study was coordinated by Heinz Hass (Ford Forschungzentrum, Aachen, Germany) and the second one by Michiel Roemer (TNO, Delft, The Netherlands). 


The applications listed above were described in several papers published in well-known international scientific journals.


It is worthwhile to emphasize here the fact that scientists from the Department of Environmental Study of the Aarhus University (Jesper H. Christensen, Jørgen Brandt and several others) developed a complicated and very efficient hemi-spherical model for studying transport of air pollutants in the Northern hemi-sphere.


Some results obtained in the Danish area over a period of sixteen consecutive years are shown below (results obtained by using measurements are also given when available).


Ammonia-ammonium levels in Denmark in the period 1989-2004



Three photos are attached below:

(a) receiving a medal from the vice-president Kostadin Ganev of the Bulgarian Academy of Sciences at the international conference on High-speed Computations held in September 2019 in the Bulgarian winter resort Borovets,

(b) the front page of one of my historical books published (in Bulgarian) by the “TRUD Publishing House”, Sofia,

(c) finishing successfully my fifth half-marathon in September 2019 in Copenhagen.







Click here to see shortened version in Bulgarian



Department of Environmental Study, Aarhus University, Denmark