Prof. Dr. Janjic made towering educational and scientific contributions, defining a successful career that spanned five decades. His early career included employment at the Center for Atmospheric Sciences of the PMF; the National Hydrometeorological Institute in Belgrade, Yugoslavia and the Republic Hydrometeorological Institute in Belgrade, Serbia.
Prolific work at the international research and education institutions, such as the European Centre for Medium-Range Weather Forecasts in United Kingdom; the University of Hamburg in Germany; the University Corporation for Atmospheric Research, The National Center for Atmospheric Research and the National Meteorological Center in the United States, rounded off his rich career.
Prof. Dr. Janjic made substantial contributions in all key areas of numerical modeling of the atmosphere that influenced scientific thought in the field. The scope of his scientific interest and expertise had been very broad, spanning all aspects of model dynamics and major aspects of model physics. His particularly significant scientific contributions of lasting value include, chronologically,
analyzing, developing and optimizing methods for numerical representation of pressure gradient force in coordinate systems that follow Earth’s surface, including incorporation of the effects of mountains in numerical models;
developing an energy and enstrophy conserving nonlinear advection scheme with controlled nonlinear energy cascade on semi-staggered horizontal model grids;
formulating and developing physical parameterizations, particularly those dealing with turbulence, moist convection, viscous sub-layer and surface processes (e.g. Bets-Miller-Janjic and Mellor-Yamada-Janjic Schemes);
developing an original approach to nonhydrostatic modeling for numerical weather prediction applications; and
developing a unified multi-scale (from meso to global scales, and from short range forecasting to climate simulation) model with several innovative and unique features.
Prof. Dr. Janjic had the leading scientific role in the development of four generations of well-known atmospheric models (HIBU, Eta, WRF NMM and NMMB models), the latter three of which being the primary tools for short-range weather forecasting in the U.S. over more than 20 years. Since the 1970s, these models have been in use at many scientific institutions and weather services worldwide for research and weather forecasting.
As evidenced by thousands of references in scientific literature (as of November 2019, Google Scholar 9000), Prof. Dr. Janjic’s scientific contributions have been influencing and inspiring the work of numerous scientists. Scientists have been using numerical models and the parameterization schemes that were developed and designed by Prof. Dr. Janjic and applied in other popular models such as the MM5 or WRF ARW. The impact of Janjic’s work reaches also the users of meteorological forecasts on all continents. For example, only the site www.meteoblue.com employing the WRF NMM and NMMB models has an average of 800,000 hits per day. The models that Prof. Dr. Janjic developed have been successfully used as drivers in other environmental applications such as the modeling for transport of atmospheric dust, pollen and sea salt, ocean dynamics and waves, and hydrology.