1. Early life and science in the USSR
Lev Gutman was born on 5 March 1923 and grew up in Moscow. His birthdate coincided with the date of Soviet Premier Josef Stalin’s death 30 years later in 1953. Consequently, his 31st birthday celebration was marred by visitors from the KGB checking whether the family was celebrating the first anniversary of Stalin’s death, and he had to prove that it was truly his birthday party by showing them his birth certificate. Even though his parents had little to do with science, Gutman developed a strong interest in mathematics during his school years and attended a special group for gifted children with mathematical inclination. In this group, he got friendly with twin brothers Isaak and Akiva Yaglom, both of whom later became famous mathematicians. As a teenager, he was fond of chess and reached a high level playing with his peers. Gutman graduated from high school in 1941 and entered Moscow State University without exams because of his Cum Laude certificate. This happened just before the German army invaded the Soviet Union on 22 June 1941. The University evacuated from Moscow to Ashkhabad, Turkmenistan, where Gutman spent his first two student years. In the middle of his studies, he was offered better conditions (higher stipend and bigger food rations) by the recruiters from the Hydrometeorological Institute, which had also evacuated to Ashkhabad. As a result, Lev graduated from the Odessa Hydrometeorological Institute, returned to Moscow in 1946, and started his scientific career (Fig. 1).
Lev Gutman in 1946 (Gutman family photograph).
Citation: Bulletin of the American Meteorological Society 105, 9; 10.1175/BAMS-D-24-0069.1
Gutman’s interests in dynamic meteorology were formed while working at the Central Institute for Weather Forecasts, which later became the Hydrometeorological Center of the Soviet Union, under the guidance of Ilya Kibel (1904–70)—a pioneer in meteorological studies based on the mathematical theory of fluid dynamics (see Izvekov 1946; Haurwitz 1946). As a mathematician, Gutman applied his tools in research areas adjacent to meteorology, such as soil temperature and moisture transfer, and ocean shallow layer problems, but his most significant early achievements were the creation of analytical mathematical models of meteorological processes, such as sea breeze, airmass flow over inclined terrain, slope winds, and convection.
During the Cold War, Soviet and western scientists were disconnected, working often in parallel without knowing about relevant achievements on the either side of the Iron Curtain. This was mitigated starting in the 1960s during the so-called Khrushchev thaw (after then Soviet Premier Nikita Khrushchev) when western scientific journals became available in libraries. Making copies of a publication, though, was always challenging, as copying was closely watched by security staff. Despite these challenges, references to papers in western journals appear in Gutman’s early 1960s publications in Russian. Moreover, international scientists started coming to scientific meetings in the Soviet Union, which helped Gutman establish personal communications with some of the period’s most famous scientists (see below). Travel abroad presented an insurmountable difficulty for Soviet scientists, however, and very few were allowed to visit western institutions. Gutman was invited many times to Europe, United States, and Japan, and his travel requests were always refused by the authorities, often without explanation.
International meetings held in the Soviet Union starting in the mid-1960s, however, provided Gutman opportunities to meet and exchange scientific ideas with prominent U.S. scientists, such as Jule Charney (1917–81), a leading world figure in meteorology and numerical weather prediction, and two pioneers in general circulation and climate modeling: Joseph Smagorinsky (1924–2005)—the Head of the Geophysical Fluid Dynamics Laboratory (GFDL) in Princeton, and Yale Mintz (1916–91)—a senior scientist at NASA Goddard Space Flight Center and later Professor Emeritus at Hebrew University in Jerusalem. Mintz traveled in 1966 to Siberia to visit the computer center headed by Gury Marchuk, where he befriended Gutman (Fig. 2). Mintz and Gutman continued their friendship long after Gutman immigrated to Israel in 1978.
Lev Gutman and Yale Mintz in 1966, cooking shish kebab on a fire near the house of Gury Marchuk, the Director of the Computer Center in Akademgorodok near Novosibirsk (Gutman family photograph.)
Citation: Bulletin of the American Meteorological Society 105, 9; 10.1175/BAMS-D-24-0069.1
Gutman met Smagorinsky at the International Conference on Sub-Grid Parameterizations in Leningrad in 1972. Participants of this conference are shown in Fig. 3; this photo was also included in Akira Kasahara’s memoirs published as an NCAR Technical Note (Kasahara 2015; Fig. 4 there), wherein he described his visits to the Union of Soviet Socialist Republics (USSR), including Novosibirsk, and the 1972 Conference in Leningrad.
International Conference on Sub-Grid Parameterizations in Leningrad, 1972. (from left to right) (first row) K. Miyakoda, V. Bugaev, M. Budyko, J. Smagorinsky, B. Bolin, A. Oboukhov, and A. Robert, the translator; (second row) German scientist, S. Manabe, A. Sarkisyan, O. Phillips, A. Yaglom, F. Bretherton, L. Gutman, and M. Yudin; (third row) T. Asai, S. Zilitinkevich, E. Feigelson, S. Kitaigorodsky, unidentified, D. Lilly, R. Jastrow, H. Panofsky, and A. Kasahara; (fourth row) German scientist, Y. Ogura, C. Rogers, P. Crutzen, J. Deardorff, P. White, and J. Brown; (fifth row) L. Gandin, V. Meleshko, H. Sundqvist, A. Wiin-Nielsen, and C. Leith, French scientist; and (sixth row) L. Matveev, M. Petrosyants, K. Bryan, P. Morel, unidentified, and E. Dobryshman. (Identifications by Garik Gutman; source: family album.)
Citation: Bulletin of the American Meteorological Society 105, 9; 10.1175/BAMS-D-24-0069.1
Soviet–American Symposium on Climate Modeling in Tashkent, 1976 [(from left to right) (first row) S. Manabe, J. Smagorinsky, M. Budyko, unidentified, translator, and unidentified; (second row) L. Gandin, Uzbek scientist, L. Gutman, I. Karol, G. Gutman, unidentified, G. North, unidentified, unidentified, Sh. Musaelyan, and V. Sergienko; (third row) T. Dmitrieva, Y. Mintz, unidentified, P. Stone, unidentified, B. Saltzman, L. Gates, R. Reck, unidentified, unidentified, V. Sadokov, V. Dymnikov, and M. Fox-Rabinovitz; and (fourth row) A. Bagrov, unidentified, unidentified, E. Borisenkov, unidentified, V. Meleshko, unidentified, V. Frolkin, unidentified, V. Penenko, and K. Vinnikov]. (Source: Gutman family photograph.)
Citation: Bulletin of the American Meteorological Society 105, 9; 10.1175/BAMS-D-24-0069.1
Both Mintz and Smagorinsky attended the Symposium on Climate Modeling in Tashkent in 1976 (Fig. 4), where, in private, Gutman discussed with them a potential scientific career in the west. Later, Gutman was told that his conversation with Smagorinsky in the bugged hotel room was recorded by the KGB so that his interest in emigration became known to the secret service. A description of the Tashkent 1976 meeting and the prevailing mood at the meetings between western and Soviet scientists during the Cold War can be found in Texas A&M climate scientist Gerald North’s memoirs (North 2020).
Among Gutman’s numerous friends and colleagues in the USSR were three prominent scientists who influenced his career and directly affected his work. Gury Marchuk (1925–2013) (Fig. 5), who had the same adviser (Ilya Kibel) as Gutman, was renowned for developing groundbreaking computational methods, particularly for nuclear reactor calculations. In the early 1960s, Marchuk was the director of the computer center in Akademgorodok near Novosibirsk in western Siberia, later becoming President of the USSR Academy of Sciences. In 1963, he invited Gutman to join his center, which already had an electronic mainframe computer, a major advance over the small group of “human calculators” working on arithmometers, i.e., “mechanical calculators,” in Gutman’s Laboratory at the High-Altitude Geophysical Institute in Nalchik. In the late 1960s, Marchuk obtained a BESM-6 for the Center—the first Soviet second-generation, transistor-based computer, which was then comparable to the CDC 6600. BESM-6 required 200 m2 of floor space and had about 192 Kb in memory (compared to 8 Gb or more in current laptops). Marchuk and Gutman had many conversations about the future of meteorology in the USSR and the outstanding problems to be tackled.
The leading meteorologists and oceanologists of the computer center of the Siberian Branch of the Soviet Academy of Sciences and the leading oceanologists of the Institute of Oceanology of the Soviet Academy of Sciences at the computer center, Akademgorodok, 1975. (from left to right) In the sitting row, (first row) L. Gutman, (third row) S. Zilitinkevich, and (fifth row) G. Marchuk (A. Monin did not attend the meeting). (Source: Gutman family photograph.)
Citation: Bulletin of the American Meteorological Society 105, 9; 10.1175/BAMS-D-24-0069.1
Andrei Monin (1921–2007), known for his achievements in “similarity theory” for turbulence in stratified fluids and for developing the Monin–Obukhov length parameter, was Gutman’s friend and colleague from their early careers. Starting in the mid-1960s, Monin was the Director of the Institute of Oceanology in Moscow for more than 20 years. Gutman and Monin frequently discussed the theory of turbulence and mesoscale meteorological problems they were working on, sometimes involving heated debates over what terms to neglect or which parameter was most important. In 1950, they published jointly a theoretical model of local winds in mountainous regions (Gutman and Monin 1950).
Sergey Zilitinkevich (1936–2021) was the Director of the Leningrad Branch of Monin’s Institute of Oceanology. He had many interactions with Gutman, as both worked on boundary layer problems. After the 1991 breakup of the USSR, Zilitinkevich worked at the Max Planck Institute for Meteorology (Hamburg, Germany), at Uppsala University (Sweden), and in his last years at the University of Helsinki (Finland). Gutman and Zilitinkevich met whenever Gutman traveled to northern Europe in the 1980s and 1990s.
Later in life, while visiting U.S. institutions, Gutman had the opportunity to meet and exchange ideas with leading meteorologists, including Ted Fujita (1920–98), Doug Lilly (1929–2018), and T. N. Krishnamurti (1932–2018). Gutman’s 1980 visit to the Center for Analysis and Prediction of Storms, Norman, Oklahoma, helped promote his earlier work, including topics in his 1972 monograph on katabatic winds, turbulent boundary layers, and air motion over thermally inhomogeneous terrain (e.g., Shapiro and Fedorovich 2007; Shapiro et al. 2022).
Most of the research in fundamental science in the USSR was conducted not at universities but at a specially created network of institutes, laboratories, and observatories. The more prestigious of the institutes were parts of the USSR Academy of Sciences; others fell within the system of specialized academies or the research arms of various government ministries. The Academy of Sciences of the Soviet Union, established in Leningrad in 1925 and moved to Moscow in 1934, included some 300 scientific institutions with over 60 thousand researchers just a couple of years before the Soviet Union’s dissolution. The academy had its own publishing house, a fleet of research ships, and a network of libraries (see Graham 1975).
Gutman spent the late 1950s and the early 1960s at the High-Elevation Institute of Geophysics in Nalchik, a city in the foothills of the Caucasus Mountains, where he organized a Laboratory for Mountain Meteorology and cultivated a group of researchers working on various mesoscale processes, e.g., Vitaly Malbachov (atmospheric vortices), Vladimir Khalkechev (valley winds), and Anatoly Amirov (clouds), who coauthored papers with Gutman. Some of them followed Gutman from Caucasus to Siberia, when he was invited to head the newly established Laboratory for Mesoscale Meteorology at the computer center in Akademgorodok near Novosibirsk in 1963. Besides the research work at the computer center, Gutman held a professorship position at Novosibirsk State University. During the early 1970s, he hosted doctoral students from different regions of the USSR, as well as early career scientists from Europe, some on extended visits (which included the Siberian winter!), such as French scientists Jean-Pierre Labarthe and Michel Rochas, or on shorter visits, e.g., Svante Bodin from Sweden. As a result of his visit, Bodin (1979) used the mesometeorological set of equations, as suggested by Gutman, to establish a coupled forecast system with a large-scale weather forecast model driving the atmospheric boundary layer.
Since the USSR’s computer capabilities significantly lagged behind those of the west, Soviet scientists often relied on analytical mathematical techniques to model atmospheric phenomena. Examples of groundbreaking accomplishments using this approach include the Monin–Obukhov similarity theory, which forms a fundamental basis for our understanding of atmospheric turbulence. Gutman similarly achieved outstanding results using analytical methods, but much of it was unknown by western scientists since it was trapped behind the Iron Curtain. Gutman’s group at his laboratory used available computer facilities to further their research on the problems of mesoscale meteorology. His insights into the physics of meteorological processes, especially those developing over rugged, thermally inhomogeneous terrain and in cumulus clouds, provided a solid underpinning for future improvements in numerical forecast models.
In the USSR, Gutman was particularly renowned for his work in the analytical solutions of complex, nonlinear equations in mesoscale meteorology, which were summarized in his seminal work, Introduction to the Nonlinear Theory of Mesoscale Mesometeorological Processes. Published in Russian in 1969, it was translated into English in 1972, Chinese in 1976, and Japanese in 1971 and became a major textbook for specialists in dynamical meteorology. With the analytical approaches, the statement of the problems and their solutions, this monograph remains relevant to this day as a basic textbook on mesoscale atmospheric processes. However, it is not well known and/or accessible to western meteorologists. More details on Gutman’s scientific career in the USSR can be found in Baklanov (2009).
Gutman immigrated to Israel in 1978 and worked for 3 years at Tel Aviv University, continuing his research in meteorology, in particular the airflow over the inclined terrain (e.g., Gutman and Melgarejo 1981). He was then invited by Louis Berkofsky (1919–2007) to be a senior researcher at the meteorological unit of the Institute for Desert Research of Beer Sheva University located on the Sede Boker Campus, 34 mi south of Beer Sheva, where his research included modeling soil temperature and moisture distributions under vegetated cover and the theory of katabatic slope winds.
Gutman’s places of work varied with climates and cultures: from Moscow to Caucasus to Siberia and later Israel. Once he emigrated from the USSR, he traveled all over the world, lecturing at scientific institutions and finally meeting colleagues previously known to him only by name. When he passed on 30 September 2001, his suitcase was already packed for a trip to Southeast Asia, where he had been invited to give a series of lectures.
2. Mesometeorological studies
As noted in the introduction, Gutman’s many studies, often done with students and collaborators, led to his compilation of a comprehensive monograph on mesoscale meteorology. This monograph contains the fundamental equations of dynamic meteorology as applied to mesoscale meteorological problems, followed by analyses of specific mesoscale phenomena.
a. System of equations for mesometeorology.
Gutman’s (1972) monograph starts with the basic equations of dynamic meteorology, from which he then derives a system of equations for mesoscale processes. These equations are later applied to specific mesoscale phenomena, which were further described in the monograph and characterized as “the least dealt with in other books.” Gutman effectively isolated mesoscale processes from synoptic-scale dynamics by decomposing the variables into two parts—“main flow” and “disturbances.” He formulated boundary and initial conditions, depending largely on each given problem, and then provided practical recommendations on when certain terms in the equations could be neglected. As mentioned in the author’s preface, “in every chapter, except the second, analytical solutions of steady-state problems precede the linear solution of unsteady problems.”
b. Local winds.
Local winds, or mesoscale circulations, are generated by local thermal inhomogeneities, such as land–water boundaries, and by terrain variations. The effects of these thermal inhomogeneities and terrain on weather are ubiquitous worldwide. Gutman provided a robust theoretical foundation to investigate and understand these mesoscale circulations.
For example, Gutman and Monin (1950) considered an idealized problem of the wind flow above an infinite thermally nonhomogeneous slope. Their analysis showed that the mechanism of these flows is complex, including forces such as buoyancy and pressure gradients acting in opposite directions. In chapter 7 of his monograph, two limiting cases of local winds are analyzed: land–sea breezes (winds over a horizontal thermally nonhomogeneous surface) and slope winds (winds over an inclined thermally homogeneous surface). It is emphasized that understanding the regularities and structure of these winds is important for their effects on climate and the distribution of local flows at shores and in mountain regions. Understanding these mesoscale phenomena is also useful for practical applications, such as aviation and local weather forecasting, which require knowledge of local winds. In referring to the publication by Jeffreys (1922) on local winds, Gutman emphasized the limitation of the linearized solutions, since with mesoscale processes the nonlinear terms associated with advection can be of the same order as other terms and hence cannot be neglected. Gutman’s first (“candidate”) dissertation was devoted to the analysis of the sea-breeze structure in a nonlinear steady-state and unsteady-state problem (Gutman 1947, 1948).
The first hydrodynamic model of the steady-state slope wind was developed by Prandtl (1942) under the assumption that the mountain slope consists of an infinite, thermally homogeneous plane and that the eddy exchange coefficients are constant. Monin (1948) considered the case with eddy coefficients varying with altitude. Gutman (1953) generalized Prandtl’s solution for a case of unsteady flow over a low-inclined slope.
Gutman continued the work on slope winds throughout his life. Together with a prominent scientist Felix Frankl (1905–61), known for his outstanding works on gas dynamics, Gutman developed a thermodynamic model of a bora—a katabatic wind that occurs, for example, in areas near the Adriatic Sea, eastern Mediterranean, and Black Sea basins (Frankl and Gutman 1960). To encourage more observational studies on slope winds, he wrote a paper on the theory of katabatic winds (Gutman 1983). His publications on this subject in the Journal of Atmospheric Sciences include the theory of downslope windstorms in Gutman (1991) and Gutman and Apterman (1992), which is pertinent not only for the Antarctic but also for many other mountainous regions of the world.
Synoptic flow over mountains and hills also generates a variety of mesoscale waves. Linearization of the problem of the airflow over mountains is permissible only when the height of the relief is low (<150 m). Therefore, to account for important effects in the solution, it was critical in earlier works of the 1950s to tackle a nonlinear system of equations. The development of the nonlinear problem started in the late 1930s by Nikolai Kochin (e.g., Kochin 1938), who found a number of wave solutions in the steady problem of the motion of a two-layer incompressible fluid above an obstacle of finite height.
Gutman’s early interest in terrain effects on airflow and local winds was motivated by his supervisor Ilya Kibel, who solved the local wind problem (Kibel 1947) using a method that was first proposed by Kochin (1938) in constructing a theory of fronts and based on the neglect of vertical accelerations. Gutman (1957d) used Kochin–Kibel’s approach to overcome the difficulties in solving nonlinear problems by simplifying the initial system of equations and filtering out the majority of wave solutions (see Gutman 1957d for details). He worked in parallel and without knowledge of contemporary publications in western literature, e.g., Queney (1948) and Ball (1956). Further, Frankl and Gutman (1961) included the Coriolis force, as well as an interface between warm and cold air masses. Their study, based on the equations of “shallow water” theory, showed that there exist subcritical and critical solutions revealing the existence of pressure jumps, which helped explain the phenomenon of a bora. Gutman pursued his work on this subject with his doctoral students and postdocs in Nalchik in the early 1960s and published results for 2D (Khatukaeva and Gutman 1962a,b) and 3D problems (Khalkechev and Gutman 1963a,b).
Orographic effects on free atmosphere airflow were studied further by Gutman and Khain (1975), where the problem of airflow around a ridge with a characteristic horizontal scale of about 100 km was considered. The solution to the system of shallow-water-type equations, which included the Coriolis force, was determined by the value of the Rossby number R, which turned out to be on the order of unity, indicating the absence of geostrophic balance in mesometeorological problems. For R > 1, the solution was shown to represent harmonic waves on the lee side, while for R < 1, there were both continuous and discontinuous solutions depending on the steepness of the ridge slopes. Gutman’s last publication on a bulk theory of airflow along high mountains came out after his death (Burde et al. 2002).
c. Thermals/cumulus.
In chapter 4 of his monograph, Gutman provided a short review of the development of the theory of “thermals” (rising jets or ascending bubbles of warm air). The first study of the hydrodynamic theory of thermals was developed by Zeldovich (1937), who showed, using simplifications of the boundary layer theory, that the steady-state problem can be reduced to the solution of ordinary differential equations. This approach was validated by numerical solutions of Schmidt (1941) for the turbulent case and Gutman (1949) for the laminar axisymmetric case.
Gutman (1972) mentioned that in studies on the theory of thermals and for cumulus clouds, the simplified equations of motion and of heat conduction are analogous. It is the existence of the release of latent heat from condensation that makes them distinct. Of course, cumulus clouds are just visual manifestations of thermals when condensation occurs, but it is essential to discriminate between them as Gutman did.
Early 1D studies of the motion of individual cloud elements included Stommel (1947), Bunker (1953), and Malkus (1954). However, 1D models cannot account for important atmospheric dynamics in cumulus clouds. Gutman constructed a theory of cumulus clouds with 2D steady-state equations of atmospheric thermohydrodynamics in 1957, which became his second (doctoral) dissertation. Ogura’s (1963) review of numerical modeling of atmospheric convection provides a short description of the nonlinear, steady-state, analytic solutions for cumulus-type convection and tornadoes obtained by Gutman (1957a,b,c, 1961), where he proposed a time-dependent axisymmetric model, including equations for moisture droplets and a simplified formulation for turbulence. More on the development of the theory and models of cumulus clouds in the 1960s can be found in Gutman’s monograph as well as in Battan’s (1959) overview of cloud physics research in the USSR, where Gutman’s (1957a) model was referenced. In reviewing the citations and research over the decade of the 1960s, Battan (1969) remarked that “it is wasteful and unscientific for the communities of cloud physicists in the United States of America, Great Britain, and the Union of Soviet Socialist Republics to be learning so little from one another.” He concluded that “in the interests of arriving more quickly at the solution of the many problems confronting cloud physicists, it is essential that we learn from the work of others, regardless of the nationality of the scientist or of the publication.” This situation changed markedly for the better with the breakup of the USSR.
State-of-the-art research investigating cloud dynamics and microphysics is presented in Khain and Pinsky (2018), including several analytical results concerning the dependence of supersaturation with height and effects of turbulence and evaporation at the cloud edges. Many of Gutman’s results concerning the structure of cloud updrafts and downdrafts in clouds and the cloud environment were confirmed. Most bulk-parameterization schemes now use a supersaturation adjustment to calculate the changes in the liquid water content and temperature in multiple cloud models. This method, developed in Gutman’s earlier works, allowed one to analytically calculate the vertical profiles of liquid water content and supersaturation. That entrainment into convective clouds is carried out by thermals of comparatively large size was confirmed by Pinsky et al. (2023), which also confirmed Gutman’s (1957a) conclusions that updrafts in the convective clouds are substantially larger in magnitude than the downdrafts and they cover a smaller area. The conclusion that the role of turbulence within clouds is much larger than outside of clouds (see, e.g., Gutman 1972) was also confirmed.
d. Mesoscale vortices.
Chapter 6 in Gutman’s monograph is devoted to mesoscale vortices, such as whirlwinds and tornadoes. Unlike larger-scale vortices, such as hurricanes, the Coriolis force can be neglected in the system of equations for small-scale vortices, such as dust devils (of several meters) and small tornadoes (on the order of a few hundred meters). The primary importance of these vortices is atmospheric buoyancy. First attempts to describe the structure of atmospheric vortices using ideal fluid models were described by Brunt (1939). These theories did not suffice for calculating the flow pattern near the axis of rotation, since the velocity in the ideal fluid at the center is infinite. Introduction of eddy viscosity made it possible to eliminate singularities at the vortex axis (e.g., Burgers 1948).
Gutman (1957b) developed a theoretical model of a vortex using the solution of nonlinear equations with the heat flux equation, allowing for atmospheric instability and the equation of motion with the buoyancy force in explicit form. He showed that in an unstably stratified atmosphere, a relatively narrow vortex with a vertical axis having large rotational velocities may develop in the presence of a small amount of external rotation, maintained by the release of potential energy associated with the instability. More on the history of the development of studies of vortices in the 1960s is described in Gutman (1972) and in Lilly (1969), which provides a brief description of Gutman’s (1957b) model.
e. Fronts.
By the late 1920s, Kochin had established general properties of meteorological discontinuity surfaces and derived simple formulas for calculating the acceleration of fronts. Neglecting vertical accelerations was used in the mid-1930s by Kibel in constructing the theory of meteorological fronts. Contributions by Gutman and his coworkers to the theory of fronts are described in Gutman’s (1972) chapter 3. In the 1960s, the theory of fronts was developed by solving the equations for incompressible fluid. The simplified description of the interaction between the velocity and temperature fields made it difficult to estimate the error introduced by this simplification. Morozovsky et al. (1998), based on Gutman’s early work on fronts, developed a hydrodynamic model of a mature steady-state front, with the boundary between cold and warm air that moved over the surface at a constant speed under the influence of a specified geostrophic wind. They were able to reduce the problem to an ordinary differential equation, which admits a closed-form solution. Based on this solution, they determined the shape of the frontal surface and the structure of the air flows in the vicinity of the front. Additionally, the solution permitted the classification of mature fronts using only two basic dimensionless parameters (see Morozovsky et al. 1998 for details).
3. Conclusions
We provided a short scientific biography of Professor Lev Gutman, the milestones of his scientific career, and a summary of his seminal works on mesoscale processes, such as the structure of breeze circulation, cumulus clouds, mountain–valley circulation, katabatic winds, vortices, and fronts. During his late scientific life, he never stopped generating ideas for new, improved solutions, returning to some old problems published earlier, and tackling them at a higher level once he felt past barriers could be overcome with new knowledge, ideas, and accumulated experience.
Lev Gutman (Fig. 6) was a pioneer in mesoscale meteorology who did not receive proper recognition in his lifetime due to the political realities of the time—the Cold War between the United States and the Soviet Union. His monograph, Introduction to the Nonlinear Theory of Mesoscale Meteorological Processes, published in English in 1972, is a significant benchmark publication that summarizes not only his research but also that of others in the Soviet Union. Starting with basic equations in dynamic meteorology, making mathematical transformations, and neglecting (or accounting for) some terms in the equations, Gutman provided original and seminal fundamental research on mesoscale weather features caused by land surface heating due to thermal and terrain inhomogeneities. His analytical solutions for different mesoscale atmospheric features can be used to test numerical model solutions, as well as to provide needed theoretical understanding, which may not be achieved in numerical models.
One of the last photographs of Professor Lev Gutman (1923–2001). (Source: Gutman family photograph.)
Citation: Bulletin of the American Meteorological Society 105, 9; 10.1175/BAMS-D-24-0069.1
Gutman’s work indirectly influenced the development of the first version of the nonhydrostatic weather prediction model at the USSR Hydrometeorological Center in the early 2000s and significantly contributed to the efforts of its research group. He also inspired work on modeling mesoscale processes at the Israeli Weather Research Center in the MM5 NCAR–NCEP modeling system (Krichak and Alpert 2002).
Professor Gutman’s contributions illustrate how research paths within two distinct political environments developed. He focused on theoretical mathematical techniques since computer resources and capabilities were limited. This contrasts with the United States and elsewhere in the west, where mesoscale meteorological studies took advantage of much superior computer resources. Bringing these two paths together will provide synergistic capabilities that are more likely to advance knowledge in mesoscale meteorology than the two paths could do independently.
Acknowledgments.
Thanks go to the organizers of the virtual session in honor of Professor Lev Gutman’s 100th anniversary at the 20th Mesoscale Processes Conference, especially Allison Milliken and Yunji Zhang, who helped in coordinating the session and providing continuous technical assistance. This virtual session allowed bringing together the few people who, albeit retired, are still active in their research and have personal memories of Lev Gutman. The session was a trigger to develop this article. We are grateful to the Editor Kristine Harper for her editorial suggestions and thorough carrying out of the review process. Thanks also go to two anonymous reviewers for valuable comments.
Data availability statement.
Not applicable as no data or software have been used in this article.
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