Physical Oceanography, Vol.
MODELING OF THERMAL AND OXYGEN CONDITIONS
IN LAKE KINNERET (ISRAEL)
V. A. Ivanov, S. P. Lyubartseva, É. N. Mikhailova,
N. B. Shapiro, and B. S. Shteinman
Within the framework of a one-dimensional model taking into account the presence of an upper
mixed layer, we compute the seasonal variation of temperature and the concentration of dis-
solved oxygen in the central part of Lake Kinneret. The temperature conditions of the lake are
determined by heat exchange with the atmosphere, and the oxygen conditions depend on gas ex-
change with the atmosphere and oxygen consumption in sediments as well as on internal sources
and sinks. The latter are connected with oxygen supply in the course of photosynthesis and its
consumption for the oxidation of labile organic substance in the water thickness. In the period of
winter convection from December to February, when the upper mixed layer reaches the bottom,
complete aeration of water takes place. The presence of thermal stratification of the lake in the
remaining time results in oxygen deficiency under the thermocline.
Increasing anthropogenic action on the environment, in particular, on lakes, makes the problem of their
conservation and rational use the focus of attention of modern water-management policy. It should be empha-
sized that the strategy of environment-protective activity must be based on the results of ecological modeling.
The rate of processes taking place in water ecosystems is governed, to a considerable extent, by the space-time
scales of thermohydrodynamic phenomena. Hence, the development and improvement of thermohydrodynamic
models represent a topical scientific problem. The solution of this problem makes it possible to pass to a higher
level of understanding of the nature of lakes and of the development of methods for the diagnosis and prediction
of their ecological state.
From the ecological viewpoint, oxygen plays an important role in the processes taking place in lakes be-
cause it affects not only the chemical processes in the lake but also living organisms. Furthermore, oxygen is
one of the fundamental factors of water quality. At present, there are numerous modern models describing oxy-
gen distribution in lakes (Table 1) that are located in various latitudinal zones. Note that, up to now, a common
theoretical model suitable for the description of the whole variety of experimental oxygen distributions in lakes
has not been developed. Every quoted model is based on a certain, far from universal, hierarchy of processes
characteristic of the dynamics and biogeochemistry of a specific water reservoir. This fact results in certain dif-
ficulties when one tries to compare different models. The model proposed in the present paper is close to the
model  from the viewpoint of the given hierarchy of processes.
Lake Kinneret is a warm monomictic lake, which, according to the classification , means that complete
mixing in it occurs once a year, in winter, at a temperature higher than
4°C. The water reservoir is stratified
from March to December. From December to February, convective mixing takes place [8, 9], and, during this
period, the water temperature is minimum and constitutes
16°C. A specific feature of the stratification of
the lake consists of the presence of a well-pronounced upper mixed layer (UML). In summer, its thickness is
and, in winter, practically the entire water thickness represents the UML. The oxygen conditions of
the lake are determined by its thermal conditions.
From January to March, oxygen distribution is practically con-
Marine Hydrophysical Institute, Ukrainian Academy of Sciences, Sevastopol; Israel Institute of Oceanology and Limnology (Kinneret
Limnologic Laboratory), Israel. Translated from Morskoi Gidrofizicheskii Zhurnal, No.
58, January–February, 2002. Origi-
nal article submitted March 30, 2000.
0928–5105/02/1201–0043 $27.00 © 2002 Plenum Publishing Corporation 43