Degree of Master of

Diurnal temperature fluctuations

CEU eTD Collection
Along with seasonal fluctuations of the AALS water temperature, diurnal variations were also analyzed in 1970-1980. It is known that wide-ranging changes of the diurnal variations of water temperature are quite common for the arid and deserted areas with extreme continental climate where the Aydar-Arnasay lakes are situated.
Diurnal temperature fluctuations of the AALS surface layer can reach 9-11˚C on the certain days of the summer period. Constant winds promote good mixing and smoothing of diurnal variations of water temperature. For example, diurnal temperature amplitude in the Tuzkan lake makes up 2-3˚C. It was observed that fluctuations of water temperature diminish with depth; at the depth totaling 7m amplitude of diurnal variations of temperature is about 1˚C (Gorelkin 1977).

2. Mineralization as the one of the major research issue

In 1970s the expedition of the Central Asian Research Hydro-meteorological Institute examined that up to 97% of water resources of the whole Aydar-Arnasay system are concentrated in the main reaches of Tuzkan and Aydarkul lakes. According to the patterns of mineralization distribution in the lakes, three major zones were identified, i.e. western and eastern reaches of Aydarkul lake, and deep-water zone of Tuzkan lake. It was concluded that both wind-induced turbulence and delayed water cycle give rise to the smooth variation of mineralization within these zones (Nurbaev and Gorelkin 2004).
Regarding the research of the mineralization in these lakes, the expedition also confirmed that in 1972-1975 mineralization in the eastern part of the Tuzkan lake made up 4- 4,5 g/l, while in the western part – 2-2,5 g/l.
Kamilov and Urchinov note the fact that in the 1980s practically there were no water discharges from the Chardara reservoir. It resulted in an increased evaporation and gradual growth of mineralization respectively, as well as a decrease of lakes’ level, siltation, and deterioration of water quality in these lakes (Kamilov and Urchinov 1995). For instance, mineralization in the Aydarkul lake was 9-10 g/l and in the end parts up to 13-14 g/l, that had an adverse effect on fish reproduction (Nikitin 1991).

CEU eTD Collection
Recently, growth of the mineralization became one of the acute problems of the Aydar- Arnasay lakes (Nurbaev and Gorelkin 2004). Several national reports and articles have been devoted to this problem (Mahmudova 2004a). For this reason, we think it necessary to provide a scientific explanation of the mineralization process, i.e. to describe the main input and output components of the AALS salt balance, features of the hydrochemical regime, and different levels of mineralization in the AALS.

1.