Академическое издательство «Гео»

Lake Baikal, natural landscapes, drought, excessive moistening, continuous periods.


Changes in hydrothermal conditions of the growing period on
the Baikal natural territory

E.V. Maksyutova* and N.N. Voropai*, **

*V.B. Sochava Institute of Geography SB RAS,
664033, Irkutsk, Ulan-Batorskaya str., 1, Russia, emaksyutova@yandex.ru
**Institute of Monitoring of Climatic and Ecological Systems SB RAS,
634055, Tomsk, Academichesky ave., 10/3, Russia, voropay_nn@mail.ru

We examine the hydrothermal conditions (the Si index) for 1961–2010 in the natural landscapes of the Prebaikalian and Transbaikalian parts of the Baikal natural territory (BNT), including the respective shores of Lake Baikal. It is found that the driest months in the Prebaikalian and Transbaikalian parts, respectively, are May–June and June, when severe droughts occur in all natural landscapes. It is established that whereas the first two decades (1961–1970, and 1971–1980) were more humid, the last two decades (1991–2000, and 2001–2010) have been characterized by the driest conditions. The study revealed the occurrence of significant (p < 0.05) positive changes from May to September, pointing to an increase in the recurrence of droughts with a maximum in July. It is found that the Transbaikalian part of the BNT is characterized by a higher recurrence rate of droughts, and by larger (in magnitude) values of the Si indices. The period under consideration showed a change in the distribution of drought phenomena across time and space. The dry conditions encompassing more than half the BNT were observed prior to 1986 in separate months of the growing period or continuously during two months. Starting in 1986, there occurred drought periods three months long or longer. The highest recurrence rate of the dry years was generally observed across the territory after the 1990s. It is shown that excessive moistening has a discrete pattern of distribution.

Lake Baikal, natural landscapes, drought, excessive moistening, continuous periods.

DOI: 10.21782/GiPR0206-1619-2016-5(20-28)