The greatest level of precipitation is reached in mountains, mainly as snow with a maximum level of 1000 mm on slopes of Fergana valley. A level of precipitation in Talas region changes from 250 up to 500 mm, on the Issyk-Kul Lake from 200 mm of precipitation on the west up to 600 mm on the east. A rain and snow drop out usually in the autumn, winter and spring; sometimes snow may drop out in May.
A potential annual level
of evaporation changes from 200 mm at a large height (more than 3500 m)
up to 1600 mm in low regions. Evaporation in main irrigated regions varies
from 1200 up to 1600 mm, much more exceeding an average level of precipitation
(400 mm).
The climate renders a significant
influence on natural and anthropogenic ecological systems. A change of
climate is one of major factors in evolution of biosphere.
Consider the brief items
of information on modern changes of climate of Kyrgyzstan, by giving main
attention to two meteorological elements:
In a long-term course of annual sums of precipitation a gradual their decrease is observed. A sum of annual deposits for period of 1965-90 has decreased on 12 mm (3%) in comparison with the previous period of 1930-64.
The analysis of distribution of atmospheric droughts (spent on a basis of an index of aridity) on a degree of their intensity for period of 1960-92 has shown a change of climatic conditions of Chu valley in direction of aridity:
It is possible to consider that the reasons of observable changes, first
of all, are anthrpogenic influence on climatic system (increase of concentration
of thermodynamically active impurities, cutting down woods, desertification,
change of properties of a spreading surface).
As an example, consider an influence of aerosol on transparency of
atmosphere on the territory of Kyrgyzstan. The temporary analysis of atmosphere
transparency coefficient shows that, in separate periods, its essential
change is observed. Such changes are connected with natural and anthropogenic
processes of global scale (volcanic eruption, dust storms, petroleum fires)
and are characteristic of the whole territory of the republic.
On a background of such decreases and increases of atmosphere transparency
caused by its global pollution, the determined component is precisely observed
indicating on gradual reduction of atmosphere transparency. It is characteristic
that a velocity of development of descending trend of atmosphere pollution
depends on a degree of urbanisation of researched region.
A decrease of atmosphere transparency was 3.6% for Tyan-Shan station
and 10.3% for Bishkek station. Estimations of anthropogenic load of global
and local scale showed that in Bishkek, being in industrial zone, the local
atmosphere pollution was 2 times exceeds a pollution caused by transboundary
transfer.
Change of climate may result in
irreversible processes in a regime of modern ice accretion of Tyan-Shan
and Pamir.
On the territory of Kyrgyzstan ice-houses occupy 8169.4 sq. km; 3400
sq. km of them forms a drain of the rivers Sir-Darya and Amu-Darya.
Now, ice-houses are in a
phase of regress. For period of 1957-80, 1081 ice-houses disappeared on
Pamir-Alai, 71 ice-houses on Zaili Alatau. A volume of ice-houses of Akshirak
massif forming drain of the river Large Narin sharply decreased.
On the average in a year, valley ice-houses of Tyan-Shan recede on 7.5-13.1 m, simultaneously their flattening takes place. A reduction of sizes of ice accretion will be displayed in aquaticity of the rivers. For example, in separate inflows of the Narin River aquacity decreases from 3.1% (Kekemeren River) up to 24.8% (Large Narin River).
