|Climate change trends and scenarios|
|<< INTRODUCTION >>|
|The analysis of climatic changes was
primarily focused on the study of changes in surface air temperature, precipitation, snow
cover, and extreme hydrometeorological events occurring in the territory of Tajikistan
during 1961-1990, and also throughout the history of instrumental observations.
The observational data provide a general picture of warming in the republic as a whole, and redistribution of precipitation in cold and warm periods.
Research work on climate change primarily included the following:
Up to - 30 meteorological stations located in various climatic zones and altitudes from 300 to 4200 m above sea level were selected to conduct the analysis.
The development of climate scenarios was based on the data received from 10 meteorological stations, representative for their locations, in accordance with the output data of leading models (GCMS), such as HadCM2, CCCM, GISS, GFD3, UK-89. Climate data for 1961-1990 was used for the modeling.
For full consideration of all factors that have impact on the climate, GCMS include physical processes related to radiation, photochemistry, thermodynamics, evaporation, condensation, etc.
In equilibrium models CO2 concentration is constant, equal to 1xCO2, 2xCO2, 4xCO2, etc. In dynamic models, CO2 concentration constantly changes for instance 1% per year.
To develop climate change scenarios based on GHG concentrations in the atmosphere, MAGICC SCENGEN and other software used to be the leading instrumental tools.
All models basically give underestimated temperature values as compared with real climate. At almost all stations the best results, per temperature and precipitation, are with the model HadCM2.
The results of the expected change in the mean annual air temperature given 2õÑÎ2 concentration through the models show that in the territory of Tajikistan the increase in temperature will vary within the range of 1,8-2,9°C. Precipitation increase is expected on some models, and decrease according to the others. It is supposed that warming in the republic will result in increased reoccurrence of very hot days and reduction of very cold ones. The maximum temperatures of air will increase, while minimum will reduce. The consequence of increased temperatures will be an enhanced hydrological cycle that will potentially cause occurrence of stronger droughts on regional and local scales.
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