Mon 24-01-2022

Climate of the Pyanj River Basin

Tajikistan’s climate is continental, subtropical, and semiarid, with some desert areas. The Köppen climate classification map of the country is shown in Figure 1. The climate changes drastically according to elevation, with temperatures falling, snowfall occurring more frequently, wind speeds and precipitation increasing.

Figure 1: Climate Classification of Tajikistan

Average annual rainfall across Tajikistan is shown in Figure 2. Temperatures in Tajikistan reflect altitude mostly, with severe and extended cold in the mountains of the Pamirs, and milder climates without severe winters in the southwest of the country – see Figure 3.

Figure 2: Average Annual Rainfall in Tajikistan

The mean annual precipitation sum in Tajikistan based on 1961-1990 (Hydromet, 2016; Aalto et al. 2017)

(Source: Hydromet, 2016)

Figure 3: Average Temperatures in Tajikistan

The average annual temperatures in the basin are shown in Figure 4 and the average annual rainfall in Figure 5

Figure 4: Average Annual Temperatures in Pyanj River Basin

Figure 5: Mean Annual Rainfall in Pyanj River Basin

    1. Impacts of Climate Change

The basin and its water resources are expected to be impacted by changes to the climate brought about by anthropological impacts on the global climate systems. In general, the impacts of climate change are likely to be felt in a number of areas – as illustrated in the following figure.

Figure 8: Impacts of Climate Change on Hydrological Cycle

Source: Impacts of Climate Change on the Cryosphere, Hydrological Regimes and Glacial Lakes of the Hindu Kush Himalayas, Lutz et all., ICIMOD 2016.

The anticipated impacts of climate change for the Pyanj Basin can be summarized as:

“Air temperatures in Vakhsh and Pyanj River Basins will increase by approximately 1.7°C between 2010 and 2050; the mean annual evapotranspiration will increase in line with temperature;

Maximum and minimum daily air temperatures are likely to increase;

Annual potential evapotranspiration will increase due to the increase in temperature;

Due to higher mean temperatures annual rainfall is likely to increase while annual snowfall is likely to decrease; and extreme daily precipitation is likely to increase;

Annual mean river flow is likely to increase in glacial sub-basins for the next 50-60 years; In non-glacial sub-basins, there is unlikely to be any significant change in mean annual flow because mean annual precipitation is not expected to change significantly;

There may be a gradual change in the seasonal distribution of river flow, with high flows occurring earlier in the year due to earlier snow and ice melting caused by higher air temperatures.

The magnitude and frequency of mudflows and floods is likely to increase.