33
suggesting an insignificant relationship. Accordingly, the rainfall erosivity increases
with the longitude but decreases with the latitude.
The highest annual R factor was observed in the southeastern part of Central
Asia, with moderate values in the northern regions, but decreased westwards, where
the lowest values were recorded. Conversely, the values gradually increased towards
Tajikistan but reduced in the western parts occupied by Turkmenistan. The spatial
distribution of the R factor always varied with regard to the annual precipitation in
Central Asia. The estimated average annual rainfall erosivity for the baseline period
ranges from 41 MJ mm ha
−1
h
−1
year
−1
to 4510 MJ mm ha
−1
h
−1
year
−1
in the west
and southeast, respectively (Fig. 4.4).
MIROC5-2.6 and MIROC5-8.5 show higher rainfall erosivity, perhaps due to the
strongly projected spatial difference in rainfall in these scenarios. In all the GCMs
and baseline precipitation, the R factor in Tajikistan, Kyrgyzstan, east Uzbekistan,
and East Kazakhstan is higher but lower in Turkmenistan, northwest Uzbekistan,
and southwest and central Kazakhstan (Fig. 4.5). Also, Fig. 4.6 presents the relative
difference between the four projected scenarios and the baseline.
Table 4.1 shows the effects of rainfall on historical and projected rainfall erosivity and erosivity density in Central Asia. GCM ensembles express that rainfall erosivity increases significantly from the baseline in all ensembles, except
BCCCSM1.1-8.5 in 2070s and IPSLCM5ALR in both RCPs (2030 and 2070). The
average value of all scenarios shows that rainfall increased in the 2030s to 262 mm
and in the 2070s to 268 mm from the baseline (254 mm). Nevertheless, MIROC5
(the 2030s and 2070s, both RCPs) predicted a higher increase in precipitation than
other models with similar scenarios and periods (Table 4.4).
Precipitation, erosivity, and density differ accordingly, given that the GCMs
exhibited consistent variations.
The average precipitation and rainfall erosivity demonstrate a steady increase in
all the GCMs in combination with the baseline precipitation output. However,
Fig. 4.4 Baseline rainfall erosivity and erosivity density
4.3 Rainfall Erosivity Analysis Under Baseline and Projected Climate
suggesting an insignificant relationship. Accordingly, the rainfall erosivity increases
with the longitude but decreases with the latitude.
The highest annual R factor was observed in the southeastern part of Central
Asia, with moderate values in the northern regions, but decreased westwards, where
the lowest values were recorded. Conversely, the values gradually increased towards
Tajikistan but reduced in the western parts occupied by Turkmenistan. The spatial
distribution of the R factor always varied with regard to the annual precipitation in
Central Asia. The estimated average annual rainfall erosivity for the baseline period
ranges from 41 MJ mm ha
−1
h
−1
year
−1
to 4510 MJ mm ha
−1
h
−1
year
−1
in the west
and southeast, respectively (Fig. 4.4).
MIROC5-2.6 and MIROC5-8.5 show higher rainfall erosivity, perhaps due to the
strongly projected spatial difference in rainfall in these scenarios. In all the GCMs
and baseline precipitation, the R factor in Tajikistan, Kyrgyzstan, east Uzbekistan,
and East Kazakhstan is higher but lower in Turkmenistan, northwest Uzbekistan,
and southwest and central Kazakhstan (Fig. 4.5). Also, Fig. 4.6 presents the relative
difference between the four projected scenarios and the baseline.
Table 4.1 shows the effects of rainfall on historical and projected rainfall erosivity and erosivity density in Central Asia. GCM ensembles express that rainfall erosivity increases significantly from the baseline in all ensembles, except
BCCCSM1.1-8.5 in 2070s and IPSLCM5ALR in both RCPs (2030 and 2070). The
average value of all scenarios shows that rainfall increased in the 2030s to 262 mm
and in the 2070s to 268 mm from the baseline (254 mm). Nevertheless, MIROC5
(the 2030s and 2070s, both RCPs) predicted a higher increase in precipitation than
other models with similar scenarios and periods (Table 4.4).
Precipitation, erosivity, and density differ accordingly, given that the GCMs
exhibited consistent variations.
The average precipitation and rainfall erosivity demonstrate a steady increase in
all the GCMs in combination with the baseline precipitation output. However,
Fig. 4.4 Baseline rainfall erosivity and erosivity density
4.3 Rainfall Erosivity Analysis Under Baseline and Projected Climate