34
IPSLCM5ALR shows a possible reduction in average precipitation and erosivity in
both periods.
4.4 Annual Erosivity Density
The separately projected annual erosivity results (Fig. 4.7) are divided by a corresponding average rainfall data subsequent in the average erosivity density ratio.
Density values of erosivity above 1 suggest that a certain amount of precipitation
may lead to relatively higher rainfall erosivity (Panagos et al. 2016a). The annual
erosivity density for the baseline period has a mean value of 1.38 MJ ha
−1
h
−1
, with
variability ranging from 0.62 to 3.69 MJ ha
−1
h
−1
. The projected variability of erosivity density is also very high because MIROC5-8.5 has the highest mean erosivity
density of 1.47 and 1.51 MJ ha
−1
h
−1
in the 2030s and 2070s, respectively, followed
by MPIESMLR-2.6 with a mean erosivity density of 1.46 MJ ha
−1
h
−1
in the 2070s
and BCCCSM1.1-2.6 and BCCCSM1.1-8.5 with mean erosivity densities of 1.45
and 1.43 in the 2070s. However, IPSLCM5ALR-2.6 and IPSLCM5ALR-8.5 (both
periods) have the lowest mean erosivity density, with an average of 1.35 MJ ha
−1
h
−1
(Figs. 4.7 and 4.8).
Fig. 4.5 Rainfall erosivity projections for the 2030s and 2070s according to RCP 2.6 and RCP 8.5
scenarios driven by the BCCCSM1.1, IPSLCM5ALR, MIROC-5, and MPIESMLR GCM models
4 Projected Rainfall Erosivity and Soil Erosion in Central Asia