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Fig. 4 Differences in several variables from the REMO simulations with and without irrigation averaged
for the summer (JJAS) 1989-1992: a mean sea-level pressure (hPa), b 2 m temperature (C),
c evapotranspiration (mm/day) and d 850 hPa winds. The shaded blue areas indicate significant differences
at the 90 % level from a two-tailed t test
discussed in earlier published literature. Figure 5 shows one of these cases that occurred
from 19 to 21 September 1991 (Mahajan et al. 1995 ). All these cases have in common that,
in the REMO simulation without irrigation, a depression forms in the Bay of Bengal, but it
stops at the east coast of India and dissolves. Only in the simulation with irrigation, the
depression is able to travel deep into land towards western India and Pakistan and to
transport moisture and precipitation into these regions, such as it has been observed.
Together with the increased local recycling of moisture due to the increased ET, this leads
to an increase in precipitation over central/western India and Pakistan, which reduces the
dry precipitation bias in this area.
For the same two model set-ups of REMO, i.e. with and without the representation of
irrigation, climate change simulations have been conducted over the South Asian model
domain following the A1B emission scenario (Gerten et al. 2011 ). Figure 6 shows that for
the projected 2-m temperature changes (2085-2099 minus 1985-1999), REMO without
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