Geography Reference
In-Depth Information
use changes have cooling effect on the surface temperature, among which the
conversion from barren or sparsely vegetated land to irrigated cropland and pasture
(19-3) will lead to a maximum decrease of the monthly average temperature (i.e.,
-0.40 C), this is because the vegetation coverage is relatively low in the less
vegetated land. While they are converted into irrigated cropland and pasture, latent
heat flux would be increased and sensible heat flux decreased resulting in the
reduction of the monthly average temperature. Besides, the cooling effect of
conversion from cropland/woodland mosaic to irrigated cropland and pasture
(6-3) is the least (i.e., -0.04 C). In winter (Fig.
7.4
b), different types of recla-
mation will cause an universal rise on the monthly average temperature. The
conversion from evergreen broadleaf forest to irrigated cropland (13-3) will lead
to a maximum increase on the monthly average temperature, with 0.17 C.
In conclusion, the effects of cultivated land reclamation on temperature vary
between seasons. Meanwhile, the impacts of different cultivated land reclamation
types on temperature are also different; this is because different types of cultivated
land reclamation will lead to different changes in vegetation types and farmland
management modes, which will result in changes of latent heat flux and sensible
heat flux, and thus lead to different effects.
7.1.3 Concluding Remarks on Land Reclamation in India
After testing and verifying the WRF model in simulating the temperature of India,
we updated the land cover data, and simulated the possible impacts of cultivated
land reclamation on the temperature in India. India is with vast cultivated land
reclaimed for agricultural production; there is, however, still a trend of reclamation
of cultivated land in the future since the population growth. The area of LUCC due
to the reclamation of cultivated land is projected to reach 1.16 million km
2
, among
which includes around 584.33 thousand km
2
of converted area from the dryland
cropland to the irrigated cropland as well as nearly 560.12 thousand km
2
of
converted area from other land use types into irrigated cropland, accounting for
50.23 and 48.15 % of the total conversion area, respectively. The proportion of
cultivated land and pasture in the study area will increase from 73.03 to 85.28 %.
The land reclamation will increase the latent heat flux and decrease the sensible
heat flux, which may be the reason for the downward trend of the monthly average
temperature in India on the whole. Specifically, it mainly decreases the tempera-
ture in summer, while increases the temperature in the winter. Besides, the rec-
lamation of cultivated land influences not only the local climate, but also the
regional climate in the neighboring districts.
This study is still preliminary and there are still some uncertainties to be further
mitigated in simulating the climatic effects of the LUCC. For example, there are
many factors influencing the regional climate and they generally act synthetically,
