Geography Reference
In-Depth Information
models (Hijmans and Graham
2006
). The WRF model is a next-generation
mesoscale numerical weather prediction system developed by a group of scien-
tists from different institutes. This model is of strong robustness for predicting the
climate changes with various parameters, such as temperature, precipitation,
radiation, and heat flux. Besides, in this study, the underlying surface data
adopted in WRF model was simulated data given by the Dynamics of Land
Systems (DLS) model.
4.1.1 Data and Methodology
4.1.1.1 Introduction of the Study Area
Northeast China (11505
0
* 13502
0
E, 3840
0
* 5334
0
N) has a total land area
of 1.24 million km
2
and covers 209 counties in Heilongjiang Province, Jilin
Province, Liaoning Province, and Inner Mongolia Autonomous Region (Fig.
4.1
).
It is the largest producing area of the corn, high quality japonica rice, and soybean
as well as the major production base of the agriculture, forestry, animal husbandry,
and industry in China. The total cultivated land area in this area is approximately
227 million hectare, accounting for 18.5 % of the national cultivated land area.
The area under crops is approximately 173 million ha and the total grain output is
approximately 87 million t in Northeast China, which account for 16.4 and 17.6 %
of the national total amount, respectively.
As a monsoon climate of medium latitudes, the amount of precipitation in
Northeast China decreases from the east and southeast to the west and northwest
on the whole area. The winter is cold and long, while there are frequent winds and
little rainfall in the spring in Northeast China. In the summer, the temperature is
high and the rainfall is very rich, the amounts of precipitation range from 400 to
700 mm in most part of Northeast China in the summer, accounting for 50-70 %
of the annual precipitation. According to the observation data of climate change
from 2000 to 2010, we calculated the change trend of temperature and precipi-
tation in Northeast China. The results showed that the temperature increased
slightly in the decade, the average growth rate per annum was 0.44 %. While the
average annual precipitation was in similar circumstance, its average growth rate
per annum was 1.16 %. There are often sunny days and the southwest winds
prevail in the autumn, but the amount of precipitation is slightly more than in the
spring. Northeast China is the coldest area in China since it is at the high altitudes,
the temperature in this region is very low in the winter and the annual temperature
difference is very large, showing obvious characteristics of the continental climate.
Besides, Northeast China can be divided into three climatic zones from north to
south, i.e., the cold temperate zone, the cool temperate zone, and the warm tem-
perate zone since it extends across a wide latitude and longitude. In addition, it can
be further divided into several climatic zones from east to west, i.e., Three River
Plain Humid Climate Zone, Lesser Khingan Mountains Climate Zone, Great
