Study area
Beijing
Tianjin
North
China
plain
Jinan
Qingdao
Jining
Yellow
Sea
China
Shanghai
400 km
400 miles
Mongolia
Study area
Beijing
North Korea
Tianjin
North
China
plain
Jinan
South Korea
Qingdao
Jining
Xi’an
Yellow river
Japan
China
Shanghai
East China Sea
400 km
400 miles