40 40 30 30 20 10 20 0 10 10 0 0 0 500 1000 1500 2000 2500 1000 2000 3000 4000 500 (a) CZ06 (b) JZ3 1 40 20 0 20 40 300 0 300 600 900 1200 1500 600 (c) CZ09 1 14 20 5 10 15 20 25 30 35 40 45 50 15 10 5 0 5 10 15 20 25 0 1 15 THE CHANGJIANG RIVER 15