The Dynamic Changes of Soil Moisture in Loess Plateau betw een - - PowerPoint PPT Presentation

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14th AIM workshop, NIES, Tsukuba, Japan, 2009,2,14-16

The Dynamic Changes of Soil Moisture in Loess Plateau

betw een 1961-2000 and under climate changes

Songcai You, Suchuang Di, Zehui Li Institute of Geographic Sciences and Natural Resources Research, CAS

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• 1. Location and Environmental Situation

Area: 517,000 km2, 5.3% of total land Precipitation: 70% in July, August and Sept. Population: 87.42 millions (2000) Water resource: 548 m3 per capita, 1/5 of national average.

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• 2. Models and Data
• Soil water balance model
• Conversion model of soil mechanical classification

between Intl. standard and U.S. standard

• Pedotransfer functions for soil field capacity estimation

1 ( ) 1 (1/ ( ) 1)exp( )

c

P r P r uR

• X

E P W W

s s s

• 1

2 B

A

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Soil effective depth (by Saxton etc, 1989), depending on soil texture and vegetation type Other models: Evaporation (Penman-Monteith), interpolation (by ANUSPLINE, Hutchinson, 1989 ), etc. Data

Soil map, soil profile data, climate data, land use map, GCM data (CCSR/NIES, A1B ),DEM data (SRTM)

• 2. Models and Data

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• 3. Outputs

Soil field capacity (in mm)

Taking soil effective depth into account

• 5

5

• 1

1

• 1

5 1 5

• 2

2

• 2

5 2 5

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3

• 3

5 3 5

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4

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5 4 5

• 5

In 1 meter depth, without considering the soil effective depth

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• 3. Outputs

1 2 3 4 5 6 7 8 9 1 1 2 3 4 5 6 7 8 9 1 1 1 1 2 土 壤 含 水 量 （ 毫 米 ） 1 9 6 1

• 1

9 7 1 9 7 1

• 1

9 8 1 9 8 1

• 1

9 9 1 9 9 1

• 2

Soil water content in Loess Plateau Region (in mm)

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<-150

• 149 - -100
• 99 - -80
• 79- -60
• 59 - -40
• 39 - -20
• 19 - 0

0 - 20 21 - 40

Soil water change (1961-2000) (A: Jan, B: Apr, C: Jul, D: Oct)

A B C D

• 3. Outputs

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The mean annual precipitation decreased by 8.4% from 443.0 mm in 1960s to 405.7 mm in 1990s.

• 4. Reasons

2 4 6 8 1 1 2 1 2 3 4 5 6 7 8 9 1 01 11 2

1 9 6 1

• 1

9 7 1 9 7 1

• 1

9 8 1 9 8 1

• 1

9 9 1 9 9 1

• 2

Precipitation change

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The mean annual evapotranspiration slightly decreased by 2.3%, from 1055.1 mm in 1960s to 1031.1mm in

• 1990s. The sunshine time decreased from 2754.1 hrs

in 1960s to 2626.7 hrs in 1990s.

• 4. Reasons

Evapotranspiration change

2 4 6 8 1 1 2 1 4 1 6 1 8 1 2 3 4 5 6 7 8 9 1 0 1 1 1 2 作物参考蒸发量

1 9 6 1

• 1

9 7 1 9 7 1

• 1

9 8 1 9 8 1

• 1

9 9 1 9 9 1

• 2

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The lowest temperature increased by 1.8 ℃ , from - 6.7℃ in 1960s to -4.9 ℃ in 1990s. The highest temperature increased by 0.6 ℃, from 21.7 ℃ in 1960s

to 22.3 ℃ in 1990s.

• 4. Reasons

Temperature changes

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5

• 1
• 5

5 1 1 5 2 2 5 1 2 3 4 5 6 7 8 9 1 0 1 1 1 2

1 9 6 1

• 1

9 7 1 9 7 1

• 1

9 8 1 9 8 1

• 1

9 9 1 9 9 1

• 2

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• 5. Changes under climate changes

2 4 6 8 1 1 2 3 4 5 6 7 8 9 1 01 11 2

1 9 6 1

• 1

9 9 2 7 1

• 2

1 Soil water content (in mm)

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<

• 1
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9

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9

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9

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9

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2 1

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6 1

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8 1

• 1
• 5. Changes under climate changes

Soil water changes (in mm) (A: Jan, B: Apr, C: Jul, D: Oct)

A B C D

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• 5. Changes under climate changes

Precipitation (in mm)

. 2 . 4 . 6 . 8 . 1 . 1 2 . 1 2 3 4 5 6 7 8 9 1 1 1 1 2 1 9 6

• 1

9 9 2 7 1

• 2

1

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• 5. Changes under climate changes
• Precip. changes (in mm) (A: Jan, B: Apr, C: Jul, D: Oct)

A B C D

<

• 1

1 1

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2 1

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3 1

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4 1

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5 1

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• 1

1 1

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2 1

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3 1

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4 1

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5 1

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9

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9

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9

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• 1

9

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2 1

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4 1

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6 1

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2 1

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• 5. Changes under climate changes

Evapotranspiration (in mm)

2 4 6 8 1 1 2 1 4 1 6 1 8 2 1 2 3 4 5 6 7 8 9 1 0 1 1 1 2 1 9 6 1

• 1

9 9 2 7 1

• 2

1

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• 5. Changes under climate changes
• Evapotran. changes (in mm) (A: Jan, B: Apr, C: Jul, D: Oct)

<

• 3
• 2

9

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9

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1 1

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2 1

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3 1

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4 1

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5 1

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A B C D

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• 5. Changes under climate changes

Temperature (℃)

• 1
• 5

5 1 1 5 2 2 5 3 1 2 3 4 5 6 7 8 9 1 0 1 1 1 2 1 9 6 1

• 1

9 9 2 7 1

• 2

1

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• 5. Changes under climate changes

Temperature (℃) (A: Jan, B: Apr, C: Jul, D: Oct)

A B C D

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• 5. Changes under climate changes

Solar radiation (in MJ/m2/month)

. 1 . 2 . 3 . 4 . 5 . 6 . 7 . 8 . 1 2 3 4 5 6 7 8 9 1 0 1 1 1 2 1 9 6 1

• 1

9 9 2 7 1

• 2

1

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• 6. Conclusions

1. The soil water content decreased compared between 1960s and 1990s, 2. Though precipitation will increase according to the projected scenario from CCSR/NIES

(A1B), soil water content will decreased, as the ranges of temperature and radiation increase are more bigger than that of temperature.