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

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

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 m 3 per capita, 1/5 of national average.

2. Models and Data � Soil water balance model � � � � W W P E X s 2 s 1 s � Conversion model of soil mechanical classification between Intl. standard and U.S. standard 1 � � P r ( ) � � c 1 (1/ P r ( ) 1)exp( uR ) 0 � Pedotransfer functions for soil field capacity estimation � � � B A

2. Models and Data � 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)

3. Outputs � Soil field capacity (in mm) 0 - 5 0 5 0 - 1 0 0 1 0 0 - 1 5 0 1 5 0 - 2 0 0 2 0 0 - 2 5 0 2 5 0 - 3 0 0 In 1 meter depth, without Taking soil effective 3 0 0 - 3 5 0 considering the soil effective depth depth into account 3 5 0 - 4 0 0 4 0 0 - 4 5 0 4 5 0 - 5 0 0

3. Outputs � Soil water content in Loess Plateau Region (in mm) 1 0 0 9 0 8 0 土 壤 含 水 量 （ 毫 米 ） 7 0 6 0 5 0 4 0 3 0 2 0 1 9 6 1 - 1 9 7 0 1 9 7 1 - 1 9 8 0 1 9 8 1 - 1 9 9 0 1 9 9 1 - 2 0 0 0 1 0 0 1 2 3 4 5 6 7 8 9 1 0 1 1 1 2

3. Outputs � Soil water change (1961-2000) (A: Jan, B: Apr, C: Jul, D: Oct) <-150 -149 - -100 A B -99 - -80 -79- -60 -59 - -40 -39 - -20 C D -19 - 0 0 - 20 21 - 40

4. Reasons � Precipitation change The mean annual precipitation decreased by 8.4% from 443.0 mm in 1960s to 405.7 mm in 1990s. 1 2 0 1 9 6 1 - 1 9 7 0 1 0 0 1 9 7 1 - 1 9 8 0 8 0 1 9 8 1 - 1 9 9 0 1 9 9 1 - 2 0 0 0 6 0 4 0 2 0 0 1 2 3 4 5 6 7 8 9 1 01 11 2

4. Reasons � Evapotranspiration change 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. 1 8 0 1 9 6 1 - 1 9 7 0 1 6 0 1 9 7 1 - 1 9 8 0 1 4 0 作物参考蒸发量 1 9 8 1 - 1 9 9 0 1 2 0 1 9 9 1 - 2 0 0 0 1 0 0 8 0 6 0 4 0 2 0 0 1 2 3 4 5 6 7 8 9 1 0 1 1 1 2

4. Reasons � Temperature changes 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. 2 5 1 9 6 1 - 1 9 7 0 2 0 1 9 7 1 - 1 9 8 0 1 5 1 9 8 1 - 1 9 9 0 1 9 9 1 - 2 0 0 0 1 0 5 0 1 2 3 4 5 6 7 8 9 1 0 1 1 1 2 - 5 - 1 0 - 1 5

5. Changes under climate changes � Soil water content (in mm) 1 0 0 8 0 6 0 4 0 1 9 6 1 - 1 9 9 0 2 0 2 0 7 1 - 2 1 0 0 0 1 2 3 4 5 6 7 8 9 1 01 11 2

5. Changes under climate changes � Soil water changes (in mm) (A: Jan, B: Apr, C: Jul, D: Oct) < - 1 0 0 - 9 9 - A B - 8 0 - 7 9 - - 6 0 - 5 9 - - 4 0 - 3 9 - - 2 0 - 1 9 - 0 0 - C 2 D 0 2 1 - 4 0 4 1 - 6 0 6 1 - 8 0 8 1 - 1 0 0

5. Changes under climate changes � Precipitation (in mm) 1 2 0 . 0 0 1 0 0 . 0 0 1 9 6 0 - 1 9 9 0 2 0 7 1 - 2 1 0 0 8 0 . 0 0 6 0 . 0 0 4 0 . 0 0 2 0 . 0 0 0 . 0 0 1 2 3 4 5 6 7 8 9 1 0 1 1 1 2

5. Changes under climate changes � Precip. changes (in mm) (A: Jan, B: Apr, C: Jul, D: Oct) A B < 0 < 0 0 - 1 0 0 - 1 0 1 1 - 2 0 1 1 - 2 0 2 1 - 3 0 2 1 - 3 0 3 1 - 4 0 3 1 - 4 0 4 1 - 5 0 4 1 - 5 0 5 1 - 6 0 5 1 - 6 0 < - 7 0 C < - 7 0 D - 6 9 - - 6 0 - 6 9 - - 6 0 - 5 9 - - 4 0 - 5 9 - - 4 0 - 3 9 - - 2 0 - 3 9 - - 2 0 - 1 9 - 0 - 1 9 - 0 0 - 2 0 0 - 2 0 2 1 - 4 0 2 1 - 4 0 4 1 - 6 0 4 1 - 6 0 6 1 - 8 0 6 1 - 8 0 8 1 - 9 0 8 1 - 9 0

5. Changes under climate changes � Evapotranspiration (in mm) 2 0 0 1 8 0 1 6 0 1 4 0 1 2 0 1 0 0 8 0 1 9 6 1 - 1 9 9 0 6 0 2 0 7 1 - 2 1 0 0 4 0 2 0 0 1 2 3 4 5 6 7 8 9 1 0 1 1 1 2

5. Changes under climate changes � Evapotran. changes (in mm) (A: Jan, B: Apr, C: Jul, D: Oct) < - 3 0 - 2 9 - - 2 A B 0 - 1 9 - - 1 0 - 9 - 0 0 - 1 0 1 1 - 2 0 2 1 - 3 C D 0 3 1 - 4 0 4 1 - 5 0 5 1 - 6 0

5. Changes under climate changes � Temperature ( ℃ ) 3 0 2 5 2 0 1 5 1 9 6 1 - 1 9 9 0 1 0 2 0 7 1 - 2 1 0 0 5 0 1 2 3 4 5 6 7 8 9 1 0 1 1 1 2 - 5 - 1 0

5. Changes under climate changes � Temperature ( ℃ ) (A: Jan, B: Apr, C: Jul, D: Oct) A B C D

5. Changes under climate changes � Solar radiation (in MJ/m2/month) 8 0 0 . 0 1 9 6 1 - 1 9 9 0 7 0 0 . 0 2 0 7 1 - 2 1 0 0 6 0 0 . 0 5 0 0 . 0 4 0 0 . 0 3 0 0 . 0 2 0 0 . 0 1 0 0 . 0 0 . 0 1 2 3 4 5 6 7 8 9 1 0 1 1 1 2

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.