Monitoring Agricultural Drought in China - Monitoring and Predicting Agricultural Drought: A Global Study - page 363

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logical data from February to June (1992-97), and dekadal (10-day) data
for agricultural season (1992-97); (3) experimental data at Yucheng Eco-
system Experimental Station, Chinese Academy of Sciences (CAS), in Shan-
dong province, and Fenqiu Ecosystem Experimental Station and CAS in
Henan province (1992-93); (4) socioeconomical data including crop pro-
ductivity, population, and county area; (5) AVHRR data (1992-97); and
(6) maps showing drought distribution and severity. The GIS integrates
these different data sets (remote sensing data, CWSI, and NDTI models) to
map soil moisture, evapotranspiration, and, finally, drought conditions.

Ti meslice Products

Tian (1993) monitored droughts in the NCP region by estimating CWSI
and relating it to soil moisture as follows:

[363

E
E p

= −

CWSI 1

Line
——
-0.1
——
Norm
PgEn

1 . 476 W
W f

= 1 − m a = 1 . 503 − ( R = . 90 ) [28.15]

w here W is the soil moisture, W f is the field capacity, and R is the corre-
la tion coefficient. Table 28.3 indicates the accuracy of drought monitoring
w ith the CWSI model. Figure 28.4 shows how timeslice products are used
to monitor drought in NCP.

[363

So il Humidity Index The SHI is calculated as

SHI j = ( Q j / SW j ) 100 [28.16]

w here SHI j is the ratio of soil moisture ( Q j ) to field capacity (SW j ), and
j v aries from 1 to 10 for soil measurement. The relationship between the
ve getation condition index (VCI) and SHI was established to enable the
us e of the AVHRR data to monitor droughts in China. The soil moisture

Table 28.3 Accuracy of drought monitoring using crop water stress index model
in 1994

Accuracy (%)

City/province March 4 March 26 April 13 April 30 May 8

Beijing 84.0 86.0 85.0 88.0 85.0

Tianjin 88.0 88.8 82.5 85.0 87.2

Henan 90.6 87.5 83.1 88.8 86.2

Anhui 83.3 80.6 86.6 83.3 83.3

Jiangsu 80.0 Cloud 75.0 81.5 80.0

Sh andong 81.4 85.7 82.8 82.8 85.7

Hebei 85.7 80.0 84.2 87.1 85.7

Source: Tian et al. (1997).